Structure Optimization And Flow Heat Transfer Characteristics Of Micro Cooling System

With the rapid development of science and technology,reduce the size of the electronic equipment,and increasing integration is increasing,this led to the unit size of heat flow density under a sharp increase,and heat dissipation of the microelectronic system is becoming more and more prominent,design research and higher heat transfer efficiency and structure more reasonable microchannel heat exchanger in order to improve the microscale heat transfer performance is of great significance.In this paper,the flat heat transfer microchannel is used as the basic model,the variable physical parameters are set,and the deionized water is used as the fluid medium.Through numerical simulation,the flow heat transfer characteristics of the heat transfer microchannel with different cross-section shapes are studied,so as to provide a reference for the structural design of the heat transfer microchannel.In this paper,three different cross-section shapes of microchannels are proposed:axisymmetric T-shape,axisymmetric cruciform and centrosymmetric cruciform.The heat transfer area and equivalent diameter of the three different cross-section shapes are all the same,only the height of the center of gravity is different.It is found that the lower the height of the center of gravity,the better the comprehensive performance,and the T-shaped microchannel heat transfer model has the best comprehensive performance.Then take the T-shaped cross-section shape as the basic shape,keep the length a₁ and a₂of the bottom and bottom unchanged,and increase the height h₁ and h₂ of the two rectangles proportionally.First,the heat transfer performance of the flow with the same heat transfer area and different equivalent diameters caused by the change of the ratio of h₁ to h₂ is studied.The following conclusions are drawn:under the same heat transfer area,with the increase of the height ratio,that is,with the increase of the equivalent diameter,the heat transfer performance of the flow increases first and then weakens.It is found that the heat transfer performance of the model is the best when the height ratio is equal to 1/2（that is,the equivalent diameter is equal to 0.1667mm）.Then,when the equivalent diameter is the same（the equivalent diameter is selected to be 0.1667mm）,the heat transfer performance of the flow is studied while the heat transfer area is different due to the change of h₁ and h₂ ratio.The following conclusions are drawn:under the same equivalent diameter,with the increase of height ratio,i.e.,with the decrease of heat transfer area,the heat transfer performance of the flow is firstly weakened and then enhanced.It is found that the heat transfer performance of the model is the best when the height ratio is equal to 1/3（i.e.,the maximum heat transfer area is equal to 4.0374mm²）.In order to further improve the performance of the heat exchanger,this paper also proposes a double-layer arrangement of microchannels.In the above results,the T-shaped cross-section micro-channel parameters with the same equivalent diameter and the same height ratio of 1/3 were selected for double row arrangement to study the flow heat transfer performance under different transverse spacing between the upper and lower rows.It is found that with the increase of the distance,the comprehensive evaluation factor of the microchannel model is unchanged at first and then gradually decreases,and the decline is more and more serious.When the transverse spacing is equal to 0mm,the corresponding microchannel model has the best comprehensive performance and the best flow heat transfer performance.