Optimization of electrostatic sensor for velocity measurement based on particle swarm optimization technique

Abstract

Electrostatic sensors are broadly applied to measure velocity of solid particles in many industries because controlling the velocity particles improves product quality and process efficiency. These sensors are selected due to their robust design and being economically viable. Optimization of different electrode sizes and shapes of these sensors is required to find the ideal electrodes associated with maximum spatial sensitivity and minimum statistical error. Uniform spatial sensitivity is a crucial factor because it would lead to increase similarity between the measured correlation velocity and true mean particle velocity. This thesis proposes a new method to optimize different parameters of electrodes for electrostatic sensors. This technique identified characteristics of the electrostatic sensor in a MATLAB code called Particle Swarm Optimization (PSO). A mathematical model of various electrodes to compute spatial sensitivity and statistical error was applied to extract geometric size information of electrodes to detect suitable equations. To validate the proposed method, different values of electrode designs were applied in experimental tests conducted in a laboratory to measure the velocity of solid particles. The experimental results were optimized through Response Surface Methodology (RSM), an optimization technique for experimentation. The optimized results showed that spatial sensitivity of circular-ring electrode is more uniform in comparison to the other electrodes. The optimal length of circular-ring electrode was between 0.577 cm and 0.600 cm. In addition, the best thickness for the electrodes was between 0.475 cm and 0.500 cm. A close agreement between optimization and experimentation verifies that the proposed method is feasible to optimize physical sizes of electrostatic sensor electrodes. These results provide a significant basis of the effect of geometric dimensions on the sensing characteristics of electrostatic sensors.