Experimental and numerical optimization of pressurized air vessel performance for water hammer mitigation

Controlling water hammer pressure is essential, necessitates a transient surge analysis to identify critical pressure points along a pipeline system. A pressurized air vessel is a pressure control device used to control both positive and negative pressure fluctuations. This study investigates three key parameters that affect the sizing of the pressurized air vessel: orifice diameter (the throttling aperture), the vessel diameter, and water volume fraction ratio. A mathematical model, developed using the FORTRAN programming language and based on the unsteady one-dimensional momentum and continuity equations, determines the optimal sizing of these parameters. These equations are solved using the method of characteristics, and the pressurized air vessel is mathematically modelled as a quasi-one-dimensional flow system. An experimental test rig, equipped with a rapid closing solenoid valve and pressure sensors, is used to validate the mathematical model results. Both the experimental and numerical results demonstrate the effectiveness of the pressurized air vessel to dampen water hammer pressure. The findings indicate that the throttling action has a significant effect on the required size of the pressurized air vessel. This study presents a novel approach that provides quantitative insights into key parameters that affect the performance of the pressurized air vessel by using the combined modelling and experimental validation. The orifice diameter is the most influential parameter on the water hammer head, vessel air head, and water level inside the vessel.