Two dimensional cavitation waterhammer model for a reservoir-pipeline-valve system

ABSTRACT

A waterhammer model was proposed to simulate a transient event with cavitation in a simple pipeline system. The governing equations for a quasi-two-dimensional model were solved through a hybrid scheme of the method of characteristics and the finite difference method considering the relationship between pressure head reduction and cavitation. An alternative method to address the boundary condition for the two-dimensional model was proposed, which improved the stability of the existing approaches. The comparison of longitudinal and radial velocity profiles between the proposed and existing models exhibited significant differences, which can be explained by the sequential generation and collapse of the cavity. The time series of the pressure head obtained through experimental transient events with vapour cavitation showed good agreement with that of the proposed model. The investigation of energy under a waterhammer showed that the pattern of transition between internal energy and kinetic energy is also substantially affected by the fate of cavitation during transient events.

Keywords:

• Waterhammer
• pipeline system
• cavitation
• two dimensional model
• energy transition

ORCID

Hyunjun Kim http://orcid.org/0000-0003-2101-8026

Sanghyun Kim http://orcid.org/0000-0001-8393-7613

Additional information

Funding

This research was supported by Ministry of Environment (MOE) [grant number RE201606133]. The authors express their appreciation for this support. They also express their gratitude to the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [grant number NRF-2017R1A6A3A01075847].