| With the increasing heat flux generated in electronic device,the traditional heat dissipation structure cannot meet requirements of high heat flux removal.At the same time,the mal-distribution heat dissipation problem of the traditional structure,which cannot meet the high-integration and high-precision heat dissipation requirements.The advantages of microstructure heat exchange are suitable in limited space and high heat transfer efficiency.Furthermore,there is also the problem of temperature mal-distribution,which is mostly caused by the flow mal-distribution.Based on the nozzle-jet/manifold/micro-pin-fin composite heat sink,this paper used its advantages of low pressure drop,low thermal resistance,and high heat transfer efficiency to optimize the topology and re-orders the flow direction.There proposed 4 topological distributions based on simple geometry,square topology,regular hexagon topology,60° diamond topology and 30° diamond topology.According to its symmetry,the simulation model of the basic heat transfer unit cell of the heat sink was established.The influence of different topological structures on the flow and heat transfer performance was analyzed.First,the flow and heat transfer contours,local convective heat transfer coefficient and average Nusselt number of the unit model are mainly used to study the interaction heat transfer character between the side of the micro-pin-fin and the bottom wall.The 30° angle diamond topology has the highest local convective heat transfer coefficient,which exceeds 450000 W/(K·m2).Then,the effects of three independent basic parameters of DN,WPF and HPF are investigated.The composite heat sink with the square topology has significant advantages,the pressure drop is only 3073 Pa,and the total thermal resistance can be as low as 9.83×10-4 Km2/W.Finally,it.is proved that it is feasible to optimize the micro-pin-fin as a porous medium.The regular hexagon topology has the lowest porosity,the highest COP/ΔT value,which has the greatest heat transfer potential.The overall average Nusselt number of the heat sink is almost 0.The optimal nozzle pore is in the range of 50-100μm to keep low pressure drop.The 30° angle diamond topology is the most sensitive to changes in porosity.As the porosity changes from 0.83 to 0.92,the pressure drop is reduced by as much as 10 times.In addition,the influence of the off-center imping jet on the heat transfer performance of the heat sink unit is investigated.The large-size micro-pin-fin shows better stability to off-center imping jet heat transfer. |
