Numerical study of the optimum counter-flow mode of air jets in a large utility furnace

作者:He BS*; Chen MQ; Yu QM; Liu SM; Fan LJ; Sun SG; Xu JY; Pan WP
来源:Computers & Fluids, 2004, 33(9): 1201-1223.
DOI:10.1016/j.compfluid.2003.06.015

摘要

The SIMPLEC algorithm with the power-law scheme and the pseudo-time-step method were employed to numerically solve the governing equations for 3-D turbulent flow field in a 2023 t/h rated boiler furnace using two grid systems. The numerical diffusion was eliminated by adding a delayed correction term. The numerical results from two gridding systems agreed quantitatively and were compared with the other and also with the experiments. The grid independent simulation results are presented for two counter-flow modes of the air jets in an isothermal model of a tangentially fired furnace. The calculated velocity distribution qualitatively agreed with the experimental data. The results suggest that, unlike the concentrated counter-flow mode (identified as case CCF), the separated counter-flow mode (identified as case SCF) can efficiently prevent flow attachment to the furnace walls. The separated mode reduces the angular moment flow rate during flow attachment and SCF improves control of the heat imbalance in the horizontal flue.