FC-72在水平矩形流道中流過一微小加熱面暫態流動沸騰熱傳及氣泡特性研究

國 立 交 通 大 學

機 械 工 程 學 系

碩 士 論 文

         

FC‐72 在水平矩形流道中流過一微小加熱面暫態流動

沸騰熱傳及氣泡特性研究 

 

Transient Flow Boiling Heat Transfer of FC-72 and

Associated Bubble Characteristics over a Small

Heated Plate in a Horizontal Rectangular Channel

 

 

 

 

      研 究 生：楊 政 陞

指 導 教 授：林 清 發 博士

中 華 民 國 九十六 年 六 月

FC‐72 在水平矩形流道中流過一微小加熱面暫態流動

沸騰熱傳及氣泡特性研究 

Transient Flow Boiling Heat Transfer of FC-72 and Associated Bubble

Characteristics over a Small Heated Plate in a Horizontal Rectangular

Channel

        研  究  生：楊  政  陞      Student：Zheng‐ShengYang 

        指導教授：林  清  發      Advisor：Tsing‐Fa Lin 

國立交通大學 

機械工程研究所 

碩士論文初稿 

A Thesis 

Submitted to Institute of Mechanical Engineering   

Collage of Engineering 

National Chiao Tung University 

In Partial Fulfillment of the Requirements 

For the degree of 

Master of Science 

 

 

In 

Mechanical Engineering 

June 2007

Hsinchu, Taiwan, Republic of China

 

誌謝

幕然回首兩年前的此時，對於離家到新竹交大求學的我而言，心

中真是充滿了既期待又害怕的複雜心情。來到交大這充滿學術研究氣

息的生活，讓我覺得在此讀書做研究是一種享受。然而，一想到即將

要離開這可愛的校園，不禁令人懷念起在此的點點滴滴。

能獲得碩士學位，首先很榮幸能接受林清發教授的指導，從文獻

資料的蒐集、實驗系統的構思設計到最後物理觀念的闡述分析，都令

我受益匪淺。而老師對我們在研究上嚴謹的要求，更深深地影響到我

日後的處事態度。而能夠順利地完成我的碩士論文，要感謝實驗室許

多臥虎藏龍的博士班：張文瑞、郭威伸、賴祐民、陳尚緯、謝汎鈞及

陳建安學長們的幫忙及指導。同學陳奎銘、李凱文、廖峻樟、黃宇歆

的互相砥礪幫忙，當然也少不了一群為實驗室注入活力、帶來歡樂的

學弟妹們：林永龍、王壹龍、李浚圩及駱長志的幫忙。得之於人者太

多，在此一同向所有幫助過我的人致謝。

即將踏出交大校門成為社會新鮮人的我，回首來時路，很慶幸並

沒辜負當初父母對我的期望；在今年能如期獲得碩士學位。我想今天

若我有任何些微的成就，父母對我的教養及支持鼓勵，是我能一路走

來的原動力，僅將我的榮耀獻予我摯愛的家人。

楊政陞

2007/6

於風城交大

FC-72 在水平矩形流道中流過一微小加熱面暫態流動沸騰熱

傳及氣泡特性研究

研究生:  楊政陞      指導教授:  林清發  博士    國立交通大學機械工程學系          摘要            本實驗是要探討雙相流冷媒循環系統針對介電冷卻液 FC-72 在截面為寬 20 毫米、高 5 毫米之水平矩形流道(水力直徑為 8 毫米)中進行，隨時間週期振盪的 流量如何影響暫態強制對流沸騰熱傳以及相關的氣泡特徵，加熱銅塊埋至於測試 段之底板中央其尺寸為直徑 10 毫米。值得注意的是冷卻液流量隨時間振盪(振盪 的形狀接近三角波)，是如何影響暫態流動沸騰將會被詳細的探討。在實驗參數 範圍上，介電液 FC-72 平均質量通率從 300 到 400 kg/m2 s 而且流量的振盪振幅為 0%、5%、10%，流量的振盪周期為 10 秒到 30 秒。除此之外，FC-72 於測試段 入口處次冷度從 0 到 10 o C、銅塊的加熱通量從 0.1 到 10 W/cm2 而系統壓力為常 壓。 由實驗結果發現介電冷卻液的振盪振幅和週期對時間平均的 FC-72 暫態的 飽和態和次冷態流動沸騰熱傳特徵沒有明顯的影響，類似穩態的流動沸騰。無論 如何，在熱通量高於起始成核沸騰的熱通量 FC-72 的暫態飽和態和次冷態流動沸 騰對熱傳係數、氣泡脫離直徑、氣泡脫離頻率、成核址密度都有顯著的振盪影響。 除此之外，在高熱通量下和振盪振幅比較大的情況下對熱傳係數、氣泡脫離直徑、 氣泡脫離頻率、成核址密度都會造成更強烈的振盪情況發生，但振盪週期的影響 並不明顯。因此，當流量隨時間增加的情況下，氣泡脫離的尺寸和成核址密度都 會下降，但氣泡脫離頻率會增加。當流量隨時間遞減的情況下，會產生相反的趨 勢。並且也發現入口處次冷度的增加會使得沸騰的熱傳係數振盪更劇烈。

FC-72 在水平矩形流道中流過一微小加熱面暫態流動沸騰熱

傳及氣泡特性研究

研究生:  楊政陞      指導教授:  林清發  博士    國立交通大學機械工程學系          摘要            本實驗是要探討雙相流冷媒循環系統針對介電冷卻液 FC-72 在截面為寬 20 毫米、高 5 毫米之水平矩形流道(水力直徑為 8 毫米)中進行，隨時間週期振盪的 流量如何影響暫態強制對流沸騰熱傳以及相關的氣泡特徵，加熱銅塊埋至於測試 段之底板中央其尺寸為直徑 10 毫米。值得注意的是冷卻液流量隨時間振盪(振盪 的形狀接近三角波)，是如何影響暫態流動沸騰將會被詳細的探討。在實驗參數 範圍上，介電液 FC-72 平均質量通率從 300 到 400 kg/m2 s 而且流量的振盪振幅為 0%、5%、10%，流量的振盪周期為 10 秒到 30 秒。除此之外，FC-72 於測試段 入口處次冷度從 0 到 10 o C、銅塊的加熱通量從 0.1 到 10 W/cm2 而系統壓力為常 壓。 由實驗結果發現介電冷卻液的振盪振幅和週期對時間平均的 FC-72 暫態的 飽和態和次冷態流動沸騰熱傳特徵沒有明顯的影響，類似穩態的流動沸騰。無論 如何，在熱通量高於起始成核沸騰的熱通量 FC-72 的暫態飽和態和次冷態流動沸 騰對熱傳係數、氣泡脫離直徑、氣泡脫離頻率、成核址密度都有顯著的振盪影響。 除此之外，在高熱通量下和振盪振幅比較大的情況下對熱傳係數、氣泡脫離直徑、 氣泡脫離頻率、成核址密度都會造成更強烈的振盪情況發生，但振盪週期的影響 並不明顯。因此，當流量隨時間增加的情況下，氣泡脫離的尺寸和成核址密度都 會下降，但氣泡脫離頻率會增加。當流量隨時間遞減的情況下，會產生相反的趨 勢。並且也發現入口處次冷度的增加會使得沸騰的熱傳係數振盪更劇烈。

