Robust Fiber-Optic Probe for In-Situ Combustion Diagnostics

ABSTRACT: Combustion diagnostics of aeropropulsion engines enable performance optimization through reduction of fuel consumption, unwanted emissions, and thermoacoustic excitation. To enhance the diagnostic capabilities of advanced optical measurement techniques, a robust optical probe enabling minimally-disruptive measurements of multiple properties inside the combustion chamber is needed. Physical Sciences Inc. (PSI) proposes to design, fabricate, test, and deliver a ruggedized probe capable of broadband imaging and spectroscopic measurements in practical combustion environments. It will employ a novel sapphire geometry mounted in a robust mechanical housing. In Phase I, PSI will design and fabricate a laboratory prototype for measuring chemiluminescence and near-infrared absorption in a geometry compatible with the narrow optical access ports found on combustion systems. Optical and thermal modeling will be performed prior to prototype fabrication. The probe will be used to measure emission and absorption in a laboratory test chamber. Chemometrics software will be used to determine species concentration and gas temperature from the optical measurements. A ruggedized probe and software package will be delivered and tested during the Phase II program. The resulting system will be useful in both military and commercial combustion diagnostics applications. BENEFIT: The proposed optical probe design will be applicable to a variety of power generation systems, including automotive and aircraft engines in addition to power plants connected to the electric grid. The real-time performance diagnostics provided by the in situ probe will enable local and system-wide optimization to maximize energy efficiency and system performance.