6-3 Concluding Remarks

Experimental measurement has been carried out here to investigate the frictional pressure drop of R-407C evaporation in the small circular tubes. Results for the frictional pressure drop have been examined in detail. The results reveal that the

almost linear and the increase is larger for a higher refrigerant mass flux. Moreover, a larger R-407C frictional pressure drop results for a higher refrigerant mass flux. But an opposite trend is noted for a rise in the refrigerant saturated temperature.

Furthermore, the imposed heat flux exhibits a negligible effect on the frictional pressure drop. Finally, an empirical correlation is proposed to correlate the present data for the frictional pressure drop.

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, q= 5 kW/m²

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, q= 5 kW/m²

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, q= 5 kW/m²

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, q= 5 kW/m²

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, q= 5 kW/m²

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, q= 5 kW/m²

G=200 kg/m²s G=300 kg/m²s G=400 kg/m²s

Variations of frictional pressure drop with inlet vapor quality at q=5 kW/m² for various mass fluxes for (a) Tsat= 5℃, (b) Tsat= 10℃ and (c) Tsat=15℃.

Fig. 6.1

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=5 kW/m²s, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=5 kW/m²s, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=5 kW/m²s, G=200 kg/m²s

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=5 kW/m²s, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=5 kW/m²s, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=5 kW/m²s, G=200 kg/m²s

T_sat = 5^oC T_sat =10^oC T_sat =15^oC

Variations of frictional pressure drop with inlet vapor quality at q=5 kW/m² for various saturated temperatures for (a) G= 200 kg/m²s, (b) G= 300 kg/m²s and (c) G= 400 kg/m²s.

Fig. 6.2

P P

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, q=10 kW/m²

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, q=10 kW/m²

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, q=10 kW/m²

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, q=10 kW/m²

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, q=10 kW/m²

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, q=10 kW/m²

G=200 kg/m²s G=300 kg/m²s G=400 kg/m²s

Variations of frictional pressure drop with inlet vapor quality at q=10 kW/m² for various mass fluxes for (a) T_sat= 5℃, (b) T_sat= 10℃ and (c) T_sat=15℃.

Fig. 6.3

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=10 kW/m²s, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=10 kW/m²s, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=10 kW/m²s, G=200 kg/m²s

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=10 kW/m²s, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=10 kW/m²s, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=10 kW/m²s, G=200 kg/m²s

Tsat = 5^oC Tsat =10^oC Tsat =15^oC

Variations of frictional pressure drop with inlet vapor quality at q=10 kW/m² for various saturated temperatures for (a) G= 200 kg/m²s, (b) G= 300 kg/m²s and (c) G= 400 kg/m²s.

Fig. 6.4

P P

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, q=15 kW/m²

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, q=15 kW/m²

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, q=15 kW/m²

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, q=15 kW/m²

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, q=15 kW/m²

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, q=15 kW/m²

G=200 kg/m²s G=300 kg/m²s G=400 kg/m²s

Variations of frictional pressure drop with inlet vapor quality at q=15 kW/m² for various mass fluxes for (a) T_sat= 5℃, (b) T_sat= 10℃ and (c) T_sat=15℃.

Fig. 6.5

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=15 kW/m²s, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=15 kW/m²s, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=15 kW/m²s, G=200 kg/m²s

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=15 kW/m²s, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=15 kW/m²s, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at q=15 kW/m²s, G=200 kg/m²s

Tsat = 5^oC Tsat =10^oC Tsat =15^oC

Variations of frictional pressure drop with inlet vapor quality at q=15 kW/m² for various saturated temperatures for (a) G= 200 kg/m²s, (b) G= 300 kg/m²s and (c) G= 400 kg/m²s.

Fig. 6.6

P P

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, G=200 kg/m²s

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =5^oC, G=200 kg/m²s

q= 5 kW/m² q=10 kW/m² q=15 kW/m²

Variations of frictional pressure drop with inlet vapor quality at T_sat= 5℃ for various heat fluxes for (a) G= 200 kg/m²s, (b) G= 300 kg/m²s and (c) G= 400 kg/m²s.

Fig. 6.7

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, G=200 kg/m²s

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =10^oC, G=200 kg/m²s

q= 5 kW/m² q=10 kW/m² q=15 kW/m²

Variations of frictional pressure drop with inlet vapor quality at T_sat=10℃ for various heat fluxes for (a) G= 200 kg/m²s, (b) G= 300 kg/m²s and (c) G= 400 kg/m²s.

Fig. 6.8

P P

0.0 0.2 0.4 0.6 0.8 1.0

(b) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, G=300 kg/m²s

(c) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, G=400 kg/m²s

(a) Evaporation Frictional Pressure Drop of R-407C in Small tubes at Tsat =15^oC, G=200 kg/m²s

q= 5 kW/m² q=10 kW/m² q=15 kW/m²

.0

Variations of frictional pressure drop with inlet vapor quality at T_sat=15℃ for various heat fluxes for (a) G= 200 kg/m²s, (b) G= 300 kg/m²s and (c) G= 400 kg/m²s.

Fig. 6.9

0.0 0.2 0.4 0.6 0.8 1.0

x

_in

0 2000 4000 6000 8000

P

f

(Pa )

Comparison of the Present Data with Yan & Lin (1998) Tsat =15^oC, G=200 kg/m²s, q= 5 kW/m²(Present data) Tsat =15^oC, G=200 kg/m²s, q= 5 kW/m²(Yan & Lin, 1998)

Comparison of the R-407C frictional pressure drop for small tubes with those for R-134a in the same small tubes from Yan and Lin (1998).

Fig. 6.10

0 5000 10000 15000 20000

P

f (Present data)

0 5000 10000 15000 20000

P

f (Correlation data)

R-407C Frictional Pressure Drop Present data

Tran et al. (2000)

-30%

+30%

Comparison of the measured data for frictional pressure drop in the evaporation of R-407C with the proposed correlation from Tran et al. (2000).

Fig. 6.11

0.00 0.02 0.04 0.06 0.08 0.10 0.12 f

tp (Experimental Data)

0.00 0.02 0.04 0.06 0.08 0.10 0.12

f

tp (Proposed correlation)

R-407C Evaporation Flow Boiling Present data

Proposed correlation

-25%

+25%

Comparison of the proposed correlations with the present data for the friction factor.

Fig. 6.12

CHAPTER 7

SATURATED FLOW BOILING OF R-407C and R-410A IN a

在文檔中 小管中新冷媒流動沸騰熱傳特性和主要機制研究(III) (頁 123-137)