Radial Swirlers With Peripheral Fuel Injection for Ultra-Low NOx Emissions

Abstract

A 76mm outlet diameter radial swirler with a dump expansion into a 140mm diameter combustor was investigated with a simulated 43% primary zone air flow at a 600K inlet temperature and one bar pressure. Two modes of peripheral fuel injection were investigated: at the 76mm swirler outlet and at the 140mm combustor wall just downstream of the swirler. This 140mm wall injector resulted in fuel injection into the swirler expansion outer recirculation zone. It was shown that the 140mm wall injection gave much higher NOx emissions than for the 76mm swirler outlet injector. These results were compared with other methods of fuel injection and the 76mm peripheral injection was shown to have superior NOx emissions than vane passage injection for all fuels except gas oil. Ultra low NOx emissions of 1ppm with 20 ppm CO, both at 15% oxygen, were demonstrated for propane and natural gas.