CFD Simulation of Air–Water Interactions in Rapidly Filling Horizontal Pipe with Entrapped Air
Publication: World Environmental and Water Resources Congress 2021
ABSTRACT
One-dimensional mathematical models have been developed in order to predict pressure transients for pipes containing entrapped air undergoing rapid filling. A common hypothesis was adopted in these models, as there exists a distinct vertical air-water interface throughout the filling process. The limitation on the assumption becomes significant for pipes with large diameter, where the filling front undergoes notable deformation due to density difference and gravity effects. This study modeled air-water interactions in a horizontal pipe over rapid filling processes, by using the compressibleInterFoam solver of OpenFOAM. Both empty and partially filled pipe filling cases were simulated and compared with rigid-column models. Comprehensive analyses are presented, including detailed velocity profile, pressure distribution, temperature variation of entrapped air, and interface evolution. The results indicate that the transient water flow is analogous to water hammer flow and that the contribution of air-water mixing on the pressure oscillation damping is considerable. The findings are helpful to better understand the physics of the flow and to improve numerical models.
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World Environmental and Water Resources Congress 2021
Pages: 495 - 507
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© 2021 American Society of Civil Engineers.
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Published online: Jun 3, 2021
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