A numerical study on Faraday-type electromagnetic flowmeter in liquid metal system, (II) - Analysis of end effect due to saddle-shaped small-sized magnets with FALCON code

In the design of the electromagnetic flowmeter (EMF) in the main cooling loop of the Japanese Prototype Fast Breeder Reactor MONJU, large-sized flat permanent magnet was adopted in order to make the end effect of the magnet as small as possible. For an EMF of a future large LMFBR, it is difficult to adopt such a large-sized magnet because of problems of a large space requirement and a tolerance against earthquake. Therefore, it is necessary to develop a novel EMF with small-sized magnets. It has been feared that the decrease of magnetic field and the end effect make the EMF's performance worse, but we have no detailed information about the end effect due to such small-sized magnets. By using the three-dimensional steady-state electromagnetic analysis code FALCON, we have studied numerically on the end effect of an EMF with saddle-shaped permanent magnets, the size of which is smaller than the pipe diameter. Consequently, it has been clarified that the performance of an EMF can be improved by utilizing the effect of the downstream end of magnets and by combining the inclined-electrodes and the effect of circumferential ends of magnets.