Transient phenomena during the emptying process of a single pipe with water–air interaction

ABSTRACT

Emptying pipelines can be critical in many water distribution networks because subatmospheric pressure troughs could cause considerable damage to the system due to the expansion of entrapped air. Researchers have given relatively little attention to emptying processes compared to filling processes. The intricacy of computations of this phenomenon makes it difficult to predict the behaviour during emptying, and there are only a few reliable models in the literature. In this work, a computational model for simulating the transient phenomena in single pipes is proposed, and was validated using experimental results. The proposed model is based on a rigid column to analyse water movement, the air–water interface, and air pocket equations. Two practical cases were used to validate the model: (1) a single pipe with the upstream end closed, and (2) a single pipe with an air valve installed on the upstream end. The results show how the model accurately predicts the experimental data, including the pressure oscillation patterns and subatmospheric pressure troughs.

Keywords:

• Air–water
• air valve
• entrapped air
• pipelines emptying
• transient flow
• water distribution networks

ORCID

Vicente S. Fuertes-Miquel http://orcid.org/0000-0003-3524-2555

Oscar E. Coronado-Hernández http://orcid.org/0000-0002-6574-0857

Pedro L. Iglesias-Rey http://orcid.org/0000-0001-8300-3255

Daniel Mora-Meliá http://orcid.org/0000-0002-6191-7299

Additional information

Funding

This study was supported by the Program Fondecyt Regular [Project 1180660] of the Comisión Nacional de Investigación Científica y Tecnológica (Conicyt), Chile, http://data.crossref.org/fundingdata/funder/10.13039/501100002848.