Challenges in Engine Health Monitoring Instrumentation During Developmental Testing of Gas Turbine Engines

摘要

Developmental testing of gas turbine propulsion systems involves iterative experimental studies right from First Engine to Test (FETT) till production release. During initial design validation tests, engines require dedicated instrumentation for carrying out online monitoring with a capability to detect and isolate impending failures which may lead to structural damage. Instrumentation may be optimized further over the developmental lifecycle to determine the general engine health and life consumption of critical parts. Instrumentation generally focuses on monitoring of structural and aerodynamic behavior of engine subsystems. It is challenging to arrive at optimum instrumentation and methodologies of measurement with respect to engine performance and structural health monitoring. Structural health monitoring of rotating engine components poses challenges in acquiring high bandwidth data through either contact or non-contact sensing techniques and further data processing. Special instrumentation systems used for measuring various parameters from rotating parts as a part of health monitoring include slip rings, rotating telemetry, and non-intrusive strain measurement systems. Instrumentation of other engine parameters includes temperature, pressure, rotational speed, casing vibration, control actuator positions, flow rate, clearance between stationary and rotating parts and lubrication oil quality. Gas turbine engines are a complex assembly of rotating and stationary parts which operate at extreme temperatures which limits the operational capability of sensors. It is a challenging task to error budget complete measurement chains and arrive at uncertainties. Various aspects discussed in this paper are complex and inter disciplinary in nature. This paper provides a bird's eye view of the challenges associated with measurement systems during developmental stage of a gas turbine engine.