Numerical Simulation Of Magnetohydrodynamic Laminar Flow In Duct With Flow Channel Insert

As the first experimental reactor, International Thermonuclear Experimental Reactor (ITER) was designed to test the relevant technical and scientific feasibility of fusion energy for peaceful purpose. In International Thermonuclear Experimental Reactor, Testing Blanket Module (TBM) system is one of the key technologies that have been recognized. It is used for power conversion and tritium breeding. The Testing Blanket Module has been significantly developed in the last few years.And the dual-coolant lithium lead is supposed to be one of the most potential blanket concepts.Liquid metal,as a cooling material, is restricted by a toroidal magnetic field about5to15Tesla. So when liquid metal is flowing in the blanket, Magnetohydrodynamic (MHD) effect caused by magnetic field will generate high MHD pressure drop and change distribution of flow field.MHD pressure drop will increase significantly along with the increasing of wall conductivity and Hartmann number. To reduce the MHD pressure drop considerably, the crucial point is increasing the electrical insulation of testing blanket structure.Flow Channel Insert (FCI) made of a silicon carbide composite was proposed to insulate flowing liquid metal and the channel walls. It separates the fluid inside the channel into two different regions, decoupling the liquid metal flow from the walls.By using the low electrical conductivity of silicon carbide composite and pressure equalization hole or slot, velocity of bulk flow will increase, velocity of gap flow will decrease, and the MHD pressure drop can be reduced to a manageable level.In this paper, the background, plan and development course of International Thermonuclear Experimental Reactor was introduced firstly. And so is Testing Blanket Module. More attention was paid to the status and research achievement on reduce Magnetohydrodynamic effect. Based on MHD module of FLUENT, problem of Magnetohydrodynamic laminar in rectangular duct was solved with Magnetic Induction Method. Analysis on the result is the main contents of this paper. Besides, grid step of structure grid on axial direction was given when FLUENT was used to solve MHD problem.First, two cases of Magnetohydrodynamic laminar in rectangular duct with different Hartmann number(Ha=100and Ha=400) were numerical simulated in this paper. Then the other cases of numerical simulation of Magnetohydrodynamic laminar in rectangular duct with FCI were proposed. Width of pressure equalization slot in these two cases is2mm and6mm. According to the result of numerical simulation, velocity on section becomes flat after uniform magnetic field was imposed on laminar flow in rectangular duct. Entrance length is shortened and MHD pressure gradient is increased greatly. When the magnetic field was enhanced, distribution of velocity on section becomes more complicated. Magnetohydrodynamic effect is also more significantly. It shows that the Flow Channel Insert is indeed an effective technique to reduce the pressure drop in the blanket. But effect of pressure equalization slot is limited to the vicinity.In addition, vortex shape current was found in the slot. Current distribution in the slot changes a lot and MHD pressure gradient increases after adding the width of pressure equalization slot. It could be called Geometric Sensitivity. As a result, for Testing Blanket Module with Flow Channel Insert, width of pressure equalization should be decreased.