Bio: Sunil Kumar is an academic researcher from Gas Turbine Research Establishment. The author has contributed to research in topic(s): Catastrophic failure & Rotor (electric). The author has an hindex of 1, co-authored 1 publication(s) receiving 1 citation(s).
••01 Jan 2021
Abstract: Rotor blade vibration in turbomachinery has been a major cause of failure due to HCF, often resulting in catastrophic damage. The primary aeromechanical design concerns are blade flutter and forced vibration that need to be quantified. The severity of blade vibratory response is almost impossible to predict using theoretical tools as it depends on the strength of excitation. Hence in order to evaluate the HCF characteristics of rotating blades, aero industry depends on measurements for actual vibratory response during engine tests. Various methods are used for measurement of rotor blade vibration. Conventionally strain gauges are extensively used for characterizing vibratory signatures of rotating blades. However, the strain gauges have their own limitations posed by operating temperatures and high-end technology is required to transmit signal from rotating components. Hence only a few blades in a rotor can be instrumented resulting in limited data capture. This paper presents a non-contact type of measurement technique using blade tip timing to capture vibratory signatures of all the blades of the rotor stage. This method is used to characterize monitor rotor blade vibrations of Low-Pressure Compressor and Low-Pressure Turbine of a developmental gas turbine engine. It has provided valuable data with respect to incipient damages, preventing catastrophic failure.
Abstract: Tip-timing technology has been widely used to monitor blade vibration of the aeroengine. In the off-line analysis of tip-timing signals, it is key and a prerequisite in blade fault diagnosis to locate the vibration event accurately. It is the most common method used to locate abnormal vibration based on the correlation of tip-timing data in adjacent revolutions. However, the data in the adjacent revolutions only include little vibration information, which results in the location performance being susceptible to noise. This paper located the vibration event using the area of the ellipse calculated based on the two-parameter plot. The relationship between the area of the fitted ellipse and the blade vibration parameters was derived for the first time in this paper. The feasibility of the method was verified using the tip-timing data of the low-pressure fan of an aeroengine. The results showed that the method can locate both synchronous resonance and rotating stall accurately. Its performance in anti-noise interference was far superior to the correlation coefficient methods due to enough information provided by multi-revolutions rather than only two revolutions. The work in this paper is of great significance for the realization of automatic processing of tip-timing signals.
Author's H-index: 1