关键词: 凝固结冰, 灭火飞机, 水箱, 高空, 冷浸, 数值模拟

Abstract:

A systematic numerical simulation study was conducted to address the issue of internal water tank solidification in firefighting aircraft under high-altitude low-temperature conditions. Based on computational fluid dynamics methods, a solidification-melting model considering fluid-structure interaction heat transfer and phase change processes was adopted. Through reasonable simplification of the complex geometric model, a quasi-three-dimensional computational model suitable for engineering analysis was developed. The influence laws of key parameters, including high-altitude cold-soak temperature, ground initial water temperature, and cold-soak time, on the freezing characteristics of the water tank were investigated. Combining with the parameter influence laws, a safety criterion using the average ice thickness of the water-release door and the water tank center temperature as criteria was proposed. The simulation results indicate that the ground initial water temperature is the primary factor affecting the freezing risk. When it is as low as 5 ℃, the cold-soak freezing risk during high-altitude flight is relatively high. The combined effect of high-altitude cold-soak temperature and cold-soak time is significant, and the flight time under low-temperature conditions needs to be strictly controlled. The research results can provide technical support for the water tank design, safety analysis, and flight operation of similar aircraft.

Key words: solidification and freezing, firefighting aircraft, water tank, high altitude, cold soak, numerical simulation