A New Processing Method for the Nonlinear Signals Produced by Electromagnetic Flowmeters in Conditions of Pipe Partial Filling

Abstract

When a pipe is partially filled with a given working liquid, the relationship between the electromotive force (EMF) measured by the sensor (flowmeter) and the average velocity is nonlinear and non-monotonic. This relationship varies with the inclination of the pipe, the fluid density, the pipe wall friction coefficient, and other factors. Therefore, existing measurement methods cannot meet the accuracy requirements of many industrial applications. In this study, a new processing method is proposed by which the flow rate can be measured with an ordinary electromagnetic flowmeter even if the pipe is only partially filled. First, a B-spline curve fitting method is applied to a limited set of measurements. Second, matrix inversion required in the B-spline curve method is optimized in order to reduce the number of needed computations. Dedicated experimental tests prove that the proposed method can effectively measure the average flow velocity of the fluid. When the fluid level of the pipeline is between 50% and 100%, the relative error is less than 3.5%.

Experimental Study of Liquid Metal Flow for the Development of a Contact-Less Control Technique

“…Another important area of metallurgy is the removal of impurities from liquid metals. Actually, there are two mechanisms for generating electromagnetic forces: conduction [8][9][10][11] and induction [12][13][14] mechanisms. The disadvantage of the conduction mechanism is the current supply to the cell subjected to high temperatures.…”