Analysis of pressure variation characteristics of aircraft fuel tank based on open venting system

Abstract The venting system flight test was carried out by the aircraft with an open venting system. This article introduces the flight test method and analyzes the mechanism of the changes in the pressure difference between the interior and exterior of the tank, under seven typical scenarios. The results indicate that the changes in pressure difference are not solely influenced by a single factor but rather by a combination of aircraft physical characteristics-related factors and fuel tank ventilation-related factors. Among the aircraft’s physical characteristics-related factors, the effect of pitch and overload variations are obvious, while the effect of roll variation is unapparent. Among the fuel tank ventilation-related factors, the variation of flight altitude and fuel consumption are the key factors resulting in the pressure difference between the interior and exterior of the tank. It is concluded that in the fuel tank venting system design, the flow path size should be matched to the maximum airflow brought by the variation of flight altitude and fuel consumption, so as to ensure that the pressure difference between the interior and exterior of the tank is within the acceptable range of the structural strength of the fuel tank.