i

Transient Flow Boiling Heat Transfer of FC-72 and Associated

Bubble Characteristics over a Small Heated Plate in a Horizontal

Rectangular Channel

Student：Zheng-Sheng

Yang Advisor：Prof. Tsing-Fa Lin

Institute of Mechanical Engineering National Chiao Tung University

ABSTRACT

This study intends to explore how a time periodic coolant flow rate affects the transient forced convective boiling heat transfer and associated bubble characteristics of FC-72 over a small heated circular copper plate flush mounted on the bottom of a horizontal rectangular channel with a cross section of 20 mm in width and 5 mm in height. The diameter of the copper plate is 10 mm. More specifically, the effects of the coolant flow rate oscillation in the form of nearly triangular wave on the transient flow boiling will be examined in detail. In the experiment the time-average coolant mass flux G is varied from 300 to 400 kg/m2s and the amplitude of the coolant mass

flux oscillation is fixed at 0%, 5% and 10% of G . The period of the coolant mass

flux oscillation varies from 10s to 30s. Besides, the liquid subcooling at the inlet of the channel ranges from 0°C to 10°C and the heat flux imposed on the heated plate varies from 0.1 to 10 W/cm2.

The experimental results show that the time-average data of the FC-72 transient saturated and subcooled flow boiling heat transfer characteristics are not affected to a significant degree by the amplitude and period of the coolant mass flux oscillation. In fact, they resemble these for the stable flow boiling. However, in the transient

ii

saturated and subccoled flow boiling of FC-72 significant temporal oscillations in the boiling heat transfer coefficient, bubble departure diameter and frequency, and active nucleation site density appear for the imposed heat flux slightly higher than that for ONB. They oscillate at the same frequency as the mass flux oscillation. Besides, at a higher imposed heat flux and for a larger amplitude of the mass flux oscillation stronger oscillations in h_2φ, dp, f and Nac are noted. But they are only slightly affected

by the period of the mass flux oscillation. Furthermore, in the time duration in which the mass flux rises with time both the size of the departing bubbles and active nucleation site density decrease, but the bubble departure frequency increases. The opposite processes occur for a sink of mass flux with time. We also note that an increases in the inlet liquid subcooling causes stronger oscillations in the boiling heat transfer coefficient.

iii

TABLE OF CONTENTS

ABSTRACT i

TABLE OF CONTENTS iii LIST OF TABLE iv LIST OF FIGURE v CHAPTER 1 INTRODUCTION 1

1.1 Motive of the Present Study 1 1.2 Literature Review 2 1.2.1 Stable Single-Phase and Convective Boiling Heat Transfer 2 1.2.2 Unstable Convective Boiling Heat Transfer 4 1.2.3 Bubble Characteristics 6 1.3 Objective of This Study 7

CHAPTER 2 EXPERIMENTAL APPARATUS AND PROCEDURES 11

2.1 Degassing Unit 11 2.2 Coolant Loop 12 2.3 Test Section 13 2.4 Hot-water Loop 14 2.5 Cold-water Loop 15 2.6 DC Power Supply 15 2.7 Data Acquisition 15

2.8Optical Measurement Technique 16 2.9 Experimental Procedures 16 2.10 Experimental Parameters 17

iv

CHAPTER 3 DATA REDUCTION 27

3.1 Single Phase Heat Transfer 27 3.2 Two Phase Flow Boiling Heat Transfer 28 3.3 Uncertainty Analysis 29

CHAPTER 4 TRANSIENT SATURATED FLOW BOILING OF FC-72 OVER A SMALL HEATED COPPER PLATE 31

4.1 Single-phase Liquid Convective Heat Transfer 31 4.2 Stable and Time-average Saturated Flow Boiling Curves and Heat

Transfer Coefficient 32 4.3Transient Flow Boiling Heat Transfer Characteristics 34 4.4Transient Bubble Characteristics in Saturated Flow Boiling 36 4.5 Correlation Equations 39

CHAPTER 5 TRANSIENT SUBCOOLED FLOW BOILING OF FC-72 OVER

A SMALL HEATED COPPER PLATE 152

5.1 Stable and Time-average Subcooled Flow Boiling Curves and Heat

Transfer Coefficient 153 5.2Transient Subcooled Flow Boiling Heat Transfer Characteristics 155 5.3Transient Bubble Characteristics in Subcooled Flow Boiling 157 5.4 Correlation Equations 161

CHAPTER 6CONCLUDING REMARKS 387

iv

LIST OF TABLES

Table 1.1 Thermodynamic properties for FC-72 --- 9 Table 1.2 Some single-phase convection heat transfer correlations for electronic

cooling --- 10 Table 2.1 Experimental parameters --- 18 Table 2.2 Thermodynamic and transport properties of the dielectric refrigerant FC-72

list --- 19 Table 3.1 Summary of the uncertainty analysis --- 30 Table 4.1 Relative amplitudes of heated surface temperature and heat transfer

coefficient oscillations in transient oscillatory saturated flow boiling for various imposed heat fluxes and the amplitude and period of the coolant mass flux oscillation --- 43 Table 5.1 Relative amplitudes of heated surface temperature and heat transfer

coefficient oscillations in transient oscillatory subcooled flow boiling ΔTsub

= 5oC for various imposed heat fluxes and the amplitude and period of the coolant mass flux oscillation --- 164 Table 5.2 Relative amplitudes of heated surface temperature and heat transfer

coefficient oscillations in transient oscillatory subcooled flow boiling at

ΔTsub = 10oC for various imposed heat fluxes and the amplitude and period

v

LIST OF FIGURES

Experiment Apparatus

Fig 2.1 Schematic diagram of experimental apparatus --- 20

Fig 2.2 Three-dimensional plots of test section along with inlet and outlet sections --- 21

Fig 2.3 Three-dimensional plots illustrating the test section in the rectangular flow-channel --- 22

Fig 2.4 Three-dimensional pictures showing (a) hollow cylindrical Teflon block and (b) cylindrical Teflon bolt --- 23

Fig 2.5 Locations of thermocouples --- 24

Fig 2.6 Schematics of the silicon chip module --- 25

Fig 2.7 Locations of the thermocouple of the inside of the polyethylene insulation --- 26

