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The Dimethyl ether (DME) kinetic model is significant to understand the DME combustion in the atmosphere containing high CO 2 concentration, such as pressurized oxy-fuel combustion process and exhaust gas recirculation, and design the combustor. In this paper, the ignition delay times (IDTs) of DME were measured in a shock tube under the conditions of equivalence ratios of 0.5, 1 and 1.5, temperature ranges from 1007 K to 1340 K, and pressures of 2 and 11 atm. A detailed kinetic model of DME named as OXYDME was put forward based on the OXY-Aramco model, and was validated by the low and high temperature IDTs, laminar flame speeds, and species profiles measured in this work and those from literatures in atmospheres of O 2 /Ar/CO 2 , O 2 /N 2 , O 2 /N 2 /He/CO 2 and O 2 /CO 2. The OXYDME model was compared with OXY-Aramco, Liu-DME model in detail. The effects of CO 2 on the DME ignition are very weak and not sensitive to the temperature and pressure. The reason for the weak effects of CO 2 is that the chemical effects of CO 2 promote ignition, which counteracts the inhibition effects caused by the physical properties of CO 2. The chaperon effects of CO 2 dominate the chemical effects. Meanwhile, the effects of the reactions with CO 2 are very small. [ABSTRACT FROM AUTHOR]

• Ignition delay times of dimethyl ether/ethane/O 2 /CO 2 mixtures were first provided. • OXYMECH predicts well on the IDTs of the mixtures in O 2 /CO 2 and O 2 /N 2 atmosphere. • IDTs of the mixtures first decrease and then increase as adding DME at 10 atm. • The effect of DME addition and CO 2 on the IDTs of the mixtures were analyzed. The ignition delay times (IDTs) of dimethyl ether (DME)/ethane/O 2 /CO 2 mixtures were measured in a shock tube at pressures of 0.8, 2, and 10 atm; temperatures within the range of 1126–1449 K; equivalence ratio of 0.5; and DME proportions within the range of 0–100%. Four chemical kinetic models named OXYMECH, AramcoMech 3.0, San-Diego 2016 and Wang-DME were validated using the IDTs measured in this work. The results indicate that the OXYMECH predicts well the experimental data under O 2 /CO 2 and O 2 /N 2 atmospheres. At P = 0.8 and 2 atm, T = 1300 K, the increase of the DME proportion inhibits the ignition of the mixtures under O 2 /N 2 and O 2 /CO 2 atmospheres. At P = 10 atm, T = 1300 K, the IDTs of the mixtures firstly decrease when DME proportion increases from 0 to 20%, and then increase when DME proportion increases from 20 to 100% under O 2 /CO 2 atmosphere, while the IDTs of the mixtures increase as the DME proportion increases under O 2 /N 2 atmosphere. The valley-values of the IDTs of the mixtures appear at the certain DME proportion at P = 10 atm, T = 1100 K and 1200 K under O 2 /N 2 and O 2 /CO 2 atmospheres. The analyses of sensitivity and the rate of production were conducted to interpret the effect of DME addition and the properties of CO 2 on the ignition of the DME/C 2 H 6 /O 2 /CO 2 mixtures. [ABSTRACT FROM AUTHOR]

• Ignition delay times of n-heptane/DME were measured in the various blending ratio. • A blended model shows favorable performance on the prediction of the ignition delay times. • The effect of DME addition on the IDTs of fuel mixtures were analyzed in detail. The addition of oxygenated fuels to fossil fuels has been considered as a promising approach for reducing the issues associated with hazardous substances. The ignition delay time data of dimethyl ether/n-heptane mixtures were obtained using a shock tube under the following conditions: pressures of 0.8, 4.5, and 10 atm; equivalence ratio of 1; temperature within the range of 1171–1571 K; and dimethyl ether proportion within the range of 0–100%. The Arrhenius dependence of the ignition delay times on temperature and pressure was fitted. The experimental results show that the ignition delay times of dimethyl ether/n-heptane mixtures are less than those of pure dimethyl ether and pure n-heptane within a certain blending ratio range. A combined model named "blended model" was proposed based on the LLNL n-heptane version 3.1 and Zhao dimethyl ether models. The effect of DME addition on the IDT of the fuel mixtures was investigated using the blended model in detail. [ABSTRACT FROM AUTHOR]

