Numerical Simulation On Partially Premixed Swirl Combustion

Currently,the huge energy consumption and resource scarcity limit our country's development seriously.At the same time,the situation of environment is critical and air pollution is serious.So the utilization and the development of clean energy technology become the top-priority.For the current policy of encouraging gas instead of coal,cancelling the small coal-fired boiler of the Beijing-Tianjin-Hebei region and promoting the use of gas boiler,etc.So in this paper the following aspects was studied:First,the process of swirl combustion in small scale combustion chamber was simulated by the large eddy simulation.And the flame structure and the rule of the pollutant emission of oxygen-diluted partially premixed/ oxygen-enriched supplemental combustion are obtained.Compared with the experimental results,the temperature of simulation is taller,the pollutant emission of simulation is lower,but the trend of flame structure,temperature distribution,emission are same.Second,large scale combustion model was built based on modular gas-fired boiler.The influence of oxygen-diluted partially premixed/ oxygen-enriched supplemental combustion 's working parameters are studied,the range of study including: the flow field structure,the temperature distribution,velocity gradient,the distribution of OH* mole fraction,the distribution of CO mole fraction,the distribution of NO mole fraction,the pollutant emission.The results shows that: higher total equivalent ratio contributes to increase the temperature of the combustion and the output of CO and NO.This rule could also be used in the increase of the partially premixed equivalent ratio and the increase of the partially premixed oxygen-diluted concentration.But the difference is the extent of increase more slightly.The optimum condition was found: the total equivalent ratio was0.7,the partially premixed equivalent ratio was 1.2,the partially premixed oxygen-diluted concentration was 17%,the oxygen-enriched concentration was 22%.The emission of NO and CO were lowest in all conditions.Last,oxygen-diluted partially premixed/ oxygen-enriched supplemental combustion technology is compared with air classification combustion technology.The range of study including: the flow field structure,the temperature distribution,velocity gradient,the distribution of OH* mole fraction,the distribution of CO mole fraction,the distribution of NO mole fraction,the pollutant emission.The results showed that: the technology of ODPP/OESC has a great advantage in the flame structure,the temperature of combustion,low pollutant emission,etc.In the appropriate conditions,the range of the indicators is even far more than air classification combustion technology.It proves that the ODPP/OESC is a clean energy technology.And the results of the study will provide basic data for the practical application of the technology.