• 沒有找到結果。

7.6 後才會相對明顯。

(三). 所有的測試通道中 90 度肋條正上方有最高的熱傳效果,沿著流線 方向二次流在肋條的後方先有一狹長型的低熱傳迴流區,之後二次流的 再接觸造成一個鐘型對稱的高熱傳區。

(四). 旋轉的科氏力效應在旋轉數為 0.023 時較旋轉數為 0.017 時明顯,

當旋轉數為 0.023 時測試通道的翼前緣面在靠近入口處就可看出紐賽 數明顯的下降,反之翼後緣面的熱傳效果則會在無因次化距離比為 3.4 後比靜止時高出一些,而當旋轉數為 0.017 時其旋轉的科氏力減弱,較 難看出翼後緣面、翼前緣面與靜止時的測試通道熱傳效果之差異,但由 測試面整體平均紐賽數來觀察,其翼後緣面的熱傳效果稍比靜止時高出 一些,而翼前緣面則有持平和稍微減弱兩種情況發生。

參考文獻

1. J.W. Baughn, 1995, “Liquid crystal methods for studying turbulent heat transfer,” International Journal of Heat and Fluid Flow, Vol.16, pp.365-375.

2. S.V. Ekkad, and J.C. Han, 2000, “A transient liquid crystal thermography technique for gas turbine heat transfer

measurements,” Measurement Science and Technology, Vol.11, pp.957-968.

3. C. Camci, K. Kim, and S.A. Hippensteele, 1992,“New hue capturing technique for the quantitative interpretation of liquid crystal images used in convective heat transfer studies,” Journal of Turbomachinery, Vol.114, pp.765-775

4. W.M. Yan, H.C. Liu, C.Y. Soong, and W.J. Yang,

2005,“Experimental study of impinging heat transfer along rib-roughened walls by using transient liquid crystal technique,”

International Journal of Heat and Mass Transfer, Vol.48, pp.2420-2428.

5. D. Cavallero, and G. Tanda, 2002 ,“An experimental investigation of forced convection heat transfer in channels with rib turbulators

by means of liquid crystal thermography,” Experimental Thermal and Fluid Science, Vol.26,pp.115-121.

6. M. Amro, B. Weiganda, R. Poser, and M. Schnieder, 2008, “An experimental investigation of the heat transfer in a ribbed triangular cooling channel,” International Journal of Thermal Sciences,

Vol.46, pp.491-500.

7. S.V. Ekkad, and J.C. Han, 1997 “Detailed heat transfer

distributions in two-pass square channels with rib turbulators,”

International Journal of Heat and Mass Transfer, Vol. 40, pp.2525–2537.

8. S.V. Ekkad, Y. Huang, and J.C. Han,1998,“Detailed heat transfer distributions in two-pass square channels with rib turbulators and bleed holes,” International Journal of Heat and Mass Transfer, Vol.41, pp.3781-3791.

9. J.C. Han, J.S. Park, and C.K. Lei, 1985, “Heat Transfer

Enhancement in Channels with Turbulence Promoters,” Journal of Engineering for Gas Turbines and Power, Vol.107, pp.628-625.

10. J.C. Han, and J.S. Park, 1988, “Developing heat transfer in

rectangular channels with rib turbulators,” International Journal of

Heat and Mass Transfer, Vol.31, pp.183-195.

11. J.S. Park, J.C. Han, Y. Huang, and S. Ou, 1992, “Heat transfer performance comparisons of five different rectangular channels with parallel angled ribs,” International Journal of Heat and Mass Transfer, Vol.35, pp.2891-2903.

12. J.H. Wagner, B.V. Johnson, and T.J. Hajek,1991,“Heat transfer in rotating passages with smooth walls and radial outward flow,”

Journal of Turbomachinery, Vol.113, pp.42-51.

13. T.M. Liou, S.W. Chang, J.H. Hung, and S.F. Chiou, 2007, “High rotation number heat transfer of a 45_ rib-roughened rectangular duct with two channel orientations,” International Journal of Heat and Mass Transfer, Vol.50, pp. 4063–4078.

14. Y.H. Liu, M.Huh, J.C. Han, and H.K. Moon,2010, “Heat Transfer and Pressure Drop inside a Triangular Channel with 45° , Inverted 45°, and 90° ribs under High Rotation Numbers,” Journal of Heat Transfer, Vol.3, pp.127-138.

