On the minimum ignition energy and its transition in the localised forced ignition of turbulent homogeneous mixtures

d’Auzay, Charles Turquand; Papapostolou, VS; Ahmed, Samer F.; Chakraborty, Nilanjan

doi:10.1016/j.combustflame.2018.12.015

Cited by 28 publications

(75 citation statements)

References 54 publications

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“…A well-known pseudo-spectral method (Rogallo 1981) is used to initialise the turbulent velocity fluctuations by an incompressible, homogeneous isotropic field with prescribed values of root-mean-square (rms) values u′ and integral length scale l t . The initial integral length scale is kept constant throughout the study at l t ∕ 0 z = 9.0 , and it remains comparable with previous computational studies of localised ignition (Turquand d'Auzay et al 2019a;Klein et al 2008;Chakraborty 2015, 2016a, b) l t ∕ u z −0.5 and the ratio of eddy turnover time t e = l t ∕u � to the energy deposition time t sp are exemplarily provided in Table 2 for…”

Section: Numerical Implementationmentioning

confidence: 54%

“…Of particular interest to this study is the transition of MIE from low to high turbulence intensities observed across a wide range of fuels, which was reported by Shy and co-workers (Huang et al 2007;Shy et al 2010Shy et al , 2017aPeng et al 2013;Jiang et al 2018) and Cardin et al (2013a, b), and it was subsequently numerically replicated by Turquand d'Auzay et al (2019a). Further work was undertaken by Turquand d'Auzay et al (2019b) on the effects of varying turbulence intensity and dilution levels on the localised forced ignition of turbulent mixing layers of CH 4 -CO 2 -air, and the effects of CO 2 dilution reported were in agreement with those of previous experimental studies (Larsson et al 2013;Mordaunt and Pierce 2014;Lafay et al 2007;Galmiche et al 2011;Zhen et al 2013;Forsich et al 2004;Biet et al 2014;Mulla et al 2016).…”

Section: Introductionmentioning

confidence: 65%

“…temperature locally assuming a value either equal to or above the adiabatic flame temperature) is always obtained at the spark location but this is not guaranteed in this computational method because a misfire can happen without any thermal runaway when the energy input is not sufficient Chakraborty 2015, 2016a). Therefore, the situations described by (i) and (ii) have been distinguished in this analysis following the previous analysis by Turquand d'Auzay et al (2019a). It is also worth noting that the terminology 'ignitability' and 'successful ignition' in the context of experimental analyses (Huang et al 2007;Shy et al 2010Shy et al , 2017aPeng et al 2013;Jiang et al 2018;Cardin et al 2013a, b) translate to "successful ignition with subsequent "selfsustained flame propagation" for the current DNS analysis.…”

Section: Mathematical Backgroundmentioning

confidence: 87%

“…Thus, finding the MIE consists of finding the values of a sp which are sufficient to either (i) produce at least a successful thermal runaway or (ii) ensure a successful thermal runaway and subsequent flame propagation once the ignitor is switched off. The stochasticity of the ignition phenomenon is a key aspect (Turquand d'Auzay et al 2019a;Mastorakos 2009;Mastorakos 2017) and cannot be overlooked. To determine the MIE experimentally (Huang et al 2007;Shy et al 2010Shy et al , 2017aPeng et al 2013;Jiang et al 2018;Cardin et al 2013a, b), one first needs to estimate the amount of energy needed to achieve just about more than 0% probability of successful ignition, and the energy required to achieve 100% ignition.…”

Section: Mathematical Backgroundmentioning

confidence: 99%

See 3 more Smart Citations

A Numerical Investigation of the Effects of Fuel Composition on the Minimum Ignition Energy for Homogeneous Biogas-Air Mixtures

