The Study On Structure Design And Heat Dissipation Characteristics Of Microchannel Radiator

With the development of microelectronic technology,high efficiency heat transfer electronic components have been applied in many fields.Too high working temperature of components will greatly reduce the stability of the work and increase the error rate of components.Microchannels have the advantages of high surface area to volume ratio,large convective heat transfer coefficient,less coolant requirement,small size,and light weight,which are most suitable for application in electronic equipment heat dissipation devices.In this paper,the fluid-structure coupling numerical simulation of microchannel heat exchangers with different shapes of concave cavity,convex rib and cob-cavity combined flow channel is carried out,and their flow heat transfer is analyzed and discussed,and the microchannel model with better overall heat transfer effect is obtained.Then the structural parameters of the model with the best overall heat transfer performance are analyzed by changing the arrangement of the concave cavity and convex rib.Finally,the microchannel model with optimal structural parameters is obtained.Firstly,nine kinds of concave cavity,convex rib and rib cavity flow channel structures were designed to compare and analyze with straight microchannel(SMC).The results show that the ribbed flow channel combines the flow heat transfer characteristics of concave cavity and convex rib,and the overall heat transfer performance is significantly improved compared with SMC.The average temperature of the heating surface of the cob channel is about 4K lower than that of the SMC,the pressure drop is between the concave channel and the convex channel,the heat transfer entropy production is 33.4%～36.8% lower than that of the SMC,and the maximum PEC value is 1.38.Secondly,staggered arrangement can make the fluid pressure distribution in the rib-ribed passage more uniform.The maximum pressure drop of the rectangular ribbed staggered microchannels(RRSMC)is more than 300 k Pa,close to half of the rectangular ribbed microchannels(RRMC),with a higher PEC value,and the overall heat transfer performance of the microchannel is significantly improved.Compared with the symmetric arrangement,the staggered arrangement has no significant influence on the pressure,temperature field and PEC value of the fluid in the ribcage passage,and even the heat transfer effect will "deteriorate" at low Reynolds number.The triangular ribbed staggered microchannels(TRSMC)had the highest PEC value(1.46).Finally,the height of the convex ribs has a significant effect on the velocity and pressure distribution in the passage,and the pressure distribution span between different rib heights is very large.Increasing aspect ratio AR can improve the heat transfer effect of the microchannel,but when increasing to a certain extent,the enhancement effect of the heat transfer ability of the microchannel will disappear.When AR=0.3 in TRSMC,the temperature of solid domain is the highest,and the temperature difference between flow and solid domain is the largest.When Re<332,the flow channel with AR=0.7 shows the maximum PEC value;when Re=730,the flow channel with AR=0.9 shows the maximum PEC value of 1.56,which indicates the best comprehensive heat transfer performance.The relative position of the ribs on both sides of the passage has significant influence on the fluid flow state.The pressure distribution on both sides of the convex ribs is seriously asymmetrical and the span is very large.The greater the spacing,the more evenly distributed the pressure.Under the same Reynolds number,when AR=0.9 and Ls= 0.1 mm in TRSMC,the maximum pressure drop,friction coefficient and flow entropy production are obtained,and the minimum is Ls=0.5mm.Among them,the distance Ls has no significant effect on the temperature field distribution and PEC value.The maximum PEC value of Ls=0.5mm is 1.56,showing the best overall heat transfer performance.In summary,the model TRSMC with the best overall heat transfer performance is obtained by numerical simulation of different shapes of concave cavities,convex ribs and different arrangement methods.After the analysis of its structural parameters,the microchannel model with the best structural parameters of aspect ratio AR=0.9 and Ls=0.5is obtained,which provides certain reference value for the field of electronic equipment heat dissipation.