A DEVELOPMENT AND NUMERICAL STUDY OF A HIGH-PRESSURE GAS TURBINE COMBUSTION CHAMBER BASED ON MESOSCALE COAXIAL SWIRLING JETS

Abstract

This paper reports on the new gas turbine combustion technology based on the mesoscale coaxial swirling jet application. The results of numerical calculations show that this original idea can be applied in high-pressure gas turbines operating at overall pressure ratio values equal to 60 or more. As studies show, the most efficient operation of the combustor is achieved when primary air and fuel are supplied through coaxial nozzles, and secondary air is supplied through holes on perforated walls of the flame tube. Dilution of the combustion zone by the secondary air plays an important role in improving the combustor parameters. It leads to the separation of the coaxial jets onto multiple flames where each coaxial jet spreads into the combustor as a confined one. Fuel and air in such jets actively interact with each other, which provides combustion intensification, whereas interaction of neighboring coaxial jets is less valuable. All this defines a situation when the most environmentally friendly modes are observed at lean equivalence ratio values φ < 0.5. In terms of both minimal pollutants emission and maximum total temperature at the combustor outlet, operating mode φ = 0.45 is the most promising. It provides the values of NO and CO emissions equal to 46.6 ppm and 48.1 ppm, respectively, and the total temperature value 1972 K.