Capacitance Planar Array Sensor for Fast Multiphase Flow Imaging

In this paper, we introduce a novel planar array sensor based on electrical capacitance (permittivity) measurements to visualize flows of multiphase mixtures along the surface of objects. The prototype sensor is formed by 32 times 32 interdigital sensing structures. It can be mounted onto the wall of pipes or vessels and thus has minimal influence on the flow. An associated electronics measures the capacitance of the fluid at each sensing structure in a multiplexed manner at high sampling rate. This way, images of the fluid distribution are produced. The electronics is able to generate up to 15 000 images/s. Results of system evaluation and results of two exemplary flow experiments are presented and discussed.