Investigating electrohydrodynamic flow and particle behavior: The role of angle between electric wind and primary airflow in electrostatic precipitators

An integrated numerical model is proposed to investigate the influence of the angular difference (θ) between the primary airflow and ionic wind on flow patterns, particle transport, and deposition in electrostatic precipitators (ESPs), particularly in comfigurations with discharge needles. The model, implemented in ANSYS Fluent v19.3.0 with the RNG k-ε turbulence closure and Q-criterion vortex analysis, incorporates the electric body force obtained by solving the electric field equations. The results indicate that θ exerts a much stronger influence on ion charge density than on electric field strength. As θ deviates from 90°, the diffusion of ion charge density increases. For θ < 90°, the enhanced ion charge density facilitates earlier particle charging, thereby improving particle removal efficiency. Altering θ also alters the isovortex surfaces, forming vortex rings and large-scale counter-rotating vortex pairs, which generate helical gas flow that affects particle transport and deposition. Particle removal efficiency first increases with θ and then decreases, peaking at θ = 60° for all particle diameters. Moreover, increasing θ or particle diameter results in more regular deposition patterns on the collecting surface.