Research On The Flame And Particle Emission Of Monodispersed N-heptane

As monodispersed fuel can decouple the process of combustion and atomization,and monodispersed fuel and air mixture are more uniform compared with engine.It makes great significance study fuel combustion and the mechanism of particle growth when take advantage of monodispersed fuel.Based on the Dibble burner,we simulate the combustion situation when piston reaches top dead center on the compression stroke by using flame of monodispersed n-heptane.Through studying the spray characteristics of ultrasonic atomization,flame of monodispersed n-heptane and particle emission,results are as follow:The set up we design and make up are suitable to study the partice emission of monodispersed n-heptane flame that the Dibble burner,the monodispersed n-heptane set up and the particle sampling and diagnosed system.The spray characteristics of ultrasonic atomization shows that n-heptane supply has little effect on the height of central injection whereas stable flow region increase with the carrier gas flux increase.The monodispersed n-heptane flame shows that there exist premixed and diffusion combustion zone.The flame length increase and premixed combustion zone decrease as coflow temperature go up.The flame length decrease and premixed combustion zone increase as central injection go up.The flame length increase and premixed combustion zone almost have no change as n-heptane supply go up.The influence of coflow temperature,central injection equivalent ratio on particle growth at various height is investigated.Monodispersed n-heptane dominates the matter at low temperature and height whereas particle dominates the matter at high temperature and height.The particle number and volume concentrations increase at the same place as central injection equivalent ratio go up.Particle number concentrations grow along with height and there is a tendency that volume concentrations increase and then decrease when equivalent ratio is high at 2,but at stoichiometric ratio particle number concentrations increase and then decrease whereas volume concentrations decrease.