Study On Heat Dissipation Characteristics Of The Combination Of Double Synthetic Jets And Small Composite Structure Fins

In recent years,with the rapid development of electronic science and technology,chips and electronic devices have continued to develop towards high integration and miniaturization,its power consumption is also increasing.The heat dissipation problem has become a bottleneck restricting the further development of chip performance and the miniaturization and portability of electronic equipment,especially in the field of aerospace.Due to the limited installation space of electronic equipment,the need for miniaturization of heat dissipation devices is more urgent.Dual synthetic jet actuators can generate periodic rich vortex structures,with advantages of zero mass flux,compact structures,low cost,no need of air sources and so on,showing broad applying prospects in the field of enhanced heat and mass transfer in small space.In this paper,starting from the requirements of small space heat dissipation,for the heat dissipation problem of high heat flux electronic components in a confined space,combined with numerical simulation and experiment,researches on the combined heat transfer characteristics of dual synthetic jets and small composite structure fins are carried out.The main contents are as follows:For the problem of limited heat transfer capability of conventional fins,a micro-protruding composite structure on the surface of fins is designed.By numerical simulation,the effects of the surface micro-protruding structure on the heat transfer performance of fins are researched.Results have shown that the micro-protruding fins can make Y-direction vorticity in the fin channel increase,more than twice that of the traditional smooth fins,augmenting the heat transfer performance by 10%.Four different surface micro-protrusion structures are designed.The enhanced heat transfer performance of the diamond-shaped micro-protrusion structure is 2～3% higher than the other three micro-protrusion structures,and the drag coefficient is 6%～10% lower.A numerical simulation study on the influence of the parameters of dual synthetic jet and the fin rib structure parameters on the enhanced heat transfer performance is carried out.Results shows that when the driven frequency is 500 Hz,the surface micro-protruding composite structure fins under the dual synthetic jets have shown uniform temperature distribution and the best heat dissipation effect.When the jet peak velocity is 20m/s,the fin temperature is retained between 40～50℃,which meets the heat dissipation requirements of most electronic equipment,having high enhanced heat exchange efficiency.With the exit shape of staggered bevel configuration,the fins have a lower and more uniform temperature distribution.The effects of surface micro-protrusion structure parameters on the flow and heat transfer characteristics are numerically studied.Results show that the rib height of the surface micro-protruding composite structure fin has a greater effect on the flow and heat transfer characteristics than the rib width.Meanwhile,the enhanced heat transfer performance is higher with the rib height of 10 mm and the rib width of 2 mm.Numerical simulations and experiments on the effects of combined dual synthetic jets and small micro-protrusion composite structures on the heat transfer characteristics in a closed small space are carried out,the results are verified by heat exchange experimental data.The influences of slot area,direction,position and quantity on the heat transfer characteristics are analyzed.As the slotting area increases,the temperature drop amplitude increases continuously.In the case of single-sided slotting or double-sided slotting,the enhanced heat transfer performance is better when the slotted area on the wall reaches 60%.The enhanced heat transfer performance of slotting along the flow direction is better than that along the span direction,and the enhanced heat transfer performance of slotting near the chip side is better than near the fin side.Considering the speed and temperature distribution,it can be known that with the same slotting area and the number of slots,the enhanced heat transfer performance on the side close to the chip is better than the slotting along the flow direction.With the increase of the number of slots,the enhanced heat transfer performance of the chip shows a trend of first rising and then saturation.When the slot area,direction and position are the same,the enhanced heat transfer performance is better when the number of slots equals 4.