CFD-based SNCR-SCR denitration process ammonia supplementing design method

The invention discloses a CFD-based SNCR-SCR denitration process ammonia supplementing design method which comprises the following steps: 1, importing a physical model of a boiler outlet flue in a CFD, wherein the physical model comprises an in-flue low-level superheater, a primary coal economizer, a secondary coal economizer, a three-level coal economizer and an air preheater, which are connected in sequence; 2, setting boundary conditions in the physical model, carrying out numerical simulation on the flowing of the input smoke in the flue to obtain the temperature and velocity field of the smoke from the inlet to the outlet of the flue, arranging an ammonia supplementing device behind the in-flue low-level superheater and mounting a catalyst layer before the air preheater; 3, calculating the mixing effect of a reducing agent at a catalyst inlet in the flue according to the structure of the ammonia supplementing device; and 4, judging whether the mixing effect satisfies the necessary sufficient condition of the ammonia supplementing device, if so, determining the structural design of the ammonia supplementing device, if not, adjusting the structural design of the ammonia supplementing device, and repeating the step 3 to until the structural design of the ammonia supplementing device is determined.