Experimental Study On The Ignition Characteristics Of A Surrogate Fuel For Chinese Kerosene

In this paper,the compositions and main physical characteristics of Chinese kerosene were analyzed.The results show that,the average molecular weight of Chinese kerosene is149.05g/mol,the H/C is 2.04,the formula is C_10.62H_21.66,the density is 0.778g/cm³,the viscosity is 2.07mm²/s.The main components of Chinese kerosene are alkanes（cycloalkanes,chain alkanes and isomers）and aromatic hydrocarbons.According to the composition and main physical characteristics of Chinese kerosene,the selection criterions of the surrogate fuel which include the average molecular weight,hydrogen-carbon ratio,cetane number and lower heating value were determined and a five-component Chinese kerosene surrogate fuel which comprising n-decane,n-dodecane,iso-cetane,methylcyclohexane,toluene was presented.The main physical characteristics of the surrogate fuel and Chinese kerosene were contrastive analyzed.The results show that the average molecular weight,hydrogen-carbon ratio,cetane number and lower heating value of the surrogate fuel which are agreed well with the corresponding criterions of Chinese kerosene.At the same time,the variation trends of the densities and kinematic viscosities of the surrogate fuel are agreed well with the corresponding experimental data of Chinese kerosene at different temperatures.In shock wave tube,the ignition characteristics of n-decane,n-dodecane,iso-hexadecane,methylcyclohexane and toluene at initial pressure of 0.1MPa,equivalent ratio of 0.5,1.0,1.5and initial temperature range of 1000-1700 K were tested.The results show that the correlation for the logarithm of the ignition delay times of these five fuels and the reciprocal ignition temperature is linear.At the same time,with the ignition temperature increasing and the equivalence ratio decreasing,the ignition delay times of these five fuels are shortening.By comparing the ignition delay characteristics of five components and Chinese kerosene under different working conditions,it can be found that the ignition delay times of toluene and methylcyclohexane are greater than that of Chinese kerosene at different equivalent ratios and initial temperatures.At the same time,with the decrease of equivalent ratio,the gap between ignition delay time of toluene,methylcyclohexane and Chinese kerosene gradually increased.At different equivalent ratios and initial temperatures,the ignition delay times of n-decane,n-dodecane and iso-hexadecane are less than that of Chinese kerosene.At the same time,with the decrease of the equivalent ratio,the gap between the ignition delay times of n-decane,n-dodecane,iso-hexadecane and Chinese kerosene gradually decreased.The ignition characteristics of mixed surrogate fuel at initial pressures of 0.1,0.3 MPa,equivalent ratios of 0.5,1.0,1.5,and initial temperature range of 1000-1700 K were tested.The results show that the correlation for the logarithm of the ignition delay times of the surrogate fuel and the reciprocal ignition temperature is linear.With the increase of the equivalent ratio or the decrease of the initial pressure and ignition temperature,the ignition delay time of the surrogate fuel gradually increases.At different initial temperatures and equivalent ratios,when the initial pressure is 0.1 MPa,the ignition delay time of the surrogate fuel is in good agreement with that of Chinese kerosene.When the initial pressure is 0.3 MPa and the equivalent ratio is 0.5 and 1.5 respectively,the ignition delay time of the surrogate fuel is in good agreement with that of Chinese kerosene in the high-temperature region,but there is a small difference between the two in the low-temperature region.When the equivalent ratio is 1.0,the two are in good agreement in the low temperature region,but there is a small difference in the high temperature region.