Performance of the porous media model for simulating flow through an electrostatic precipitator

Abstract

An electrostatic precipitator (ESP), which filters the fine particles present in the exhaust gas generated from a power plant, has a better particle-collection efficiency when there exists a uniform flow in the dust collection chamber. However, most former investigations examined the flow distribution via numerical approaches that modeled the perforated plates within the inlet diffuser as porous media, which have not been adequately validated. Therefore, the aim of this study was to examine the performance of the porous media model for simulating the flow through perforated plates of an ESP diffuser by numerical simulation and experiment. Simulation results using the porous media model were compared with those obtained with a fully resolved mesh precisely describing the complete geometry of the entire perforated plate. The results obtained with both these methods were consistent with experimental results obtained upstream of the inlet diffuser, but the porous media model could not accurately simulate the flow distribution across the perforated plates. Overall, this model failed to predict the deflection of incoming flow on the solid bars and the wakes behind the bars, and could not reflect the vena contracta phenomenon occurring within the holes of the plate. As a result, the simulated flow distribution at the entrance of the main dust-collection chamber differed from that observed in the experiment, which resulted in poor prediction of the flow field inside the chamber. Therefore, this porous media model requires further improvement for wide-scale adoption in industrial practical applications, e.g., ESP for flue gas treatment in power plants.