The influence of unbalance identification position on the transient dynamic balancing of a single-disk rotor without trial weights

Abstract

The unbalance originating from rotor manufacturing errors induces vibrations in the rotor system, which significantly jeopardizes the stability of aeroengines. Therefore, addressing this issue through dynamic balancing is crucial for preventing catastrophic failures. However, traditional dynamic balancing methods, whether the modal balancing method or the influence coefficient method, require the rotor to start and stop multiple times, which undoubtedly reduces the balancing efficiency. To overcome this limitation, this paper introduces a transient dynamic balancing method without trial weights. It then delves into the impact of unbalance identification positions on the transient dynamic balancing of rotor systems using this approach. The rotor system model is constructed via the finite element method. Drawing on modal balancing theory, both continuous and isolated unbalances are considered to determine the unbalanced excitation forces. The continuous unbalance is derived from the principal mode, while the isolated unbalance is calculated based on the continuous unbalance. Subsequently, unbalance parameters, including azimuths, eccentricity, and weight, are identified by analyzing the unbalanced excitation forces at characteristic points. Counterweights are strategically added in the opposite direction of the identified unbalances to complete the rotor system balancing process. Additionally, the study investigates the identification errors of unbalances at various positions along the shaft. Simulation and experimental results demonstrate that the proposed balancing method effectively mitigates rotor system vibrations. The errors of the unbalance parameters identified at different positions using the proposed method are extremely minimal, demonstrating high accuracy and reliability of the method. More significantly, by enabling vibration data acquisition in confined spaces, this method substantially enhances the efficiency of on-site rotor balancing operations.