Gas-Particle Flow Characteristics of a Centrally-Fuel-Rich Primary Air Burner: Simulation and Experiment

The flow field within a three-level conical ring concentrator of a centrally-fuel-rich swirl coal combustion burner has been studied both experimentally and numerically. Measured and calculated values of gas velocities downstream from the third conical ring are in good agreement. In the outlet region after the third-level ring, a peak and a valley in the mean axial velocity profiles are seen to move respectively towards the axis and towards the wall; both decrease gradually in magnitude. The maximum in the relative axial particle volume flux appears at axial distance x/D=0.5. From simulations, oval-shaped recirculation zones appear behind each conical ring, the axial length increases as the ring level increases. Moreover, as x/D increases, in the region -1.0<;x/D<;0, the relative axial velocities increase monotonically and the functional dependence with axial distance is basically linear. The peak value of the relative axial velocities is located at axial distance x/D=0.26.