| The energy crisis and environmental pollution are the decisive issues which humanity is facing in the 21 st century.Alcohol as a renewable biomass energy source can effectively alleviate the above problems.Methanol and ethanol have been widely used as alternative fuels.Butanol has the same huge potential application,but the industrial cost of the fermentation process from its mother liquor ABE(AcetoneButanol-Ethanol)to butanol is too high,so the direct use of ABE as an alternative fuel has attracted more and more attention and research..In this experiment,the micro-explosion and combustion characteristics of ABE/aviation kerosene blend fuel were studied in a single droplet layer.Studying from a single droplet level avoids interference from complex internal conditions of the engine,which facilitates a more detailed and accurate study of the physicochemical properties of the fuel.Alcohols are mixed with kerosene as an alternative fuel.due to the different boiling points of various components,the low-boiling components rapidly boil and vaporize in a high-temperature environment to generate bubbles,which cause the entire droplet to expand and break.This phenomenon is called micro-explosion.The microexplosion phenomenon is very important for the atomization and combustion of droplets in the combustion process of ABE/kerosene mixed fuel,and has great research value.The experiment is mainly divided into two parts.The first part is to explore the effects of various experimental conditions(droplet size,ABE and kerosene ratio,ABE internal ethanol and butanol ratio)on the microburst characteristics of ABE/kerosene single droplets.The experimental results show that:(1)With the increase of ABE ratio,the severity of droplet micro-explosion increases first and then decreases;(2)Under the same conditions,when the proportion of ethanol in ABE increases,the severity of droplet micro-explosion increases obviously.And according to the bubble formation process inside the droplet,the low solubility of ethanol in kerosene is the main cause of this phenomenon;(3)the droplet size has little effect on the severity of the microexplosion of the droplet,but the severity of the micro-explosion is similar.Of the two sets of droplets,smaller droplets are more likely to break.The second part of the research is mainly to explore the effect of droplet microexplosion on the combustion characteristics of droplets.The experimental results show that:(1)The micro-explosion of droplets occurs before the droplets ignite,due to the large latent heat of ABE vaporization inside the droplets,boiling When a large amount of heat is absorbed,the ignition delay period of the liquid droplets becomes long;(2)the micro-explosion phenomenon causes the droplets to be released by the heat stored in the form of latent heat of vaporization during the ignition delay period,and the droplets are broken,and the droplets are microscopically The explosion phenomenon causes the burning rate of the droplets to be significantly accelerated.(3)A method for quantifying the flame stability of droplets during micro-explosion is proposed,and it is concluded by this method that the micro-explosion of droplets will cause obvious fluctuations in the droplet flame,which indicates that the combustion stability of the droplets decreases to some extent.. |
