A 2D model to design MHD induction pumps

R. Stieglitz - J. Zeininger

Institute for Nuclear and Energy Technologies (IKET), Forschungszentrum Karlsruhe, Post Box 3640, D-76021 Karlsruhe, Germany

Abstract
Technical liquid metal systems accompanied by a thermal transfer of energy such as reactor systems, metallurgical processes, metal refinement, casting, etc., require a forced convection of the fluid. The increased temperatures and more often the environmental conditions as, e.g., in a nuclear environment, pumping principles are required, in which rotating parts are absent. Additionally, in many applications a controlled atmosphere is indispensable, in order to ensure the structural integrity of the duct walls. An interesting option to overcome the sealing problem of a mechanical pump towards the surrounding is offered by induction systems. Although their efficiency compared to that of turbo machines is quite low, they have several advantages, which are attractive to the specific requirements in liquid metal applications such as: -- low maintenance costs due to the absence of sealings, bearings and moving parts; -- low degradation rate of the structural material; -- simple replacement of the inductor without cut of the piping system; -- fine regulation of flow rate by different inductor connections; -- change of pump characteristics without change of the mechanical set-up. Within the article, general design requirements of electromagnetic pumps (EMP) are elaborated. The design of two annular linear induction pumps operating with sodium and lead--bismuth are presented and the calculated pump characteristics and experimentally obtained data are compared. In this context, physical effects leading to deviations between the model and the real data are addressed. Finally, the main results are summarized. Tables 4, Figs 4, Refs 12.