Sensing for aerospace combustor health monitoring

Abstract

Purpose This paper proposes new methods of fault detection for fuel systems in order to improve system availability. Novel fault systems are required for environmentally friendly lean burn combustion, but can carry high risk failure modes particularly through their control valves. The purpose of the developed technology is the rapid detection of these failure modes, such as valve sticking or impending sticking, and therefore to reduce this risk. However, sensing valve state is challenging due to hot environmental temperatures, which results in a low reliability for conventional position sensing. Design/methodology/approach Starting with the business needs elicited from stakeholders, a quality functional deployment process is performed to derive sensing system requirements. The process acknowledges the difference between test-bed and in-service aerospace needs through weightings on requirements and maps these customer requirements to systems performance metrics. The design of the system must therefore optimise the sensor suite, on- and off-board signal processing and acquisition strategy. Findings Against this systems engineering process, two sensing strategies are outlined which illustrate the span of solutions, from conventional gas path sensing with advanced signal processing to novel non-invasive sensing concepts. While conventional sensing may be feasible within a test cell, the constraints of aerospace in-service operation may necessitate more novel alternatives. Acoustic emission (detecting very high frequency surface vibration waves) sensing technology is evaluated to provide a non-invasive, remote and high temperature tolerant solution. Through this comparison, the considerations for the end-to-end system design are highlighted to be critical to sensor deployment success in-service. Practical implications The paper provides insight into different means of addressing the important problem of monitoring faults in combustor systems in gas turbines. By casting of the complex design problem within a systems engineering framework, the outline of a toolset for solution evaluation is provided. Originality/value The paper provides three areas of significant contributions: a diversity of methods to diagnosing fuel system malfunctions by measuring changes fuel flow distributions, through novel means, and the combustor exit temperature profiles (cause and effect); the use of analytical methods to support the selection (types and quantities) and placement of sensors to ensure adequate state awareness while minimising their impact on the engine system cost and weight; and an end-to-end data processing approach to provide optimised information for the engine maintainers allowing informed decision-making.

Temperature-Decoupled Single-Crystal MgO Fiber-Optic Fabry–Perot Vibration Sensor Based on MEMS Technology for Harsh Environments

“…Vibration is a key parameter for safety monitoring in aero-engine testing and an important reference for analyzing faults [1][2][3]. As the thrust-to-weight ratio of the aeroengine increases, the combustion chamber developments lean toward a high-temperature rise and high heat capacity.…”

High-Temperature Fiber-Optic Fabry–Perot Vibration Sensor Based on Single-Crystal Sapphire

“…Vibration sensors have a wide range of applications in earthquake monitoring, tsunami monitoring, aero engines, geological exploration and nuclear reactors [ 1 , 2 , 3 , 4 ]. At present, there are several types of vibration sensor, such as piezoelectric [ 5 , 6 ], piezoresistive [ 7 ], capacitive [ 8 ] and fiber-optic vibration sensors [ 9 ].…”

Simulation Design of Surface Acoustic Wave Sensor Based on Langasite Coplanar Integration with Multiple Parameters

“…A LiNbO 3 /SiO 2 /Si structure is adopted to manufacture a SAW temperature sensor, which has good linearity and resolution at 20–100 °C [ 6 ]. Another temperature/pressure combined sensor using LiNbO 3 as the base material can measure pressure at 0–6 bar and a temperature of 30–150 °C [ 7 ].…”