Numerical Simulation of Transient Flow in Pressurized Water Pipeline with Trapped Air Mass

Abstract

The 2D VOF (volume of fluid) model is introduced in this paper to simulate rapid filling process in pressurized water conveyance pipeline with trapped air mass. The movement of gas-water interface, pressure distribution, maximum pressure and position of its occurrence during filling process are modeled and analyzed. According to results, sudden pressure increase caused by water striking on pipe wall could happen, and is sensitively influenced by geometry parameters of pipeline. When occurrence time of water striking on pipe wall is prior or close to that of maximum air pressure, maximum pressure of is obviously greater than maximum air pressure numerically. With increase of diameter of pipeline, maximum pressure of increases gradually, and phenomenon becomes clearer when inlet pressure is higher. Obviously, above-drawn conclusions are essentially different from those based on one- dimensional model, such as the maximum air pressure is maximum pressure of system and the maximum pressure changes with diameter of pipeline but slightly, which are caused by inherent limitations of simplification and basic assumptions of one-dimensional model.