Numerical study of the effect of imaginary circle diameter and initial flow field on the aerodynamic field in a tangentially fired furnace

In this paper, the effect of the imaginary circle diameter φ_i and the initial flow field on the aerodynamic field in a tangentially fired furnace was studied by numerical simulation and experiments in the cold model. Results show that merely reducing the imaginary circle diameter φ_i can not significantly reduce the rotational diameter φ_i in the range considered. The flow still rotates counter-clockwise stably and does not change rotation direction when the direction of all jet axes are deflected suddenly to the opposite rotation direction by up to 5.4° in a counter-clockwise flow field. It is the first time that the numerical simulation results were obtained which agreed quite well with this experimental phenomena qualitatively. The experimental data, i.e., the rotational diameter φ_i and the maximum velocity on the symmetric central line of furnace V_m, are only a bit larger than the simulation results. It is shown that the initial flow field has an important influence on the aerodynamic field in the furnace. Other measures have to be taken as well in order to reduce φ_i to resist slagging and high temperature corrosion of furnace tubes. Moreover, a new kind of grid arrangement was proposed in this paper, which can reduce effectively the false diffusion at the exit zone of burner.