Numerical Simulation Of Natural Convection Heat Transfer With Liquid Metal

Liquid metal in the blankets of nuclear fusion reactors flows under a strong magnetic field.The liquid metal flow cuts the magnetic field to generate induced current,and the induced current generates Lorentz force in the magnetic field,thereby causing a magnetohydrodynamic(MHD)effcet.The non-uniform volumetric heat deposited by the neutrons produces buoyancy-driven in the gravitational field.The combination of these two effects can change the flow and heat transfer properties in the liquid metal blankets.The strength,direction of the magnetic field,the geometry of the liquid metal blankets,and the wall conductivity have the effect on the energy conversion to the liquid metal blankets.Therefore,the heat transfer caused by buoyant flow is a key issue in the liquid metal blankets.Numerical simulation is an important method for study MHD flow because of the high cost of MHD flow experimental research.Base on the MHD flow solver in the OpenFOAM environment developed by the research group,the insulated MHD heat transfer solver and the fluid-solid coupling MHD flow heat transfer solver combine four-step projection algorithm,compatible conservation algorithm and fluid-solid boundry coupling algorithm.This study begins with the verification of heat transfer under zero magnetic field to determine the settings related to natural convection,laying the foundation for subsequent research.Then the insulated MHD flow heat transfer solver was developed and verified.The numerical results and literature results show the applicability of the solver.The natural convection heat transfer simulation is performed on a cavity with an aspect ratio of 7.5,and the magnetic field suppresses the convection intensity.The effects of different directions and strength of the magnetic field on natural convection are analyzed from the perspectives of speed,current and heat transfer efficiency.The fluid-solid coupling MHD flow heat transfer solver for coupling the temperature is referred from the potential coupling method.A square cavity is used as the verification object,which is consistent with the results of previous researchers.The natural convection characteristics in the conductive cavity are analyzed from the three aspects of wall conductivity,magnetic field strength and direction.It mainly studies its effects on velocity distribution,current field,Lorentz force distribution and heat transfer efficiency.This study has completed the development and verification of the MHD flow heat transfer solver.Reasearch on nature convection heat transfer of MHD flow lays the foundation for the subsequent study of heat transfer in the liquid metal blankets.