The Experts below are selected from a list of 5565 Experts worldwide ranked by ideXlab platform
Yong Qian - One of the best experts on this subject based on the ideXlab platform.
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experimental studies on the key parameters controlling the combustion and emission in premixed charge compression ignition concept based on diesel surrogates
Applied Energy, 2019Co-Authors: Yong Qian, Zhiyong Wu, Zilong Li, Chenxu Jiang, Xingcai LuAbstract:Abstract Compared with the traditional diesel combustion mode, the premixed charge compression ignition mode only changes the fuel injection strategy combined with a certain ratio of exhaust gas recirculation, which needs little change to the overall engine. Studies on the effects of the Cetane number and volatility of the diesel fuels are critical to the combustion, emissions and load range expansion of the premixed charge compression ignition mode. Based on the multi-component surrogate fuels, this paper controlled the Cetane number and the volatility of diesel surrogates by changing the components and their proportions combined with the adjustment of fuel injection parameters to study the factors that affect the combustion and emissions of the premixed charge compression ignition mode. The Cetane number of fuels played a decisive role in the combustion phase under the same injection strategy. The decrease of Cetane number of the direct injected fuels led to the increase of CO and HC emissions. Low Cetane fuels helped to inhibit premature combustion of pilot injected fuel. The decrease in fuel Cetane number could suppress the emissions of accumulated particles. Changing the volatility of the fuel had limited effects on the combustion phase and combustion speed. High volatility fuel could effectively reduce the CO and HC emissions in the premixed charge compression ignition mode although it cannot fundamentally solve the high CO and HC emission problems caused by the premixed strategy. Increasing the volatility of the fuel could reduce the concentration of accumulated particles. Under the premise of ensuring that the NOx emissions were lower than 200 ppm via adjusting the injection parameters, increasing fuel volatility may decrease the indicated fuel consumption as low as 178 g/kWh.
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a study on the low to intermediate temperature ignition delays of long chain branched paraffin iso Cetane
Proceedings of the Combustion Institute, 2019Co-Authors: Yue Qiu, Yebing Mao, Sixu Wang, Can Ruan, Wencao Tao, Yong QianAbstract:Abstract Iso-Cetane (2, 2, 4, 4, 6, 8, 8-heptamethylnonane) is known as a primary reference fuel for Cetane number rating and is regarded as an applicable component for surrogate diesel fuel. In this study, ignition delays for iso-Cetane homogeneous mixture were measured at equivalence ratios varying from 0.5 to 2.0, compressed pressures of 10, 15 and 20 bar, and compressed temperatures of 620–880 K in a heated rapid compression machine (RCM). Two-stage ignition characteristic of iso-Cetane was observed for all mixtures. Negative temperature coefficient (NTC) behavior of iso-Cetane ignition delay appears in the temperature range of 670–730 K, which is significantly lower than that of other large hydrocarbons. Influences of compressed temperature, compressed pressure, and mixture composition on iso-Cetane ignition delays were also investigated. It is found that the total ignition delays shorten with the increase of compressed pressure, equivalence ratio and oxygen mole fraction. The first-stage ignition delays exhibit Arrhenius-like dependence on compressed temperature and are relatively insensitive to the change of other parameters. In addition, modeling study was conducted using an updated iso-Cetane kinetic model developed from a literature iso-Cetane mechanism. Simulation results show that the total ignition delays are underestimated while the temperature range of the NTC behavior is overestimated. Rate of production (ROP) analysis prior to the first-stage ignition was also conducted to identify the controlling reactions generating and consuming OH and HO2 radicals in low-temperature (low-T) reaction pathways.
William J Pitz - One of the best experts on this subject based on the ideXlab platform.
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detailed chemical kinetic reaction mechanisms for primary reference fuels for diesel Cetane number and spark ignition octane number
Proceedings of the Combustion Institute, 2011Co-Authors: Charles K Westbrook, William J Pitz, Marco Mehl, Henry J. CurranAbstract:A detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel Cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel Cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to several test problems are presented, describing fuel/air autoignition variations with changes in fuel Cetane and octane numbers, and others describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100).
