Reduce Mechanical Kinetic Mechanism Of Multicomponent Surrogate Fuel Of Biodiesel And Numerical Simulation Study

The energy shortage and environmental pollution of China are increasingly serious. We can achieve the control of combustion process, by chemical kinetic mechanism and engine combustion process research. This paper builds chemical kinetics mechanism of diesel and biodiesel, and research the combustion process and emission mechanism by three-dimensional CFD coupling chemical kinetics model in different altitudes.At first, we build a n-heptane mechanism which includes regular and unregular emissions, the n-heptane mechanism include 64 species and 181 reactions. Comparing with the data of shock tube experiments, premixed n-heptane flames experiments, premixed ethane flames experiments, Sandia combustion chamber experiments and engine experiments data, the results validate that the mechanism can predict the ignition and combustion process, and emission of diesel engine accurately.We choose n-heptane, methyl n-butanoate (MB) and methyl crotonate(MB2D) as biodiesel alternatives. The biodiesel alternatives reduced mechanism is built by adding the reduced n-heptane mechanism into the MB and MB2D reduced mechanism, and the biodiesel alternatives include 122 species and 395 reaction. The validation of the MB and MB2D reduced mechanism is by shock tube, diffusion or oppose-flow flame and laminar flame experiment, the result explain that the reduced mechanism can accurately predict ingnition and combustion process, and important intermediate species. The reduced mechanism is used in a CFD code, simulation results is compered with engine experiments, and the results validate that the mechanism can predict the ignition and combustion process of engine accurately, as well emission of NOx and soot.By researching the combustion process and PAHs, NOx, soot emission mechanism by three-dimensional CFD coupling chemical kinetics model in different altitudes, we get the following conclusions:The peak pressure and temperature decrease, and ignition delay time increase accompany with the altitude increase. The concentration of C2H2、A1、A2R5 and A4 are increasing quickly; NOx emission decrease following altitude increase; With altitude increasing, soot cann’t be oxidized for the concentration of O2 and OH decrease quickly, so soot emission will get worsen at high altitude.