Numerical Investigations On The Characteristics Of Free Surface MHD-Flow And Heat Transfer

The phenomena of free surface fluid flow with heat transfer need usually to be solved in a range of metallurgical processes, foundry and fusion liquid wall technology. There is instability in interface for free surface fluid flow due to the surface renewal, fluctuation effects, which will bring detrimental effects for engineering applications. However, the instability of interface will enhance the surface heat transfer. The phenomena become a key research point how to control the free surface fluid flow and heat transfer in these Fields of Hydrodynamics and Engineering Thermodynamics. The motion of an electrically conducting liquid across the magnetic field induces a current, which can interact with a magnetic field to generate a Lorentz body force, i.e. MHD, MagnetoHydroDynamics (MHD) effects. This resulting is accompanied by a characteristics change of fluid flow and heat transfer, such as big pressure drop and heat transfer decreasing.The numerical method of MHD is reviewed, and encountered problem on MHD numerical model is expatiated. On basis of previous research, an Induced-Magnetic-Field Equation MHD model for multi-phase fluid flow with free surface is developed, which will be solved by the solver of scalar transport equation based on the User-Define- Function (UDF) in MHD module of the computational fluid dynamics software (FLUENT) to calculate velocity profile, temperature distribution, and pressure distribution by considering the coupling of the fluid flow field and the uniform/non-uniform magnetic field. The MHD code has been testified numerically comparing other code results.The flow behaviors and heat transfer characteristics of free surface lithium liquid flow are simulated and analyzed by developing a MHD k-εturbulence model and Large Eddy Simulation method. The numerical results show that the magnetic field can suppress turbulent viscosity, degrade surface heat transfer coefficient and mean bulk temperature, and delay the wake separation. For applied fields, the separation point will moves forward around cylinder, surface temperature and temperature gradient near surface will degrade with Re increasing; meanwhile, the induced current and Lorentz force decrease with Re increasing. The local flow characteristics and heat transfer will be established as a reference for the engineering applications for free surface MHD-flow.