Heat transfer of R134 a 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 tran...Heat transfer of R134 a 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 in the range of effective heat fluxes from 0 to 138.4 W/cm2 with mass flow velocities from 2.12 to 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/(cm^(2)·K)with the critical heat flux of 88.4 W/cm2.展开更多
Experiments were conducted to investigate the heat transfer characteristics and cooling performance of subcooled liquid,water,flowing through rectangular cross-section microchanneled structures machined on a stainless...Experiments were conducted to investigate the heat transfer characteristics and cooling performance of subcooled liquid,water,flowing through rectangular cross-section microchanneled structures machined on a stainless steel plate.Heat transfer or flow mode stransition was observed when the heating rate or wall temperature was increased.This transition was found to be suggestively induced by the variation in liquid thermophysical properties due to the significant rise of liquid temperature in the microstructures.The influence of such parameters as liquid velocity,subcooling,property variation,and microchannel geometric configuration on the heat transfer behavior,cooling performance and the heat transfer and liquid flow mode transition were also investigated.The experiments indicated that both single-phase forced convection and flow boiling characteristics were quite different from those in normal-sized tubes and the heat transfer was obviously intensified.展开更多
基金financially supported by the National Nature Science Foundation of China(Grant No.U1504524,No.51706061,No.51876055,and No.51806060)。
文摘Heat transfer of R134 a 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 in the range of effective heat fluxes from 0 to 138.4 W/cm2 with mass flow velocities from 2.12 to 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/(cm^(2)·K)with the critical heat flux of 88.4 W/cm2.
基金This project is finmanced by the National Natural Science Foundation of China.
文摘Experiments were conducted to investigate the heat transfer characteristics and cooling performance of subcooled liquid,water,flowing through rectangular cross-section microchanneled structures machined on a stainless steel plate.Heat transfer or flow mode stransition was observed when the heating rate or wall temperature was increased.This transition was found to be suggestively induced by the variation in liquid thermophysical properties due to the significant rise of liquid temperature in the microstructures.The influence of such parameters as liquid velocity,subcooling,property variation,and microchannel geometric configuration on the heat transfer behavior,cooling performance and the heat transfer and liquid flow mode transition were also investigated.The experiments indicated that both single-phase forced convection and flow boiling characteristics were quite different from those in normal-sized tubes and the heat transfer was obviously intensified.
