Author(s): S. N. Chan

Linked Author(s):

Keywords: Scroll vortex intake; Swirling flow; Air-core; Volume-of-Fluid method

Abstract: Scroll vortex intakes are vortex drop structures commonly used in water supply, drainage and sewerage systems, characterized by a vortex chamber with its wall curling inwards to the dropshaft and a horizontal bottom. The stormwater flows into the intake via an eccentrical approach channel, which imparts vortex motion to the flow, forming a swirling vortex flow with a stable air core through the center of dropshaft. Over past decades, much effort has been devoted to investigating the scroll intake vortex flow, yet the understanding and predictions of the vortex flow is still far from complete due to a lack of detailed investigation on its velocity field and air core characteristics. In this work, a three-dimensional (3D) computational fluid dynamics (CFD) model using the Volume-of-Fluid (VOF) method is used for investigating the complex flow of a scroll vortex intake. The CFD model predictions are validated with detailed flow profile, flow velocity and air core measurements on a physical hydraulic model. It is found that the vortex flow in the scroll chamber resembles a free vortex and the circulation is approximately equal to that at the inlet to the chamber, with a thin bottom boundary layer. For the vortex flow at the bellmouth outlet, the tangential velocity distribution satisfies a Rankine vortex. Furthermore, the vortex flow at the bellmouth outlet possesses a circulation constant which is smaller than that in the chamber.

DOI: https://doi.org/10.26077/5qw4-ne72

Year: 2019