The Analysis Of Stable Combustion Ability For Petal Swirl Burner Based On Cold Condition

With the aim of efficient combustion in electricity department being put forward, it has great significance for improving the combustion ability of burner and ensuring the economical operation of power plant to enhance the competitive ability of electric power industry. Because of the obvious advantage of swirl burner compare with straight burner in reducing flue gas bias and slagging. It is the common means that the enterprises install new swirl burner and adjust the distribution of primary air and secondary air to improve combustion effect. But due to the shortage of coal resources in our country, power plants usually use the mixed coal and swirl burner cannot adapt the low quality coal so that the combustion efficiency decreases obviously. It is necessary to analysis the new swirl burner around the world and explore the stationary combustion mechanism and adjustment methods. Only in this way can we develop the suitable swirl burner faster.Taking the new swirl burner as the example, basing on the theory of numerical simulation, I set up the physical model and calculate the flow field on different speed of primary and secondary air and analyze the way of stable combustion.The last, I determined the optimal speed of primary and secondary wind. All that can provide some reference for developing the swirl burner.The simulation results show that, the petal swirl burner is different from the common swirl burner in the principle of stable-combustion and there are radial and axial black-flows forming at the peak black. The flue gas can heat coal in the axial recirculation region where it has heat transfer on cut level. In the radial recirculation region, it can depend on convective heat transfer to strengthen the effect of combustion and its ability is several times more than convective heat transfer. At the same time, a part of the coal has a tendency of moving to the center and the coal moves at the export repeatedly which can not only increase the center density of the pulverized coal but also avoid mixing with secondary wind early and reduce the formation of NOX effectively. By adjusting the primary and secondary wind air distribution, we can effectively improve burner’s stable-combustion ability. The axial recirculation is smaller and the combustion ability is lower because of the existence of primary air, but it can adjust the distance between axial recirculation zone and the burner to avoid slagging. When the speed of primary air is certain, with the increase of internal secondary air velocity, the area of axial recirculation zone increases and the combustion effect is improved. If we adjust the blade angle to increase the tangential velocity of internal secondary air, the radial recirculation zone will decrease, while the axial recirculation zone will become larger. So we should choose appropriate velocity of primary and secondary air to increase the axial or radial recirculation zone so that the boiler can adapt different coal, and only in this way can we improve the stable combustion ability. Consequently, the analysis provides a reliable reference for the application of the burner and the development of the swirl burner.