15. W.L. Fu, L.M. Wright, and J.C. Han, 2006, “Heat Transfer in Two-Pass Rotating Rectangular Channels (AR= 2:1) with Discrete Ribs,” AIAA Journal of Thermophysics and Heat Transfer, Vol.20,

pp.569–582.

16. B.J. Syson, R.G. Pilbrow, and J.M. Owen, 1996, “Effect of

rotation on temperature response of thermochromic liquid crystal,”

International Journal of Heat and Fluid Flow, Vol.17, pp491-499.

17. G.D. Lock, Y. Yan, P.J. Newton, M. Wilson, and J. M. Owen, 2005, “Heat Transfer Measurements Using Liquid Crystals in a Preswirl Rotating-Disk System,” Journal of Engineering for Gas Turbines and Power, Vol127, pp.375-382.

18. N. Zhang, J. Chiou,S. Fann, and W.-J. Yang, 1993, “Local heat transfer distribution in a rotating serpentine rib-roughened flow passage,” Journal of Heat Transfer, Vol.115, pp.560-567.

19. W.L. Fu, L.M. Wright, and J.C. Han, 2004, “Heat Transfer in Two-Pass Rotating Rectangular Channels (AR=1:2 and AR=1:4) with 45° Angled Rib Turbulators,” ASME paper No

GT2004-53261.

20. L.M. Wright, W.L. Fu, and J.C. Han, 2005, “Influence of Entrance Geometry on Heat Transfer in Rotating Rectangular Cooling

Channels (AR54:1) With Angled Ribs,” Journal of Heat Transfer, Vol.127, pp.378-387.

21. Y.H. Liu, M. Huh, and J.C. Han, 2008, “Heat Transfer in a Two-Pass Rectangular Channel (AR=1:4) Under High Rotation Numbers,” Journal of Heat Transfer, Vol.130, 081701-1 to 081701-9.

22. W.L. Fu, L.M. Wright, and J.C. Han, 2005, “Buoyancy Effects on Heat Transfer in Five Different Aspect-Ratio Rectangular Channels with Smooth Walls and 45-Degree Ribbed Walls,” ASME Paper No GT 2005-68493.

23. W. Kays, M. Crawford, and B. Weigand, 2005, Convective Heat and Mass Transfer, McGraw Hill, New York.

24. G. Su, H.C. Chen, J.C. Han, and J. D. Heidmann, 2004,

“Computation of Flow and Heat Transfer in Two-Pass Rotating Rectangular Channels (AR=1:1, AR=1:2, AR=1:4) with 45-Deg Angled Ribs by a Reynolds Stress Turbulence Model,” ASME Paper No GT 2004-53662.

25. K.M. Kim, D.H. Lee, and H.H. Cho, 2007, “Detailed measurement of heat/mass transfer and pressure drop in a rotating two-pass duct with transverse ribs,” Heat and Mass Transfer, Vol.43, pp.801-815.

26. R.E. Critoph, M.K. Holland, and M. Fisher, 1999, “Comparison of

steady state and transient methods for measurement of local heat transfer in plate fin-tube heat exchangers using liquid crystal thermography with radiant heating,” International Journal of Heat and Mass Transfer, Vol.42, pp.1-12.

27. A.Valencia, M. Fiebig, and N.K. Mitra, 1995, “Influence of heat conduction on determination of heat transfer coefficient by liquid crystal thermography,” Experimental Heat Transfer, Vol.8,

pp.271-279.

28. G. Wagner, M. Kotulla, P. Ott, B. Weigand, and J. von Wolfersdorf, 2005, “The transient liquid crystal technique:

influence of surface curvature and finite wall thickness,” Journal of Turbomachinery, Vol.127, pp.175-182.

29. R. J. Moffat, 1988, “Describing the uncertainties in experimental results,” Experimental Thermal and Fluid Science, Vol.1, pp.3-17.

30. S. J. Kline and F. A. McClintock, 1953, “Describing Uncertainties in Single-Sample Experiments,” Mechanical Engineering, Vol.75, pp.3-8.

