| Microchannel heat sinks have been widely used in fields such as aerospace,aviation,medical equipment,and micro electronic devices due to their simple structure,easy encapsulation,and efficient heat transfer ability.However,with the gradual increase in the integration level of electronic devices in small volumes,their high-strength heat transfer performance poses a stricter test for electronic devices.The issue of higher heat flux density and smaller heat dissipation space has become one of the challenges faced by efficient heat dissipation technology for electronic devices.In order to ensure the stability and reliability of microelectronic devices in operation,efficient and reliable design schemes are particularly important.Therefore,the topology optimization design method is applied to the structural design of microchannel radiator in this paper.Based on the finite element method,the fluid solid conjugate heat transfer process is analyzed,and a multi-objective topology optimization model is established.The topology optimization design and numerical simulation analysis are carried out for the heat dissipation problems with different inlet and outlet modes and different inlet conditions,and the threedimensional model is constructed to verify its effectiveness.It mainly includes the following parts:First,four geometric modeling with different single inlet and single outlet arrangements were constructed,and the parallel inlet and outlet arrangement was taken as an example to explore the influence of fluid volume fraction ratio on topology optimization configuration,and then the subsequent calculation was carried out with the optimal fluid volume fraction ratio as the constraint.Then,with different Reynolds number as variables and the maximization of heat transfer as the objective function,the optimization design problem of the channel with uniform heat source distribution was solved,and a clear channel structure was obtained.Next,the two best inlet and outlet arrangements for heat transfer performance will be weighted using a dual objective function of maximizing heat transfer and minimizing fluid energy dissipation.The results show that as the weight coefficient value continues to increase,the average temperature of the entire design domain gradually decreases,while the inlet and outlet pressure drop also increases.Secondly,four microchannel heat exchangers with two inlets and two outlets were designed,and topology optimization was carried out with the maximization of heat transfer as the single objective function and the maximization of heat transfer and fluid energy dissipation as the double objective functions respectively.Taking different Reynolds number as variable,the optimization design problem of channel distribution under uniform heat source was solved,and two structures with optimal heat transfer performance were obtained.For the two structures with the best heat transfer performance,the double objective function weighting method is used for topology optimization.The results show that as the weight coefficient gradually increases,the number of branch structures in the design domain gradually increases,the width of the channel narrows,and the heat transfer area increases,resulting in a decrease in the average temperature of the design domain.At the same time,the inlet and outlet pressure drop also significantly increases.This is because when the proportion of heat transfer increases during the optimization process,the pressure drop loss must be taken as the cost.Finally,in order to verify the heat transfer performance of the model obtained by the topology optimization method,the channel structure model of the double diagonal parallel inlet and outlet layout structure is selected when the weight coefficient value is 0.4,and it is constructed into a three-dimensional channel structure.By comparing numerical simulation calculations with traditional straight channels,the effects of pressure drop,Nusselt number,thermal resistance,and maximum temperature in the design domain were analyzed.The results show that the average temperature,maximum temperature and thermal resistance of the topology optimization configuration are lower than those of the traditional straight channel at the same inlet velocity,and the Nusselt number is higher than that of the traditional straight channel.In addition,its pressure drop is also smaller than that of traditional straight channels.Therefore,the comprehensive heat transfer performance of the channel structure obtained by using the topology optimization design method is better. |
