Comprehensive Comparison of the Combustion Behavior for Low-Temperature Combustion of <i>n</i>-Nonane

Guo, Junjiang; Peng, Weijun; Zhang, Shijie; Lei, Jiazhi; Jing, Jiantong; Xiao, Ruyi; Tang, Shiyun

doi:10.1021/acsomega.9b03786

“…In Figure 1 b,c, after the upper end of the flame reached the surface of the porous media, the lower end of the flame still developed laterally but did not pass through the porous medium and eventually the flame was quenched. 17 That is to say, the flame was quenched in the porous media.…”

Section: Resultsmentioning

confidence: 99%

Effect of Metal Foam Mesh on Flame Propagation of Biomass-Derived Gas in a Half-Open Duct

Wang

¹

,

Wang

²

,

Zhu

³

et al. 2020

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The effect of metal foam mesh on flame propagation of biomass-derived gas in a half-open duct was studied. The explanations are based essentially on the experimental investigations of premixed biomass-derived gas explosions carried out in a rectangular half-open combustion chamber. The initial temperature T 0 and pressure P 0 were 300 K and 1.0 atm, respectively. The key parameters of explosive characteristics, such as flame propagation images and explosive overpressure, were analyzed by changing the porosity, the pore density of porous metal foams, and the gas components. The results show that the use of porous metal foam has a significant inhibitory effect on the gas explosion. Although the combustion structure of the flames is similar, the action of the porous metal foam during the experiment also shows the characteristics consistent with the obstacles. When the porosity of the porous foam is 97%, the flame can be stimulated to produce turbulence, and then the shock–flame interaction generated by the reflection of the lead shock wave can enhance the explosion propagation and promote the explosion escalation. However, with the increase of hole density, the existence of the porous metal foam by momentum loss and heat loss to curb the spread of the explosion not only hindered the flow of not flammable but also extracted energy from the expansion of the combustion products at the same time. This study also confirms that the biological hydrogen and methane component has a vital role in the flame, and a reasonable hydrogen and methane ratio can improve the flame burning to get more economic value.

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“…The initial calculated pressure is ranged from 3.5 to 3.2 × 10 7 Pa, which covers the working range of the common combustion devices, and the explosion temperature searching range is 350–2500 K. Other criteria like an average pressure increase rate of 3%/ms can be found for the determination of the cool flame ignition. 21 …”

Section: Numerical Approach Methodsmentioning

confidence: 99%

“…The initial calculated pressure is ranged from 3.5 to 3.2 × 10 7 Pa, which covers the working range of the common combustion devices, and the explosion temperature searching range is 350−2500 K. Other criteria like an average pressure increase rate of 3%/ms can be found for the determination of the cool flame ignition. 21 Three different detailed chemical kinetic models are used in this study, which are the comprehensive iso-octane combustion model (KAUST), 22 Aramco 2.0 model, 23 and methane/ propane oxidation model 24 from the National University of Ireland Galway (NUIG). As the KAUST and Aramco 2.0 models include larger hydrocarbon molecules, only the C3 subset species and related reactions are used in this study.…”

Section: Numerical Approach Methodsmentioning

confidence: 99%

On the Second Explosion Limits of Hydrogen, Methane, Ethane, and Propane

Yu

¹

,

Ma

²

,

Tang

³

2020

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In this work, we have first investigated the explosion limit behaviors from hydrogen to propane through numerical simulations and validated with the available experimental data. The shape of the explosion limit curves and the possible turning points ( P 1–2 , T 1–2 ), first to second limit transition, and ( P 2–3 , T 2–3 ), second to third limit transition that bound the second explosion limit as a function of the fuel carbon number, have been examined. Results show that with an increase of methane mole fraction in the hydrogen/methane system, the upper turning point ( P 1–2 , T 1–2 ) remains almost unchanged and the lower transition point ( P 2–3 , T 2–3 ) rotates counterclockwise around ( P 1–2 , T 1–2 ). With a further increase of carbon number, ( P 1–2 , T 1–2 ) moves to the lower-pressure and -temperature region and ( P 2–3 , T 2–3 ) gradually moves to the lower-pressure and higher-temperature region. The slope of the second explosion limit is inversely proportional to the carbon number, k PT = 0.0069 – 0.005/( X c – 0.7), approximately. Second, a sensitivity analysis has been conducted to study the elementary reaction on the second explosion limits. The results show that the chain branching and termination reactions governing the explosion limit of hydrogen have a little effect on the second explosion limit of methane. The C 2 H 5 O 2 H decomposition to form OH radicals is dominant in controlling the nonmonotonic behavior of the second explosion limit of C 2 H 6 . The second explosion limit behavior of propane is governed by three sets of reactions in the low-temperature oxidation process.

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“…Another criterion like an average pressure rise rate of 3%/ms was used for the determination of cool flame ignition. 33 The explosion limit is the temperature vs pressure boundaries between the explosion and nonexplosion conditions.…”

Section: Methodsmentioning

confidence: 99%

“…The first is that they exhibit negative temperature coefficients of the reaction rate. 1 Newitt and Thornes found that the spontaneous ignition temperature of the propane–oxygen mixtures showed a negative temperature coefficient (NTC) behavior. 2 A characteristic negative coefficient behavior was also observed when the ignition delay times for the propane/air mixtures were plotted as a function of temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ozone Addition on the Cool Flame and Negative Temperature Coefficient Regions of Propane–Oxygen Mixtures

Yu

¹

,

Ma

²

2020

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In this study, the effects of ozone addition on the cool flame and NTC (negative temperature coefficient) regions of stoichiometric C 3 H 8 /O 2 mixtures are computationally studied through the explosion limit profiles. The results show that with minute quantities of ozone addition (the mole fraction of ozone is 0.1%), the cool flame area is enlarged to the low-temperature region. Further increases in the mole fraction of ozone gradually weaken the NTC behavior, and a monotonic explosion limit is eventually achieved. The sensitivity analysis of the main reactions involving ozone reveals that the explosion limit is mainly controlled by the ozone unimolecular decomposition reaction O 3 (+M) = O 2 + O (+M). However, as its reverse reaction is a third-body reaction, this reaction will lose its effect on the explosion limit in the high-pressure region. On the contrary, the reaction O 3 + HO 2 = OH + O 2 + O 2 has a significant effect on the explosion limit in the high-pressure and low-temperature region, as the concentration of HO 2 increases through the rapid third-body reaction H + O 2 + M = HO 2 + M.

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Comprehensive Comparison of the Combustion Behavior for Low-Temperature Combustion of n-Nonane

Cited by 9 publications

References 31 publications

Effect of Metal Foam Mesh on Flame Propagation of Biomass-Derived Gas in a Half-Open Duct

Effect of Metal Foam Mesh on Flame Propagation of Biomass-Derived Gas in a Half-Open Duct

On the Second Explosion Limits of Hydrogen, Methane, Ethane, and Propane

Effect of Ozone Addition on the Cool Flame and Negative Temperature Coefficient Regions of Propane–Oxygen Mixtures

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