Evaluation of Frictional Pressure Drop Correlations During Flow Boiling of Refrigerants in Micro-Fin Tubes

2020 ◽  
Author(s):  
Weiyu Tang ◽  
Wei Li ◽  
Jianxin Zhou
Keyword(s):  
Pressure Drop ◽  
Flow Boiling ◽  
Predictive Ability ◽  
Operating Conditions ◽  
Commercial Application ◽  
Equivalent Diameter ◽  
Specific Work ◽  
Frictional Pressure Drop ◽  
Data Points ◽  
Fin Tubes

Abstract Due to the widely commercial application of micro-fin tube and eco-friendly refrigerants, more general frictional pressure drop correlations is demanded for better prediction, and this study is aimed at compared existing correlations and provide guides for the furthermore improvement. Experimental data points for frictional pressure drop during flow boiling of refrigerants in horizontal micro-fin tubes were extracted from literature and our previous experimental work to evaluate numerous existing frictional pressure drop correlations and specify their applicability to meet the urgent demand of extensive application of eco-friendly refrigerants. The database consists of 949 data points covering eleven refrigerants (R1233zd(Z), R410A, R1234ze(E), R410A, R22, R32, R1234ze(Z), R22, R134a, R245fa and R1234yf included), and the involved operation conditions are as follows: mass velocity 94–888 kg m−2s−1, vapor quality 0.04–0.99, heat flux 3.9–85.2 kW m−2, and equivalent diameter 2.12–11.84mm. Eight existing general frictional pressure drop correlation including Cavallini et al., Kuo and Wang, Wongsangam et al. and Rollman and Spindler correlation were evaluated against the present database. In addition, the Churchill et al. model was employed in several correlation to improve their performance. It was found that none of these correlations was capable of providing a satisfactory prediction for a general operation condition. A detailed predictive ability of these correlation against specific work fluids were given for reference, and their individual parametric-trend predictive ability were also compared under varied operating conditions using several datasets.

A General Frictional Pressure Drop Correlation for Condensation in Microfin Tubes

2017 ◽  
Author(s):  
Zhichuan Sun ◽  
Wei Li
Keyword(s):  
Pressure Drop ◽  
Reduced Pressure ◽  
Error Band ◽  
Frictional Pressure Drop ◽  
New Correlation ◽  
Data Points ◽  
Fin Tubes ◽  
Microfin Tubes ◽  
Experimental Pressure ◽  
Good Agreement

Experimental pressure drop data of condensation from the previous literature were collected to develop a general frictional pressure drop correlation for horizontal micro-fin tubes. The collected database contained 481 data points, covering nine working fluids at average saturated condensing temperatures ranging between 14 and 65°C, with mass velocities ranging from 50 to 800 kg/m2s, and average vapor qualities from 0.11 to 0.91. The hydraulic diameter of micro-fin tubes varied from 2.16 to 5.67 mm and was employed in the calculation of Reynolds number. The Fanning frictional factor was calculated by adopting the Churchill model with the empirically fitted relative roughness. Four existing pressure drop correlations developed for micro-fin tubes were evaluated by the database for condensation in micro-fin tubes. The correlation proposed by Cavallini et al. was the best prediction model among them, predicting 85.6% of the collected data points within the 30% error band. In addition, a new correlation based on the Martnelli parameter Xtt modified by incorporating the reduced pressure was proposed to predict the present database, which showed a good agreement.

A General Correlation for Frictional Pressure Drop of Flow Boiling in Plate Heat Exchangers

2020 ◽  
Author(s):  
Weiyu Tang ◽  
Tong Lv ◽  
Boren Zheng ◽  
Wei Li
Keyword(s):  
Pressure Drop ◽  
Heat Exchangers ◽  
Flow Boiling ◽  
Saturation Pressure ◽  
Influence Factors ◽  
Two Phase ◽  
Plate Heat ◽  
General Correlation ◽  
Frictional Pressure Drop ◽  
Data Points

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.

Analysis of Flow Boiling Frictional Pressure Drop in Plate Heat Exchangers

2020 ◽  
Vol 13 (3) ◽  
Author(s):  
Weiyu Tang ◽  
Tong Lv ◽  
Wei Li ◽  
S. A. Sherif ◽  
Zahid Ayub ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Heat Exchangers ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Two Phase ◽  
Plate Heat ◽  
Frictional Pressure Drop ◽  
Data Points ◽  
Geometrical Factors ◽  
Fanning Friction Factor

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.

Effects of Material on the Heat Transfer of R410A During Condensation and Evaporation

2020 ◽  
Author(s):  
Weiyu Tang ◽  
Boren Zheng ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Predictive Ability ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Acceptable Error ◽  
Error Band ◽  
Data Points ◽  
Inner Diameter ◽  
Dry Out

Abstract An Experimental investigation was conducted to demonstrate the effect of material on the heat transfer characteristics of R410A during evaporation inside two horizontal plain tubes with the same inner diameter of 6mm, and they are made of aluminum and stainless, respectively. The variation of vapor quality for test section were kept at 0.2–0.9, and mass velocities varied from 100 kg m−2s−1 to 400 kg m−2s−1. A series of single-phase and repetitive experiments was conducted to verify the accuracy and reliability of the test rig firstly. Various flow patterns including stratified, slug, and annular flow even dry-out may exist during the flow boiling experiments, while both ΔT-dependent and ΔT-independent flow are included for the test conditions of condensation. The results for evaporation have shown that the plain aluminum tube performs the best for all tested mass velocities. Several different correlations were employed to predict the present data and their predictive ability were compared. The results indicate that the Liu and Winterton can predict all the data points in an acceptable error band, and the slightly worse thermal performance of the stainless-steel tube may be attributed to the relatively low thermal conductivity. For condensation, little difference was found between two tested tubes, which means that the material and roughness may have little effect on the heat transfer performance during condensation.

Flow boiling in horizontal flattened tubes: Part I – Two-phase frictional pressure drop results and model

2009 ◽  
Vol 52 (15-16) ◽  
pp. 3634-3644 ◽  
Author(s):  
Jesús Moreno Quibén ◽  
Lixin Cheng ◽  
Ricardo J. da Silva Lima ◽  
John R. Thome
Keyword(s):  
Pressure Drop ◽  
Flow Boiling ◽  
Two Phase ◽  
Frictional Pressure Drop
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