Study On Influence Of Import Parameters On NO_x Formation Characteristics In Can-annular Combustion Chamber

China is in a period of rapid economic development,energy consumption has increased year by year,and environmental pollution problems have become increasingly prominent.Developing low-pollution combustion technology is an effective way to reduce pollutant emissions from the source.The wide application of can-annular combustion chambers makes it difficult to adjust the import parameters.Therefore,that the reasonable distribution of combustion characteristics and the low-pollutant emissions are urgently solved.The effects of pilot fuel ratio,equivalence ratio,inlet pressure and intake air temperature on the combustion and NOx formation characteristics of the can-annular combustor are studied by RANS,which provides a reference for its operation.The main research contents and conclusions are as follows:Firstly,using GAMBIT software to model and mesh the can-annular combustion chamber,three grid number models are drawn.Cold and hot state calculations were performed on the model to verify grid independence.According to the determined number of grid models,the simulated values of the NOx concentration at different loads and the experimental values of the literature were compared and analyzed,which confirmed the validity of the model.Secondly,the effects of pilot fuel ratio,equivalence ratio,inlet pressure and intake air temperature on combustion and pollutant generation characteristics were studied.The flow field,temperature field and thermal NOx formation rate distribution in the combustion chamber were analyzed in depth.The results show that:1)As the pilot fuel ratio increases,the proportion of diffusion combustion increases,the flame temperature on pilot nozzle rises,the high temperature zone expands,the rate of thermal NOx formation increases,NOx emissions increase,and CO emissions decrease;the duty ratio is maintained at 4.5%to 5%level is most conducive to tissue combustion and control of export pollutants.2)As the equivalence ratio increases,the axial velocity and temperature peak increase,the range of the high temperature region expands,the thermal NOx formation rate increases,the outlet NOx concentration increases,and the CO does not change much.Maintaining the equivalent ratio at the level of 0.48 to 0.52 to control NOx formation can reduce overall pollutant emissions.3)As the inlet pressure increases,the axial velocity gradually decreases,and the range expands in the radial direction;the temperature increases,the high temperature zone slightly expands;the NOx emission increases slightly,the CO emission slightly decreases;the inlet pressure on the pollution overall impact of emissions is small.4)Increasing the intake air temperature significantly accelerates the combustion reaction rate,the axial velocity of the central section increases,the high temperature range of the combustion chamber expands,the thermal NOx formation rate increases sharply and the high rate range expands significantly,Therefore,the NOx concentration increases significantly.CO emissions are drastically reduced.