In order to analyze the complex chemical kinetic mechanism systematically and find out the redundant species and reactions, a numerical platform for mechanism analysis and simplification is established basing on Path ...In order to analyze the complex chemical kinetic mechanism systematically and find out the redundant species and reactions, a numerical platform for mechanism analysis and simplification is established basing on Path Flux Analysis （PFA）. It is used to reduce a detailed mechanism for flame inhibited by phosphorus containing compounds, a reduced mechanism with 65 species and 335 reactions is obtained. The detailed and reduced mechanism are both used to calculate the freely-propagating premix C3H8/air flame with different dimethyl methylphosphonate doped over a wide range of equivalence ratios. The concentration distributions of free radicals and major species are compared, and the results under two different mechanisms agree well. The laminar flame speed obtained by the two mechanisms also matches well, with the maximum relative error introduces as a small value of 1.7%. On the basis of the reduced mechanism validation, the correlativity analysis is conducted between flame speed and flee radical concentrations, which can provide information for target species selection in the further mechanism reduction. By analyzing the species and reactions fluxes, the species and reaction paths which contribute the flame inhibition significantly are determined.展开更多
Ignition delay times of multi-component biomass synthesis gas （bio-syngas） diluted in argon were measured in a shock tube at elevated pressure （5, 10and 15 bar, 1 bar = 105 Pa）, wide temperature ranges （1,100-1,7...Ignition delay times of multi-component biomass synthesis gas （bio-syngas） diluted in argon were measured in a shock tube at elevated pressure （5, 10and 15 bar, 1 bar = 105 Pa）, wide temperature ranges （1,100-1,700 K） and various equivalence ratios （0.5, 1.0, 2.0）. Additionally, the effects of the variations of main constituents （H2：CO = 0.125-8） on ignition delays were investigated. The experimental results indicated that the ignition delay decreases as the pressure increases above certain temperature （around 1,200 K） and vice versa. The ignition delays were also found to rise as CO concentration increases, which is in good agreement with the literature. In addition, the ignition delays of bio-syngas were found increasing as the equivalence ratio rises. This behavior was primarily discussed in present work. Experimental results were also compared with numerical predictions of multiple chemical kinetic mechanisms and Li＇s mechanism was found having the best accuracy. The logarithmic ignition delays were found nonlinearly decrease with the H2 concentration under various conditions, and the effects of temperature, equivalence ratio and H2 concentration on the ignition delays are all remarkable. However, the effect of pressure is rela- tively smaller under current conditions. Sensitivity analysis and reaction pathway analysis of methane showed that R1 （H ＋O2= O -9 OH） is the most sensitive reaction promot- ing ignition and R13 （H ＋O2 （＋M） = HO2 （＋M））, R53（CH3＋H （＋M）= CH4 （＋M））, R54 （CH4＋H= CH3 ＋ H2） as well as R56 （CH4 ＋ OH = CH3 ＋ H2O） are key reactions prohibiting ignition under current experimental conditions. Among them, R53 （CH3 ＋ H （＋M） = CH4 （＋M））, R54 （CH4 ＋ H = CH3 ＋ H2） have the largest posi- tive sensitivities and the high contribution rate in rich mixture. The rate of production （ROP） of OH of R1 showed that OH ROP of R1 decreases sharply as the mixture turns rich. Therefore, the ignition delays become longer as the equiva- lence ratio increases.展开更多
基金Supported by the National Natural Science Foundation of China （51176181）, the National Basic Research Program of China （2012CB719704）, and the Research Fund for the Doctoral Program of Higher Education （20123402110047）.
文摘In order to analyze the complex chemical kinetic mechanism systematically and find out the redundant species and reactions, a numerical platform for mechanism analysis and simplification is established basing on Path Flux Analysis （PFA）. It is used to reduce a detailed mechanism for flame inhibited by phosphorus containing compounds, a reduced mechanism with 65 species and 335 reactions is obtained. The detailed and reduced mechanism are both used to calculate the freely-propagating premix C3H8/air flame with different dimethyl methylphosphonate doped over a wide range of equivalence ratios. The concentration distributions of free radicals and major species are compared, and the results under two different mechanisms agree well. The laminar flame speed obtained by the two mechanisms also matches well, with the maximum relative error introduces as a small value of 1.7%. On the basis of the reduced mechanism validation, the correlativity analysis is conducted between flame speed and flee radical concentrations, which can provide information for target species selection in the further mechanism reduction. By analyzing the species and reactions fluxes, the species and reaction paths which contribute the flame inhibition significantly are determined.
基金supported by the Key Fundamental Research Projects of Science and Technology Commission of Shanghai(14JC1403000)
文摘Ignition delay times of multi-component biomass synthesis gas （bio-syngas） diluted in argon were measured in a shock tube at elevated pressure （5, 10and 15 bar, 1 bar = 105 Pa）, wide temperature ranges （1,100-1,700 K） and various equivalence ratios （0.5, 1.0, 2.0）. Additionally, the effects of the variations of main constituents （H2：CO = 0.125-8） on ignition delays were investigated. The experimental results indicated that the ignition delay decreases as the pressure increases above certain temperature （around 1,200 K） and vice versa. The ignition delays were also found to rise as CO concentration increases, which is in good agreement with the literature. In addition, the ignition delays of bio-syngas were found increasing as the equivalence ratio rises. This behavior was primarily discussed in present work. Experimental results were also compared with numerical predictions of multiple chemical kinetic mechanisms and Li＇s mechanism was found having the best accuracy. The logarithmic ignition delays were found nonlinearly decrease with the H2 concentration under various conditions, and the effects of temperature, equivalence ratio and H2 concentration on the ignition delays are all remarkable. However, the effect of pressure is rela- tively smaller under current conditions. Sensitivity analysis and reaction pathway analysis of methane showed that R1 （H ＋O2= O -9 OH） is the most sensitive reaction promot- ing ignition and R13 （H ＋O2 （＋M） = HO2 （＋M））, R53（CH3＋H （＋M）= CH4 （＋M））, R54 （CH4＋H= CH3 ＋ H2） as well as R56 （CH4 ＋ OH = CH3 ＋ H2O） are key reactions prohibiting ignition under current experimental conditions. Among them, R53 （CH3 ＋ H （＋M） = CH4 （＋M））, R54 （CH4 ＋ H = CH3 ＋ H2） have the largest posi- tive sensitivities and the high contribution rate in rich mixture. The rate of production （ROP） of OH of R1 showed that OH ROP of R1 decreases sharply as the mixture turns rich. Therefore, the ignition delays become longer as the equiva- lence ratio increases.
