High intensity colorless distributed combustion for ultra low emissions and enhanced performance

Abstract

Combustion characteristics of colorless distributed combustion have been investigated for application to gas turbine combustors. Very high intensity distributed combustion has been shown for application to stationary gas turbine engines. Various configurations examined have revealed reverse cross-flow mode to be more favorable for desirable combustion characteristics. The reverse-cross flow geometry is further investigated experimentally at range thermal intensities from 53 to 85 MW/m 3 atm with specific focus on exhaust emissions, radical emission, global flame photographs and flowfield using novel but simplified geometry for easy transition to applications in gas turbine engine applications. The high combustion intensity demonstrated here is higher than that used in present stationary gas turbine engines. Numerical simulations are also performed and compared with the experiments for the new design configuration under non-reacting conditions. Ultra low NO x emissions are achieved for both the novel premixed (1 ppm) and non-premixed (4 ppm) combustion modes reported here. Carbon monoxide levels of about 30 ppm are achieved in both novel premixed and non-premixed modes of combustion with a pressure drop of less than 5% across the combustor at the favorable condition. Almost no visible flame color in the reaction zones are observed for both novel premixed and non-premixed modes with volume distributed combustion so that this mode is termed as colorless distributed combustion. This mode of volume distributed colorless combustion is dramatically different than that used in contemporary gas turbine combustion operating under lean premixed, lean direct injection or rich burn, quick quench lean burn gas turbine combustion.