Engine Emission Control Using Optimized Cooling Air Distribution between Combustor and Turbine Hot Section

Presented paper is focused on turbine hot section cooling system design and the effects that it has on overall engine emission characteristics. Much consideration is given to industrial gas turbines due to their continuous operation as prime drivers for electric power generators and mechanical driven equipment like gas compressors and pumps. Although aircraft engines present a major part of the installed power in the gas turbine market, they play a less significant role in pollution due to a relatively short operating mission.

The paper provides analyses of compressed air distribution in a typical advanced gas turbine engine. The air distribution in a combustor section, role of air/fuel ratio in a primary zone and its effect on NO_x and CO formation are reviewed in detail. Means of emission improvement with the application of advanced combustor liner cooling techniques and optimized configurations for cooling of the combustor-turbine vane endwall transition are analyzed using practical design examples. The impact of overall engine thermal efficiency on emissions is discussed in comparison with the conventional characteristic that is based on parts of pollutants per million in the engine exhaust.