Study On The Effect Of Fuel Composition On Premixed Laminar Combustion Characteristics Of ABE

N-butanol is a good alternative fuel for internal combustion engines,which can mitigate energy crisis and air pollution.During the actual production of n-butanol,the separation and purification of it from the fermentation broth increase the energy consumption and limit the wider application of bio-butanol,so attention is paid to the intermediate production of acetone-n-butanol-ethanol（ABE）fuel.Due to the difference in fermentation technology and environment,the component content of ABE mixtures is diverse.At present,there are few studies about the effect of fuel composition on premixed laminar combustion characteristics of ABE mixtures.Carrying out this research can provide necessary data for the verification and improvement of the chemical kinetic mechanism of ABE and the turbulent combustion in the engine,as well as has important guiding value for engine operation.In the present study,through the experiment of the outwardly expanding spherical flames and simulation of one-dimensional planar flames,the effects of laminar combustion characteristics of ABE mixtures with different component contents and initial conditions were investigated,and chemical kinetic analysis of the combustion processes of mixtures was also conducted.The main contents and conclusions of the present study are as follows.（1）The laminar burning velocity of the n-butanol-acetone mixture decreases slightly with the increase of acetone content.The laminar burning velocity of the n-butanol-ethanol mixture increases with the increase of ethanol content.When the component content ratio of the ABE mixture is 0.2:9:0.8 and 0.8:9:0.2,the change of the component content has no significant effect on the laminar burning velocity.Comparing the two ABE mixtures with a content ratio of 1:5:4 and 4:5:1,the laminar burning velocity of the mixture with more ethanol content is significantly larger.The component content has a small effect on the Markstein length,but the equivalence ratio has a greater effect on it.（2）The peak value of the mole fraction of the stable component in the flame and the axial distance corresponding to the peak value change with the component content and equivalence ratio.The change of component content has no obvious influence on the main consumption channels of acetone,n-butanol and ethanol in the ABE flame,and the consumption amount change with the content of the component.The elementary reactions that have the greatest effect on the laminar burning velocity of ABE mixtures with different component contents are related to small molecules.Compared with the free radicals in the n-butanol-acetone flame,the peaks of the mole fractions of H,O,and OH in the n-butanol-ethanol flame are smaller,while the peaks of the molar fractions of CH₃ and HO₂ are not much different.In ABE flames with different component contents,the peak of the rate of production of H in R3 OH+H₂<=>H+H₂O is the largest,in order of R31,R28,and R2,indicating that the flame mainly generates H through the reaction of OH and H₂.The peak value of the rate of production of OH in H+O₂<=>O+OH is the largest,which indicates that OH is mainly generated by the reaction of H with O₂ in the flame.