Experimental Investigation of Heat Transfer in Microchannel with Inlet Cavitation Structure

Heat transfer of R134a through the microchannel with an inlet reentrant cavitation structure was investigated for high flux thermal management of electronic devices. The cavitating flow patterns, pressure, and heat transfer characteristics were studied at the range of effective heat fluxes from 0–138.4 W/cm2 with mass flow velocities from 2.12–5.23 m/s. A stable and ideal starting point of two phase flow and heat transfer was commendably provided by the inlet cavitation orifice. There existed an axis deviation liquid jet after the micro-orifice. The refrigeration vapor was generated from the cavitation structure but liquidized at the downstream of the channel. The wall temperature along flow orientation presented an opposite trend under the test states with or without heat input. The cavitation structure can significantly suppress the flow oscillation in microchannels and the outlet pressure fluctuation reduced about 72% compared with the fluctuation at the entrance. The heat transfer coefficient had been distinctly impacted by heat flux at lower heat input and then maintained the value nearly constant of 11.0 W/(cm2·K) with the critical heat flux of 88.4 W/cm2.