Unbalance Error Compensation Method of Aircraft APU Turbine Rotor Based on Blade Sorting

The unbalance error of turbine rotor in aircraft auxiliary power unit (APU) can increase abnormal vibration and reduce service life. Therefore, the measurement and compensation of unbalance error of turbine rotor are crucial during the assembly process of aircraft APU. This article proposes an unbalance error compensation method of aircraft APU turbine rotor based on blade sorting. The method can reduce the residual unbalance by accurately adjusting the arrangement order of blades around turbine disk. To further compensate the unbalance error introduced by the assembly error of blades, the static unbalance error of turbine rotor is measured by the balancing machine after the first blade sorting and assembly, and the secondary optimization strategy is carried out by swapping several blades. The experiment results show that the proposed method can compensate the unbalance error introduced by turbine disk and blades. Especially, the secondary optimization strategy can compensate the unbalance error introduced by the assembly error and improve assembly precision. The static unbalance error of APU turbine rotor has been reduced from 15.0 to 2.68 g $\cdot $ mm after secondary optimization, and the assembly accuracy has been improved by 82.1%. Thus, the unbalance error compensation method proposed in this article can provide reference guide for intelligent assembly of blades in aircraft APU turbine rotor.