Blade Vibration Difference-Based Identification of Blade Vibration Parameters: A Novel Blade Tip Timing Method

Abstract

Blade tip timing (BTT) technology is one of the most effective methods for vibration monitoring and health management of rotating blades. However, in actual applications, more blade vibration information means more BTT probes need to be installed, and the calculation of the expected arrival time (ToA) of the blade means the calculation errors introduced to measurement results. In this present study, the relationship between blade vibration (BV) and blade vibration difference (BVD) is investigated, and it can be concluded that blade vibration difference can estimate blade vibration. Then, a two-probe blade vibration measurement system is built and six sets of blade vibration differences can be obtained. Subsequently, this paper researches the parameters identification method of blade vibration based on the blade vibration difference. In the end, BTT experiments show that the blade vibration difference can be measured by the BTT system with high-accuracy, and blade vibration parameters can be analyzed based on the blade vibration difference. Strain experiments demonstrate that the frequency of blade vibration identified by the BTT method is consistent with the strain measurement results. As compared to prior methods, this work, besides reducing the number of probes, eliminates the calculation error of the expected arrival time and is applied for the blade vibration monitoring of any rotating machinery.