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detailed chemical kinetic reaction mechanisms for primary reference fuels for diesel Cetane number and spark ignition octane number
Presented at: 33rd International Symposium on Combustion Beijing China Sep 01 - Sep 06 2010, 2010Co-Authors: Charles K Westbrook, William J Pitz, Marco Mehl, Henry J. CurranAbstract:For the first time, a detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel Cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel Cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to two test problems are presented, one describing fuel/air autoignition variations with changes in fuel Cetane numbers, and the other describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100). The final reaction mechanism for the primary reference fuels for diesel fuel and gasoline is available on the web.
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the autoignition of iso Cetane at high to moderate temperatures and elevated pressures shock tube experiments and kinetic modeling
Combustion and Flame, 2009Co-Authors: Matthew A Oehlschlaege, Charles K Westbrook, Justi Steinberg, William J PitzAbstract:Iso-Cetane (2,2,4,4,6,8,8-heptamethylnonane, C{sub 16}H{sub 34}) is a highly branched alkane reference compound for determining Cetane ratings. It is also a candidate branched alkane representative in surrogate mixtures for diesel and jet fuels. Here new experiments and kinetic modeling results are presented for the autoignition of iso-Cetane at elevated temperatures and pressures relevant to combustion in internal combustion engines. Ignition delay time measurements were made in reflected shock experiments in a heated shock tube for {phi} = 0.5, 1.0, and 1.5 iso-Cetane/air mixtures at temperatures ranging from 879 to 1347 K and pressures from 8 to 47 atm. Ignition delay times were measured using electronically excited OH emission, monitored through the shock tube end wall, and piezoelectric pressure transducer measurements, made at side wall locations. A new kinetic mechanism for the description of the oxidation of iso-Cetane is presented that is developed based on a previous mechanism for iso-octane. Computed results from the mechanism are found in good agreement with the experimental measurements. To our knowledge, the ignition time measurements for iso-Cetane presented here are the first of their kind. (author)
Charles K Westbrook - One of the best experts on this subject based on the ideXlab platform.
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detailed chemical kinetic reaction mechanisms for primary reference fuels for diesel Cetane number and spark ignition octane number
Proceedings of the Combustion Institute, 2011Co-Authors: Charles K Westbrook, William J Pitz, Marco Mehl, Henry J. CurranAbstract:A detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel Cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel Cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to several test problems are presented, describing fuel/air autoignition variations with changes in fuel Cetane and octane numbers, and others describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100).
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detailed chemical kinetic reaction mechanisms for primary reference fuels for diesel Cetane number and spark ignition octane number
Presented at: 33rd International Symposium on Combustion Beijing China Sep 01 - Sep 06 2010, 2010Co-Authors: Charles K Westbrook, William J Pitz, Marco Mehl, Henry J. CurranAbstract:For the first time, a detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel Cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel Cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to two test problems are presented, one describing fuel/air autoignition variations with changes in fuel Cetane numbers, and the other describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100). The final reaction mechanism for the primary reference fuels for diesel fuel and gasoline is available on the web.
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the autoignition of iso Cetane at high to moderate temperatures and elevated pressures shock tube experiments and kinetic modeling
Combustion and Flame, 2009Co-Authors: Matthew A Oehlschlaege, Charles K Westbrook, Justi Steinberg, William J PitzAbstract:Iso-Cetane (2,2,4,4,6,8,8-heptamethylnonane, C{sub 16}H{sub 34}) is a highly branched alkane reference compound for determining Cetane ratings. It is also a candidate branched alkane representative in surrogate mixtures for diesel and jet fuels. Here new experiments and kinetic modeling results are presented for the autoignition of iso-Cetane at elevated temperatures and pressures relevant to combustion in internal combustion engines. Ignition delay time measurements were made in reflected shock experiments in a heated shock tube for {phi} = 0.5, 1.0, and 1.5 iso-Cetane/air mixtures at temperatures ranging from 879 to 1347 K and pressures from 8 to 47 atm. Ignition delay times were measured using electronically excited OH emission, monitored through the shock tube end wall, and piezoelectric pressure transducer measurements, made at side wall locations. A new kinetic mechanism for the description of the oxidation of iso-Cetane is presented that is developed based on a previous mechanism for iso-octane. Computed results from the mechanism are found in good agreement with the experimental measurements. To our knowledge, the ignition time measurements for iso-Cetane presented here are the first of their kind. (author)
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hydrocarbon ignition automatic generation of reaction mechanisms and applications to modeling of engine knock
Symposium (International) on Combustion, 1992Co-Authors: Charles K Westbrook, C Chevalier, W J Pitz, J Warnatz, H MelenkAbstract:A computational technique is described which automatically develops detailed chemical kinetic reaction mechanisms for large aliphatic hydrocarbon fuel molecules. This formulation uses the LISP language to apply general rules which identify the chemical species produced, the reactions between these species, and the elementary reaction rates for each reaction step. Reaction mechanisms for Cetane (n-hexadecane) and most alkane fuels C{sub 7} and smaller are developed using this automatic technique, and detailed sensitivity analyses for n-heptane and Cetane are described. These reaction mechanisms are then applied to calculation of knock tendencies in internal combustion engines. The model is used to study the influence of fuel molecule size and structure on knock tendency, to examine knocking properties of fuel mixtures, and to determine the mechanisms by which pro-knock and anti-knock additives change knock properties.
