Numerical simulation of three-dimensional electrohydrodynamics of spiked-electrode electrostatic precipitators

The three-dimensional flow interaction between the primary flow and the secondary flow (often called an electric wind or ionic wind) for tuft/point corona in the wire-duct type electrostatic precipitators (ESPs) has been investigated in the past. This study was further extended to incorporate the alternately oriented point corona on the wire-plate type electrodes, which are commonly used for the industrial ESPs. The secondary flow distribution without gas flow consists of a pair of long-elliptic and circulatory cells between spikes points along the wire. However, the flow rotation between spiked points is the same direction, which is opposite to that of the point corona electrode. The flow interaction is described using dimension-less number, N_EHD, which is the ratio of the ionic wind velocity to the primary flow velocity. When the primary flow exists, a pair of long-elliptic spiral flows is formed in the direction of the gas flow between ground plates. When the relative distance between the spike point spacing and the wire-to-plate spacing (or the ratio of S_z/d) is greater than 0.17, the organized long-elliptic spiral flow is formed. When S_z/d is less than 0.1, the organized spiral flow is diminished, resulting in turbulence.