Numerical Simulation Of Liquid Metal MHD Effect And Heat Transfer Of Duct Turbulent Flow Based On RANS Methods

In the nuclear fusion reactor,the magnetohydrodynamic(MHD)effect interacts with buoyancy,which affects the features of liquid metal moving and heat transfer.Therefore,from the perspective of the liquid metal blankets design,it is necessary to study the magnetic fluid heat transfer and MHD effect.First,the Reynolds-averaged Navier-Stokes(RANS)equations method is one of the main research methods in the magnetohydrodynamic.The RANS method can be used to solve the problems of turbulence by statistical averaging the variables in the turbulent flow field.The existing shortcoming of the MHD k-w turbulence model was improved in this piper.A new MHD k-w turbulence model was proposed by studying the electromagnetic dissipation term of the magnetic fluid turbulence model.Based on the four-step projection,compatible conservation,and the fluid-solid coupling algorithm,a conducting MHD turbulent solver and an insulating MHD turbulent heat transfer solver have been developed.Then,the correctness of the insulating MHD turbulent heat transfer solver was verified.It was found that the turbulent Prandtl number has an ace influence on the turbulent heat transfer of magnetic fluid,and the thickness of the hot wall temperature boundary layer increases with the increase of the turbulent Prandtl number.It is found that the laminar fluidization occurs in MHD turbulent heat transfer flow when the ratio of Reynolds number to Hartmann number is less than 100.With the increase of Reynolds number,on the one hand,the heat transfer efficiency of the hot wall can be improved,and on the other hand,the MHD pressure drop in the tube can be increased too.It was also found that the velocity circulation becomes large near the hot wall with the increase of Richardson number.Furthermore,numerical simulation of the magnetic fluid turbulence in the conducting rectangular tube verifies the correctness of the solid-wall conducting magnetic fluid turbulence solver,and two k-w models of the improved and developed can be applied to the research of MHD flow in the conducting tube.At the same time,studies have shown that: At high Hartmann number,strong velocity jets will be formed in the parallel layer,but the peak value of the velocity jets will decrease gradually with the increase of Reynolds number.Most of the turbulent kinetic energy of the magnetic fluid is in the parallel layer.The turbulent kinetic energy in the parallel layer increases with the increase of Reynolds number,but the turbulent kinetic energy in the core region decreases with the increase of Reynolds number.The analysis of the dimensionless MHD shows that the larger the Hartmann number,the smaller the influence of the Reynolds number on the dimensionless MHD pressure drop.In summary,in terms of turbulence model,the original MHD k-w turbulence model was improved and a new MHD k-w turbulence model was developed.In terms of solver,a conducting MHD turbulent solver and an insulating MHD turbulent heat transfer solver were developed.After verifying the correctness of the above turbulence models and solvers,the MHD flow and heat transfer of duct flow were numerically simulated,and the influence of Reynolds number and Hartmann number on the MHD effect and heat transfer of duct flow was analyzed.