Correlations between Particle Collection Behaviors and Electrohydrodynamics Flow Characteristics in Electrostatic Precipitators

Abstract

Electrostatic precipitators (ESPs) are widely used to eliminate particulate matter emissions from industrial sources. However, the complex electrohydrodynamics (EHD) flow in ESPs can cause controversial conclusions on particle collection. This paper established an ESP model with an additional source term added to the equation of gas momentum conservation. Correlations between particle motion behaviors and EHD flow characteristics were investigated regarding various discharge voltage, particle size, and electrode position. Results show that the EHD flow presented a back-and-forth distribution between the electrode and plate. The peak value of vy can be as high as 0.15 m s-1. The EHD flow can cause four possible types of particle motion status. The dominant factor for particle motion switched between the electric force and drag force along with the particle motion trajectory. There existed an escaping window at the ESP inlet. Particles released from this window penetrated through the ESP rather than be collected. Modifying the ESP geometry and increasing voltage can narrow the escaping window. When the ESP channel width was narrowed from 0.06 to 0.05 m, the maximum NEHD could increase by 73.4% from 0.94 to 1.63. Consequently, the collection efficiency was significantly improved. The collection efficiency can even amount to 100% for particles sized 2.5 μm.

Numerical Simulation and Analytical Evaluation of the Collection Efficiency of the Particles in a Gas by the Wire-Plate Electrostatic Precipitators

“…Particles are injected into the computational domain from the inlet surface, and the motions and charging process of particles were calculated once through the domain. Collection efficiency as a function of the particle diameter can be obtained by using Equation (23). Figure 10 shows the particle tracking pathlines with respect to residence time for the case of 1 mm wire diameter, 55 kV, and U in = 1 m/s in the 230 mm wide channel.…”

“…lection efficiency as a function of the particle diameter can be obtained by using Equation (23). Figure 10 shows the particle tracking pathlines with respect to residence time for the case of 1 mm wire diameter, 55 kV, and Uin = 1 m/s in the 230 mm wide channel.…”

“…A few numerical strategies have been improved to simulate the flow field of primary fluid and particles, the electric field in the ESP, and the space charge density including the finite volume method [16], the boundary element method [17,18], and the finite differencing technique [19]. The researchers also examined the impact of various operating conditions and ESP geometries on collection efficiency [20][21][22][23]. In another study, Wen et al (2016) presented a numerical model to explain the particle transport, flow field, and electric field of guidance-plate-covered ESPs [24].…”

Review on Enhancement of Electrostatic Precipitator in Automobiles

“…It is observed that collection efficiency is greatly improved. [1] It is based on increasing dust dust-collecting efficiency of an ESP. The collection efficiency of an ESP is affected by mud particles collected by the electrodes.…”