Study on PAH Precursors and Some Important Species in Diesel Engine Combustion Process Using Detailed Chemical Kinetics and Sensitivity Analysis
In order to reveal the effects of mixture concentrations on diesel engine exhaust emissions, by using a detailed chemical kinetic mechanism of n-heptane oxidation and chemical kinetics analysis code, numerical simulations were made on the formation and development course of young soot precursor particles and other important intermediates or radicals in diesel engine combustion processes, whose fuel-air equivalence ratios are from 0.3 to 0.6. The results indicate that, by reducing the mixture concentration, lower temperature combustion can be achieved. The soot emissions sharply decrease when combustion temperatures are away from the “temperature window of soot formation. The mixture concentration has a significant impact on reaction intermediates or radicals. The aggregate yields of acetylene(C2H2) and propargyl(C3H3), which are precursors of polycyclic aromatic hydrocarbons(PAH), and other important species, such as hydroxide radical(OH), hydroperoxyl radical(HO2),hydrogen peroxide(H2O2), formaldehyde(CH2O) and carbon monoxide(CO)in the process of fuel combustion, can be successfully controlled by means of altering the mixture concentration, and then the control of exhaust emissions from a diesel engine can be obtained. Eighteen main reaction of the model fuel n-heptane oxidation were discovered by a sensitivity analysis, eight of which are peroxyalkyl radical(C7H15O2) isomerization, five, hydroperoxy-heptyl radical decomposition, two, n-heptane(NC7H16) oxidation by hydroxide radicals, two, ketohydroperoxide molecule(NC7KET) degradation and one, hydrogen peroxide decomposition. And the effects of these reactions were analyzed.
diesel engine polycyclic aromatic hydrocarbon numerical simulation mixture concentration radical
Chang-pu Zhao Xiao-wei Wang Xu-yang Sun Nai-zhuan Chen
State Key Laboratory of Engines, Tianjin University
国际会议
天津
英文
1-10
2009-08-19（万方平台首次上网日期，不代表论文的发表时间）