| Atomization evaporation and combustion of liquid mist is an extremely complicated process,in order to improve combustion efficiency and reduce pollutant emission,this requires us to carry out detailed research and analysis on atomization process and combustion process of liquid mist.Based on this objective,the atomization process and combustion process of turbulent liquid mist(Lean premixed prevaporated,LPP)technology were studied in this paper.Based on the experimental system,the premixed chamber,the nozzle and the combustion chamber are simplified,the physical geometry model is established,and the CFD software is used to simulate the combustion process of LPP in order to explore the mechanism and the influencing factors of the atomization evaporation process and the combustion process of the turbulent liquid mist.The atomization,evaporation and combustion process of liquid mist under different preheating air temperature,swirl intensity and burner structure are analyzed.Firstly,by simplifying the bubble atomizer and adopting the discrete phase model and evaporation law,the numerical simulation of the atomization evaporation in the premixed room under different preheating air temperature and swirl intensity of premixed chamber is carried out,and the higher the preheating air temperature is,the faster the liquid mist evaporates,and the shorter the liquid droplet existence time,the shorter the liquid mist torch by tracking the particle orbit and analyzing the velocity and concentration field in the premixed chamber.The swirl intensity should not be too large or too small,too large or too small to be detrimental to the downstream combustion;using the acoustic analogy model to analyze the outlet pressure oscillation of the premixed chamber,it is observed that the premixed evaporation process will cause a certain degree of thermoacoustic oscillation and will affect the combustion process.Secondly,under the condition of atomization evaporation,by using the EDC model,the combustion process numerical simulation is carried out after ignition in high temperature area,and the combustion characteristics and instability of different preheating air temperature,the inlet swirl intensity of the premixed chamber and the swirl intensity of the combustor inlet are analyzed,and the suitable preheating air temperature and The swirl intensity at the inlet of the premixed chamber and the swirl intensity at the inlet of the combustor can make the combustion effect better,emission less,and keep the combustion stable.When using the rotary swirl burner,the combustion effect is better than the pure cyclone,and there is almost no pollutant emission.It can be concluded from the angle of preheating air temperature,swirl intensity and burner structure to improve the atomization evaporation process of liquid mist,and then to improve the combustion process so as to reduce the emission and reduce the unstable combustion. |
