Real-Time Estimation of Gas Turbine Engine Damage Using a Control Based Kalman Filter Algorithm

Abstract

A second generation Kalman filter algorithm is described that has sufficient accuracy and response for real-time detection and estimation of gas turbine engine gas path damage caused by normal wear, mechanical failures and ingestion of foreign objects. The algorithm was developed for in-flight operation of aircraft engines but also has application for marine and industrial gas turbines. The control measurement and microcomputer requirements are described. The performance and sensitivity to engine transients and measurement errors is evaluated. The algorithm is demonstrated with actual engine data of ice and bird ingestion tests.

Using neural networks for sensor validation

“…The corrected rotor speed is plotted as a function of the corrected fuel flow in Figure 10 for the 1260 operating points. Equation (5)(6)(7)(8) gives the relationships used to calculate the corrected terms. theta T / T 2 std = , T std = 518.7°F (5) delta P / P 2 std = , P std =14.67 psia…”

“…An onboard model was used in references [1,6,7]. In reference [6], a piecewise linear model of an engine is used in conjunction with a Kalman filter to provide an estimate of engine damage.…”

“…In reference [6], a piecewise linear model of an engine is used in conjunction with a Kalman filter to provide an estimate of engine damage. Reference [7] used an online model as part of a control system.…”

Reduced-Order Modeling and Wavelet Analysis of Turbofan Engine Structural Response due to Foreign Object Damage (FOD) Events

“…It may also be abrupt as is the case when foreign objects are ingested by the engine. Changes in component efficiencies, high and low spool speeds, and thermodynamic parameters have been determined/observed during foreign object damage (FOD) events [3,4]. In some cases, these parameter changes alone may not be conclusive proof that a FOD event has occurred.…”

“…For approximately two decades techniques based on the Kalman filter algorithm have been applied to turbofan engine diagnostics [3,4]. Specifically, analytical (or virtual) measurements provided by Kalman filter estimators have been used for detection of engine degradation via estimation of a set of health parameters, which are generally not measurable themselves (e.g., compressor efficiency) and are calculated via knowledge of measurable quantities.…”