Surge Analysis of Air Vessel with Different Connection Types in Pressurized Water Delivery Systems

Air vessels have been commonly applied to prevent water hammer related to pump operations, but their connection types and effects have rarely been discussed. In this study, surge analysis of air vessels with three different connection types was conducted using the perturbation method. The coefficients of impedance and friction were introduced to the influence of the type of connection on the transient conditions in the vessel and the pipe. A mathematical model of the double-connecting pipe air vessel (DCP-AV) was established based on the method of characteristics (MOC). The hydraulic transient simulation of a practical water delivery project was then conducted to verify the accuracy of the analysis. The results showed that the theoretical analysis, Runge-Kutta method, and numerical simulation were in good agreement. Additionally, the DCP-AV combined with a one-way valve was found to considerably reduce the maximum water level in the vessel, and reduce the maximum pressure of the pipeline.