Zenghui Wang

Numerical Study of MHD Natural Convection of Liquid Metal with Wall Effects

Three-dimensional natural convection of liquid metal under a uniform magnetic field in a cubic enclosure is numerically simulated. The opposite sides of the cubic enclosure are isothermal, and the other four walls are adiabatic. The temperature gradient is perpendicular to the gravity vector. Three different magnetic field directions are applied in the computing model, respectively; namely, parallel to the temperature gradient, parallel to the gravity vector, and mutually perpendicular to them. Different wall electrical conductivities are also adopted in the simulation. Based on the Bousssinesq assumption, the numerical simulation of natural convection with Rayleigh number of 105, 25,000, and 1000, Prandtl number (physical property of Pb-17Li under 573 K) of 0.0321, and Hartmann number of 100, 50, and 10 are performed using a projection method to simulate the incompressible liquid metal flow and a consistent and conservative scheme to calculate the electromagnetic force at a nonuniform rectangular collocated grid. The influences of magnetic field directions and wall electrical conductivities on MHD flows are also studied.

Simulation of MHD Flows in Liquid Metal Blanket with Flow Channel Insert

Abstract A direct simulation of 3D liquid metal flow in the DCLL (Dual Coolant Lead Lithium) blanket is conducted to study the distribution of pressure and velocity influenced by different material properties of FCI (Flow Channel Insert). A consistent and conservative scheme and projection method on a collocated mesh (Ni et al., J Comp Phys 227 (2007)174-204 and 227 (2007) 205-228) are employed to solve the incompressible Navier-Stokes equations with the Lorentz force included based on an electrical potential formula. As an illustration, three blanket flows have been considered: liquid metal flow in a channel without FCI, with a silicon carbide FCI and with a FCI made of conductive material. It is shown that liquid metal flows in blanket with FCI are 3D developing flows. It is verified that: MHD pressure drop can be reduced by using silicon carbide FCI; PES (Pressure Equilibrium Slot) can balance the pressure difference between two sides of FCI near the slot but the pressure difference is still very large far away from PES; conductive FCI cannot reduce MHD pressure drop. Due to the leakage of current circuit across the slot, with PES opened at one side, a strong reversed velocity is observed in PES. The comparison of velocity distribution between numerical simulation and experiment from LEVI (Xu et al., ISFNT-9, 2009) is conducted. The difference shows that further experimental and numerical analysis is needed.

An analysis of flowing liquid lithium-lead eutectic corrosion of structural steels in fusion reactors

Purpose The liquid lithium-lead breeding blanket in the international thermonuclear experimental reactor is one of the major international concerns and one of the potential conceptual designs for the fusion reactor. Design/methodology/approach Reduced activation ferritic-martensitic steels are being considered for application in future fusion technology as the relevant structural material, which will be in contact with the lithium-lead breeding material. Findings According to the test results, comprehensive evaluations of these findings have been performed to determine the wastage rates and mechanisms for the conceptual design of the fusion reactor. Originality/value From micro to macro, systematic cross-scale models are needed for the understanding of corrosion/wastage mechanisms in fusion reactor engineering applications.

MHD Analysis of Flow Channel Insert with Holes and Slots for Dual Coolant and/or Dual Function Lead Lithium Blanket

A consistent and conservative scheme on a rectangular collocated grid system designed to calculate the current density and the Lorentz force by solving the electrical potential equation for magnetohydrodynamics (MHD) at low magnetic Reynolds numbers is used to conduct the MHD flows in the dual‐coolant lead lithium (DCLL) blanket. Details of the numerical code for analysis of a 3‐D MHD flow in a channel of a liquid metal with flow channel insert (FCI), which plays a very important role in the fusion reactor blanket are presented in this paper. The velocity and pressure distribution of flow channel insert (FCI) made of SiC and 3‐D flow effects are studied using this scheme. Two kinds of pressure equilibrium mechanism in FCI are considered: slots or holes. The pressure and velocity of the two cases are studied.