Numerical study on the flow characteristics of ultrahigh pressure gas affected by valve opening time based a real gas model

As high-pressure gas pipe valve systems are widely used in the industrial field, it is significantly important to understand the gas flow characteristics during the opening process of the valves. However, temperature and pressure greatly affect the physical parameters of gases such as density and the specific heat at high pressures, and the gas state will no longer conform to the ideal gas law. In order to investigate the flow characteristics of ultrahigh pressure gas in the pipe under different valves and opening times, a real gas model for the pressure of 40 MPa was established in this paper. Three typical valves were employed, which were the ball valve, the butterfly valve, and the gate valve. In addition, the distributions of gas pressure and velocity in the pipe were studied with the valve opening time ranging from 0.1 to 1 s, as well as the variation rules of pressure, velocity, and flow in the downstream section of the pipeline. The results show that the larger the valve opening time, the smaller the pressure rise rate in the downstream section, and the flow coefficient of the three valves gradually increases during the opening process. When the valve is fully open, the flow coefficients of the ball, gate, and butterfly valves are 0.7 m³/h, 0.26 m³/h, and 0.2 m³/h, respectively.