Liquid Fuel Burner with Orifice Insertion for Low Noxious Emissions from Combustion System

This paper presents the effect of inserting swirier outlet orifice plate of different sizes at the exit plane of the radial air swirier in liquid fuel burner system. Tests were carried out with three different orifice plates with area ratios (orifice area to swirier exit area ratio) between 1.0 to 0.7 using 280mm inside diameter combustor of 1000mm length. Tests were conducted using commercial diesel as fuel. Fuel was injected at the back plate of the 45° vane angle swirier outlet using central fuel injector with single fuel nozzle pointing axially outwards. The aim of the insertion of orifice plates was to create the swirier pressure loss at the swirier outlet phase so that the swirier outlet shear layer turbulence was maximised to assist with fuel/air mixing. In the present work, orifice plate with smaller area ratios exhibited very low NOx emissions for the whole operating equivalence ratios. NOx reduction of more than 20% ivas achieved for orifice with 0.7 area ratio compared to area ratio of 1.0. Other emissions such as carbon monoxide increased with decrease in orifice area ratios. This implies that good combustion was achieved using smallest area ratios of orifice plate.