Numerical Investigation and Analysis of Gas Leakage Process in High-Pressure Duct of Civil Aircraft

The high-pressure duct system is used in environmental control system of civil aircraft, which provides the fresh air to the cooling system. Once the gas in the duct system leaks, it can cause serious damage to the safety of the surrounding environment. During the design of high-pressure duct system, the gas leakage process needs to be studied, and the heat transfer and flow characteristics should be analyzed to evaluate the effect of the gas leakage on the surrounding environment. In this paper, the three-dimension dynamic simulation method is applied to obtain the gas leakage process in the high-pressure duct system, and the fluid-structure interaction is also considered. Based on the numerical simulation results, the variation of the heat transfer and flow characteristics of leaked gas with leak-age time is obtained; the influence factors of the gas leakage process, including the inlet pressure and the air-layer sealing, are studied. The results show that, the pressure ratio at the leakage holes has a significant effect on the heat transfer and flow characteristics for gas leakage process, and the high-pressure ratio leads to the shock wave of the gas, which decreases the detection accuracy of the leakage gas in the high-temperature and high-pressure duct system.