Research On Numerical Analysis And Optimization Method Of Composite Vapor Chamber With Grooved Wick

With the rapid development of microelectronic technology and optoelectronic technology,various electronic devices and components are developing for better performance and high integration.At the same time,it also causes heat dissipation problems in the limited space and high heat flux.As a novel device of phase-change heat transfer,the vapor chamber can effectively solve the above thermal management problems because of its high thermal conductivity and large condensation area.In recent years,a variety of novel vapor chambers emerge in endlessly,among which the composite vapor chambers show some good performances.Commonly used experimental methods need high cost and long period,and there is no existing numerical method aiming at this kind of vapor chamber.At the same time,the internal working mechanism and the influence of structural parameters are not clear,resulting in the limited optimization design methods.In this paper,a composite vapor chamber with grooved wick was taken as the research object.Through the development of a numerical method applicable to this kind of vapor chamber,the internal working mechanism was analyzed and revealed.Based on this,an optimization design method of the vapor chamber was established,the structural parameters and shape were optimized,and the performance of heat and mass transfer was improved.The main research works of this paper are as follows:(1)The heat and mass transfer numerical analysis model of the composite vapor chamber with grooved wick was established.Using a decoupled method assuming that the vapor core is an isothermal zone between the evaporator wick and the condenser wick,the numerical analysis models of the solid wall,the wick zone,and the vapor core were developed,respectively.And the validity of the model was verified.(2)The effects of different kinds of structural parameters on the heat and mass transfer performance of the vapor chamber were discussed.The results show that the optimal porosity configuration varies with the powder diameter.Larger powder diameter results into smaller optimal porosity,and vice versa.The influences of the groove parameters on the performance of the vapor chamber are in competition.Larger groove parameter values can enhance the thermal performance and benefit the vapor flow,while smaller ones can facilitate the liquid circulation.Based on the analysis,an optimized wick with a central column was proposed.(3)A parameter optimization method of the vapor camber was proposed based on design of experiment and response surface.Multiple sets of sampling points were generated using the design of experiment method.And the response relationship between the groove parameters and the optimization objectives was established through the response surface model.Then,the thermal and hydraulic performances of the vapor chamber with different groove parameter configurations were studied.Besides,the genetic algorithm was used to conduct the single-objective optimization design and multi-objective optimization design,respectively,and the optimum groove parameters under different optimization objectives were obtained.(4)A shape optimization method of the vapor chamber was proposed based on the adjoint method.By solving the government equations and adjoint equations of the computational domain,the wick was optimized in the cylindrical coordinate and the Cartesian coordinate,respectively.The liquid pressure drop with the optimized structures was reduced by 23.3% and 18.5%,respectively,improving the performance for the liquid backflow.Through the above works,a set of performance analysis and optimization method of vapor chambers based on numerical analysis is established in this paper,which improves the degree of freedom for the design of vapor chambers and is expected to provide technical support for numerical analysis and optimization of vapor chambers.