Computational fluid dynamics for sub-atmospheric pressure analysis in pipe drainage

Abstract

The occurrence of sub-atmospheric pressure in the drainage of pipelines containing an air pocket has been known as a major cause of several serious problems. Accordingly, some system malfunction and pipe buckling events have been reported in the literature. This case has been studied experimentally and numerically in the current research considering objectives for a better understanding of: (i) the emptying process, (ii) the main parameters influencing the drainage, and (iii) the air-water interface deformation. Also, this research demonstrates the ability of a computational fluid dynamic (CFD) model in the simulation of this event. The effects of the air pocket size, the percentage and the time of valve opening on the pressure variation have been studied. Results show the pipeline drainage mostly occurs due to backflow air intrusion. The worst case scenario is associated with a fast valve opening when a tiny air pocket exists in the pipeline.

Keywords:

• Computational fluid dynamics (CFD)
• emptying process
• entrapped air simulation
• experimental set-up
• realizable k-ϵ turbulence model
• sub-atmospheric pressure
• volume of fluid (VOF) multiphase model

This article is referred to by:

Closure to “Computational fluid dynamics for sub-atmospheric pressure analysis in pipe drainage” by Mohsen Besharat, Óscar E. Coronado-Hernández, Vicente S. Fuertes-Miquel, Maria Teresa Viseu and Helena Margarida Ramos, J. Hydraulic Res. 58(4), 2020, 553–565, https://doi.org/10.1080/00221686.2019.1625819

Acknowledgements

The authors want to thank the project REDAWN (Reducing Energy Dependency in Atlantic Area Water Networks) EAPA_198/2016 from Interreg Atlantic Area Programme 2014–2020 for the support on the extended knowledge of some members. Also, the authors acknowledge the hydraulic lab of Universitat Politècnica de València in Spain for providing the experimental facility.

Additional information

Funding

This work is supported by Fundação para a Ciência e Tecnologia (FCT), Portugal [grant number PD/BD/114459/2016].