Saturated Flow Boiling Fig 4.1 Comparison of the present steady single-phase liquid convection heat transfer data with the correlation of Gersey and Mudawar (1992) for (a) h_1φ vs. G an (b) Nu_L vs. ReL --- 44

Fig 4.2 Time-average flow boiling curves for various coolant mass fluxes for stable saturated flow boiling (a) and transient saturated flow boiling for tp=10 sec (b), 20 sec (c) and 30 sec (d)--- 45

Fig 4.3 Time-average flow boiling curves for various coolant mass fluxes for transient saturated flow boiling at tp=10 sec (a), 20 sec (b) and 30 sec (c) --- 47

Fig 4.4 Time-average flow boiling heat transfer coefficients for various coolant mass fluxes for stable saturated flow boiling (a) and transient saturated flow boiling at tp=10 sec (b), 20 sec (c) and 30 sec (d) --- 49

Fig 4.5 Time-average flow boiling heat transfer coefficients for various coolant mass fluxes for transient saturated flow boiling at tp=10 sec (a), 20 sec (b) and 30 sec (c) --- 51

Fig 4.6 Time variations of the copper plate temperature in stable saturated flow boiling for various imposed heat fluxes at (a) G=300 kg/m2s and (b) G=400 kg/m2s --- 53

Fig 4.7 Time variations of (a) imposed coolant mass flux and (b) copper plate temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =10 sec.(q_ONB=2.84 w/cm2 at G =300 kg/m2s) --- 54 Fig 4.8 Time variations of (a) imposed coolant mass flux and (b) copper plate

vi

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =10 sec.(qONB=3.09 w/cm

2 _{at G}

=400 kg/m2s) --- 55 Fig 4.9 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =20 sec.(qONB=2.62 w/cm

2 _{at G}

=300 kg/m2s) --- 56 Fig 4.10 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =20 sec.(q_ONB=3.05 w/cm2 at G

=400 kg/m2s) --- 57 Fig 4.11 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =30 sec.(qONB=3.02 w/cm

2 _{at G}

=300 kg/m2s) --- 58 Fig 4.12 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =30 sec.(q_ONB=3.47 w/cm2 at G

=400 kg/m2s) --- 59 Fig 4.13 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300±10% kg/m2_{s with t}

p =10 sec.(qONB=2.70 w/cm2 at G

=300 kg/m2s) --- 60 Fig 4.14 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =10 sec.(qONB=3.15 w/cm

2 _{at G}

=400 kg/m2s) --- 61 Fig 4.15 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =20 sec.(q_ONB=2.19 w/cm2 at G

=300 kg/m2s) --- 62 Fig 4.16 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =20 sec.(qONB=3.06 w/cm

2 _{at G}

=400 kg/m2s) --- 63 Fig 4.17 Time variations of (a) imposed coolant mass flux and (b) copper plate

vii

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =30 sec.(qONB=2.17 w/cm

2 _{at G}

=300 kg/m2s) --- 64 Fig 4.18 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =30 sec.(qONB=3.02 w/cm

2 _{at G}

=400 kg/m2s) --- 65 Fig 4.19 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat

transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300± 5% kg/m2s with tp =10 sec --- 66

Fig 4.20 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400± 5% kg/m2s with tp =10 sec --- 67

Fig 4.21 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300± 5% kg/m2_{s with t}

p =20 sec --- 68

Fig 4.22 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400± 5% kg/m2s with tp =20 sec --- 69

Fig 4.23 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300± 5% kg/m2s with tp =30 sec --- 70

Fig 4.24 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400± 5% kg/m2s with tp =30 sec --- 71

Fig 4.25 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300± 10% kg/m2s with tp =10 sec --- 72

Fig 4.26 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400± 10% kg/m2s with tp =10 sec --- 73

Fig 4.27 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300± 10% kg/m2s with tp =20 sec --- 74

Fig 4.28 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400± 10% kg/m2s with tp =20 sec --- 75

viii

transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=300± 10% kg/m2s with tp =30 sec --- 76

Fig 4.30 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory saturated flow boiling for various imposed heat fluxes for G=400± 10% kg/m2s with tp =30 sec --- 77

Fig 4.31 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=4.01 W/cm2

and (b) q=8.25 W/cm2 for G=300±5% kg/m2s with tp =10 sec --- 78

Fig 4.32 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.98 W/cm2 and (b) q=8.26 W/cm2 for G=400±5% kg/m2s with tp =10 sec --- 79

Fig 4.33 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.93 W/cm2 and (b) q=8.24 W/cm2 for G=300±5% kg/m2s with tp =20 sec --- 80

Fig 4.34 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.96 W/cm2 and (b) q=8.23 W/cm2 for G=400±5% kg/m2s with tp =20 sec --- 81

Fig 4.35 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.93 W/cm2 and (b) q=8.21 W/cm2 for G=300±5% kg/m2s with tp =30 sec --- 82

Fig 4.36 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.47 W/cm2 and (b) q=8.20 W/cm2 for G=400±5% kg/m2s with tp =30 sec --- 83

Fig 4.37 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=4.04 W/cm2 and (b) q=8.17 W/cm2 for G=300±10% kg/m2s with tp =10 sec --- 84

Fig 4.38 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=4.01 W/cm2 and (b) q=8.20 W/cm2 for G=400±10% kg/m2s with tp =10 sec --- 85

Fig 4.39 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.41 W/cm2 and (b) q=8.21 W/cm2 _{for G=300±10% kg/m}2_{s with t}

p =20 sec --- 86

Fig 4.40 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.95 W/cm2 and (b) q=8.22 W/cm2 _{for G=400±10% kg/m}2_{s with t}

p =20 sec --- 87

Fig 4.41 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.39 W/cm2 and (b) q=8.18 W/cm2 for G=300±10% kg/m2s with tp =30 sec --- 88

ix

Fig 4.42 Time variations of coolant mass flux and inlet pressure in transient oscillatory saturated flow boiling for various imposed heat fluxes at (a) q=3.95 W/cm2 and (b) q=8.20 W/cm2 for G=400±10% kg/m2s with tp =30 sec --- 89

Fig 4.43 Photos of stable saturated boiling flow at certain time instants for various imposed heat fluxes for (a) G =300 kg/m2s and (b) G =400 kg/m2s --- 90 Fig 4.44 Photos of transient oscillatory saturated flow boiling flow at certain time

instants for various imposed mass fluxes for q=6.2 W/cm2 _{at G=300±5%}

kg/m2s with oscillation tp=10s --- 91

Fig 4.45 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 at G=300±5% kg/m2s with oscillation tp=10s --- 92

Fig 4.46 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=400±5% kg/m2s with oscillation tp=10s --- 93

Fig 4.47 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=9.0 W/cm2 at G=400±5% kg/m2s with oscillation tp=10s --- 94

Fig 4.48 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=300±5% kg/m2s with oscillation tp=20s --- 95