Pressurized oxy-fuel combustion is considered to be a new generation of oxy-fuel combustion technology owing to its low emission and high efficiency. In this study, the ignition delay times (IDTs) for propane under O 2 /CO 2 /Ar atmospheres were measured in a shock tube at varying pressures and equivalence ratios. A chemical kinetic model (OXYMECH 2.0) for pressurized oxy-fuel combustion was developed by updating several key elementary reactions in our previous model (OXYMECH 1.0). OXYMECH 2.0 was validated based on experimentally measured IDTs for methane, ethane, and propane in O 2 /CO 2 , O 2 /N 2 , and O 2 /Ar atmospheres in a pressure range of 1–250 atm, as well as laminar flame speeds (LFSs) in pressure and temperature ranges of 1–4 atm and 298–543 K, respectively. The OXYMECH 1.0, Aramco 3.0, CRECK, and DTU models were also evaluated; the results indicate that OXYMECH 2.0 performs better than other models in terms of predicting the IDTs and LFSs of C 1 –C 3 alkanes in O 2 /CO 2 and O 2 /N 2 atmospheres. A detailed comparison between the OXYMECH 2.0 and Aramco 3.0 models was also performed. The influences of the pressure, equivalence ratio, and CO 2 concentration on the IDTs of propane were analyzed in detail. [ABSTRACT FROM AUTHOR]

Pressurized oxy-fuel combustion is a promising oxy-fuel technology owing to its high efficiency and low emission. The ignition delay times of ethane under O 2 /CO 2 atmosphere were determined in a shock tube at different pressures, equivalence ratios, and C 2 H 6 and CO 2 concentrations. The results suggested that the ignition delay times decrease with the increasing ethane concentration at 0.8, 2.0, and 10 bar, while the effect of the fuel concentration on the ignition delay times is not sensitive to the pressure. The ignition delay times increased with the increasing equivalence ratio at 0.8 and 2.0 bar, while the effect of the equivalence ratio decreased with the increasing pressure from 0.8 to 2.0 bar. At 10 bar, the effect of the equivalence ratio on the ignition delay times further weakened at high temperatures, while the ignition delay times decreased with the increasing equivalence ratio in the low-temperature range. An updated model (OXYMECH) was developed and updated on the basis of our previous work, providing yields in good agreement with the experimental data under all conditions, while Aramco 2.0 showed poor prediction of the experimental results at 10 bar. Analysis of the sensitivity and the rate of production indicated that updating the rate constants of the reactions C 2 H 6 + HO 2 ⇔ C 2 H 5 + H 2 O 2 , H + O 2 (+M) ⇔ HO 2 (+M), CH 3 + HO 2 ⇔ CH 3 O + OH, 2HO 2 ⇔ H 2 O 2 + O 2 , C 2 H 4 + H (+M) ⇔ C 2 H 5 (+M), and H + O 2 ⇔ O + OH improves the performance at 10 bar. [ABSTRACT FROM AUTHOR]

