Research about Influence of Imaginary Circle Diameter on Velocity Field near Burner Region

With a view to the slag problem on the water-cooled wall and super-heater at furnace exit of a 670t/h power-plant boiler burning pulverized coal, which burners were arranged in the form of six corners tangentially firing, Phase Doppler Anemometer (PDA) was applied to investigate the gas-solid two-phase velocity field near the burner region for the first time. Two experimental cases were investigated, one is the original case, and another is the improved case which the imaginary tangential circle diameter of secondary air at the top layer burners was increased, the gas-solid two-phase velocity field near the burner region was measured under two cases. Experiment study show that the flow-field structure of tangentially fired boiler which the burners were arranged in six corners, differ from that of the burners were arranged in four corners. To a certain extent, flow-field in furnace can be improved by adopting homocentric two tangential circles arrangement form of primary air and second air.