Online monitoring of nonaxisymmetric flow profile with a multielectrode inductance flowmeter

A modified filtered backprojection (FBP) algorithm based on S-L filter function is developed to monitor the velocity profile of nonaxisymmetric flow inside a circular pipe with a multielectrode electromagnetic flowmeter (EMF). This algorithm is simpler than the singular value decomposition and pseudo-inverse based algorithms and fast enough to be used in online monitoring of flow profile. In order to further improve its real-time performance, a simplified algorithm is also proposed. Three kinds of nonaxisymmetric flow profile, i.e. profiles with a single peak, with double peaks and with one peak and one reflux are simulated to evaluate the performance of the proposed algorithms. The projection data are obtained by solving the electric field equation. With these data the velocity profile of the pipe flow can be reconstructed using the new algorithms. The reconstructed profiles have been compared with those obtained by using simple backprojection method. Results obtained demonstrate that the algorithms can be used to monitor the velocity profile of nonaxisymmetric pipe flows.