Experimental analysis of the 3D flow leading into an electrostatic precipitator

An electrostatic precipitator (ESP) is an air pollution reduction facility, which has a particle separation efficiency that varies with flow uniformity. Previous experimental research on ESPs has typically utilized simple models with uniform inlet flow and single-point measurement invasive instruments that affect the flow. Most of these studies were not able to properly analyze the complex three-dimensional internal flow structure. Prior numerical research typically modeled the perforated plates within the diffuser as porous media, which yielded inaccuracies in the flow structure. To address these limitations, this study employed a noninvasive flow measurement technique—magnetic resonance velocimetry (MRV)—to experimentally analyze the three-dimensional flow structure leading into and inside the diffuser of a realistic ESP model. The experimental results revealed non-uniform flow within the inlet ducts due to the wake of a guide vane in the upstream bifurcation region. As the flow passed through curved ducts, the non-uniform flow distribution was exacerbated before reaching the diffuser inlet and eventually led to the formation of a large recirculation zone within the diffuser. Inside the diffuser, mixing between the individual jets exiting the perforated plates and the recirculation zones occurred in a complicated manner. The non-uniform flow at the diffuser exit negatively affects the flow distribution entering the collection plates. Overall, this study highlights the significance of the upstream flow uniformity when designing ESPs. Graphical abstract