Spray Characteristics Of Surrogate Fuel Of RP-3 Kerosene

A mixture of 14% n-decane,10% n-dodecane,30% iso-cetane,36% methylcyclohexane and 10% toluene was used as a surrogate fuel for domestic RP-3 aviation kerosene,which could better characterize the ignition and combustion of RP-3 aviation kerosene.In order to validate the physical properties and to study the spray mechanism of the surrogate fuel,spray tests were carried out based on an improved Phase Doppler Particle Analyzer synthetic experiment platform,under conditions of fuel temperature of 25 ? and-15 ?,fuel supply pressure of 200 k Pa,300 k Pa,400 k Pa,500 k Pa and 600 k Pa.The distances between measured sections and the nozzle are 10 mm,25 mm and 45 mm.The spray cone angles were obtained by using high-speed camera and image processing function based on MATLAB / GUI.The velocity means and size of fuel droplets were obtained by using Phase Doppler Particle Analyzer.The effect of spray condition and temperature on the spray characteristics were analyzed.Comparisons were made between the experimental results of the surrogate fuel and the domestic RP-3 aviation kerosene.The following conclusions were obtained:For domestic RP-3 aviation kerosene,the oil droplet axial velocity,radial velocity,film thickness and weber number were obtained.The cone angle and the droplet mean velocity increases while SMD decreases with weber number.The droplet mean velocity is larger as the droplet is closer to the center line in the horizontal direction.SMD increases with the distance between measured section and nozzle.A fitting formula of SMD was obtained by analyzing the influence of droplet diameter,velocity mean and fuel supply pressure on SMD.It was found that the fuel supply pressure had the greatest influence on SMD of single-way centrifugal nozzle.When the temperature decreases,the cone angle decreases,the droplet velocity mean increases,and SMD increases.For the surrogate fuel,although the density and viscosity of each single component are different from that of RP-3 aviation kerosene,and the density of the blended fuel is consistent with that of RP-3 aviation kerosene.The cone angle was smaller than RP-3 aviation kerosene,and the influence of temperature on cone angle decreased with the increase of fuel supply pressure.The droplet mean velocity increases with the increase of fuel supply pressure and decreases with the increase of the distance between measured section and nozzle.Compared with the surrogate fuel,the increase of the distance between measured section and nozzle has a greater influence on the droplet mean velocity than RP-3 aviation kerosene.With the increase of the distance between the measured section and the nozzle,the droplet velocity mean decreases,SMD decreases,and the decreasing rate gradually slows down.When the pressure increases,SMD decreases,and the decreasing rate gradually slows down.When the temperature decreases,the cone angle decreases,the droplet velocity mean increases,and SMD increases.Temperature has a greater impact on RP-3 aviation kerosene than the surrogate fuel.For the two kinds of fuel,the variation trend of spray characteristics are similar,but the details are different.The current research could provide a reliable basis for the verification of physical properties and substitutability of the surrogate fuel.