Autonomous planar conductivity array sensor for fast liquid distribution imaging in a fluid coupling

In this article, we introduce a new autonomous planar array sensor based on the measurements of electrical conductivity which has been applied to the visualization of fluid distributions inside a fluid coupling during normal operation. The sensor is composed of approximately 1000 interdigital sensing structures which are used to measure the two-dimensional electrical conductivity distribution at the sensor's surface with a fast multiplexed probing-sensing scheme at up to 10 kHz frame rate. Two such sensors were used to measure dynamic two-phase flow patterns in a fluid coupling at full operation at 790 rpm speed. Therefore, the sensors were mounted on the pressure-side and the suction-side walls of a blade channel inside a test coupling. The whole measurement system is run on a battery and controlled via wireless link, thus being fully autonomous, which enables sensor and electronics to rotate together with the coupling.