Research on the design method of mode transition control law for Ma6 external parallel TBCC engine

To achieve a fast and reliable mode transition of the Ma 0–6 external parallel TBCC engine, a design method for the transition state control law is developed. The design parameters of the TBCC engine are obtained based on the mission requirements of hypersonic aircraft. For the key mode transition process of the combination engine, a segmented mode transition strategy is formulated with the objectives of smooth thrust and continuous flow. The mode transition control law of the combination engine is designed and optimized using the Hooke-Jeeve Direct Search Method. The results demonstrate that the proposed design method for the mode transition control law can effectively enable a fast and smooth mode transition of the combination engine, with a total duration of 7 s. During the mode transition process, the total thrust fluctuation during the transition from the turbofan windmill state to the turbofan shutdown state is the largest, and the maximum relative error between the total thrust and the expected value during the mode transition process is 0.4 %.