The investigation on flow boiling heat transfer of R134a in micro-channels

The present study reports an experimental evaluation of heat transfer characteristic of R134a flow boiling in micro-channel heat sink. The heat sink is composed of 30 parallel rectangular micro-channels with cross-sectional dimensions of 500μm width and depth, as well as total length 30mm. Experiments were conducted with heat flux up to 80.212 W/cm2, mass velocity ranging from 373.33 to 1244.44 kg/m2s, vapor quality ranging from 0.06 to 0.9. The wall temperature of heat sink heated could be controlled at around 50°C. Heat transfer coefficient could be up to 180 kW/m2K. Two dominating flow patterns were observed by analyzing boiling curves. The heat transfer characteristics of nucleate boiling and convective boiling were presented in the study. Revised correlations of R134a flow boiling in micro-channel heat sink were carried out with the consideration of nucleate boiling and convective boiling mechanisms.