A generalized method for sub-idle modeling of aircraft engines

Aircraft engine starting is usually defined as the operating range between zero and engine idle speed. A high-fidelity model of this process can be used not only for analysis and optimization of the start-up process, but also to reduce huge costs of rig test. In this paper a component level model of the process is developed using component characteristics extrapolation method to solve the key problem of lacking map data of components in low rotation speed; meanwhile, the volume dynamics is used to match different components which can avoid complex iterative calculations. The influence of fuel-to-air ratio of combustion efficiency and total pressure loss coefficients of different components during the starting process are also taken into consideration. The simulation results show that the model can simulate the ground starting process accurately.