Study on permanent magnet flowmeter for liquid sodium, (1). Theoretical investigation of end effect of magnetic field

This paper describes a theoretical study on the end effect of circular transverse field electromagnetic flowmeters. It is shown that the voltage induced between the top and bottom electrodes is not strictly proportional to the mean velocity but is slightly influenced by the velocity distribution of the fluids, due to end effect. The difference in the sensitivity of the flowmeter between turbulent and laminar flows is practically negligible when (intensity of magnetic field/diameter of the pipe)>1.5. Calculated results for the induced voltage are presented for the case where the pipe wall is a conductor and the magnetic field distribution arbitrary. As examples the end effect, correction factors have been calculated for the case where liquid sodium and 304 stainless steel are used as fluid and pipe wall. (author)