Fig 4.49 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 at G=300±5% kg/m2s with oscillation tp=20s --- 96

Fig 4.50 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=400±5% kg/m2s with oscillation tp=20s --- 97

Fig 4.51 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=9.0 W/cm2 at G=400±5% kg/m2s with oscillation tp=20s --- 98

Fig 4.52 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=300±5% kg/m2_{s with oscillation t}

p=30s --- 99

Fig 4.53 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 at G=300±5% kg/m2_{s with oscillation t}

p=30s --- 100

Fig 4.54 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=400±5% kg/m2s with oscillation tp=30s --- 101

x

Fig 4.55 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=9.0 W/cm2 at G=400±5% kg/m2s with oscillation tp=30s --- 102

Fig 4.56 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=300±10% kg/m2s with oscillation tp=10s --- 103

Fig 4.57 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 at G=300±10% kg/m2s with oscillation tp=10s --- 104

Fig 4.58 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=400±10% kg/m2s with oscillation tp=10s --- 105

Fig 4.59 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=8.9 W/cm2 at G=400±10% kg/m2s with oscillation tp=10s --- 106

Fig 4.60 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=300±10% kg/m2s with oscillation tp=20s --- 107

Fig 4.61 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 at G=300±10% kg/m2s with oscillation tp=20s --- 108

Fig 4.62 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 at G=400±10% kg/m2s with oscillation tp=20s --- 109

Fig 4.63 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=9.0 W/cm2 at G=400±10% kg/m2_{s with oscillation t}

p=20s --- 110

Fig 4.64 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.1 W/cm2 at G=300±10% kg/m2_{s with oscillation t}

p=30s --- 111

Fig 4.65 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 _{at G=300±10%}

kg/m2s with oscillation tp=30s --- 112

Fig 4.66 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=6.2 W/cm2 _{at G=400±10%}

kg/m2s with oscillation tp=30s --- 113

Fig 4.67 Photos of transient oscillatory saturated flow boiling flow at certain time instants for various imposed mass fluxes for q=9.0 W/cm2 at G=400±10%

xi

kg/m2s with oscillation tp=30s --- 114

Fig 4.68 Mean bubble departure diameters for various coolant mass fluxes for stable saturated flow boiling (a) and various imposed heat fluxes for transient saturated flow boiling for G=300±5% kg/m2s with tp=10 sec (b), 20sec (c) and

30 sec (d) --- 115 Fig 4.69 Mean bubble departure diameters for various imposed heat fluxes for transient

saturated flow boiling for G=300±10% kg/m2_{s with t}

p=10 sec (a), 20sec (b)

and 30 sec (c) --- 117 Fig 4.70 Mean bubble departure diameters for various imposed heat fluxes for transient

saturated flow boiling for G=400±5% kg/m2s with tp=10 sec (a), 20sec (b) and

30 sec (c) --- 118 Fig 4.71 Mean bubble departure diameters for various imposed heat fluxes for transient

saturated flow boiling for G=400±10% kg/m2s with tp=10 sec (a), 20sec (b)

and 30 sec (c) --- 119 Fig 4.72 Mean bubble departure diameters for various periods of the mass flux

oscillation for transient saturated flow boiling for G=300±5% kg/m2s with (a) q=6.2 W/cm2 and (b) q=7.5 W/cm2 --- 120 Fig 4.73 Mean bubble departure diameters for various periods of the mass flux

oscillation for transient saturated flow boiling for G=300±10% kg/m2s with (a) q=6.2 W/cm2 and (b) q=7.5 W/cm2 --- 121 Fig 4.74 Mean bubble departure diameters for various periods of the mass flux

oscillation for transient saturated flow boiling for G=400±5% kg/m2s with (a) q=6.2 W/cm2 and (b) q=9.0 W/cm2 --- 122 Fig 4.75 Mean bubble departure diameters for various periods of the mass flux

oscillation for transient saturated flow boiling for G=400±10% kg/m2s with (a) q=6.2 W/cm2 and (b) q=9.0 W/cm2 --- 123 Fig 4.76 Mean bubble departure diameters for various amplitudes of the mass fluxes

oscillation for transient saturated flow boiling for q=6.2 W/cm2 with period=10 sec (a), 20 sec (b), and 30 sec (c) --- 124 Fig 4.77 Mean bubble departure frequencies for various coolant mass fluxes for stable

saturated flow boiling (a) and various imposed heat fluxes for transient saturated flow boiling for G=300±5% kg/m2_{s with t}

p=10 sec (b), 20sec (c) and

30 sec (d) --- 125 Fig 4.78 Mean bubble departure frequencies for various imposed heat fluxes for

transient saturated flow boiling for G=300±10% kg/m2_{s with t}

p=10 sec (a),

20sec (b) and 30 sec (c) --- 127 Fig 4.79 Mean bubble departure frequencies for various imposed heat fluxes for

xii

20sec (b) and 30 sec (c) --- 128 Fig 4.80 Mean bubble departure frequencies for various imposed heat fluxes for

transient saturated flow boiling for G=400±10% kg/m2s with tp=10 sec (a),

20sec (b) and 30 sec (c) --- 129 Fig 4.81 Mean bubble departure frequencies for various periods of mass flux

oscillation for transient saturated flow boiling for G=300±5% kg/m2s with (a) q=6.2 W/cm2 _{and (b) q=7.5 W/cm}2 _{--- 130}

Fig 4.82 Mean bubble departure frequencies for various periods of mass flux oscillation for transient saturated flow boiling for G=300±10% kg/m2s with (a) q=6.2 W/cm2 and (b) q=7.5 W/cm2 --- 131 Fig 4.83 Mean bubble departure frequencies for various periods of mass flux

oscillation for transient saturated flow boiling for G=400±5% kg/m2_{s with (a)}

q=6.2 W/cm2 and (b) q=9.0 W/cm2 --- 132 Fig 4.84 Mean bubble departure frequencies for various periods of mass flux

oscillation for transient saturated flow boiling for G=400±10% kg/m2s with (a) q=6.2 W/cm2 and (b) q=9.0 W/cm2 --- 133 Fig 4.85 Mean bubble departure frequencies for various amplitudes of the mass fluxes

oscillation for transient saturated flow boiling for q=6.2 W/cm2 with period=10 sec (a), 20 sec (b), and 30 sec (c) --- 134 Fig 4.86 Mean active nucleation site densities for various coolant mass fluxes for stable

saturated flow boiling (a) and various imposed heat fluxes for transient saturated flow boiling for G=300±5% kg/m2s with tp=10 sec (b), 20sec (c) and

