Generalized Two-Phase Pressure Drop and Heat Transfer Correlations in Evaporative Micro/Minichannels

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Hee Joon Lee ◽  
Dong Yao Liu ◽  
Y. Alyousef ◽  
Shi-chune Yao
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Bond Number ◽  
Two Phase ◽  
Channel Size ◽  
Working Fluids ◽  
Operational Conditions ◽  
Wide Range ◽  
Existing Data ◽  
Phase Pressure

Existing databases and correlations in literature on the microchannel pressure drop and heat transfer are reviewed in this paper. From this review, it is found that none of the existing correlations can cover the wide ranges of working fluids, operational conditions, and different microchannel dimensions. In addition, the importance of the Bond number, which relates the nominal bubble dimension or capillary parameter with the channel size, is revealed in this paper. Using the Bond number, improved correlations of pressure drop and heat transfer are established, which predict the existing data well over a wide range of channel sizes, fluids, and operational conditions.

Generalized Two-Phase Pressure Drop and Heat Transfer Correlations in Evaporative Micro/Mini-Channels

2007 ◽  
Author(s):  
Hee Joon Lee ◽  
Dongyao Liu ◽  
Shi-Chune Yao ◽  
Y. Alyousef
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Bond Number ◽  
Micro Channel ◽  
Two Phase ◽  
Working Fluids ◽  
Operational Conditions ◽  
Micro Channels ◽  
Wide Range ◽  
Existing Data

Existing data base and correlations in literature on the micro-channel pressure drop and heat transfer are reviewed. None of the existing correlations can cover the wide range of working fluids, operational conditions and different microchannel dimensions. The importance of the Bond number, which relates the nominal bubble dimension or capillary parameter with the channel size, is revealed. Using the Bond number, improved correlations of pressure drop and heat transfer are established. The new correlations predict the existing data well over wide ranges of working fluids, operational conditions and dimensions of micro-channels. Furthermore, Bond number could be used as a criterion to classify a flow path as a micro-channel or conventional macro-channel.

Two-Phase Pressure Drop and Boiling Heat Transfer in a Single Horizontal Microchannel

2006 ◽  
Author(s):  
Cheol Huh ◽  
Moo Hwan Kim
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Local Flow ◽  
Heat Transfer Coefficients ◽  
Phase Pressure

With a single microchannel and a series of microheaters made with MEMS technique, two-phase pressure drop and local flow boiling heat transfer were investigated using deionized water in a single horizontal rectangular microchannel. The test microchannel has a hydraulic diameter of 100 μm and length of 40 mm. A real time observation of the flow patterns with simultaneous measurement are made possible. Tests are performed for mass fluxes of 90, 169, and 267 kg/m2s and heat fluxes of from 100 to 600 kW/m2. The experimental local flow boiling heat transfer coefficients and two-phase frictional pressure gradient are evaluated and the effects of heat flux, mass flux, and vapor qualities on flow boiling are studied. Both the evaluated experimental data are compared with existing correlations. The experimental heat transfer coefficients are nearly independent on mass flux and the vapor quality. Most of all correlations do not provide reliable heat transfer coefficients predictions with vapor quality and prediction accuracy. As for two-phase pressure drop, the measured pressure drop increases with the mass flux and heat flux. Most of all existing correlations of two-phase frictional pressure gradient do not predict the experimental data except some limited conditions.

Experimental Adiabatic Two-Phase Pressure Drops of R134a, R236fa and R245fa in Small Horizontal Circular Channels

2011 ◽  
Author(s):  
Chin L. Ong ◽  
John R. Thome
Keyword(s):  
Pressure Drop ◽  
Flow Boiling ◽  
Homogeneous Model ◽  
Prediction Methods ◽  
Two Phase ◽  
Pressure Drops ◽  
Wide Range ◽  
Small Channels ◽  
Experimental Pressure ◽  
Phase Pressure

Experimental adiabatic two-phase pressure drops data for refrigerants R134a, R236fa and R245fa during flow boiling in small channels with internal diameters of 1.03, 2.20 and 3.04 mm are presented. The main purpose was to investigate the effects of channel confinement on adiabatic two-phase pressure drops. Thus, the two-phase pressure drop trends were systematically investigated over a wide range of test conditions for all three refrigerants and channel sizes. Statistical comparisons have also been made by comparing the experimental pressure drop data database with various macroscale and microscale prediction methods from the literature. The comparison showed relatively moderate accuracy for three prediction methods developed for macroscale flows, i.e. Baroczy and Chisholm, Friedel and the homogeneous model with the Cicchitti et al. viscosity relation. As for microscale prediction methods, the Cioncolini et al. annular flow model worked best with 68.5% of the data within ± 30%, followed by the Sun and Mishima and the Zhang et al. methods. Combining this database with the LTCM lab’s earlier database for 0.509 and 0.790 mm channels, there appears to be no evidence of a macro-to-microscale transition, at least with respect to two-phase pressure drops.

Two-phase pressure drop and flow boiling heat transfer in an enhanced dimpled tube with a solid round rod insert

2017 ◽  
Vol 75 ◽  
pp. 1-13 ◽  
Author(s):  
Zahid H. Ayub ◽  
Adnan H. Ayub ◽  
Gherhardt Ribatski ◽  
Tiago Augusto Moreira ◽  
Tariq S. Khan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Two Phase ◽  
Flow Boiling Heat Transfer ◽  
Phase Pressure

scholarly journals Two-Phase Pressure Drop Calculations in Small Diameter Inclined Tubes

2012 ◽  
Vol 1 (3) ◽  
pp. 168 ◽  
Author(s):  
Arun Autee ◽  
S.Srinivasa Rao ◽  
Ravikumar Puli ◽  
Ramakant Shrivastava
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Water Pressure ◽  
Small Diameter ◽  
Bond Number ◽  
Two Phase ◽  
Circular Tubes ◽  
Frictional Pressure Drop ◽  
Micro Channels ◽  
Phase Pressure

Effect of inclination on two-phase frictional pressure drop was investigated in small diameter circular tubes with inner diameters of 4.0, 6.0, 8.0 and 10.0 mm using air and water. Pressure drop was measured and compared with various existing models commonly used for macro and micro channels such as homogeneous, Lockhart-Martinelli, Chisholm, Friedel, Mishma Hibiki, and Zang Mishma. It was found that existing correlations are inadequate in predicting pressure drop for small diameter inclined tubes. The void fraction is calculated using a general void fraction correlation in two-phase flow for various pipe orientations. Based on analysis of present experimental frictional pressure drop data, a correlation is proposed for predicting Chisholm parameter C in small diameter inclined tubes. There was a significant ordering of pressure drop data with respect to Reynolds number, Webber number and Bond number for each diameter.

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