Study on Mathematic Model of Air Valve Based on Real Gas Characteristics

Abstract

Air valve is an important measure of water hammer protection in long water supply system. Accurate simulation of the air-inlet and air outlet process of air valve is directly relative to the safety of water supply engineering. Operational principle of air valve is analyzed and new mathematic model of air valve is built based on Van der Waals equation. Protective function of air valve in transient process caused by valve closing is analyzed with the characteristics method. The result shows the new mathematic model of air valve presents a series of new characteristics in the process of air-inlet and air-outlet comparing with the old mathematic model based on ideal-gas state equation.