30 sec (d) --- 135 Fig 4.87 Mean active nucleation site densities for various imposed heat fluxes for

transient saturated flow boiling for G=300±10% kg/m2s with tp=10 sec (a),

20sec (b) and 30 sec (c) --- 137 Fig 4.88 Mean active nucleation site densities for various imposed heat fluxes for

transient saturated flow boiling for G=400±5% kg/m2s with tp=10 sec (a),

20sec (b) and 30 sec (c) --- 138 Fig 4.89 Mean active nucleation site densities for various imposed heat fluxes for

transient saturated flow boiling for G=400±10% kg/m2s with tp=10 sec (a),

20sec (b) and 30 sec (c) --- 139 Fig 4.90 Mean active nucleation site densities for various periods of mass flux

oscillation for transient saturated flow boiling for G=300±5% kg/m2s with (a) q=6.2 W/cm2 _{and (b) q=7.5 W/cm}2 _{--- 140}

Fig 4.91 Mean active nucleation site densities for various periods of mass flux oscillation for transient saturated flow boiling for G=300±10% kg/m2s with (a) q=6.2 W/cm2 and (b) q=7.5 W/cm2 --- 141

xiii

Fig 4.92 Mean active nucleation site densities for various periods of mass flux oscillation for transient saturated flow boiling for G=400±5% kg/m2s with (a) q=6.2 W/cm2 and (b) q=9.0 W/cm2 --- 142 Fig 4.93 Mean active nucleation site densities for various periods of mass flux

oscillation for transient saturated flow boiling for G=400±10% kg/m2s with (a) q=6.2 W/cm2 and (b) q=9.0 W/cm2 --- 143 Fig 4.94 Mean active nucleation site densities for various amplitudes of the mass fluxes

oscillation for transient saturated flow boiling for q=6.2 W/cm2 with period=10 sec (a), 20 sec (b), and 30 sec (c) --- 144 Fig 4.95 Comparison of the measured data for mean bubble departure diameter for

saturated flow boiling of FC-72 with the proposed correlation --- 145 Fig 4.96 Comparison of the measured data for mean bubble departure diameter for

transient saturated flow boiling of FC-72 with the proposed correlation --- 146 Fig 4.97 Comparison of the measured data for mean bubble departure frequency for

saturated flow boiling of FC-72 with the proposed correlation --- 147 Fig 4.98 Comparison of the measured data for mean bubble departure frequency for

transient saturated flow boiling of FC-72 with the proposed correlation --- 148 Fig 4.99 Comparison of the measured data for mean active nucleation site density for

saturated flow boiling of FC-72 with the proposed correlation --- 149 Fig 4.100 Comparison of the measured data for mean active nucleation site density for

transient saturated flow boiling of FC-72 with the proposed correlation --- 150 Fig 4.101 Comparison of the measured data for boiling heat flux for stable saturated

flow boiling of FC-72 with the proposed correlation --- 151

Subcooled Flow Boiling

Fig 5.1 Time-average flow boiling curves for various coolant mass fluxes for stable subcooled flow boiling (a) and transient subcooled flow boiling at △Tsub =5oC

for tp=10 sec (b), 20 sec (c) and 30 sec (d)--- 166

Fig 5.2 Time-average flow boiling curves for various coolant mass fluxes for transient subcooled flow boiling at △Tsub =5oC for tp=10 sec (a), 20 sec (b) and 30 sec

(c) --- 168 Fig 5.3 Time-average flow boiling curves for various coolant mass fluxes for stable

subcooled flow boiling (a) and transient subcooled flow boiling at △Tsub

=10oC for tp=10 sec (b), 20 sec (c) and 30 sec (d) --- 170

Fig 5.4 Time-average flow boiling curves for various coolant mass fluxes for transient subcooled flow boiling at △Tsub =10oC for tp=10 sec (a), 20 sec (b) and 30 sec

(c) --- 172 Fig 5.5 Time-average flow boiling curves for various inlet subcoolings for stable

xiv

subcooled flow boiling at (a) G=300 kg/m2s and (b) G=400 kg/m2s --- 174 Fig 5.6 Time-average flow boiling curves for various inlet subcoolings for transient

subcooled flow boiling at (a) G=300±5% kg/m2s and (b) G=400±5% kg/m2s at tp=10 sec --- 175

Fig 5.7 Time-average flow boiling curves for various inlet subcoolings for transient subcooled flow boiling at (a) G=300±5% kg/m2s and (b) G=400±5% kg/m2s at tp=20 sec --- 176

Fig 5.8 Time-average flow boiling curves for various inlet subcoolings for transient subcooled flow boiling at (a) G=300±5% kg/m2s and (b) G=400±5% kg/m2s at tp=30 sec --- 177

Fig 5.9 Time-average flow boiling curves for various inlet subcoolings for transient subcooled flow boiling at (a) G=300±10% kg/m2_{s and (b) G=400±10%}

kg/m2s at tp=10 sec --- 178

Fig 5.10 Time-average flow boiling curves for various inlet subcoolings for transient subcooled flow boiling at (a) G=300±10% kg/m2s and (b) G=400±10% kg/m2s at tp=20 sec --- 179

Fig 5.11 Time-average flow boiling curves for various inlet subcoolings for transient subcooled flow boiling at (a) G=300±10% kg/m2s and (b) G=400±10% kg/m2s at tp=30 sec --- 180

Fig 5.12 Time-average flow boiling heat transfer coefficients for various coolant mass fluxes for stable subcooled flow boiling (a) and transient subcooled flow boiling at △Tsub =5oC for tp=10 sec (b), 20 sec (c) and 30 sec (d) --- 181

Fig 5.13 Time-average flow boiling heat transfer coefficients for various coolant mass fluxes for transient subcooled flow boiling at △Tsub =5oC for tp=10 sec (a), 20

sec (b) and 30 sec (c) --- 183 Fig 5.14 Time-average flow boiling heat transfer coefficients for various coolant mass

fluxes for stable subcooled flow boiling (a) and transient subcooled flow boiling at △Tsub =10oC for tp=10 sec (b), 20 sec (c) and 30 sec (d) --- 185

Fig 5.15 Time-average flow boiling heat transfer coefficients for various coolant mass fluxes for transient subcooled flow boiling at △Tsub =10oC for tp=10 sec (a),

20 sec (b) and 30 sec (c)--- 187 Fig 5.16 Time-average flow boiling heat transfer coefficients for various inlet

subcoolings for stable subcooled flow boiling at (a) G=300 kg/m2s and (b) G=400 kg/m2s --- 189 Fig 5.17 Time-average flow boiling heat transfer coefficients for various inlet

subcoolings for stable subcooled flow boiling at (a) G=300±5% kg/m2s and (b) G=400±5% kg/m2s at tp=10 sec --- 190

xv

subcoolings for stable subcooled flow boiling at (a) G=300±5% kg/m2s and (b) G=400±5% kg/m2s at tp=20 sec --- 191

Fig 5.19 Time-average flow boiling heat transfer coefficients for various inlet subcoolings for stable subcooled flow boiling at (a) G=300±5% kg/m2s and (b) G=400±5% kg/m2s at tp=30 sec --- 192

