Improvement Method of Turbofan Engine Full-Envelope Acceleration Control Schedule

The acceleration control schedule directly affects the response speed and operation safety of the engine. In order to improve the engine responsiveness, a full envelope engine acceleration control plan based on isotherm was proposed. A similarity conversion error analysis was conducted for steady-state and dynamic processes, respectively, and it was proved and verified that the key parameters have higher accuracy on similarity conversion at the same fan inlet temperature. Based on this conversion error theory, an improved method of full envelope acceleration control schedule is proposed. This method designs multiple acceleration control schedules at different equal fan inlet temperatures, and then obtains the acceleration control schedules under different isotherms in the envelope by linear interpolation. The results show that the improved acceleration control schedule compared to the traditional single operating point optimization of the acceleration control schedule, the time required for the engine to accelerate to 98% of the maximum speed reduced by 7.2%, the maximum speed increased by 1%. The fan and compressor surge margin and pre turbine temperature did not exceed the limit. Therefore, compared with the traditional single operating point optimization method, this method not only improves the accuracy of the acceleration control schedule obtained in the envelope, but also ensures that the engine can have better acceleration performance under the premise of safe and stable operation of the envelope. © 2022, Editorial Department of Journal of Propulsion Technology. All right reserved.