It has been over 40 years since the electromagnetic flowmeter came into practical use. Since then many improvements have been made to the actual meter and many theoretical problems have been solved. Shercliff derived two-dimensional weighting functions and showed how sensitive a magnetic flowmeter with a uniform magnetic field would be to flow profile. A few authors obtained general solutions of the weighting function for the three-dimensional case. Furthermore, Smyth and Al-Khazraji calculated two-dimensional weighting functions for a flowmeter with finite electrode length.
However, most of these analyses are based on certain assumptions; such as point electrodes, nonconductive wall and/or two-dimensional analysis. If these assumptions are not satisfied, mathematical difficulties are encountered in solving the problem analytically.
This paper proposes a discrete approximation suitable for investigation of a magnetic flowmeter. This method simulates the conductive fluid inside a pipe by using virtual resister circuit network.
Applying this method to magnetic flowmeters which have wall contamination and which are connected with adjacent conductive pipes, approximate weighting functions are obtained. From investigation of calculated signal error with flow test the simulation method has been proved to be effective to predict the error in the case where complex boundary conditions are encountered.
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