Fig 5.20 Time-average flow boiling heat transfer coefficients for various inlet subcoolings for stable subcooled flow boiling at (a) G=300±10% kg/m2_{s and}

(b) G=400±10% kg/m2s at tp=10 sec --- 193

Fig 5.21 Time-average flow boiling heat transfer coefficients for various inlet subcoolings for stable subcooled flow boiling at (a) G=300±10% kg/m2s and (b) G=400±10% kg/m2s at tp=20 sec --- 194

Fig 5.22 Time-average flow boiling heat transfer coefficients for various inlet subcoolings for stable subcooled flow boiling at (a) G=300±10% kg/m2s and (b) G=400±10% kg/m2s at tp=30 sec --- 195

Fig 5.23 Time variations of the copper plate temperature in stable subcooled flow boiling for various imposed heat fluxes for △Tsub =5oC at (a) G=300 kg/m2s

and (b) G=400 kg/m2s --- 196 Fig 5.24 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =10 sec.(qONB=3.59 w/cm

2

at G =300 kg/m2s) --- 197 Fig 5.25 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =10 sec.(q_ONB=4.45 w/cm2

at G =400 kg/m2s) --- 198 Fig 5.26 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2_{s with t}

p =20 sec.(q_ONB=3.43 w/cm2

at G =300 kg/m2s) --- 199 Fig 5.27 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =20 sec.(qONB=4.35 w/cm

2

at G =400 kg/m2s) --- 200 Fig 5.28 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =30 sec.(q_ONB=3.40 w/cm2

xvi

Fig 5.29 Time variations of (a) imposed coolant mass flux and (b) copper plate temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =30 sec.(qONB=4.35 w/cm

2

at G =400 kg/m2s) --- 202 Fig 5.30 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =10 sec.(q_ONB=3.44

w/cm2 at G =300 kg/m2s) --- 203 Fig 5.31 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2_{s with t}

p =10 sec.(qONB=4.51

w/cm2 at G =400 kg/m2s) --- 204 Fig 5.32 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =20 sec.(qONB=3.34

w/cm2 at G =300 kg/m2s) --- 205 Fig 5.33 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =20 sec.(q_ONB=3.90

w/cm2 at G =400 kg/m2s) --- 206 Fig 5.34 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =30 sec.(qONB=3.34

w/cm2 at G =300 kg/m2s) --- 207 Fig 5.35 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =30 sec.(q_ONB=3.84

w/cm2 at G =400 kg/m2s) --- 208 Fig 5.36 Time variations of the copper plate temperature in stable subcooled flow

boiling for various imposed heat fluxes for △Tsub =10oC at (a) G=300 kg/m2s

and (b) G=400 kg/m2s --- 209 Fig 5.37 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =10 sec.(q_ONB =4.33

w/cm2 _{at G =300 kg/m}2_{s) --- 210}

Fig 5.38 Time variations of (a) imposed coolant mass flux and (b) copper plate temperature in transient oscillatory subcooled flow boiling for various

xvii

imposed heat fluxes for G=400±5% kg/m2s with tp =10 sec.(q_ONB=6.13 w/cm2

at G =400 kg/m2s) --- 211 Fig 5.39 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =20 sec.(qONB=4.28 w/cm

2

at G =300 kg/m2s) --- 212 Fig 5.40 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =20 sec.(q_ONB=6.04 w/cm2

at G =400 kg/m2s) --- 213 Fig 5.41 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2_{s with t}

p =30 sec.(qONB=4.79 w/cm2

at G =300 kg/m2s) --- 214 Fig 5.42 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =30 sec.(qONB=5.96 w/cm

2

at G =400 kg/m2s) --- 215 Fig 5.43 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =10 sec.(q_ONB=4.32

w/cm2 at G =300 kg/m2s) --- 216 Fig 5.44 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =10 sec.(qONB=5.58

w/cm2 at G =400 kg/m2s) --- 217 Fig 5.45 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =20 sec.(q_ONB=4.30

w/cm2 at G =300 kg/m2s) --- 218 Fig 5.46 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2_{s with t}

p =20 sec.(qONB=5.47

w/cm2 at G =400 kg/m2s) --- 219 Fig 5.47 Time variations of (a) imposed coolant mass flux and (b) copper plate

xviii

imposed heat fluxes for G=300±10% kg/m2s with tp =30 sec.(q_ONB=4.28

w/cm2 at G =300 kg/m2s) --- 220 Fig 5.48 Time variations of (a) imposed coolant mass flux and (b) copper plate

temperature in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =30 sec.(qONB=5.44

w/cm2 at G =400 kg/m2s) --- 221 Fig 5.49 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat

transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =10 sec--- 222

Fig 5.50 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =10 sec--- 223

Fig 5.51 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =20 sec--- 224

Fig 5.52 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =20 sec--- 225

Fig 5.53 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2_{s with t}

p =30 sec--- 226

Fig 5.54 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2_{s with t}

p =30 sec--- 227

Fig 5.55 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =10 sec --- 228

Fig 5.56 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =10 sec --- 229

Fig 5.57 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =20 sec --- 230

Fig 5.58 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =20 sec --- 231

Fig 5.59 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various

xix

imposed heat fluxes for G=300±10% kg/m2s with tp =30 sec --- 232

Fig 5.60 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =30 sec --- 233

Fig 5.61 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2_{s with t}

p =10 sec--- 234

Fig 5.62 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =10 sec--- 235

Fig 5.63 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =20 sec--- 236

Fig 5.64 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =20 sec--- 237

Fig 5.65 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±5% kg/m2s with tp =30 sec--- 238

Fig 5.66 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±5% kg/m2s with tp =30 sec--- 239

Fig 5.67 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =10 sec --- 240

Fig 5.68 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =10 sec --- 241

Fig 5.69 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =20 sec --- 242

Fig 5.70 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =20 sec --- 243

Fig 5.71 Time variations of (a) imposed coolant mass flux and (b) flow boiling heat transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=300±10% kg/m2s with tp =30 sec --- 244

xx

transfer coefficients in transient oscillatory subcooled flow boiling for various imposed heat fluxes for G=400±10% kg/m2s with tp =30 sec --- 245

Fig 5.73 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=3.59 W/cm2 and (b) q=8.19 W/cm2 for G=300±5% kg/m2s with tp =10 sec --- 246

Fig 5.74 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.55 W/cm2

and (b) q=8.17 W/cm2 for G=400±5% kg/m2s with tp =10 sec --- 247

Fig 5.75 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.96 W/cm2 and (b) q=8.17 W/cm2 for G=300±5% kg/m2s with tp =20 sec --- 248

Fig 5.76 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.46 W/cm2 and (b) q=8.11 W/cm2 for G=400±5% kg/m2s with tp =20 sec --- 249

