Investigations on Emission Characteristics of a Liquid-Fueled Trapped Vortex Combustor

The combustion and emission formation process of liquid fuel in the trapped vortex combustor(TVC) are very complicated. A trapped vortex combustor with replaceable bluff-bodies was designed to investigate these processes. The bluff-body widths varied from 0.021 m to 0.036 m. Experimental tests were carried out. Liquid RP-3 aviation kerosene was used in the tests. Emissions were measured under atmospheric pressure. The combustion process was analyzed theoretically in the viewpoints of relative evaporation time, mixing time and reaction time. Numerical simulations were also conducted to help analyze the formation and depletion processes of pollutants in TVC. The results reveal that atomization was a critical factor for formation and depletion processes of pollutants. By controlling mixing speed of burned and unburned gases and thus fuel-air uniformity, turbulence intensity could also affect emission levels. In addition, residence time also affected the emissions by affecting combustion completeness and the time for NO_x formation. All these factors were combined in a complicated way to affect combustion process and pollutant emissions.