圖1-1:高溫的工作環境造成葉片損壞 (http://jp.hjenglish.com/new/p178783/)

圖1-2:渦輪葉片冷卻技術分類

圖 1-3:E3 stage-2 轉子葉片設計(Halila et al., 1982; NASA CR 167955)

Smectic structrure Namatic structrure Cholesteric structrure Molecules

Plane of alignment

Director

圖 1-4:液晶種類

圖 1-5:膽固醇液晶排列方式(I.C. Khoo,2007)

圖 1-6:感溫液晶顏色變化圖(LCR Hallcrest)

圖 1-7:RGB 色彩空間

(http://www.infocellar.com/graphics/color-theory.htm)

圖 1-8:HSV 色彩空間(Wapcaplet, 2005)

1

2 3

11

5 7 6

9 8

10

4 12

13 14

15

16 17

18

圖 3-1:實驗平台架構圖

圖 3-2:三種入口區高度圖(無導角)

圖 3-3:圓形導角擺設位置

圖 3-4:測試區立體與平面圖

寬度 15mm rib 高 1.5mm

圖 3-5:測試冷卻通道完整示意圖(3 比 1 突縮型)

圖 4-1:感溫液晶校正曲線

圖 4-2:拍攝角度變化對感溫液晶校正曲線之影響

圖 4-3:占空比(Duty cycle)示意圖

圖 4-4:占空比變化對感溫液晶校正曲線之影響

圖 4-5:不同加熱時間之溫度分布圖

圖 4-6:不同加熱時間之紐賽數分布圖

圖 4-7:溫度增量與時間變化圖

圖 4-8:不同時間步階間隔之紐賽數分布圖

圖 4-9:90 度肋條結構與二次流動情形

圖 4-10:完全發展型入口之紐賽數分布圖

圖 4-11:完全發展型入口在旋轉數為 0.023 之紐賽數分布圖

圖 4-12:完全發展型入口在旋轉數為 0.017 之紐賽數分布圖

圖 4-13:完全發展型入口沿流線方向之紐賽數比

圖 4-14:完全發展型入口在旋轉數為 0.023 時沿流線方向之紐賽 數比

圖 4-15:完全發展型入口在旋轉數為 0.017 時沿流線方向之紐賽 數比

圖 4-16:3 比 2 突縮型入口之紐賽數分布圖

圖 4-17:3 比 2 突縮型入口在旋轉數為 0.023 之紐賽數分布圖

圖 4-18:3 比 2 突縮型入口在旋轉數為 0.017 之紐賽數分布圖

圖 4-19:3 比 2 突縮型入口沿流線方向之紐賽數比

圖 4-20:3 比 2 突縮型入口在旋轉數為 0.023 時沿流線方向之紐賽 數比

圖 4-21:3 比 2 突縮型入口在旋轉數為 0.017 時沿流線方向之紐賽 數比

圖 4-22:3 比 1 突縮型入口之紐賽數分布圖

圖 4-23:3 比 1 突縮型入口在旋轉數為 0.023 之紐賽數分布圖

圖 4-24:3 比 1 突縮型入口在旋轉數為 0.017 之紐賽數分布圖

圖 4-25:3 比 1 突縮型入口沿流線方向之紐賽數比

圖 4-26:3 比 1 突縮型入口在旋轉數為 0.023 時沿流線方向之紐賽 數比

圖 4-27:3 比 1 突縮型入口在旋轉數為 0.017 時沿流線方向之紐賽 數比

圖 4-28:3 比 1 突縮型入口外加圓型導角之紐賽數分布圖

圖 4-29:3 比 1 突縮型入口外加圓型導角在旋轉數為 0.023 之紐 賽數分布圖

圖 4-30:3 比 1 突縮型入口外加圓型導角沿流線方向之紐賽數比

圖 4-31:3 比 1 突縮型入口外加圓型導角在旋轉數為 0.023 時沿流 線方向之紐賽數比

圖 4-32:不同入口條件在雷諾數為 15000 時沿流線方向之紐賽數 比

圖 4-33:不同入口條件在雷諾數為 25000 時沿流線方向之紐賽數 比

圖 4-34:靜止時紐賽數比分布圖

圖 4-35:旋轉時紐賽數比分布圖

圖 4-36:紐賽數比隨旋轉數變化分布圖

圖 4-37:紐賽數比較圖【9】

圖 4-38:突縮型入口紐賽數比比較圖【11】

圖 4-39:熱傳文獻比較-測試通道設計 Park et al. (1992) 【11】

相關文件