(1.School of MechanicalElectronic and Vehicle Engineering,Beijing University of Civil Engineering and Architecture,Beijing102616,China;2.State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
In order to research the ignition characteristics of diesel in CO2-O2 environment, an ignition delay time model was established using mixture of 70% nheptane and 30% toluene as diesel fuel. The model took into account the flame retardant effect of high CO2 concentration on ignition and obtained the functional relationship of ignition delay time with temperature, density and concentration by using multiple linear regression analysis method. The ignition delay time model was verified by combining the simulation of nheptane/toluene coupling mechanism and the test of visual constant volume combustion bomb, and the important factors affecting the ignition characteristics under different working conditions were investigated. The results show that the model can well predict the diesel ignition delay time in CO2-O2 environment, and the average error is 5.71% in 50%CO2environment. The thermal effect of CO2 plays a dominant role in the impact on ignition delay time and the thirdbody collision effect of CO2 promtes significantly the ignition when the CO2volume fraction is greater than 60%. In addition, the CO2 concentration variation has a significant effect on the rate of OH radical production.
ZHANG Yuewei,YAO Shengzhuo,LIU Yongfeng,LIU Haifeng,SONG Jin′ou.
Effect of Toluene Addition on Ignition Characteristics of N-Heptane under High CO2 Concentration[J]. Vehicle Engine. 2022, 0(4): 8-16
