Experimental Study of Flow Characteristics in Vortex Drop Shaft

Abstract

Vortex drop shafts are utilized to dissipate and transport the energy of flows in sewerage networks. A vortex drop shaft is composed of three parts: the inlet structure, the vertical shaft, and the dissipation chamber. This study evaluated the performance of the dissipation chamber in terms of flow energy dissipation, the type of outflow (e.g., subcritical and supercritical), and the amount of pressure imposing on the chamber bottom. To improve the performance of the dissipation chamber, four elements—a baffle, a weir, a venturi, and a sump—were implemented. Then the influence of each element on the performance of the dissipation chamber was investigated. The results revealed that such elements dissipated the inflow to the chamber by 90.5%–96.9%. These elements also take part in controlling outflow and decreasing pressure on the chamber bottom. Considering flow energy dissipation, the type of outflow and imposing pressure on the dissipation chamber bottom, appropriate geometric dimensions for the elements inside the dissipation chamber are proposed.