Session

Session 1 2022

Start Date

10-26-2022 12:00 AM

Abstract

Critical submergence for square water intakes in an open channel flow has been investigated experimentally and numerically in this paper. The depth of water at which the tail of a free surface vortex core just reaches the tip of an intake causing air entrainment is referred to as critical submergence. The formation of an air-entraining vortex in the vicinity of an intake is considered to be a severe problem for pumps. Experiments were conducted in a concrete flume of 9.47 m length, 0.5 m wide, and 0.6 m deep with an intake of size 0.04 m×0.04 m under uniform flow for different flow conditions. A three-dimensional Multiphase CFD Model was also developed for simulating critical submergence for the intakes. SST k-ω turbulence model together with the volume of fluid (VOF) two-phase (water-air) model were used to simulate the flow field in the water intake system. In the CFD simulation study, critical submergence was identified using phase volume fraction analysis and free surface streamline analysis. From both experimental and numerical studies, it is found that the approach flow Froude number and intake flow Froude number play an important role for estimating critical submergence depth. The critical submergence increases with an increase in intake Froude number and decreases with an increase in approach Froude number for a square Intake. The outcomes of the CFD simulation were validated with experimental data.

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Oct 26th, 12:00 AM

Experimental and Numerical Investigation on Critical Submergence for Square Water Intakes

Critical submergence for square water intakes in an open channel flow has been investigated experimentally and numerically in this paper. The depth of water at which the tail of a free surface vortex core just reaches the tip of an intake causing air entrainment is referred to as critical submergence. The formation of an air-entraining vortex in the vicinity of an intake is considered to be a severe problem for pumps. Experiments were conducted in a concrete flume of 9.47 m length, 0.5 m wide, and 0.6 m deep with an intake of size 0.04 m×0.04 m under uniform flow for different flow conditions. A three-dimensional Multiphase CFD Model was also developed for simulating critical submergence for the intakes. SST k-ω turbulence model together with the volume of fluid (VOF) two-phase (water-air) model were used to simulate the flow field in the water intake system. In the CFD simulation study, critical submergence was identified using phase volume fraction analysis and free surface streamline analysis. From both experimental and numerical studies, it is found that the approach flow Froude number and intake flow Froude number play an important role for estimating critical submergence depth. The critical submergence increases with an increase in intake Froude number and decreases with an increase in approach Froude number for a square Intake. The outcomes of the CFD simulation were validated with experimental data.