Author(s): Qingzhi Hou; Youxu Song

Linked Author(s): Qingzhi Hou

Keywords: Geysering; Mass shedding rate; Physical experiment; Slug flow; Three-dimensional CFD model

Abstract: Deep tunnel drainage systems have been widely used in many majority cities in the world to solve the urban waterlogging problems. During the rapid filling process of deep tunnels, entrapped air pockets occur due to complex water-air interaction, which are continuously compressed by surrounding water and carry a high pressure. When the compressed air pocket travels to a dropshaft of the deep tunnel, the sudden pressure release propels the water slug ending with a blowing-out of air-water mixture and causing a pressure oscillation harmful to the tunnel system. This phenomenon is known as geysering. To study the water slug characteristics and its influencing factors, the mechanisms of liquid shedding from the tail of the water slug plays a vital role. In this paper, the mass shedding rate of the water slug in the dropshaft with a dead-end orifice of different sizes is studied experimentally and numerically. The results show that the numerical simulations are in good agreement with the experimental data. When the aperture ratio is greater than 0.3, it has no effect on the slug mass shedding rate.

DOI: https://doi.org/10.3850/iahr-hic2483430201-414

Year: 2024