Optimization for the Starting Process of Turbofan Engine Under High-Altitude Environment

The control of the starting process for turbofan engine is a difficult task, especially under high-altitude and low-temperature environment, where its characteristics are more complex and strongly nonlinear. In this paper, the working characteristics of the starting process were analyzed and the corresponding mathematical model was established first. In the starting process control problem, since the fuel supply act as the main control parameter, the model of the fuel regulator system was also built. Then, according to the control requirements and combined with models, an optimization expression for minimization of starting time with working and physical constraints was given. The genetic algorithm was utilized to solve the constrained optimization problem and the performance was compared with the classical one that is acquired from actual flight test data. Without exceeding the temperature bound, the starting time can be shortened by about 30%. Moreover, during the unloading process, the starting time in the plateau state and the highest exhaust temperature are reduced by 18.2% ~ 29.3% and 4.7% ~ 8.6%, respectively.