The Influence of Fuel Composition and Spray Characteristics on Particulate Formation

A series of tests are conducted in a tubular, continuous flow combustor containing a 15 cm diameter combustion liner. Fuel is supplied to the flame zone through a circular array of 30 equispaced miniature airblast atomizers. The objective is to achieve a sensibly uniform mixture strength in the fuel-air mixture entering the flame zone. This, in turn, ensures uniform conditions of temperature and chemical composition at any given axial distance downstream of the fuel injection plane.

A unique feature of this fuel injection system is that it allows the mean drop size of the fuel spray to be varied while maintaining all other flow properties constant. Thus, experimental data on particulates and other pollutant emissions can be acquired under controlled conditions of pressure, inlet air temperature, and fuel mean drop size, at any given axial distance downstream of the fuel injection plane. This means that all observed differences in pollutant formation can be attributed directly to variations in chemical properties.

The results obtained on several selected fuels demonstrate the effects of variations in fuel composition, fuel drop size and combustor operating conditions on the emissions of particulates over a range of pressures from 1.01 to 1.52 MPa (10 to 15 atmos.).