Effect of gear baffle on isothermal flow from radial bias combustion burner

The aerodynamic properties of swirling jet coming out from the swirl burner were studied with the structures of a central gear baffle and an ordinary baffle on a cold model test rig of Radial Bias Combustion (RBC) burner using the rotating hot film probing method to measure the mean velocities, turbulent stresses, skewness coefficient of isothermal swirling jet. The measurements show that the diameter of the internal recirculation zone (IRZ) reduces under the structure of central gear baffle, and the related reversed ratio increases by 20 percent. The turbulent normal stresses double while turbulent shear stresses triple. The probability density function of the mean stream instantaneous velocity approaches a Gauss distribution faster. Because of the increase of reversed flow and turbulent fluctuation intensity in the exit swirling jet of RBC burner, the process of pulverized coal combustion can be enhanced by the structure of gear baffle.