The Design Of Micro-channel Radiator And Numerical Investigation Of The Flow And Heat Transfer Characteristics

With the rapid development of electronic technology,electronic equipment tends to be miniaturized,integrated,and intelligent,which has led to a sharp increase in the power density of electronic chips.In order to meet the needs of the development of the electronics industry,a miniature heat exchanger with compact structure,light weight and high efficiency is designed.An important factor affecting the life of the heat exchanger is the temperature uniformity.Thus,based on the heat dissipation requirements of an electronic chip,this paper designs the geometric structure of the heat exchanger.After verifying that the simulation results are accurate and reliable,the effects of different inlet flow Re numbers on the flow and heat transfer in the radiator are analyzed,and the paper proposes the optimization scheme of installing a baffle in the radiator,and analyzing the impact of the baffle layout on each channel of the radiator and the total thermal resistance and pressure drop of the radiator.The specific work results are as follows:Firstly,based on the geometric constraints on the length and width of the electronic chip being 52.5 mm × 45 mm and the heat power requirement of 120W,the rectangular cross-sectional aspect ratio was selected to be 2,and the number of micro-channel heat sinks was determined to be 26,and meanwhile the channel spacing is 0.5 mm.Taking into account the characteristics of the inlet fluid distribution and outlet confluence in the radiator,the geometric parameters of the inlet,outlet,and upper and lower chambers are determined to set up the overall geometric structure of the micro-channel radiator,which are to meet the chip the heat dissipation performance requirements.Secondly,based on the range of the inlet flow Re that is from 248 to 621,after verifying the accurate and reliable simulation results of the laminar flow model,the flow and heat transfer characteristics of the micro-channel radiator under different Re were studied by using the FLUENT solver.The flow rate,average temperature of the heat wall,heat transfer and pressure drop distribution of each channel are obtained.The results show that the heat dissipation of each channel is between 4.2W and 4.6W,and the flow rate of the channel near the symmetry plane of the radiator is greater than the channel on both sides.The change law of channel pressure drop and Nu are the same as the flow change trend;and as the inlet flow Re increases,the flow distribution deviation of each channel increases from 0.1 to 0.18;the pressure drop of the radiator rises from 271 Pa to 890 Pa,and the total thermal resistance decreased from 0.14 to 0.095.Finally,it is proposed that when the baffle is arranged in the radiator,based on the inlet flow Re is 621,the effects of the flow and heat transfer in the radiator under five factors such as different baffle spacing,arrangement number,baffle arrangement height,baffle channel length and inlet chamfer are analyzed.The calculation results show that the narrowing of the baffle spacing is conducive to the uniform distribution of fluid in the radiator,which reduces the average wall temperature and the total thermal resistance of the radiator,but meanwhile increases the pressure drop of the radiator.With the increase of the number of baffles,the pressure drop of the radiator is increasing,and the standard deviation of the channel fluid distribution is first rising and then falling.The thermal resistance of the radiator is the smallest when the baffle number is 15.With the increase of the height of the baffle,the change law of the standard deviation of the flow distribution in the radiator is different with the trend of thermal resistance and pressure drop.The uniformity of flow distribution is best when the baffle height is 6 mm,and the thermal resistance and pressure drop are optimized when the baffle height is 4 mm,and the average temperature of the wall channels is also lower,which is showed good flow and heat dissipation characteristics.With the increase of the length of the baffle,the standard deviation and pressure drop of the channel flow distribution in the radiator show an increasing trend,and the heat resistance of the radiator is the smallest when the baffle length is 2 mm.The thermal resistance and standard deviation of flow distribution are rising when the inlet chamfer is increased,while the pressure drop is the smallest at 6°.