Experimental Study Of Hydrogen Addition On The Laminar Flame Characteristics Of RP-3 Kerosene

As the military increasingly fierce competition in the world aviation,transcendental ramjet with its advantages of simple structure and light weight have drawn the attention of the national military researchers.How to realize the rapid hydrocarbon fuel ignition and stable combustion is the key problem which need to be solved in transcendental scramjet development process.The study found that the hydrocarbon fuel adding active fule is an effective way to solve the problem.However,basic research data of national relevant field is lacking.Based on this purpose,this paper studies the carried out small molecule gas H2 added to the RP-3 kerosene laminar combustion characteristic of experimental research.In order to gain the main influencing factors of combustion characteristics of RP-3 kerosene,the flame propagation characteristics of RP-3 kerosene over the temperature range of 390~450 K,the pressure range of 0.1~0.7 MPa,and the equivalence ratio range of 0.9~1.4 were measured in the constant volume combustion bomb.The results show that flame outside surface is smooth with low equivalent ratio,some cracks or folds appear on the flame front when equivalent ratio rise to 1.4;when the initial pressure rise from 0.1 MPa to 0.7 MPa in the late development of flame,the flame front surface becomes unsmooth;flame developing speed goes up with the rise of initial temperature.Markstein length gradually decreases with the increase of the equivalent ratio or the increase of initial pressure;however,the effect of the initial temperature on the Markstein length is uncertainty.With the increasing of the equivalence ratio,the laminar burning velocity of RP-3 kerosene illustrates an increase initially and then decreases gradually.The highest laminar burning velocity is measured when the equivalence ratio is 1.2;laminar burning velocity increases with the decrease of initial pressure or the increase of initial temperature.The peak combustion pressure along with the increase of the ratio of yield showed a trend of decrease after the first increase rapidly.With the increasing of initial pressure or the decreasing of initial temperature,the peak combustion pressure gradually increase.In order to illustrate the effects of hydrogen addition on the combustion characteristics of RP-3 kerosene,the flame propagation characteristics over the temperature range of 390~420 K,the pressure range of 0.1~0.3 MPa,and the equivalence ratio range of 0.9~1.5 were measured in the constant volume combustion bomb.The results show that on the condition of different initial temperature,initial stress and equivalent ratio,with the increase of hydrogen mixing ratio,the flame front surface mixture gradually appears crack or fold,increasing the the instability of the flame,which is established by decreased Markstein length.Furthermore,with hydrogen addition ratio increasing,the laminar burning velocity and combustion pressure peak of RP-3 kerosene/hydrogen mixture illustrates an increase gradually.