Research On Topology Optimization And Heat Transfer Enhancement Design Of Microchannel Heat Sink Based On Entransy Theory

With the emerge of information technology,such as 5G,artificial intelligence and edge computing,thermal management technology has become a key breakthrough point in the development of microelectronic chip technology.Microchannel heat sink is an ideal choice for the thermal management of microelectronic chips due to its small volume,easy integration and high heat and mass transfer efficiency.However,most of the existing microchanne heat sink designs are size or shape design based on the existing structures,leading to a simple structure and low heat transfer coefficient,which gradually dissatisfy the heat dissipation requirement of high heat-flux chips.How to further enhance heat transfer is an urgent problem to be solved in the field of microchannel design.To date,there are still two major obstacles to overcome in the field of enhanced heat transfer: Imperfect enhanced heat transfer theory and limitations of optimized design methods.In terms of enhanced heat transfer theory,entransy theory has local and global concepts,which can not only be used to analyze the heat transfer enhancement mechanism and direct enhanced heat transfer design,but also be used to comprehensively measure the convective heat transfer efficiency.In terms of optimized design methods,topology optimization can directly obtain the optimal performance of enhanced heat transfer design of microchannel heat sink under fixed volume and material constraints.Therefore,introducing entransy theory and topology optimization method into the field of heat transfer enhancement of microchannel design can effectively solve the problems of imperfect enhanced heat transfer theory and limitations of optimized design methods.In this paper,entransy-based topological microchannel heat sinks were constructed.The heat transfer enhancement mechanism of the topological microchannel heat sinks was also analyzed based on the local entransy theory.Based on the entransy analysis results,the topological microchannel heat sinks were secondary designed to further enhance heat transfer from both macro and micro viewpoints.Finally,the numerical simulation and experimental investigation were done to verify the correctness of the entransy-based topological design.The main contents of this paper were as following:(1)Heat transfer model of microchannel heat sink based on entransy theory was established.The macro-micro definition of entransy was first elaborated,and the entransybased microchannel convective heat transfer model was established.In the microchannel convective heat transfer model,the entransy theory was re-recongnized from the viewpoints of heat transfer and fluid flow.The local entransy theory was constructed to analyze the heat transfer enhancement mechanism.The correctness and applicability of the entransy-based microchannel convective heat transfer model were also verified by theoretical and simulation analysis.(2)Topology optimization design of microchannel heat sink based on entransy theory.The pseudo 3D topology optimization model of microchannel heat sink was first established.Methods of outside surface viscous dissipation,adaptive heat transfer coefficient,convective heat transfer efficiency objective and auxiliary objective function were proposed to solve the problems of low accuracy,incompatibility of heat transfer and fluid flow performance and grey element of topology optimization.Then,the influence of different key parameters on the optimal design was discussed and the pseudo 3D topology optimization model of microchannel heat sinks with the optimal parameters was constructed.Based on this model,topology optimization designs of microchannel heat sink under different heat sources,flow conditions and multilayer conditions were studied,and the universality and applicability of the pseudo 3D topology optimization model based on entransy theory were verified.(3)Numerical analysis and secondary heat transfer enhancement design of the topological microchannel heat sinks.The numerical model of topological microchannel heat sink was established.The effects of different fluid flow,heat flux and multi heats,flows and layers on the heat transfer,fluid flow and comprehensive performance of topological designs were investigated.Then,the local entransy theory was adopted to analyze the heat transfer enhancement mechanism,and enhanced heat transfer zone was divided according to the local entransy distribution.Based on the enhanced heat transfer division,the machinability and secondary heat transfer enhancement design were done,and the final designs that met the heat dissipation requirements of industrial high heat flux CPU were designed.(4)Topological microchannel heat sink performance test platform construction and experimental testing.Topological microchannel heat sinks were machined by laser processing and the corresponding performance test platform was constructed.The heat transfer,fluid flow and convective heat transfer irreversibility were experimentally investigated.The correctness of topological design and secondary designs was verified.And then,the experimental results were also compared with the simulation results to further verify the reliability of simulation analysis,and provided a complete idea for enhancing heat transfer design based on entransy theory.