Numerical simulations were performed for a 300 MW tangentially fired pulverized-coal boiler to investigate the influence of SOFA yaw angle on residual swirling of flue gas at the furnace outlet.The distributions of flue velocity and temperature under conditions with different SOFA yaw angles were analyzed

and the results show that

the temperature field and velocity field in the main combustion zone under condition with reversed SOFA are similar to that with unreversed SOFA

indicating the reverse-tangent at the SOFA has little effect on the main combustion zone.When the SOFA yaw angle is 12°and 18°

there are anticlockwise and clockwise residual swirling of flue gas in horizontal gas pass separately.Moreover

the bias of temperature is slight than that of the velocity.When the SOFA yaw angle is 15°

the distribution of velocity and temperature at the entrance of horizontal flue is more homogeneous.Therefore

the optimal SOFA yaw angle is 15°.