Flow field and thermal characteristics in a model of a tangentially fired furnace under different conditions of burner tripping

摘要

Tangentially fired furnaces are vortex-combustion units and are widely used in steam generators of industrial plants. The present study provides a numerical investigation of the problem of turbulent reacting flows in a model furnace of a tangentially fired boiler. The importance of this problem is mainly due to its relation to large boiler furnaces used in thermal power plants. In the present work, calculation of the flow field, temperature and species concentration-contour maps in a tangentially-fired model furnace are provided. The safety of these furnaces requires that the burner be tripped (its fuel is cut off) if the flame is extinguished. Therefore, the present work provides an investigation of the influence of number of tripped burners on the characteristics of the flow and thermal fields. The details of the flow, thermal and combustion fields are obtained from the solution of the conservation equations of mass, momentum and energy and transport equations for scalar variables in addition to the equations of the turbulence model. Available experimental measurements were used for validating the calculation procedure. The results show that the vortex created due to pressure gradient at the furnace center only influenced by tripping at least two burners. However, the temperature distributions are significantly distorted by tripping any of the burners. Regions of very high temperature close to the furnace walls appear as a result of tripping the fuel in one or two of the burners. Calculated heat flux along the furnace walls are presented.