Gas Species Emissions
Gas turbine engine exhaust gas emissions include CO2 and H2O as well as CO, NOx, unburned hydrocarbon fuel (THC) and smoke. Gas samples are extracted from many points in the exhaust plume at the nozzle exit by a probe rake system, transported through many feet of heated tubing, and analyzed by gas analyzers. Profiles of engine performance in terms of combustion efficiency and fuel/air ratio indicate zones of incomplete combustion. Bulk averages of the multi-point samples are used to define the pollution emission indexes, pounds of pollutant generated per 1000 pounds of fuel consumed.
As aircraft and stationary source gas turbine engines become more efficient emission measurements systems must be capable of analyzing very low levels of CO, NOx, and THC. Gas turbine engine emission measurements are costly in terms of infrastructure and engine run time required, especially at high power conditions. Therefore, new cost-effective methods are required that facilitate emissions measurements during the engine development through certification cycle.
With endorsement from the regulatory agencies, new gas analysis techniques are being evaluated. Among the new techniques are FTIR multi-gas analyzers and MEMS chemical gas sensors that may expand the role of emission measurements from ground testing to on-board diagnostics and active engine control functions. Development of new emission measurement processes is on-going in universities and industry with funding from agencies such as SBIR, DoE, and OSD T&E/S&T. Oversight, evaluation and documentation of advancements is within the charter of the SAE E-31 Committee for Aircraft Engine Exhaust Measurements.
Strategic Advisory Board (SAB) Members Addressing This Need
Makel Engineering, Inc.