Study On The Sooting Tendencies Based On Laser Measurement

The energy and environment crisis have led people to investigate the alternative energy.And the biomass fuel gradually enters people’s life with its advantages of renewable and low emission.China is a huge energy consumer and should pay more attention to the research of biomass fuel.In addition,pollutantion generated by combustion of fuel,such as soot,polycyclic aromatic hydrocarbons(PAH),NOx,etc.,contaminate the environment and threaten people’s health.The experiments on the engines show that anisole,the derivative of lignin,can significantly affect the emission of pollutants.So the anisole is of great value to be investigated.In order to explore the impact of second-generation biomass fuel,the anisole,on the soot formation.This paper uses a laboratory alternative of the traditional diesel,the n-heptane as a base fuel.The mixed fuel is configurated by adding different contents of anisole to n-heptane.A stable soot formation process is expected in a stable laminar counter-flow diffusion flame.Then the Light Extinction(LE)and the Laser Induced Incandescence(LII)were used to measure the soot formation.The experiments show that the anisole promotes soot formation.As the content of anisole in the mixed fuel increases from 0 to 30% by the step of 5%,soot volume fraction increases almost exponentially.Some experiments show that the benzene ring in the fuel promotes the formation of soot,but the oxygen in the fuel inhibits the formation of soot.This experiment shows that a benzene ring promotes the formation of soot more than the inhibition of soot by an oxygen atom.In this paper,the characteristics of soot formation in the laminar counter-flow diffusion flame are further studied by changing the strain rate and the oxygen content in the oxidant.When the oxidant has a high oxygen content,more soot is produced.When the oxygen content in the oxidant increases from 30% to 40% by the step of 5%,the soot volume fraction almost linearly increases.When the velocity of the fuel flow and the oxidant flow become larger,the strain rate also increases,and the soot formation is decreased.When the velocity of the fuel flow and the oxidant flow increases from 15 cm/s to 25 cm/s by the step of 5cm/s,the soot produced almost linearly decreased.The parameters above in this experimental study have a great influence on the soot formation in the laminar counterflow flames.And the influence follows the order: the oxygen content in oxidant > the content of anisole in the fuel > the velocity of the fuel flow and the oxidant flow.