scholarly journals Evaporation Heat Transfer and Pressure Drop of Refrigerant R134a in a Plate Heat Exchanger

1997 ◽  
Author(s):  
Yi-Yie Yan ◽  
Tsing-Fa Lin ◽  
Bing-Chwen Yang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Vapor Quality ◽  
Plate Heat ◽  
Evaporation Heat ◽  
Evaporation Heat Transfer

The characteristics of evaporation heat transfer and pressure drop for refrigerant R134a flowing in a plate heat exchanger were investigated experimentally in this study. Two vertical counter flow channels were formed in the exchanger by three plates of commercialized geometry with a corrugated sine shape of a chevron angle of 60°. Upflow boiling of refrigerant R134a in one channel receives heat from the hot downflow of water in the other channel. The effects of the heat flux, mass flux, quality and pressure of R134a on the evaporation heat transfer and pressure drop were explored. The preliminary measured data for the water to water single phase convection showed that the heat transfer coefficient in the plate heat exchanger is about 9 times of that in a circular pipe at the same Reynolds number. Even at a very low Reynolds number, the present flow visualization in a plate heat exchanger with the transparent outer plate showed that the flow in the plate heat exchanger remains turbulent. Data for the pressure drop were also examined in detail. It is found that the evaporation heat transfer coefficient of R134a in the plates is quite different from that in circular pipe, particularly in the convective evaporation dominated regime at high vapor quality. Relatively intense boiling on the corrugated surface was seen from the flow visualization. More specifically, the present data showed that both the evaporation heat transfer coefficient and pressure drop increase with the vapor quality. At a higher mass flux the pressure drop is higher for the entire range of the vapor quality but the heat transfer is only better at high quality. Raising the imposed wall heat flux was found to slightly improve the heat transfer. While at a higher system pressure the heat transfer and pressure drop are both slightly lower.

Evaporation Heat Transfer and Pressure Drop of Refrigerant R-134a in a Plate Heat Exchanger

1999 ◽  
Vol 121 (1) ◽  
pp. 118-127 ◽  
Author(s):  
Y.-Y. Yan ◽  
T.-F. Lin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Plate Heat Exchanger ◽  
Vapor Quality ◽  
Plate Heat ◽  
Evaporation Heat ◽  
Evaporation Heat Transfer ◽  
R 134A

The evaporation heat transfer coefficient and pressure drop for refrigerant R-134a flowing in a plate heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated sine shape of a chevron angle of 60 deg. Upflow boiling of refrigerant R-134a in one channel receives heat from the hot downflow of water in the other channel. The effects of the mean vapor quality, mass flux, heat flux, and pressure of R-134a on the evaporation heat transfer and pressure drop were explored. The quality change of R-134a between the inlet and outlet of the refrigerant channel ranges from 0.09 to 0.18. Even at a very low Reynolds number, the present flow visualization of evaporation in a plate heat exchanger with the transparent outer plate showed that the flow in the plate heat exchanger remains turbulent. It is found that the evaporation heat transfer coefficient of R-134a in the plates is much higher than that in circular pipes and shows a very different variation with the vapor quality from that in circular pipes, particularly in the convective evaporation dominated regime at high vapor quality. Relatively intense evaporation on the corrugated surface was seen from the flow visualization. Moreover, the present data showed that both the evaporation heat transfer coefficient and pressure drop increase with the vapor quality. At a higher mass flux the pressure drop is higher for the entire range of the vapor quality but the evaporation heat transfer is clearly better only at the high quality. Raising the imposed wall heat flux was found to slightly improve the heat transfer, while at a higher refrigerant pressure, both the heat transfer and pressure drop are slightly lower. Based on the present data, empirical correlations for the evaporation heat transfer coefficient and friction factor were proposed.

scholarly journals Local heat transfer coefficients during the evaporation of 1,1,1,2-tetrafluoroethane (R-134a) in a plate heat exchanger

2009 ◽  
Vol 74 (4) ◽  
pp. 427-440 ◽  
Author(s):  
Emila Zivkovic ◽  
Stephan Kabelac ◽  
Slobodan Serbanovic
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Vapor Quality ◽  
Plate Heat ◽  
Evaporation Heat ◽  
R 134A ◽  
The Heat Transfer Coefficient

The evaporation heat transfer coefficient of the refrigerant R-134a in a vertical plate heat exchanger was investigated experimentally. The area of the plate was divided into several segments along the vertical axis. For each of the segments, the local value of the heat transfer coefficient was calculated and presented as a function of the mean vapor quality in the segment. Owing to the thermocouples installed along the plate surface, it was possible to determine the temperature distribution and vapor quality profile inside the plate. The influences of the mass flux, heat flux, pressure of system and the flow configuration on the heat transfer coefficient were also taken into account and a comparison with literature data was performed.

Evaporation Heat Transfer and Pressure Drop of HFC-134a Inside a Plate Heat Exchanger

2001 ◽  
Author(s):  
B. Ouazia
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Plate Heat Exchanger ◽  
Vapor Quality ◽  
Transfer Coefficients ◽  
Plate Heat ◽  
Evaporation Heat ◽  
Evaporation Heat Transfer

Abstract An experimental investigation was carried out to provide data on heat transfer coefficient and pressure drop for upward flow of refrigerant 134a in a typical plate heat exchanger. Upflow boiling of R-134a in one channel receives heat from the hot downflow of water in the two adjacent channels. Measurements were conducted on three sets of plates with chevron angles of 0°, 30°, and 60°, and the effects of mean vapor quality, mass flux, and heat flux on the evaporation heat transfer and pressure drop were explored. It was found that the channels with small chevron angle have higher heat transfer than channels with large chevron angle, for both subcooling and vapor quality inlet conditions. It was clear that the heat transfer coefficients were not sensitive to the heat flux but were dependent on the flow conditions (mass velocity and vapour quality). Based on the experimental data, empirical correlations for the evaporation heat transfer enhancement factor and the two-phase pressure drop multipliers were proposed.

