Investigation of field electrode geometries in capacitive flow measurement

In this paper we present a new electrode arrangement for capacitive spatial filtering, which provides an increased sensitivity to permittivity changes inside the pipe and furthermore offers the potential to resolve a spatial velocity distribution. The original filter design makes use of semi ring shaped electrodes operated as transmitters and corresponding opposed receivers mounted on a section of nonconducting pipe. An advanced setup, consisting of transmitter and receiver ring electrodes alternately placed along the pipe axis, is proposed. In contrast to the original electrode design, where the electrical field lines pass the pipe interior in a radial orientation perpendicular to the flow direction they propagate in parallel to the flow direction. The aims of the new electrode design are an improved measurement sensitivity and the ability to resolve the spatial velocity distribution inside the measurement volume.