Characterization of electrohydrodynamic flow in a plate-plate electrostatic precipitator with a wire-cylinder pre-charger by data-driven vortex and residence time analysis

The two-stage electrostatic precipitator (ESP) is widely used for indoor air cleaning field, while both the Particle Image Velocimetry (PIV) observations and well-characterized quantitative descriptions are probably scarce. In this work, we propose to use vortex analysis, which is the main quantitative method for flow field, and the relative residence time method (RRT) to evaluate the electrohydrodynamic flow (EHD) in a plate-plate ESP. The effects of electrical energization, pre-charger polarity and primary gas flow velocity are studied. Two vortex indexes sort the particle flow as five patterns and increase almost linearly with applied voltage. Four final particle statuses, penetrated, collected, stagnant and back-mixed are clarified by RRT method. The data generated by RRT are utilized to derive the PIV index for further analysis of the ESP performance. The trend, which rises first and drops later, suggests PIV index is expected to pave a new way to clarify the relationship between the ESP flow patterns and particle collection efficiency.