Passive Optical Sensor for Real Engine Diagnostics

ABSTRACT: Diagnostic measurements in gas turbine combustors and augmentors are challenging due to the hostile environment and limited optical access afforded by real engines. Probes that are inserted into the flow are generally undesirable because the probes inherently influence the flow and must be cooled to survive the extreme heat flux. Optical sensors that flush-mount on existing combustor surfaces and that can passively measure quantities such as heat release and fuel distribution would be of great use to engine developers seeking to better understand the performance and characteristics of real engine systems. In this project we will develop fiber-optically coupled, passive optical sensors for measuring heat release and equivalence ratio in real engines. The measurement is based on chemiluminescence emission from C2* and CH* radicals within the flame. Individual sensors can be used for time resolved, line-of-sight measurements, or multiple sensors can be synched for correlating the spatial distribution of flame dynamics or for tomography. In Phase I, we will develop a proof-of-concept sensor prototype and demonstrate its performance using a high optical access afterburner rig. In Phase II, we will optimize sensor performance, packaging, and the engine interface. We will then demonstrate the sensor under real engine conditions. BENEFIT: The outcome of this project will be a well developed modular heat release and equivalence ratio sensor suitable for rapid transition. The sensor could potentially provide novel insight into local processes in real combustion systems and will be a valuable tool for CFD validation. We expect to commercialize the sensor via licensing to an existing supplier of combustion diagnostic tools. The sensor will then be available for use in a wide range of military and commercial combustion systems.