Two-Phase Heat Transfer and Pressure Drop

2017 ◽  
pp. 329-416
Author(s):  
Randall F. Barron ◽  
Gregory F. Nellis
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Two Phase ◽  
Two Phase Heat Transfer

Experimental Study on Two-Phase Heat Transfer of FC-72 in Microchannels Heat Sink

2009 ◽  
Author(s):  
Xiao Hu ◽  
Guiping Lin ◽  
Hongxing Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Flow Rate ◽  
Mass Flux ◽  
Heat Sink ◽  
Heat Fluxes ◽  
High Mass ◽  
Two Phase ◽  
Two Phase Heat Transfer

A closed-loop two-phase microchannels cooling system using a micro-gear pump was built in this paper. The microchannels heat sink was made of oxygen-free copper, and 14 parallel microchannels with the dimension of 0.8mm(W)×1.5mm(D)×20mm(L) were formed by electric spark drilling followed by linear cutting which separated the channels from each other. The heat transfer performance was evaluated by the fluid temperature, the pressure drop across the micro-channels and the volumetric flow rate. Experiments were performed with refrigerant FC-72 which spanned the following conditions: initial pressure of Pin = 73 kPa, mass velocity of G = 94 – 333 kg/m2s, outlet quality of xe,out = 0 – superheat and heat flux of q″= 25–140 W/cm2. The result showed that, the maximum heat flux achieved 96 W/cm2, as the heating surface temperature was kept below 85 °C and critical heat flux occurred in the condition of low flow rate. Average two-phase heat transfer coefficients increased with the heat flux at low mass flux (G = 94 and 180 kg/m2s) and all heat fluxes, high mass flux (G = 333 kg/m2s) and all heat fluxes, and moderate mass fluxes (G = 224kg/m2s) under low and moderate heat fluxes (q″<110 W/cm2 for G = 224 kg/m2s), which was a feature of nucleate boiling mechanism. Pressure drop through microchannels heat sink was found to be below 4kPa.

Single and Two-Phase Heat Transfer in a Low-Density, 3-Dimensional Microchannel

2005 ◽  
Author(s):  
Mark W. Snyder ◽  
James E. Bryan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Single Phase ◽  
Working Fluid ◽  
Low Density ◽  
Total Resistance ◽  
Two Phase ◽  
Copper Strip ◽  
3 Dimensional ◽  
Two Phase Heat Transfer

A test section was developed to study 3-D microchannel surfaces made from copper strip. Selected results were presented for single and two-phase heat transfer through a low-density, 3-D micro channel using ethanol as the working fluid. Details of the single phase and two-phase heat transfer and fluid flow can be resolved from the experimental data. For 4 selected cases the total resistance was measured to be lower as the flow transitioned to two-phase flow for a given pressure drop. However, as the rate of two-phase heat transfer increased so did the pressure drop fluctuations.

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