Experimental and kinetic study on ignition of DME/n-butane mixtures under high pressures on a rapid compression machine

Wu, Han; Shi, Zhi‐Cheng; Lee, Chia Fon; Zhang, Hongguang; Xu, Yonghong

doi:10.1016/j.fuel.2018.03.129

Cited by 22 publications

(23 citation statements)

References 62 publications

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“…Dimethyl ether (DME) is generally considered as a promising fuel additive or alternative fuel [4,[20][21][22][23][24][25][26] because of low particulate emission, low auto ignition temperature, and rapid vaporization upon injection, which comes from its high cetane number (5560) (suitable for compression ignition engines), high oxygen content (35 wt%), low boiling point (249 K), and relatively low vapor pressure (easy to handle and transport) characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Amin

Liu

et al. 2018

Combustion and Flame

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The effects of dimethyl ether (DME) addition to ethylene fuel on sooting tendencies with varying pressure were investigated in counterflow diffusion flames by using a laser scattering technique. Sooting limit maps were determined in the fuel (XF) and oxygen (XO) mole fraction plane, separating sooting and non-sooting regions. The results showed that when DME is mixed to ethylene, the sooting region was appreciably shrank, especially in the cases of soot formation/oxidation (SFO) flames as compared with the cases of soot formation (SF) flames. This indicated an inhibiting role of DME on sooting. An interesting observation was that the critical XO required for sooting initially decreased and then increased with the DME mixing ratio to ethylene β for the cases of SF flames, exhibiting a non-monotonic behavior. This implied a promoting role of DME on sooting when small amount of DME is mixed to ethylene. As the pressure increased, the sooting region generally expanded. Specifically, the range of β in promoting soot formation extended with pressure. This implies that a strategy in reducing soot by adding DME to ethylene at high pressures required a large amount of DME addition. To interpret the observed phenomena, kinetic simulations including reaction pathway and sensitivity analyses were conducted with the opposed-flow flames model using the KAUST-Aramco PAH Mech. The results showed that the thermal effect of DME addition on sooting tendency monotonically decreases with . The chemical effect was found to be the main contributor to the DME addition effect on sooting tendency, resulting in the non-monotonic sooting limt behavior. The pathway analysis showed the role of methyl radicals generated from DME promoted incipient benzene ring formtion when small amount of DME was added, which can be attributed to the soot promoting role of DME addition for small β.

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Section: Introductionmentioning

confidence: 99%

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Amin

Liu

et al. 2018

Combustion and Flame

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“…The reason for different promoting effect patterns on the ignition characteristics of n‐butane at different initial temperatures will be presented later in the ROP and sensitivity analysis section. The definition of the reduction rate on the ignition delay time as follows:

Reduction rate = \frac{τ_{normaln ‐ butane} ‐ τ_{R_{TBHP}}}{τ_{n ‐ butane}} \times 100 %

where τ n‐butane is the ignition delay time of pure n‐butane, and τ R TBHP is the ignition delay time of n‐butane/TBHP fuel with the TBHP addition ratio of R TBHP . It can be seen from Figure , at 750 K, the reduction rate rises slowly as R TBHP increases, which means, the promoting effect of TBHP addition on the ignition of n‐butane weakens gradually as R TBHP increases.…”

Section: Resultsmentioning

confidence: 99%

“…The reason for different promoting effect patterns on the ignition characteristics of n-butane at different initial temperatures will be presented later in the ROP and sensitivity analysis section. The definition of the reduction rate on the ignition delay time 19 as follows:…”

Section: Effect Of Tbhp Addition Ratiomentioning

confidence: 99%

“…It is a normal method to improve ignition and combustion characteristics of n‐butane with blending other flammable fuels in references. For example, Zhong et al found that the catalytic ignition temperature of n‐butane blending with hydrogen was reduced, in addition, thermal and chemical effects of the hydrogen addition were analyzed.…”

Section: Introductionmentioning

confidence: 99%

“…It was found that the DME blending could reduce the ignition delay time of n‐butane. Wu et al used a rapid compression machine to measure ignition delay times of n‐butane/DME fuels. The results indicated that the DME blending reduced the ignition delay time of n‐butane, and this reduction is more notable in the NTC region.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation on ignition intensification of n‐butane with tert‐butyl hydroperoxide (TBHP) addition

et al. 2019

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Summary Aimed to intensify the ignition and combustion process of n‐butane fuel in micro internal combustion (IC) engines, ignition delay characteristics of n‐butane/air mixtures with tert‐butyl hydroperoxide (TBHP) addition ratios below 10% were investigated numerically by CHEMKIN‐PRO software. Results show that ignition delay times of n‐butane can be shortened nonlinearly with TBHP addition at initial temperatures of 650 K to 1000 K, namely, the reduction rate of ignition delay times rises slowly as the TBHP addition ratio increases. In addition, the negative temperature coefficient (NTC) behavior can be weakened significantly with TBHP addition at 650 K to 1000 K. Especially, the ignition delay time of n‐butane can be reduced about 32 times with 10% TBHP addition at 750 K. However, the ignition intensification effect of TBHP addition is slight when the initial temperature is above 1000 K. The acting mechanism of TBHP addition was investigated in detail by the rate of production and consumption (ROP), sensitivity, and reaction pathway analysis. The ROP analysis shows that the released and quickly consumed OH radicals with TBHP addition play an important role in promoting n‐butane ignition at the lower initial temperature. However, the relatively slow consumption rate of OH radicals at higher temperature weakens the intensification effect. Furthermore, the sensitivity analysis and reaction pathway analysis indicate that the dominated elemental reactions and reaction pathway vary significantly with TBHP addition at lower initial temperature.

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Application of response surface methodology to optimize the emissions and performance of a dual fuel engine using diesel and dimethyl ether

Kumar

Yadav

2023

Env Prog and Sustain Energy

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In this study, the combustion and exhaust emission characteristics of a single‐cylinder, water‐cooled, four‐stroke VCR engine at a fixed CR were evaluated using DME and diesel with timed manifold injections of 2, 3, 4, and 5 ms for DME and conventional diesel settings. The investigational trials showed that DME has the capability to reduce NOx and OP while used in an optimized range and to have clean combustion characteristics. Induction of DME under low to medium load conditions resulted in a reduction in NOx, OP, and BTE with an increase in HC, whereas at higher load settings, NOx increased with an increase in diesel energy share. The dual fuel combustion was characterized by a short ignition delay, an early start of combustion, and increased in‐cylinder pressure due to the increased compression work input during the cycle. The absence of carbon–carbon bonds in DME molecules caused low soot emissions during dual fuel combustion. After experimentation, RSM was applied to the results for parametric optimization and found to be a useful tool for reducing the error as well as minimizing the number of trials. The optimum settings were achieved at 2 kW load and 4 ms duration, where the desirability function reached a value of 0.94189. The regression equations developed by the model were validated by 9 random experiments, and the error is found to be acceptable. The engine should be operated at medium load to control NOx, and the DME energy share should be low and near 50%.

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Experimental and kinetic study on ignition of DME/n-butane mixtures under high pressures on a rapid compression machine

Cited by 22 publications

References 62 publications

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Numerical investigation on ignition intensification of n‐butane with tert‐butyl hydroperoxide (TBHP) addition

Application of response surface methodology to optimize the emissions and performance of a dual fuel engine using diesel and dimethyl ether

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