Experimental Study On Spray Characteristics And Soot Distribution Of RP-3 And Diesel

With the continuous development of the military forces of various countries,the issue of military equipment fuel reserves and safety has drawn more and more attention all over the world.In order to further simplify the fuel logistics support system and improve the vehicle adaptability of fuel type,more and more researchers come into the filed of "single fuel in the battlefield",that is,all power equipment must be drivable using aviation kerosene.However,quantitative study on the soot distribution of kerosene is still blank.This paper first bulid up a electric heating constant volume combustion chamber and then,verifies the repeatability of the test results.Based on a high-power pulse LED light source,High Frequency Diffused Background Light Extinction Imaging(HFDBLEI)system for quantitative measurement of Soot is constructed and corresponding image processing program is written.Using the electric heating constant volume combustion chamber with schlieren imaging system and HFDBLEI,the effect of injection pressure,ambient temperature and ambient oxygen concentration on the spray and soot distribution characteristics of aviation kerosene(RP-3)/diesel fuel is investigated.The results show that: as injection pressure increases,better fuel/air mixture is formed,which is helpful to reduce formation of soot.Fuel/air mixture and soot formation of RP-3 are better than diesel especially under high injection pressure.With the increase of ambient temperature,the evaporating spray morphology remains remain unchanged,but the liquid length decreases,the onset time and initial location of soot advance,the soot mass increase.Comparing with diesel,the soot mass of RP-3 is lower under different ambient temperature.With the decrease of ambient oxygen concentration,higher equivalence ratio decreases the soot mass of RP-3,but the effect on diesel is complex: the soot mass of diesel first increase with the increase of ambient oxygen concentration,and the maximum value results at 17%.When the ambient oxygen concentration is 19%,the soot mass drop to minimum.By combining the liquid length data under different condition,it can be found that combustion states have no effect on liquid length.R25(RP-3/diesel blend with a volume ratio 25:75)significantly shortens the diesel spray penetration and liquid length,enhances the spray diffusion,has little effect on the initial time and position of diesel soot generation,but reduces the soot concentration and quality.