By using CFD software

the numerical simulation of boiler charateristics and distribution of flow field

temperature field

and concentration field in an ultra-supercritical 1000 MW double-tangential firing boiler of one power plant has been carried out

the influence of additional air under different operating conditions being given.Results show that the influence of additional air upon distribution of NOx concentration isn't large

the tangential or anti-tangential additional air

however

has effect upon deviation of flue gas temperature and flue gas velocity in each cross-section along the direction of furnace height.This result has guiding significance for temperature distribution variation in the furnace and for emission of pollutants.