Research On Heat Dissipation Performance Of Micro-channel Two-phase Heat Sink For IGBT Module

With the continuous development of electronic packaging technology and micromachining technology,the emerging electronic devices and mechanical components represented by IGBT(Insulated Gate Bipolar Transistor)are becoming increasingly miniaturized and integrated,the heat flux of mechanical and electronic devices is increasing,and the Its thermal management problem is getting more and more serious.The flow boiling heat transfer in the microchannel has the advantages of strong heat transfer capacity,extremely high heat transfer coefficient,good temperature uniformity and less working fluid charge.It is an ideal heat dissipation method for IGBT modules.With the advancement of processing technology and the reduction of the processing cost of micro-channels,the micro-channel flow boiling heat exchanger has great development prospects.In this paper,a microchannel flow boiling heat sink for IGBT heat dissipation is designed,and the heat transfer performance of the microchannel is verified by establishing a theoretical model,simulation analysis,design optimization,and building a performance test experimental bench to study its heat transfer performance from both theoretical and experimental aspects.In this way,the application value of microchannel boiling heat transfer in the field of thermal management of new electronic devices is verified,and it provides a reference for the design and popularization of IGBT module microchannel flow boiling heat sink.The main work of this paper is as follows:1)Design a microchannel flow boiling heat sink for IGBT modules.Based on the heat sink,a three-dimensional numerical model is established.The model is used to optimize the size and structure of the microchannels,and investigate the optimal solution for the number of microchannels and the height of the channels under the set conditions.With the help of this three-dimensional model,the temperature distribution and flow pattern evolution of the designed heat sink are simulated and analyzed,and the uniformity of the temperature at different positions of the inlet and outlet,as well as the temperature distribution and flow pattern evolution under different mass flow rates and heat flux are investigated.The law of temperature distribution changing with mass flow and heat flux is summarized.Finally,the performance of the heat sink under the high heat flux of 500 and 1000 k W/m~2 is analyzed and evaluated.2)A performance test bench for the micro-channel flow boiling heat sink of IGBT is built.Taking the two-phase microchannel heat sink as the research object,and use the experimental method to test the micro-channel heat sink with R245fa as the working fluid when the heat flux is 0-200 k W/m~2 and mass flow rate of 100-300kg/(m~2s),and the pressure drop characteristics of the microchannel and the variation law of the boiling heat transfer coefficient with the heat flux are obtained.Finally,the same working conditions are selected to compare the experimental results and numerical simulations.Taking the conditions of mass flow rate of 150 and 250 kg/(m~2s)as an example,which the heat flux range is 0-200k W/m~2.The average superheat and pressure drop are used as comparison parameters to check whether the simulation and experimental data are consistent.3)The experimental study on the heat transfer characteristics of the non-azeotropic mixture of R245fa and R134a in the microchannel flow boiling heat sink is carried out,and the results are compared with the experimental results of R245fa.The pressure drop characteristics at the inlet and outlet of the microchannel and the variation law of the boiling heat transfer coefficient with the heat flux using the non-azeotropic working fluid R245fa/R134a are obtained.It is found that mixing a small amount of high-boiling point components into the low-boiling-point working fluid will inhibit the nucleation and growth of bubbles to a certain extent,thus,the average heat transfer coefficient under the undried condition is slightly lower than that of the pure working fluid,but it also effectively delays drying.Under the condition of lower mass flow and higher heat flux,it is less likely that the heat transfer performance will deteriorate significantly,which can not only meet the heat dissipation requirements of the device,but also greatly increase the reliability of the microchannel flow boiling heat sink,which has great development prospects.