Study On Enhanced Heat Transfer Performance Of A Branch And Combined-branch Microchannel Heat Sink

With the rapid development of high-power equipment such as aerospace technology and computers,the degree of miniaturization and integration of electronic equipment is increasing,and the heat flux density during operation is also increasing.This leads to a sharp rise in the temperature of electronic equipment,affecting the working performance and service life of the equipment.Combining the advantages of traditional rectangular microchannels and fractal microchannels,a branch and combined-branch microchannel heat sink is designed in this paper.By numerical simulation,the flow and heat transfer performance in microchannels were studied when branch tilt angle,branch hydraulic diameter,the distance between branch and combined-branch,number of micro groups,arrangement of micro groups,and on-off width of micro groups varied.And based on the second law of thermodynamics,the thermal performance of microchannels was analyzed to determine the optimal structure of microchannels.From the perspective of changing the parameters of the branch structure,as the branch tilt angle increases,the Nusselt number and Performance Evaluation Criterion(PEC)of the microchannels continue to increase;when the branch hydraulic diameter increases,the Nusselt number and PEC first increase and then decrease;when the distance between branch and combined-branch increases,the Nusselt number and PEC first increase and then decrease.When the branch structure parameter are the branch tilt angle is 90°,the highest temperature of the microchannel is the lowest at 318.9 K,a decrease of 11.9 K,an increase of 85.7% in Nusselt number,and the PEC is the best at 1.44.From the perspective of changing the parameters of the micro groups structure,when the number of micro groups increases,the Nusselt number of microchannels first increases and then decrease,and the PEC continuously increase;when the arrangement of the micro groups changes,the Nusselt number and PEC of the microchannels are both the largest when the arrangement of the microchannels is gradual and gradually dense,when the on-off width of the microchannel increases,the Nusselt number and PEC first increase and then decrease,but their performance decreases compared to microchannels without on-off structures.When the arrangement of micro group is gradual and gradually dense,the highest temperature of the microchannel is the lowest at 318.2 K,the Nusselt number is biggest at37.7,and the PEC is the best at 1.44.From an energy perspective,with the increase of the branch tilt angle,the total entropy production and the fire dissipation of the microchannel are continuously decreasing;with the increase of branch hydraulic diameter and the distance between branch and combinedbranch,the total entropy production and fire accumulation dissipation first decrease and then increase;when the branch structure parameter are the branch tilt angle is 90°,the total entropy production has been reduced by 40%,and the fire dissipation has been reduced by28.7%,the thermal performance is the best.With the increase of the number of micro groups,the total entropy production and fire product dissipation first decrease and then increase;the total entropy production and fire accumulation dissipation are minimum when the micro groups arrangement is gradual and gradually dense;with the increase of the micro on-off width,the total entropy production and the fire product dissipation first decrease and then increase,but both are higher than those of the non on-off structure,when the number of micro groups is 8,the arrangement of micro groups is gradual and gradually dense,the total entropy production and the fire accumulation dissipation are both the lowest,with 37.2 W/K and 1900.5 W/K,the thermal performance is the best.