Simulation And Experimental Study On Two-phase Heat Transfer Characteristics In Microchannels

With the continuous development of the emerging technology of MEMS, the feature size of the electronic devices gradually enters the submicron scale. Due to the nonuniform heat flux spatially, the local hot spots on high performance IC chips raise the maximum of junction temperature and reduce the performance and reliability of electronic equipment. Two-phase flow microchannel heatsink can have far more than 100w/cm2 cooling efficiency, and has the advantages of temperature consistency, smaller volume and less dosage of coolant. In order to further deepen the understanding of two-phase flow heat transfer characteristics in microchannels and compensate for the lack of experimental research, it is of great significance to study the two-phase heat transfer characteristics by the numerical simulation method.Based on the analysis of the microscale effect and the basic theory of the flow and heat transfer, around the two-phase flow and heat transfer characteristics in microchannels, this paper mainly completes the following aspects of content:(1) Unlike the method of experiments in the past, this paper considers the numerical simulation method to study the two-phase flow in microchannels and proposes a set of numerical simulation method for flow boiling phenomena in microchannels. The simulation method takes into account the low reynolds number effect in microchannels and the mass transfer in the process of phase transitions, and can be used to simulate the heat transfer and pressure drop characteristics of two-phase flow in microchannels.(2) Based on the numerical simulation method of flow boiling in microchannels, The simulation study on heat transfer characteristics of two-phase flows in microchannels. This paper puts forward a research on the influence of two-phase flow and heat characteristics according to the outcome of numerical simulation on factors such as the inlet velocity, refrigerant working fluid, the geometry parameters of microchannels.(3) In order to compare and analyze the numerical simulation results of flow boiling, a set of microchannel flow boiling experiment system has been designed and processed successfully, to solve the challenges of high power heat source simulation in limited space, the combination scheme and structure sealing of experimental devices. The experiments has been done according to the standard experimental procedures with the microchannel flow boiling experiment system. After the acquisition and analysis of experimental data, the experimental results are in good agreement with the simulation results and the validity of the numerical simulation method is verified.