涡轴发动机振能转移优化设计方法与实验研究

In order to optimize the unbalanced response characteristics of the dual-rotor system with mid turbine frame and make it operate stably in a wide range of rotational speeds under the same unbalance, an optimization design method of vibration energy transmission for the dual-rotor system with mid turbine frame was proposed, the finite element dynamic characteristics calculation and dynamic optimization design of the dual-rotor system model were carried out. After optimization, the acceptability of the model under self-excitation modes exceeds 0.8, which can meet the design requirements of acceptable mode. Taking a turboshaft engine as the reference object, a set of dual-rotor experimental device with mid turbine frame was designed and processed, which can simulate the dynamic characteristics of the dual-rotor system with mid turbine frame under four different stiffnesses. The dynamic characteristic calculation verification test was carried out by using the experimental device. Under the four stiffness combinations, the error of critical speed of the experimental device under self-excitation modes is not more than 7%, which indicates that the established model of the dual-rotor system with mid turbine frame is accurate. The unbalanced response peak comparison test and the anti-vibration characteristic comparison test were carried out by using the experimental device. Compared with the stiffness combination before optimization, under the optimal stiffness combination, the unbalanced response peak of power turbine decreased by 51.49%, and the maximum allowable unbalance increased by 79.21%, which shows that the vibration energy transmission optimization design has a significant effect on reducing the unbalanced response of power turbine and improving the anti-vibration characteristics of power turbine. The long time ‘resonance’ experiment was carried out on the experimental device before and after the optimization of vibration energy transmission. The experimental device before optimization could not run for a long time at critical speed, which could not meet the design requirements of acceptable mode. For the optimized experimental device, the unbalanced response of power turbine at critical speed of its self-excitation 1st mode increased by 5.37%, and the unbalanced response of gas generator at critical speed of its self-excitation 1st mode increased by 1.39%, which could meet the design requirements of acceptable mode.