A banked wide-angle diffuser with application to electrostatic precipitators

Abstract

This article introduces a simple and robust method of achieving low-velocity, uniform flow in a wide-angle diffuser upstream of an electrostatic precipitator used to control particulate emissions. A diffuser is inherently vulnerable to boundary layer separation, which greatly deteriorates flow uniformity, adversely affecting electrostatic precipitator performance. Conventionally, two different approaches are used to prevent separation in a diffuser: either reduce the adverse pressure gradient inside the diffuser or increase near-wall fluid momentum to overcome the existing adverse pressure gradient. The present alternative simultaneously incorporates both approaches through the use of an ultra-high porosity cylinder bank and outperforms the predominant technology in terms of flow uniformity.