The magnetic field and performance calculations for an electromagnetic pump of a liquid metal

For an annular-type electromagnetic pump of a liquid metal, the magnetic field is found in closed form by means of the Fourier transform method for two-dimensional field analysis based on an equivalent current sheet model, so that the terms contributing to the normal thrust and the end effect are analytically identified. Analytical solutions for the magnetic vector potentials are compared with numerical ones obtained from the finite difference equation, and they turn out to be in good agreement regardless of the assumption of infinite permeability used in the analytical approach. As a result of closed-form solutions, the electromagnetic body force exerted on a liquid metal flow and the efficiency of the pump are calculated without going through tedious time-consuming numerical work usually accompanied by troublesome convergence problems. The calculated results for estimating the influence of end effects on the performance of the electromagnetic pump clearly show that the end effects give rise to the obstructive force to the liquid metal flow at inlet and outlet ends of the pump. In addition, the efficiency is found to be lowered due to end effects, especially when the speed of the flow is high.