Millikelvin温区烧结式换热器流动与传热特性数值模拟研究OA

Kapitza thermal resistance at the interfaces between liquid helium and solid components significantly affects the flow and heat transfer performance of porous-media heat exchangers(PMHEs)in the Millikelvin temperature regime.To explore the influence of Kapitza thermal resistance on the heat transfer efficiency of sintered porous media heat exchangers,a clear understanding of its impact is essential for enhancing interfacial heat transfer efficiency in sintered heat exchangers.In this work,a local thermal non-equilibrium model is established,which comprehensively considers axial heat conduction,viscous dissipation effect and the variation characteristics of Kapitza thermal resistance with temperature,to describe the heat transfer behavior in the porous media region.Fluid flow within the sintered sponges is described using the Brinkman-Forchheimer equations.The results show that the proposed model can effectively capture the temperature jump phenomenon at the interface between liquid helium and solid.Based on the above model,the variation laws of temperature and pressure under different working conditions are analyzed,and the underlying heat transfer mechanism is revealed.Furthermore,the effects of Kapitza thermal resistance and axial heat conduction on heat transfer performance are investigated,and the influence mechanism of parameters such as flow rate,heat transfer area and sintering parameters on flow and heat transfer performance is systematically discussed.