Paper Title
Analysis of The Influence of Valve Closing Time on Water Hammer Effect

Long-distance heating and transportation is of great significance to air pollution prevention and control and help peak carbon dioxide emissions and carbon neutralization. In practice, the opening and closing of valves will cause problems such as water hammer impact. In this paper, taking the heating network of Ningxia Huadian Lingwu Company's first-stage heating network project to Yinchuan as the object, the influence of different valve closing times on water hammer effect is studied by using numerical simulation software. The research shows that the pressure changes before the valve are different under different valve closing times. However, no matter how long the valve is closed, a pressure peak will appear at the upstream of the valve, and the closer it is to the valve, the greater the pressure peak will be, and the maximum value, namely the maximum surge pressure, will be reached at the valve. Reducing the opening and closing speed of the valve can slow down the impact effect of water hammer to a certain extent, which shows that the longer the valve closing time, the smaller the maximum surge pressure and the gentler the pressure oscillation. Keywords - Long-Distance Heating, Close Valve, Water Hammer Effect, Numerical Simulation.