Jet Engine Passive Optical Sensor

Combustion stability is an ongoing challenge for military gas turbine engines. Instabilities such as augmentor screech involve high-speed, 3D flow and flame structures. The mechanisms that control some combustion instabilities are poorly understood. Diagnostics that elucidate the mechanism(s) of combustion instability are needed to increase the robustness of current engines and to develop improved design rules for future systems. Diagnostic measurements in gas turbine engines are challenging due to the hostile environment and limited optical access. In this program, we are developing fiber optically coupled, passive optical sensors for measuring heat release and fuel distribution in gas turbine engines and combustor rigs. Under a previous SBIR Phase II, we developed an imaging sensor involving low-speed cameras and imaging. Emissions imaging is generally signal limited for this application, which limited our system to low frame rates under the previous program. Under the currently proposed program, we will extend the system capabilities for high-speed emissions imaging of heat release and fuel distribution in augmentors flames. We will also perform a detailed calibration of the system, and demonstrate the system on an engine. We anticipate achieving a Technology Readiness Level (TRL) of 7 under the proposed work.