Heat transfer coefficient and pressure drop during refrigerant R-134a condensation in a plate heat exchanger

2008 ◽  
Vol 62 (1) ◽  
Author(s):  
Emila Djordjević ◽  
Stephan Kabelac ◽  
Slobodan Šerbanović
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Vapor Quality ◽  
Plate Heat ◽  
R 134A ◽  
The Heat Transfer Coefficient

AbstractThe condensation heat transfer coefficient and the two-phase pressure drop of refrigerant R-134a in a vertical plate heat exchanger were investigated experimentally. The area of the plate was divided into several segments along the vertical axis. For each of the segments, local values of the heat transfer coefficient and frictional pressure drop were calculated and presented as a function of the mean vapor quality in the segment. Owing to the thermocouples installed along the plate surface, it was possible to determine the temperature distribution and vapor quality profile inside the plate. The influences of the mass flux and the heat flux on the heat transfer coefficient and the pressure drop were also taken into account and a comparison with previously published experimental data and literature correlations was carried out.

scholarly journals Studies on the Heat Transfer Coefficient and Pressure Drop of Several Kinds of Plate Heat Exchanger

1968 ◽  
Vol 32 (11) ◽  
pp. 1127-1132,a1 ◽  
Author(s):  
Katsuto Okada ◽  
Minobu Ono ◽  
Toshio Tomimum ◽  
Hirotaka Konno ◽  
Shigemori Ohtani
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
The Heat Transfer Coefficient

scholarly journals Mean heat transfer coefficients during the evaporation of 1,1,1,2-tetrafluoroethane (R-134a) in a plate heat exchanger

2007 ◽  
Vol 72 (8-9) ◽  
pp. 833-846 ◽  
Author(s):  
Emila Djordjevic ◽  
Stephan Kabelac ◽  
Slobodan Serbanovic
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Transfer Coefficients ◽  
Plate Heat ◽  
Evaporation Heat ◽  
The Mean ◽  
R 134A

In this study the transfer coefficient of evaporation heat of the refrigerant 1,1,1,2-tetrafluoroethane (R-134a) in a vertical plate heat exchanger was experimentally investigated. The results are presented as the dependancy of the mean heat transfer coefficient for the whole heat exchanger on the mean vapor quality. The influences of mass flux, heat flux and flow configuration on the heat transfer coefficient were also taken into account and a comparison with previously published experimental data and literature correlations was made. .

Heat Transfer and Pressure Drop Analysis of Chilled Water and Ice Slurry in a Plate Heat Exchanger

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Rajinder Singh ◽  
Surendra Singh Kachhwaha
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Ice Slurry ◽  
Plate Heat ◽  
Overall Heat Transfer Coefficient ◽  
Chilled Water

The present study reports the experimental validation of thermohydraulic modeling for prediction of pressure drop and heat transfer coefficient. Experiments were performed on plate heat exchanger using chilled water and ice slurry as secondary fluids. Propylene glycol (PG) and mono-ethylene glycol (MEG) are used as depressants (10%, 20%, 30%, and 40% concentration) in ice slurry formation. The results show that thermohydraulic modeling predicts the pressure drop and overall heat transfer coefficient for water to water and water to ice slurry within the discrepancy limit of ±15%.

Evaporation Heat Transfer and Pressure Drop of Refrigerant R-410A Flow in a Vertical Plate Heat Exchanger

2003 ◽  
Vol 125 (5) ◽  
pp. 852-857 ◽  
Author(s):  
Y. Y. Hsieh ◽  
T. F. Lin
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchanger ◽  
Vertical Plate ◽  
Plate Heat Exchanger ◽  
Vapor Quality ◽  
Plate Heat ◽  
Evaporation Heat ◽  
The Mean ◽  
Evaporation Heat Transfer

Experiments are carried out here to measure the evaporation heat transfer coefficient hr and associated frictional pressure drop ΔPf in a vertical plate heat exchanger for refrigerant R-410A. The heat exchanger consists of two vertical counterflow channels which are formed by three plates whose surface corrugations have a sine shape and a chevron angle of 60 deg. Upflow boiling of refrigerant R-410A receives heat from the hot downflow of water. In the experiments, the mean vapor quality in the refrigerant channel is varied from 0.10 to 0.80, the mass flux from 50 to 100 kg/m2s, and the imposed heat flux from 10 to 20 kW/m2 for the system pressure fixed at 1.08 and 1.25 MPa. The measured data indicate that both hr and ΔPr increase with the refrigerant mass flux except at low vapor quality. In addition, raising the imposed heat flux is found to significantly improve hr for the entire range of the mean vapor quality. However, the corresponding friction factor ftp is insensitive to the imposed heat flux and refrigerant pressure. Based on the present data, empirical correlations are provided for hr and ftp, for R-410A in the plate heat exchanger.

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