Henry J. Curran - One of the best experts on this subject based on the ideXlab platform.
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detailed chemical kinetic reaction mechanisms for primary reference fuels for diesel Cetane number and spark ignition octane number
Proceedings of the Combustion Institute, 2011Co-Authors: Charles K Westbrook, William J Pitz, Marco Mehl, Henry J. CurranAbstract:A detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel Cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel Cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to several test problems are presented, describing fuel/air autoignition variations with changes in fuel Cetane and octane numbers, and others describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100).
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detailed chemical kinetic reaction mechanisms for primary reference fuels for diesel Cetane number and spark ignition octane number
Presented at: 33rd International Symposium on Combustion Beijing China Sep 01 - Sep 06 2010, 2010Co-Authors: Charles K Westbrook, William J Pitz, Marco Mehl, Henry J. CurranAbstract:For the first time, a detailed chemical kinetic reaction mechanism is developed for primary reference fuel mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethyl nonane for diesel Cetane ratings. The mechanisms are constructed using existing rules for reaction pathways and rate expressions developed previously for the primary reference fuels for gasoline octane ratings, n-heptane and iso-octane. These reaction mechanisms are validated by comparisons between computed and experimental results for shock tube ignition and for oxidation under jet-stirred reactor conditions. The combined kinetic reaction mechanism contains the submechanisms for the primary reference fuels for diesel Cetane ratings and submechanisms for the primary reference fuels for gasoline octane ratings, all in one integrated large kinetic reaction mechanism. Representative applications of this mechanism to two test problems are presented, one describing fuel/air autoignition variations with changes in fuel Cetane numbers, and the other describing fuel combustion in a jet-stirred reactor environment with the fuel varying from pure 2,2,4,4,6,8,8-heptamethyl nonane (Cetane number of 15) to pure n-hexadecane (Cetane number of 100). The final reaction mechanism for the primary reference fuels for diesel fuel and gasoline is available on the web.
Yachao Chang - One of the best experts on this subject based on the ideXlab platform.
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Understanding the Relationship between Cetane Number and the Ignition Delay in Shock Tubes for Different Fuels Based on a Skeletal Primary Reference Fuel (n-Hexadecane/Iso-Cetane) Mechanism
Energy & Fuels, 2015Co-Authors: Yachao ChangAbstract:A new skeletal oxidation mechanism for the primary reference fuel (PRF) was established with a decoupling methodology. The mechanism is composed of n-hexadecane and iso-Cetane submechanisms, containing 44 species and 139 reactions. Using the present mechanism, the relationship between Cetane number and the ignition delay in shock tubes was investigated. First, based on the ignition delay data in shock tubes, the Cetane number of various fuels was estimated using the present PRF mechanism and a weighted least-squares method. The prediction of Cetane number investigated in this study primarily focused on the operating conditions of practical diesel engines (i.e., the equivalence ratio of 1.0 and pressures from 19–80 atm), which encompass the Cetane number from 15 to 100. Under the test operating conditions, the mean absolute deviation of the predicted Cetane number is within 3.327. Furthermore, according the Cetane number of different fuels, the ignition delays in shock tubes were reproduced by the present ...