Super lean (usually Φ < 0.5) and ultra-lean (usually Φ < 0.3) combustion are regarded as promising combustion techniques owing to high fuel economy and low emission. Ethane is one of the key components of natural gas. In the present study, the ignition delay times (IDTs) of ethane/oxygen/argon mixture were measured behind reflected shock waves at three equivalence ratios of 0.5, 0.1, 0.05, two pressures of 1.68, 9.0 atm, and in the temperature range of 1120 – 1351 K. The OXYMECH2.0, proposed in our previous works, is modified in the present study by updating several elementary reactions. The modified OXYMECH is validated by ethane IDTs of super lean combustion measured in the present study, in high CO 2 atmospheres and O 2 /Ar atmospheres from the literature as well as laminar flame speeds (LFSs) under O 2 /N 2 and O 2 /CO 2 atmospheres. Aramco3.0, San Diego, NUIGMech0.9, and CRECK-GB models are also evaluated by ethane IDTs measured in the present study, the results show that modified OXYMECH, NUIGMech0.9, and CRECK-GB models provide equally accurate predictions for experiments. The NUIG Mech0.9 and CRECK-GB are further evaluated using the ethane IDTs in high CO 2 atmospheres and experimental LFSs of ethane under O 2 /N 2 and O 2 /CO 2 atmospheres, the results show that modified OXYMECH has good performance in predicting IDTs and LFSs of ethane. The detailed comparisons of IDTs and LFSs prediction between modified OXYMECH and CRECK-GB models are conducted. The effects of superabundant air, which is the air excess with equivalence ratio decreases from Φ 1 to Φ 2 , on the ignition in super lean combustion consist of the dilution and oxidation effects, which are studied in the present study in detail. It is very interesting that the dilution effects promote the ignition while the oxidation effects inhibit the ignition at Φ < 0.3 and P = 9.0 atm. [ABSTRACT FROM AUTHOR]

• The IDTs of DME /propane mixtures in O 2 /CO 2 atmospheres were measured. • A detail kinetic model referred as the DME-C 3 H 8 model was constructed. • The effects of the DME blending ratio were studied using the DME-C 3 H 8 model. • The effects of CO 2 and pressure on the ignition were discussed in detail. This work measured the ignition delay times (IDTs) of dimethyl ether (DME)/propane mixtures in O 2 /CO 2 atmosphere in a shock tube at an equivalence ratio of 0.5, a temperature range of 1157–1380 K, pressures of 2 and 10 atm, and a DME blending ratio range of 0–100%. A detailed kinetic model referred to as the DME-C 3 H 8 model was constructed based on the OXYMECH 2.0 model and the DME sub-mechanism of Aramco 3.0. The DME-C 3 H 8 , Aramco 3.0, NUIG 1.0, and Dames models were evaluated through the IDTs obtained in the present study, and from literature in O 2 /N 2 and O 2 /Ar atmosphere. The impact of the DME blending ratio was investigated using the DME-C 3 H 8 model, and results show that the IDTs in O 2 /CO 2 atmosphere at pressures of 2 and 10 atm decrease linearly with increased DME blending ratio; there exists a clear synergy effect between DME and propane in the O 2 /N 2 atmosphere at the pressure of 2 atm, which is significantly weakened at the pressure of 10 atm. The impact of CO 2 and pressure on the ignition were discussed in detail. [ABSTRACT FROM AUTHOR]

Pressurized oxy-fuel combustion is deemed an advanced oxy-fuel combustion technique due to the lower cost and little decrease in the generating efficiency compared to conventional PC system without CO 2 capture. Butane is an important composition of petroleum and natural gas. In this work, the ignition delay times (IDTs) for n-butane and i-butane under O 2 /CO 2 atmospheres were measured in a shock tube at different equivalence ratios (Φ) and pressures. Based on our previous C 1 C 3 model Oxymech2.0 and the C 4 sub-model of Aramco3.0, a chemical kinetic model Oxymech2.0 Plus was updated. Oxymech2.0 Plus was validated by the newly measured IDTs of butane under O 2 /CO 2 atmospheres. The model was also validated by the literature experimental data for IDTs of n-butane and i-butane at O 2 /Ar and O 2 /N 2 atmospheres, laminar flame speeds of n-butane and i-butane in air, and species profiles of n-butane and i-butane pyrolysis. The comparison between Oxymech2.0 Plus and Aramco 3.0 models was also conducted in detailed. The results show that the updated reactions in the study significantly improve the prediction of IDTs, laminar flame speeds and species profiles of butane in O 2 /CO 2 atmospheres. The effects of equivalence ratios and CO 2 on the IDTs of n-butane and i-butane were analyzed. [ABSTRACT FROM AUTHOR]