APPARATUS FOR MONITORING FLUID FLOW IN A PIPE USING ELECTROMAGNETIC VELOCITY TOMOGRAPHY

摘要

An apparatus for monitoring a fluid flow in a pipe using electromagnetic velocity tomography (EVT), the apparatus comprising a pipe defining a flow conduit, a coil system comprising electrically conductive wires located externally of the flow conduit for generating composite magnetic fields within the flow conduit, and an array of electrodes located externally of the flow conduit for detecting voltages induced in an electrically conducting fluid flowing thorough the magnetic field, wherein the position of the electrically conductive wires around the flow conduit is defined by a coordinate system having mutually orthogonal x and y axes extending in positive and negative directions in a first plane from an origin located at a geometrical centre of a cross-section of the flow conduit, the first plane being orthogonal to a longitudinal direction of the flow conduit, the coil system comprising first and second coils located on respective opposite sides of the x axis, wherein each of the first and second coils comprises K sub-coils, wherein K>1 and in each of the first and second coils the respective sub-coils are electrically connected together, wherein in each of the first and second coils the respective sub-coils are mutually circumferentially nested together and extend parallel to the longitudinal direction of the flow conduit whereby each of the sub-coils, when viewed in cross-section orthogonal to the longitudinal direction, comprises a respective pair of wire batches on respective opposite sides of the y axis and the first and second coils cumulatively comprise a series of the wire batches which are mutually spaced around at least one first circular line surrounding a circumference of the flow conduit, each wire batch comprising a plurality of the electrically conductive wires crossing the first plane in a direction orthogonal to the first plane, wherein there are 2K wire batches in each of the first and second coils and 4K wire batches in total in the first and second coils, wherein the wire batches of the first coil are located within the angular range 0 th wire batch subtends an angle θk, and each kth wire batch comprises Nk wires and Nk is proportional to |cos θk|.