Author(s): Ruilin Feng; Elias Tasca; Mike Van Meerkerk; Mohsen Besharat; Ling Zhou; Helena Ramos; Uros Karadzic

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Keywords: Urban drainage system; Two-phase flow; Entrapped air; Physic experiments

Abstract: There are more attention about the occurrence of two-phase transient flows related to safety of urban drainage system (UDS), significantly influencing by rapid urbanization and the impacts of climate change. The problem of air entrapment at a high point of an undulating UDS profile is investigated used the Deltares Beta-Loop facility. The experiments’ test section could be replaced to consider two downward pipe angles, namely 10° and 30°. A wide range of hydraulic variables are covered in this experiment, including three different velocities (0.6, 0.9, and 1.2 m/s), various air pocket volumes, and two distinct transient scenarios (i. e., pump ramp-up and pump ramp-down) inducing transient flow conditions in the system. Additionally, two boundary conditions were tested namely closed-end and open-end along with the use of an air valve. The pressures, pressure difference, air-water flow patterns, and temperature curves are simultaneous recording for clearly depicts their correlations. The experiment focuses on four parts: 1) analysis of air movement, air water mixing phenomenon and the dynamic change of air-water coupling in UDS; 2) analyze the correlation between pipe angles and air dynamics; 3) reveal the dynamic response and blocking characteristics of air volumes in the two-phase transient process; 4) explore the system response mechanism of two-phase flow with exhaust facilities in the pipeline. More specifically, this research used Beta-Loop facility to investigate air entrapment in piping systems during unsteady flows, effectively enhancing air-water dynamics comprehension and aiding in the refinement of current numerical simulations.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P2068-cd

Year: 2025