This invention discloses an online monitoring method for external leakage in aircraft hydraulic systems based on a mechanistic model, belonging to the field of hydraulic
system technology. It aims to solve the technical bottlenecks of existing aircraft hydraulic
system external leakage monitoring, such as poor real-time performance, high
false alarm rate, and inability to detect the leakage amount and rate. The method includes the following steps: First, a mechanistic model is constructed based on the law of conservation of
mass. Combined with
temperature and pressure data monitored by airborne sensors, the oil volume inside each hydraulic component outside the tank is calculated according to volumetric deformation characteristics, deriving the theoretical value of the oil volume inside the self-pressurized tank. Second, the mechanistic model is corrected by comparing the theoretical value with the actual monitored value using flight parameter data under leak-free conditions, eliminating inherent errors. Finally, real-time flight parameter data is input to recalculate the theoretical value, and compared with the real-time monitoring value from the
level sensor to determine if the
system is leaking. If leakage occurs, the leakage amount and rate are calculated, and an early warning result is output. This invention relies on existing airborne sensors, requiring no additional equipment or sensors. It can effectively distinguish between normal oil fluctuations and actual leakage, improving monitoring accuracy and real-time performance. It provides data support for the handling and maintenance of aircraft hydraulic system leakage faults and has certain
engineering application value.