Planar array sensor for high-speed component distribution imaging in fluid flow applications

A novel planar array sensor based on electrical conductivity measurements is presented which may be applied to visualize surface fluid distributions. The sensor is manufactured using printed-circuit board fabrication technology and comprises of 64 x 64 interdigital sensing structures. An associated electronics measures the electrical conductivity of the fluid over each individual sensing structure in a multiplexed manner by applying a bipolar excitation voltage and by measuring the electrical current flowing from a driver electrode to a sensing electrode. After interrogating all sensing structures, a two-dimensional image of the conductivity distribution over a surface is obtained which in turn represents fluid distributions over sensor's surface. The employed electronics can acquire up to 2500 frames per second thus being able to monitor fast transient phenomena. The system has been evaluated regarding measurement accuracy and depth sensitivity. Furthermore, the application of the sensor in the investigation of two different flow applications is presented.