Numerical Modelling And Experimental Investigation On New Low-NO_x Gas Burner

A new type low-NO_x gas burner and its combustion experimental system was been designed for gas fuel’s low pollutant emission, which combined fuel-staging combustion、flue gas recycle and fuel scattered burning, according to “ West-East natural gas transmission”、the “coal to fuel gas” policy promoted as well as the widely usage of natural gas as high quality, high efficiency and clean energy in various industries. This research includes the numerical modeling and experimental investigation of velocity field and temperature field in the combustion chamber and NO_x content in combustion products.Design and manufacture 12 different structures of new type low-NO_x gas burner. According to relevant bibliographies at home and abroad, a new type low-NO_x gas burner with different structures were designed on the basis of previous study on gas cleaning combustion technology, which can form multi-point spread long flame, reduce combustion peak flame temperature, evenly distribute the furnace heat load and form ultra-low NO_x. In addition, traditional gas burners were designed in order to compare with self-excited oscillating-jet burners.Numerical modeling on new low NO_x gas burner and traditional gas burners was done. The basic control equation was analyzed and proper mathematical model was chose. The geometrical and physical model was installed based on the standard size of new type low-NO_x gas burner. Then, the grid partition method was built. The boundary conditions of numeral model were described according to the thermal load and environmental parameters. And the residual was set according to the convergence criteria, and the result was produced. Since the reference plane is taken from xz and yz plane, the velocity field, temperature field and concentration field of NO_x were described. The results from numerical simulation verified that new type of low-NO_x gas burner can effectively reduce the combustion chamber combustion temperature, thereby reducing NO_x content in the products. So the conclusion comes that new type low-NO_x gas burner can realize low pollutant of natural gas combustion.Experimental research on new low NO_x gas burner and traditional gas burners was done. According to the measurement of each measured point in combustion chamber, the temperature distribution was deduced and the components of the combustion product were studied, then the best structure type in 12 of the burner structure and it’s combustion characteristics of different load & different excess air coefficient conditions was concluded. At last,combined with the numerical simulation results,acquired the final conclusions through comprehensive contrast of combustion and pollutant emission characteristics that this design of burner and experimental system can realize low pollutant emission in industrial boilers & industrial furnaces.This topic provided theory basis for the usage of new type low-NO_x gas burner according to the structure characteristics of itself and application needs of industrial boiler & industrial furnace.