Identification of blade vibration parameters based on improved blade tip timing technology and two-factor analysis method

Abstract Long-term complex alternating loads will significantly impact the lifespan of blades. As a non-contact measurement method, blade tip timing (BTT) is regarded as an efficient technique for blade vibration monitoring as it reflects the condition of blades. Most of the existing parameter identification methods need several sensor and strict probe layout requirements; thus, an inappropriate sensor layout may fail BTT measurements. Using fewer sensors can reduce the impact on the compressor casing strength and the cost of test system. Considering arrangement, cost, and safety restrictions, in this work, a novel blade vibration parameters identification method via a single BTT sensor is proposed. A method of improved BTT technology is presented which obtain two-channel vibration displacement sequence using a single sensor. The elliptic model between two-channel vibration displacement sequence is established. Based on the model, the relationship between blade vibration parameters and elliptic geometric parameters is derived. Numerical simulation and experimental results show that the method is highly feasible and robust. The advantage of this method is that it utilizes only one sensor and achieves high accuracy identification of blade vibration parameter, which provides a new idea to blade vibration monitoring.