The objective of this research is to demonstrate the feasibility of using acoustic pyrometry methods to take measurements in harsh, chemically reacting flow such as gas turbine engine combustion chambers. Conventional methods utilize flow invasive devices, have line of sight requirements, or use exterior parameters to measure the internal temperatures of a combustion chamber. Acoustic pyrometry methods can avoid many of these compromises and have been applied to a wide variety of industrial systems including the measurement of furnace exit gas temperatures, waste-to-energy boilers, cement kilns, metal treatment furnaces, and many other applications. The passive system works on the concept that temperature affects the speed of sound through a fluid. This work establishes that passive acoustic pyrometry is a viable option for determining combustor performance and for measuring fuel-to-air ratios and temperatures from acoustic resonances in an engine. The results include the ability to monitor temperature distributions and develop algorithms to obtain several other data sets. The work detailed includes research performed and compared with results obtained using conventional methods at NASA Glenn Research Center and Rolls Royce.
