Analytical and numerical modelling of trapped air pockets in hydraulic pipeline systems

Pekolj, Jošt (author), Bergant, Anton (author), Perpar, Matjaž (author), Ješe, Uroš (author)

During the operation of water-filled pipelines, air can get trapped in the primary water flow in the form of air trapped pockets or moving bubbles. Consequently, entrained air may change the liquid-filled-pipeline system’s transient response significantly. It could have either a beneficial or a detrimental effect on pressure oscillations. The effect is dependent on the spatial dimensions and other physical properties of the pipeline system, the amount, the location of the air pocket(s), and the nature of the transient excitation. This paper provides an overview of modeling the rigid and elastic water columns in a hydraulic pipeline system with an entrapped air pocket. It presents one-dimensional analytical and numerical solutions for the transient filling of the pipeline system, with the numerical model based on the method of characteristics (MOC).The research aims to analyse the effects of water column elasticity under varying system parameters. Simulation results indicate that higher air pocket pressures are achieved in the rigid column model and that the effects of water column elasticity are most pronounced with a small air length ratio and a high initial pressure difference between the reservoir and the air pocket.

• Language: English
• Keywords: water hammer, pipelines, trapped air pocket, analytical solutions, methods of characteristics
• Work type: Article
• Typology: 1.08 - Published Scientific Conference Contribution
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 1-6
• Numbering: Vol. 1483
• PID: 20.500.12556/RUL-170659
• UDC: 621.22:621.64
• ISSN on article: 1755-1315
• DOI: 10.1088/1755-1315/1483/1/012018
• COBISS.SI-ID: 242317827
• Publication date in RUL: 11.07.2025

Record is a part of a proceedings

• Title: 9th IAHR meeting of the workgroup on cavitation and dynamic problems in hydraulic machinery and systems
• COBISS.SI-ID: 242309891

Record is a part of a journal

• Title: IOP Conference Series : Earth and Environmental Science
• Publisher: Institute of Physics
• ISSN: 1755-1315
• COBISS.SI-ID: 4403041

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: vodni udar, cevovodi, ujet zračni mehur, analitične rešitve, metoda karakteristik

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: L2-1825
• Name: Modeliranje zračnih mehurjev ujetih v hidravličnih cevnih sistemih