Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication

A field-focusing imaging sensor for fast visualization of multiphase flows

Da Silva, M. J.; Hampel, U.


A novel imaging sensor based on multichannel capacitance measurement is introduced in this article. The field-focusing sensor uses a multitude of strip electrodes located at two opposing and parallel walls of a vessel, whereby the opposing electrodes run perpendicular to each other. By the use of a special multiplexed excitation-sensing scheme a focusing of the electrical field to well-defined regions within the sensor is achieved which allows the sensor to individually interrogate each one of those regions and thus to two-dimensionally map the flow constituents contained by the sensor. Associated electronics can generate up to 625 frames per second. The sensor can be considered as a high-speed capacitance ‘camera’ for a channel flow. Electrical field simulations with finite element method confirm the focusing effect explored by the sensor. The imaging capability is shown by the visualization of a stratified air-water mixture. Furthermore, the sensor was used to monitor the transient behaviour of the mixing of two substances with different densities.

Keywords: electrical capacitance; sensor; flow visualization; multiphase flow; electrical field simulation; finite element method