Research On Heat Transfer Enhancement And Performance Optimization Of Complex Structure Microchannel Heat Sink

With the rapid development of science and technology,electronic devices are moving towards miniaturization and high integration.The problem of high temperature damage of electronic devices needs to be solved urgently.Compared with conventional heat exchanger,microchannel heat sink has the advantages of high heat exchange capacity and small volume to meet the heat dissipation needs of electronic devices.The flow and heat transfer characteristics of complex structure microchannel heat sink under laminar flow conditions are analyzed by CFD numerical simulation technology with deionized water as the cooling medium.The influence mechanism of the shape of complex structure on microchannel heat transfer is analyzed and combined with microchannel heat sink to verify the heat transfer enhancement of this structure.The numerical simulation results are as follows.(1)Under the condition of a single structural parameter,with the increase of the length width ratio of the groove,the pressure drop synergy angle and f gradually decrease,the minimum value of Tave,heat transfer synergy angle and entransy dissipation value Evh is obtained when the length width ratio of the groove ?c=0.4,while the maximum value of Nu and PEC is obtained when ?c=0.4.With the increase of groove height ratio,Tave,f,heat transfer synergy angle and pressure drop synergy angle gradually decrease,while Nu and PEC gradually increase,and the entransy dissipation value is tubulent and finally reach the lowest.With the increase of the length width ratio of fin,Tave,heat transfer synergy angle,entransy dissipation value decreases gradually,and Nu,f,pressure drop synergy angle increases gradually.With the increase of the length width ratio of fin,PEC increases first and then decreases,maximum value is obtained when ?1=1.0.(2)Under the condition of composite structural parameters,with the increase of the distance between slot and rib,the heat transfer synergy angle gradually increases,Tave and PEC first increase and then decrease,Nu and f first decrease and then increase.The maximum value of PEC is obtained when the distance between slot and rib S=0.00?m,indicating that the enhanced heat transfer effect is the best at this time,and the minimum value of the pressure drop synergy angle is obtained when S=0.15?m,and the minimum value of the entransy dissipation value is obtained when S=-0.15?m.With the increase of the number of cycles,the dissipation value of Tave,heat transfer synergy angle,entransy dissipation decreases gradually,and the number of Nu,f and pressure drop synergy angle increases gradually.The maximum value of the PEC is obtained when R=20.With the change of the topology in the complex microchannel,the simulation shows that the trapezoidal groove has the best enhanced heat transfer effect,and the rhombic pin rib has the best enhanced heat transfer effect.At this time,the heat transfer synergy angle is the minimum,and the entransy dissipation value is the minimum,which shows that the enhanced heat transfer capacity of the microchannel is the best when the complex structure is trapezoidal groove with rhombic rib.(3)Under the combination of complex structure and microchannel heat sink,adding complex structure to microchannel heat sink can reduce the average temperature of heat source,improve the heat transfer capacity of microchannel heat sink,and further improve the synergistic effect of velocity field and temperature field,but it will produce more resistance loss and reduce the synergistic effect of velocity field and pressure drop gradient.