Experiment And Numerical Simulation Study Of Effervescent Atomization

Atomization technology disperse the liquid fuel into small droplets,which can effectively improve the liquid fuel evaporation and combustion speed,thus improving the combustion efficiency,increasing burning rate and reducing emissions.Compared with the traditional atomization method,the effervescent atomization has the advantages of less wear and tear,wider adaptability and stronger atomization ability.It has been applied in combustion,but its atomization mechanism,the formation of droplets,Combustion pollution control,etc.have not yet fully studied clearly.How to improve the output the effervescent atomization single nozzle still needs further study.Therefore,it is necessary to continue to carry out the study of effervescent atomization.In this paper,the particle size calculation formula of effervescent atomization is deduced from the internal two-phase flow theory and jet theory It is proved that the particle size of bubble droplet is determined by the nozzle outlet bubble rate ?,the nozzle outlet diameter d0,the air density ? ? and the atomization gas density ? g and the nozzle outlet gas-liquid velocity ratio S of effervescent atomization.And the fitting formula for calculation particle size in engineering is put forward.In order to make the bubble atomization applied to high liquid flow conditions,an annular nozzle was designed and the atomization experiment of the nozzle was carried out.The relationship between the droplet size and the mass flow ratio of the annular nozzle was discussed.It was found that the droplet size of annular nozzle was more sensitive to gas-liquid mass flow ratio and the nozzle has a wider regulation range.The experimental results show that the higher the liquid temperature,the smaller the droplet diameter,but the influence is limited.The combustion performance of the nozzle with different gas-liquid mass flow ratio is studied using numerical simulation.The simulation results show that the designed nozzle has good performance,wide application range and stable combustion flame.Compared with the hole nozzle,the annular nozzle of the diesel atomized combustion has a little lowermaximum combustion temperature,but a relatively higher temperature region,which can effectively reduce the NOx emissions,and increase combustion efficiency.The effect of gas-liquid ratio and atomization pressure on combustion is mainly due to the change of atomization particle size and spray velocity.The larger gas-liquid ratio,the smaller the atomization particle size,but if the spray speed is too high,it will make the flame difficult to maintain stable,which will course a blow off or extinguish.