Fig 5.77 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.95 W/cm2 and (b) q=8.15 W/cm2 for G=300±5% kg/m2s with tp =30 sec --- 250

Fig 5.78 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.48 W/cm2 and (b) q=8.10 W/cm2 for G=400±5% kg/m2s with tp =30 sec --- 251

Fig 5.79 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.39 W/cm2 and (b) q=8.14 W/cm2 for G=300±10% kg/m2s with tp =10 sec --- 252

Fig 5.80 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.50 W/cm2 and (b) q=8.12 W/cm2 for G=400±10% kg/m2s with tp =10 sec --- 253

Fig 5.81 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.43 W/cm2 and (b) q=8.10 W/cm2 for G=300±10% kg/m2s with tp =20 sec --- 254

Fig 5.82 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.02 W/cm2 and (b) q=8.19 W/cm2 _{for G=400±10% kg/m}2_{s with t}

p =20 sec --- 255

Fig 5.83 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.43 W/cm2 and (b) q=8.11 W/cm2 _{for G=300±10% kg/m}2_{s with t}

p =30 sec --- 256

Fig 5.84 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.88 W/cm2 and (b) q=8.12 W/cm2 for G=400±10% kg/m2s with tp =30 sec --- 257

xxi

Fig 5.85 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.33 W/cm2 and (b) q=8.12 W/cm2 for G=300±5% kg/m2s with tp =10 sec --- 258

Fig 5.86 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=6.13 W/cm2 and (b) q=8.81 W/cm2 for G=400±5% kg/m2s with tp =10 sec --- 259

Fig 5.87 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.28 W/cm2 and (b) q=8.05 W/cm2 for G=300±5% kg/m2s with tp =20 sec --- 260

Fig 5.88 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=6.04 W/cm2 and (b) q=8.78 W/cm2 for G=400±5% kg/m2s with tp =20 sec --- 261

Fig 5.89 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.79 W/cm2 and (b) q=8.74 W/cm2 for G=300±5% kg/m2s with tp =30 sec --- 262

Fig 5.90 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.96 W/cm2 and (b) q=8.73 W/cm2 for G=400±5% kg/m2s with tp =30 sec --- 263

Fig 5.91 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.32 W/cm2 and (b) q=8.10 W/cm2 for G=300±10% kg/m2s with tp =10 sec --- 264

Fig 5.92 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.58 W/cm2 and (b) q=8.22 W/cm2 for G=400±10% kg/m2s with tp =10 sec --- 265

Fig 5.93 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.30 W/cm2 and (b) q=8.06 W/cm2 _{for G=300±10% kg/m}2_{s with t}

p =20 sec --- 266

Fig 5.94 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.47 W/cm2 and (b) q=8.08 W/cm2 _{for G=400±10% kg/m}2_{s with t}

p =20 sec --- 267

Fig 5.95 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=4.28 W/cm2

and (b) q=8.05 W/cm2 for G=300±10% kg/m2s with tp =30 sec --- 268

Fig 5.96 Time variations of coolant mass flux and inlet pressure in transient oscillatory subcooled flow boiling for various imposed heat fluxes at (a) q=5.44 W/cm2

and (b) q=8.07 W/cm2 for G=400±10% kg/m2s with tp =30 sec --- 269

Fig 5.97 Photos of stable subcooled boiling flow at certain time instants for various imposed heat fluxes at ΔTsub= 5oC for (a) G =300 kg/m2s and (b) G =400

xxii

kg/m2s --- 270 Fig 5.98 Photos of transient oscillatory subcooled flow boiling flow at certain time

instants for various imposed mass fluxes for q=6.2 W/cm2 and ΔTsub= 5oC at

G=300±5% kg/m2s with oscillation tp=10s --- 271

Fig 5.99 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 and ΔTsub= 5oC at

G=300±5% kg/m2_{s with oscillation t}

p=10s --- 272

Fig 5.100 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 and ΔTsub= 5oCat

G=400±5% kg/m2s with oscillation tp=10s --- 273

Fig 5.101 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.9 W/cm2 _{and ΔT}

sub= 5oCat

G=400±5% kg/m2s with oscillation tp=10s --- 274

Fig 5.102 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.1 W/cm2 and ΔTsub= 5oCat

G=300±5% kg/m2s with oscillation tp=20s --- 275

Fig 5.103 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 and ΔTsub= 5oCat

G=300±5% kg/m2s with oscillation tp=20s --- 276

Fig 5.104 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=400±5% kg/m2s with oscillation tp=20s --- 277

Fig 5.105 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.9 W/cm2 and ΔTsub= 5oCat

G=400±5% kg/m2s with oscillation tp=20s --- 278

Fig 5.106 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.1 W/cm2 and ΔTsub= 5oC at

G=300±5% kg/m2s with oscillation tp=30s --- 279

Fig 5.107 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=300±5% kg/m2s with oscillation tp=30s --- 280

Fig 5.108 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=400±5% kg/m2s with oscillation tp=30s --- 281

Fig 5.109 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.8 W/cm2 and ΔTsub= 5oCat

G=400±5% kg/m2s with oscillation tp=30s --- 282

xxiii

instants for various imposed mass fluxes for q=6.1 W/cm2 and ΔTsub= 5oCat

G=300±10% kg/m2s with oscillation tp=10s --- 283

Fig 5.111 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=300±10% kg/m2s with oscillation tp=10s --- 284

Fig 5.112 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 _{and ΔT}

sub= 5oCat

G=400±10% kg/m2s with oscillation tp=10s --- 285

Fig 5.113 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.8 W/cm2 and ΔTsub= 5oCat

G=400±10% kg/m2s with oscillation tp=10s --- 286

Fig 5.114 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.0 W/cm2 and ΔTsub= 5oCat

G=300±10% kg/m2s with oscillation tp=20s --- 287

Fig 5.115 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=300±10% kg/m2s with oscillation tp=20s --- 288

Fig 5.116 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.5 W/cm2 and ΔTsub= 5oCat

G=400±10% kg/m2s with oscillation tp=20s --- 289

Fig 5.117 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.9 W/cm2 and ΔTsub= 5oCat

G=400±10% kg/m2s with oscillation tp=20s --- 290

Fig 5.118 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.1 W/cm2 and ΔTsub= 5oCat

G=300±10% kg/m2s with oscillation tp=30s --- 291

Fig 5.119 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=300±10% kg/m2s with oscillation tp=30s --- 292

Fig 5.120 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=7.4 W/cm2 and ΔTsub= 5oCat

G=400±10% kg/m2_{s with oscillation t}

p=30s --- 293

Fig 5.121 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.9 W/cm2 and ΔTsub= 5oCat

