A method of injecting ammonia gas into ammonic injection grid(AIG)system by using Venturi stick tier has been put forward

and a comparison with traditional ammonia gas injecting mode being made.The method of injecting ammonia gas by using Venturi stick tier simplified the ammonia injecting system;adopting slit injection

decreased the probabality of clogging in nozzle;and being convenient to be installed

being simple in debugging and smaller in pressure loss.Utilizing the basic theory of hydrodynamics

the numerical calulation of flow field

pressure drop

and mixed effect in working section of the Venturi stick tier has been carried out using FLUENT software

revealing the inner flow characteristics in the Venturi stick tier.