Method and experimental verification of low-speed high-precision dynamic balancing for flexible rotors based on single-piece unbalance control

To address the engineering challenges of high cost, operational risks, and inefficient maintenance for component replacement associated with conventional high-speed balancing equipment, a low-speed high-precision balancing method for flexible rotors based on single-component residual unbalance control is proposed. The ISO allowable residual unbalance formula was employed to quantify the counterweight requirements for different precision grades (G6.3 to G0.4), and low-, medium-, and high-precision combined balancing as well as single-component balancing scenarios were simulated. A power turbine rotor test rig was constructed, and full-speed (0-5000 r/min) comparative tests were conducted. The results demonstrate that the proposed method achieves precise balancing by selecting sensitive component planes based on modal analysis. High-precision single-component combined balancing (49.1% critical amplitude reduction and 53.1% operating amplitude reduction) exhibits negligible performance differences from conventional high-speed balancing (53.6% critical amplitude reduction and 49.5% operating amplitude reduction), with a maximum deviation of only 8.7%, enabling the substitution of high-speed balancing. Single-component balancing on sensitive planes shows a critical amplitude difference of only 3.09% compared with combined balancing, which enables rapid balancing in component replacement scenarios.