Topology Optimization Of Cooling Structures For Electronic Devices

With the great need of making electronic chips miniaturization,integration and cheaper,the power density of chips has been increasing dramatically,and the problem of high density heat flux becomes more and more serious.The heating of electronic chips has become one of the mian obstacle in the development of microelectronics industry.A large amount of researches had showed that high temperature is the main reason for the malfunction of electronic devices.The chips used in electronic devices have the characteristics of high density heat flux formed in some specific area and the heat power is tend to accumulate in those locations also called hot-spots,which could lead to high temperature in hot-spots.Therefore,the performance of the chip depends on the effectiveness of the cooling structures for electronic equipment such as implantable heat conduction path,plate heat pipe or called vapour chamber and fin structure.This paper is aimed to optimize the performance of the cooling structure for electronic equipment.The topology optimization method is used to optimize the structure:(1)In order to meet different requirements of chips' cooling,the heat conduction path is optimized,and the calculation of non-uniform heat source and different shape design area is also conducted,then the optimization model of the plane heat conduction path is extended to three dimensions condition,the result of 3D model could be applied to the optimization of heating plate with a certain thickness.(2)To improve the uniformity of temperature distribution of plate heat pipes,topology optimization method is conducted to aid the design of the fluid channels within plate heat pipes.In this paper,the channels were simplified as a high-conductivity material,the method was applied to find a higher performance channel structure with the amount of material unchanged.The optimization aimed to minimize the temperature variance.Numerical experiments were conducted to analyze the influence of material heat conductivity ratio and Bi number on the topology of the fluid channel structure.Topology distribution and temperature distribution images were obtained,the impacts of material heat conductivity and Bi number were discussed as well.Results showed that the design of topology optimization was superior to the design without optimizations.(3)To deal with the dissipate heat problem,heat dissipation structures tend to be multi-dimension and sophisticated.A predisposed topology optimization model for rectangular fins is introduced for free convection heat transfer enhancement.Numerical experiments are carried on under different area ratios and logistic function is applied in this model.The predisposed distribution method is effective and topological fins' entransy dissipations are less than the uniform distribution fins'.Then based on FloTHERM simulations,the average temperature and maximum temperature of the heating plate are improved comparing to rectangular fins' design which proves that topology optimal fins are effective.(4)The introduction of convection heat transfer coefficient in the gray cell will inevitably lead to the increase of the number of gray cells.In order to solve the problem mentioned before,the cellular automata processing method,the predisposed method and the hybrid method are put forward.At the same time,the number of gray cells is reduced by 100%,and the effectiveness and applicability of the bybrid method are verified by multicondition simulation examples.