Experimental Study of Flame Combustion of Pulverized Coal Fuel in a Two-Stage Vortex Burner

The paper presents a study of the aerodynamics of flame combustion of coal fuel in a burner device with thermal power of 50 kW. The burner device was a two-stage tangential swirler. In the first stage, air was supplied tangentially with axial pilot supply of propane. In the second stage, the pulverized coal mixture with heated secondary air was supplied. During the experiments, the efficiency of coal fuel combustion was studied with co-swirl and counter-swirl of the second stage relatively to the first one. The temperature was measured on the wall and in the center along the muffle swirl chamber. The gas composition of the combustion products was measured at the outlet of the swirl chamber. The profiles of the mean axial and tangential velocity along the length of the swirl chamber were measured with the two-component laser Doppler anemometer (LDA) system. Particles of unburned coal fuel served as signal tracers. The obtained results have led to a conclusion about the efficiency of the system for pulverized coal fuel combustion in the counter-swirl mode for enhancement of mixing and combustion.