Investigation on Residual Swirl and Flue Gas Imbalance in Large Tangentially Fired Boiler

抄録

There exists the serious problem of flue gas imbalance at the entry of horizontal gas-pass in many large tangentially fired utility boilers used presently in China. In this paper, the experimental and computational investigations on residual swirl and flue gas imbalance are carried out based on an isothermal model of 600 MW tangentially fired boiler. The Porosity method and the improved non-uniform QUICK scheme are presented in 3-D numerical simulation in order to simulate the platen superheater correctly and reduce the pseudo-diffusion effectively. The numerical results agree well with the experiment. The calculated results of flow field in furnace, diameter of actual tangential circle, the distribution of swirling intensity along height of furnace and the effects of the structures of nose and the platen superheater on residual swirl and velocity deviation are presented. The forming cause and influencing factors of flue gas imbalance are discussed. Meanwhile, the means to diminish the deviation are introduced.