Papapostolou

Turquand

Chakraborty

2020

Flow Turbulence Combust

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The minimum ignition energy (MIE) requirements for ensuring successful thermal runaway and self-sustained flame propagation have been analysed for forced ignition of homogeneous stoichiometric biogas-air mixtures for a wide range of initial turbulence intensities and CO2 dilutions using three-dimensional Direct Numerical Simulations under decaying turbulence. The biogas is represented by a CH4 + CO2 mixture and a two-step chemical mechanism involving incomplete oxidation of CH4 to CO and H2O and an equilibrium between the CO oxidation and the CO2 dissociation has been used for simulating biogas-air combustion. It has been found that the MIE increases with increasing CO2 content in the biogas due to the detrimental effect of the CO2 dilution on the burning and heat release rates. The MIE for ensuring self-sustained flame propagation has been found to be greater than the MIE for ensuring only thermal runaway irrespective of its outcome for large root-mean-square (rms) values of turbulent velocity fluctuation, and the MIE values increase with increasing rms turbulent velocity for both cases. It has been found that the MIE values increase more steeply with increasing rms turbulent velocity beyond a critical turbulence intensity than in the case of smaller turbulence intensities. The variations of the normalised MIE (MIE normalised by the value for the quiescent laminar condition) with normalised turbulence intensity for biogas-air mixtures are found to be qualitatively similar to those obtained for the undiluted mixture. However, the critical turbulence intensity has been found to decrease with increasing CO2 dilution. It has been found that the normalised MIE for self-sustained flame propagation increases with increasing rms turbulent velocity following a power-law and the power-law exponent has been found not to vary much with the level of CO2 dilution. This behaviour has been explained using a scaling analysis and flame wrinkling statistics. The stochasticity of the ignition event has been analysed by using different realisations of statistically similar turbulent flow fields for the energy inputs corresponding to the MIE and it has been demonstrated that successful outcomes are obtained in most of the instances, justifying the accuracy of the MIE values identified by this analysis.

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Section: Numerical Implementationmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 65%

Section: Mathematical Backgroundmentioning

confidence: 87%

Section: Mathematical Backgroundmentioning

confidence: 99%

See 2 more Smart Citations

A Numerical Investigation of the Effects of Fuel Composition on the Minimum Ignition Energy for Homogeneous Biogas-Air Mixtures

Papapostolou

Turquand

Chakraborty

2020

Flow Turbulence Combust

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“…The conventional spark ignition systems have limitations in obtaining a robust ignition in high pressure (boosted engine), lean or EGR-diluted environment [14]. Therefore, the rising of the energy transferred to the mix is mandatory for the spark plug system, in particular for high turbulence intensity [15,16]. This improvement is reached, for example, through the implementation of high-energy inductive ignition systems [3,17,18,19].…”

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

et al. 2020

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The Radio-Frequency Corona Ignition System is characterised by a wide initial combustion volume and precursors production, via radical insemination by the streamers, in addition to high released thermal energy. These features lead to faster combustion, a higher tolerance for lean mixtures and EGR dilutions and, in general, more adaptability. The thermal energy released by the igniter to the surrounding medium can help to understand the performance, the behaviour and the application range. This paper proposes a systematic experimental analysis of the thermal energy released by the igniter at room temperature, via pressure-based calorimetry. This analysis, carried out at different pressures (up to 10 bar) and medium type (air or nitrogen), is extended to the whole range of the corona igniter control parameters, namely streamer duration and driving voltage. The latter is proportional to the maximum electrode voltage, as shown in the model here presented, and as confirmed by experiments. The results show, for all the vessel pressures, the high energetic efficiency of the ignition system and the high amount of the released energy. The latter is found to increase linearly with the corona streamers duration and quickly with the driving voltage up to the streamer-to-arc transition threshold. The efficiency tends to reach a defined upper limit. For each tested point, the energy released to pure nitrogen is higher than to air, which evidences the impact of the oxygen presence under streamer exposure.

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Experimentation on minimum ignition temperature for boron blended fireworks flash powder dust cloud at normal and inert environmental conditions

Arumugachamy¹,

Pandian²,

Jeyasubramanian³

2021

Fire and Materials

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Summary In fireworks industries, mixing and filling of chemicals are being done manually and hence, dust formation is inevitable. Due to inherent nature of ingredients like aluminium metal powder, which has more combustible and the possibilities of dust explosion are merely high. Nowadays, the use of boron as a replacement of aluminium in firecracker mixtures is being researched upon. Hence, this paper aims at measuring the minimum ignition temperature (MIT) of existing and boron blended firework composition by using Godbert Greenwald furnace. Nowadays, many firework industries are employing automation. In such places, by limiting the level of oxygen supply with Nitrogen gas, the accidents can be avoided. Hence, the limiting oxygen concentration (LOC) is also measured. It has been concluded that the probability of ignition is higher when the replacement level of aluminium with boron is less than 70% at a concentration of 1456 g/m3 with less than 75% inert gas level. The safe margin has been found which will be useful for risk assessment study.

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On the minimum ignition energy and its transition in the localised forced ignition of turbulent homogeneous mixtures

Cited by 28 publications

References 54 publications

A Numerical Investigation of the Effects of Fuel Composition on the Minimum Ignition Energy for Homogeneous Biogas-Air Mixtures

A Numerical Investigation of the Effects of Fuel Composition on the Minimum Ignition Energy for Homogeneous Biogas-Air Mixtures

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

Experimentation on minimum ignition temperature for boron blended fireworks flash powder dust cloud at normal and inert environmental conditions

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