G=400±10% kg/m2_{s with oscillation t}

p=30s --- 294

Fig 5.122 Photos of stable subcooled boiling flow at certain time instants for various imposed heat fluxes at ΔTsub= 10oC for (a) G =300 kg/m2s and (b) G =400

xxiv

Fig 5.123 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.7 W/cm2 and ΔTsub= 10oC at

G=300±5% kg/m2s with oscillation tp=10s --- 296

Fig 5.124 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oC at

G=300±5% kg/m2s with oscillation tp=10s --- 297

Fig 5.125 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=400±5% kg/m2s with oscillation tp=10s --- 298

Fig 5.126 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=9.6 W/cm2 and ΔTsub= 10oCat

G=400±5% kg/m2s with oscillation tp=10s --- 299

Fig 5.127 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.7 W/cm2 and ΔTsub= 10oCat

G=300±5% kg/m2s with oscillation tp=20s --- 300

Fig 5.128 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=300±5% kg/m2s with oscillation tp=20s --- 301

Fig 5.129 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=400±5% kg/m2s with oscillation tp=20s --- 302

Fig 5.130 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=9.5 W/cm2 and ΔTsub= 10oCat

G=400±5% kg/m2s with oscillation tp=20s --- 303

Fig 5.131 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.6 W/cm2 and ΔTsub= 10oC at

G=300±5% kg/m2_{s with oscillation t}

p=30s --- 304

Fig 5.132 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.0 W/cm2 and ΔTsub= 10oCat

G=300±5% kg/m2_{s with oscillation t}

p=30s --- 305

Fig 5.133 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.0 W/cm2 _{and ΔT}

sub= 10oCat

G=400±5% kg/m2s with oscillation tp=30s --- 306

Fig 5.134 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=9.5 W/cm2 _{and ΔT}

sub= 10oCat

G=400±5% kg/m2s with oscillation tp=30s --- 307

Fig 5.135 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.7 W/cm2 and ΔTsub= 10oCat

xxv

G=300±10% kg/m2s with oscillation tp=10s --- 308

Fig 5.136 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=300±10% kg/m2s with oscillation tp=10s --- 309

Fig 5.137 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.2 W/cm2 and ΔTsub= 10oCat

G=400±10% kg/m2_{s with oscillation t}

p=10s --- 310

Fig 5.138 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=9.7 W/cm2 and ΔTsub= 10oCat

G=400±10% kg/m2s with oscillation tp=10s --- 311

Fig 5.139 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.7 W/cm2 _{and ΔT}

sub= 10oCat

G=300±10% kg/m2s with oscillation tp=20s --- 312

Fig 5.140 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=300±10% kg/m2s with oscillation tp=20s --- 313

Fig 5.141 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=400±10% kg/m2s with oscillation tp=20s --- 314

Fig 5.142 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=9.6 W/cm2 and ΔTsub= 10oCat

G=400±10% kg/m2s with oscillation tp=20s --- 315

Fig 5.143 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=6.7 W/cm2 and ΔTsub= 10oCat

G=300±10% kg/m2s with oscillation tp=30s --- 316

Fig 5.144 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=300±10% kg/m2s with oscillation tp=30s --- 317

Fig 5.145 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.1 W/cm2 and ΔTsub= 10oCat

G=400±10% kg/m2s with oscillation tp=30s --- 318

Fig 5.146 Photos of transient oscillatory subcooled flow boiling flow at certain time instants for various imposed mass fluxes for q=8.9 W/cm2 and ΔTsub= 10oCat

G=400±10% kg/m2s with oscillation tp=30s --- 319

Fig 5.147 Mean bubble departure diameters for various coolant mass fluxes for stable subcooled flow boiling (a) and various imposed heat fluxes for transient subcooled flow boiling for G=300±5% kg/m2s and ΔTsub= 5oC with tp=10 sec

xxvi

Fig 5.148 Mean bubble departure diameters for various imposed heat fluxes for transient subcooled flow boiling for G=300±10% kg/m2s and ΔTsub= 5oC with tp=10 sec

(a), 20sec (b) and 30 sec (c) --- 322 Fig 5.149 Mean bubble departure diameters for various imposed heat fluxes for transient

subcooled flow boiling for G=400±5% kg/m2s and ΔTsub= 5oC with tp=10 sec

(a), 20sec (b) and 30 sec (c) --- 323 Fig 5.150 Mean bubble departure diameters for various imposed heat fluxes for transient

subcooled flow boiling for G=400±10% kg/m2s and ΔTsub= 5oC with tp=10 sec

(a), 20sec (b) and 30 sec (c) --- 324 Fig 5.151 Mean bubble departure diameters for various period of mass flux oscillation

for transient subcooled flow boiling for G=300±5% kg/m2s and ΔTsub= 5oC

with (a) q=6.1 W/cm2 and (b) q=7.5 W/cm2 --- 325 Fig 5.152 Mean bubble departure diameters for various period of mass flux oscillation

for transient subcooled flow boiling for G=300±10% kg/m2s and ΔTsub= 5oC

with (a) q=6.1 W/cm2 and (b) q=7.4 W/cm2 --- 326 Fig 5.153 Mean bubble departure diameters for various period of mass flux oscillation

for transient subcooled flow boiling for G=400±5% kg/m2s and ΔTsub= 5oC

with (a) q=7.4 W/cm2 and (b) q=8.9 W/cm2 --- 327 Fig 5.154 Mean bubble departure diameters for various period of mass flux oscillation

for transient subcooled flow boiling for G=400±10% kg/m2s and ΔTsub= 5oC

with (a) q=7.4 W/cm2 and (b) q=8.9 W/cm2 --- 328 Fig 5.155 Mean bubble departure diameters for various amplitudes of the mass fluxes

oscillation for transient subcooled flow boiling for q=7.4 W/cm2 and ΔTsub=

5oC with period=10 sec (a), 20 sec (b), and 30 sec (c) --- 329 Fig 5.156 Mean bubble departure frequencies for various coolant mass fluxes for stable

subcooled flow boiling (a) and various imposed heat fluxes for transient subcooled flow boiling for G=300±5% kg/m2_{s and ΔT}

sub= 5oC with tp=10 sec

(b), 20sec (c) and 30 sec (d) --- 330 Fig 5.157 Mean bubble departure frequencies for various imposed heat fluxes for

transient subcooled flow boiling for G=300±10% kg/m2_{s and ΔT}

sub= 5oC with

tp=10 sec (a), 20sec (b) and 30 sec (c) --- 332

Fig 5.158 Mean bubble departure frequencies for various imposed heat fluxes for transient subcooled flow boiling for G=400±5% kg/m2s and ΔTsub= 5oC with

tp=10 sec (a), 20sec (b) and 30 sec (c) --- 333

Fig 5.159 Mean bubble departure frequencies for various imposed heat fluxes for transient subcooled flow boiling for G=400±10% kg/m2s and ΔTsub= 5oC with

tp=10 sec (a), 20sec (b) and 30 sec (c) --- 334