Evaporation plavs an important role in the cylinder combustion process.so the study of fiel evaporation characteristics is very important to improve the combustion performance of internal combustion engine.In this stu...Evaporation plavs an important role in the cylinder combustion process.so the study of fiel evaporation characteristics is very important to improve the combustion performance of internal combustion engine.In this study,ethanol diesel was used as the base fuel.The evaporation characteristics of droplets at different ambient temperatures(623 K.923 K)were investigated by adding alumina nanoparticles with different mass fractions(1%,2.5%)to ethanol diesel.The results show that the evaporation states of three kinds of droplets(et hanol diesel,base fuel with 1%alumina nanoparticles,base fuel with 2.5%alumina nanoparticles)are similar in the low temperature environment,and nanoparticles inhibit the evaporation of the droplets.At low temperature,the higher the concentration of nanoparticles is,the slower the evaporation rate is.However.in the high temperature environment,nanoparticles significantly promote droplet evaporation.and the phenomenon of micro explosion is obvious.By analvzine the evaporation processes of two different temperatures,we kuow that nanoparticles first.gather on the surface of the droplet,theu form a protective shell,and finally reduce the evaporation rate of the droplet at low temperature.In the high temperature environment,mucleation sites and bubbles are formed in the interior of the droplet:as the droplet is heated further,mucleation sites and bubbles first gather and then fuse:the bubbles gradually expand and burst rapidly.causing micro explosion of the droplets.and most of them are evaporated in the micro explosion.展开更多
基金the Foundation Research Project of Jiangsu Province(the Natural Science Fund:No.BK20180982)。
文摘Evaporation plavs an important role in the cylinder combustion process.so the study of fiel evaporation characteristics is very important to improve the combustion performance of internal combustion engine.In this study,ethanol diesel was used as the base fuel.The evaporation characteristics of droplets at different ambient temperatures(623 K.923 K)were investigated by adding alumina nanoparticles with different mass fractions(1%,2.5%)to ethanol diesel.The results show that the evaporation states of three kinds of droplets(et hanol diesel,base fuel with 1%alumina nanoparticles,base fuel with 2.5%alumina nanoparticles)are similar in the low temperature environment,and nanoparticles inhibit the evaporation of the droplets.At low temperature,the higher the concentration of nanoparticles is,the slower the evaporation rate is.However.in the high temperature environment,nanoparticles significantly promote droplet evaporation.and the phenomenon of micro explosion is obvious.By analvzine the evaporation processes of two different temperatures,we kuow that nanoparticles first.gather on the surface of the droplet,theu form a protective shell,and finally reduce the evaporation rate of the droplet at low temperature.In the high temperature environment,mucleation sites and bubbles are formed in the interior of the droplet:as the droplet is heated further,mucleation sites and bubbles first gather and then fuse:the bubbles gradually expand and burst rapidly.causing micro explosion of the droplets.and most of them are evaporated in the micro explosion.
