Analysis of Flow Boiling Frictional Pressure Drop in Plate Heat Exchangers

Author(s):  
Weiyu Tang ◽  
Tong Lv ◽  
Wei Li ◽  
S. A. Sherif ◽  
Zahid Ayub ◽  
...  

Abstract Plate heat exchangers are widely used in various industries for many years. The corrugated channels on the plates effectively enhance the turbulence of flow boiling and complicate the prediction of pressure drop. This article presents a brief review about effects of various operating and geometrical factors on frictional pressure drop during flow boiling in plate heat exchangers. Experimental data points of frictional pressure drop were collected from the previous literature to develop a general correlation. The database contained 591 data points, covering six different refrigerants, mass flux range 5.5–130 kg/m2/s1, heat flux 0–15 kW/m2, vapor quality 0.04–0.96, saturation temperature −25 to 61 C°, chevron angle 20 deg–65 deg, and hydraulic diameter 1.7–5.35 mm. In this study, several existing correlations were compared with the database, and most of them seem fail to give an acceptable prediction. A new correlation was proposed with multiple regression analysis in terms of two-phase Fanning friction factor. The new method showed a good agreement with the present database and predicted 70.2% and 91.7% of data points within ±30% and ±50% errors, respectively.

Author(s):  
Weiyu Tang ◽  
Tong Lv ◽  
Boren Zheng ◽  
Wei Li

Abstract Plate heat exchangers are widely used in various industries for many years. The corrugated channels on the plates effectively enhance the turbulence of flow boiling and complicate the prediction of pressure drop. This paper presents a brief review about the influence factors of frictional pressure drop during flow boiling in plate heat exchangers. Experimental data points of frictional pressure drop were collected from previous literatures to develop a general correlation. The database contained 454 data points, covering eight refrigerants, mass flux range 5.5–137 kg m-2 s-1, heat flux 0–30 kW m-2, vapor quality 0.07–0.95, saturation pressure 0.11–2.7 MPa, chevron angle 30°–70° and hydraulic diameter 1.7–5.4 mm. In this work, several existing correlations were compared with the database, and all of them seem fail to give an acceptable prediction. A new correlation was proposed with multiple regression analysis in terms of two-phase Fanning friction factor. The new method showed good agreement and predicted 63.2% and 92.9% of data points within ±30% and ±50% errors, respectively.


2016 ◽  
Vol 24 (02) ◽  
pp. 1630004 ◽  
Author(s):  
Byung Hoon Shon ◽  
Seung Won Jeon ◽  
Yongchan Kim ◽  
Yong Tae Kang

In this paper, condensation and evaporation characteristics of low global warming potential (GWP) refrigerants such as R-1234yf and R-1234ze series are reviewed. This review focuses on heat transfer and pressure drop in plate heat exchangers. Mass flux is considered as an important factor while saturation temperature is not for condensation and evaporation process in plate heat exchangers. The dryout phenomenon occurs occasionally and gives greatly harmful impact on evaporation heat transfer. It is found that R-1234yf and R-1234ze(E) give slightly lower heat transfer performance than R-134a for both condensation and evaporation processes. Generally, low GWP refrigerants presented in this review give lower heat transfer coefficient and higher frictional pressure drop than the conventional refrigerants. Nevertheless, R-1234ze(Z) gives superior heat transfer performance than other refrigerants in condensation. R-32 gives remarkable performance in evaporation, but it gives relatively high GWP compared to other low GWP refrigerants.


2014 ◽  
Vol 13 (1) ◽  
pp. 59
Author(s):  
J. D. Oliveira ◽  
J. B. Copetti ◽  
I. C. Dias ◽  
M. H. Macagnan

Evaporators with mini and micro channels are one of the main focuses in the design and development of equipment applied to compact refrigeration systems. The objective of this work is to investigate pressure drop of natural refrigerant, isobutane (R-600a), in the single-phase flow through two small tubes, with 1.0 mm and 2.6 mm of internal diameter. Also, the pressure drop was analyzed in the boiling flow in a 2.6 mm internal diameter tube. The experimental tests included mass velocities of 188, 240, 280 and 370 kg/(m²s), heat fluxes in the range from 0 to 134 kW/m² and boiling flow the saturation temperature of 22 ºC and vapor quality up to 0.8. It was possible to observe the significant influence of the diameter and mass velocity on the total pressure drop and the frictional pressure drop, respectively. The experimental frictional pressure drop in flow boiling in 2.6 mm of internal diameter was compared with four different correlations in literature.


2016 ◽  
Vol 78 (8-4) ◽  
Author(s):  
Agus Sunjarianto Pamitran ◽  
Sentot Novianto ◽  
Normah Mohd-Ghazali ◽  
Nasruddin Nasruddin ◽  
Raldi Koestoer

Two-phase flow boiling pressure drop experiment was conducted to observe its characteristics and to develop a new correlation of void fraction based on the separated model. Investigation is completed on the natural refrigerant R-290 (propane) in a horizontal circular tube with a 7.6 mm inner diameter under experimental conditions of 3.7 to 9.6 °C saturation temperature, 10 to 25 kW/m2 heat flux, and 185 to 445 kg/m2s mass flux. The present experimental data was used to obtain the calculated void fraction which then was compared to the predicted void fraction with 31 existing correlations. A new void fraction correlation for predicting two-phase flow boiling pressure drop, as a function of Reynolds numbers, was proposed. The measured pressure drop was compared to the predicted pressure drop with some existing pressure drop models that use the newly developed void fraction model. The homogeneous model of void fraction showed the best prediction with 2% deviation


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