Experimental and numerical study of the ignition of hydrogen-air mixtures by a localized stationary hot surface

Mével, Rémy; Melguizo-Gavilanes, J.; Boeck, Lorenz R.; Shepherd, Joseph E.

doi:10.1016/j.ijheatfluidflow.2019.02.005

Cited by 21 publications

(4 citation statements)

References 39 publications

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“…They observed that the boundary layer development and flow separation have crucial impacts on the ignition process, which is consistent with the experimental results of Mével et al. (2016, 2019). Usually, ignition occurs between the front stagnation point and the location of flow separation, and the ignition position moves downstream as the particle temperature decreases.…”

Section: Introductionsupporting

confidence: 89%

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Theoretical analysis on the ignition of a combustible mixture by a hot particle

Chen

2022

J. Fluid Mech.

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Mechanical spark is an important ignition source in various industrial processes involving combustible mixtures and it may cause serious safety issues. In this work, we analysed the ignition induced by hot particles in a combustible mixture. In Semenov's transient ignition criterion, we introduced a hypothetical heat loss coefficient accounting for the temperature inhomogeneity and obtained a revised ignition criterion which allows us to calculate the ignition delay time. Explicit expressions for the critical ignition temperature were derived and used to demonstrate the primary impacts of temperature inhomogeneity on the ignition process. Consistent with experimental and numerical results, the temperature inhomogeneity is intensified by either reducing the particle size or convective heat transfer at the particle surface, resulting in an increase of the critical ignition temperature. For flow separation on the particle surface, the boundary layer problem was solved based on a Blasius series. A temperature gradient for ignition was defined at the location of flow separation to reproduce the experimentally observed phenomenon that ignition prefers to occur first near the flow separation position. It is shown that the unsteadiness of particle cooling makes negligible contribution to the ignition process because of the exceedingly large density ratio between the particle and the ambient gas. In addition, the finite residence time of ignition for a fluid parcel due to its elevation from the particle surface leads to additional growth in the critical ignition temperature. However, such a correction appears to be inconsequential because the ignition of the fluid parcel restricted to the Frank–Kamenetskii region is close to the particle surface.

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Section: Introductionsupporting

confidence: 89%

“…Previous studies (Mével et al. 2016, 2019; Melguizo-Gavilanes et al. 2017 a , b ) demonstrated that, at the critical ignition state, i.e.…”

Section: The Effect Of Temperature Inhomogeneity On Ignition By a Hot...mentioning

confidence: 94%

Theoretical analysis on the ignition of a combustible mixture by a hot particle

Chen

2022

J. Fluid Mech.

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“…A reaction pathway analysis showed that HSI was essentially driven by a linear chain chemical process, revealing the influence of chemical mixture properties on HSI sensitivity [25,26]. Furthermore, it indicated that the non-uniformity, heterogeneous chemistry, and reaction of the hot-surface temperature could affect the HSI threshold, as well as the location of ignition [27]. Eckhoff examined the experimental data from the HSI of mixtures, clarifying the minimum ignition temperature (MIT) and auto-ignition temperature (AIT) [28].…”

Section: Introductionmentioning

confidence: 99%

Effect of Lateral Airflow on Initial HSI and Flame Behavior of Marine Fuel in a Ship Engine Room: Experiment and Analysis

Wang,

Ming,

Liu

et al. 2023

JMSE

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The flame behavior of engine fires, such as those caused by leaked fuel coming into contact with an ignition source, is significant in practical applications, where flame detection is used to minimize the damage of the attendant ship fire safety problem. In this work, the flame behavior of hot-surface ignition (HSI) under crossflow was studied, with a particular focus on the difference in lateral airflow velocities for HSI-driven flame deviations at the windward and leeward sides of a ship engine room; a problem such as this has not previously been quantified. Full-scale experiments were conducted in a ship engine room using marine diesel and hydraulic oil as the fuel, and by adopting lateral airflow with the velocities of 0 m/s, 1.0 m/s, 3.0 m/s, and 5.0 m/s, together with an HSI mechanism consisting of marine diesel and hydraulic oil coming into contact with elevated hot-surface temperatures. The results show that the effects of disturbing the combustible gaseous mixture for marine fuel HSI, at both the windward and leeward sides, strengthened as the airflow velocity increased. The HSI position of the leaked marine fuel in the engine room was strongly dependent on ventilation, while that under the airflow condition decreased with the increase in the hot-surface temperature. A model was proposed to characterize this difference on the basis of the HSI height, which was defined as the ratio of the height during the initial HSI to the stationary period. The results indicate that the scale of the flame gradually increased in the horizontal direction, which was significantly different from the result in the scenario without mechanical ventilation. The results also revealed that the fluctuation of hydraulic oil through the temperature field was significant and lasted for a long time under a low HSI temperature.

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“…In addition, GPs offer high continuous hot surface temperatures ( T HS ) up to 1400 K and fast heating rates of 550 K/s, which allows them to ensure inflammation of hardly ignitable mixtures. 21 More fundamental work directed toward understanding ignition mechanisms of GP induced inflammation of n-hexane 22 and hydrogen 23 in air was done in constant volume vessels, while several researchers applied GPs in practical application to enhance combustion in various types of compression ignition (CI) engines. Borgqvist et al 11 reported a positive effect of GP assistance on combustion stability and combustion efficiency in low load experiments of a gasoline fueled PPCI engine.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on controlled hot surface assisted compression ignition (HSACI) in a naturally aspirated single cylinder gas engine

Judith

Kettner

Koch

et al. 2022

International Journal of Engine Research

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Homogeneous charge compression ignition (HCCI) promises low [Formula: see text] emissions and high efficiency due to fast combustion at low temperatures. However, the control of combustion timing represents a serious challenge due to the lack of dedicated ignition control parameters. This challenge is addressed in this work by means of a hot surface ignition (HSI) system, whose core element consists of a shielded, electrically heated ceramic glow plug. In this approach, termed as hot surface assisted compression ignition (HSACI), a small portion of mixture is thought to ignite in the vicinity of the shielded glow plug and to subsequently propagate to the main combustion chamber in order to initiate bulk-gas auto-ignition. Adjusting the hot surface temperature enables to either advance or retard the onset of combustion and thus, allows to control combustion timing. This paper presents experimental results of initial engine trials, using the HSACI concept in a naturally aspirated single cylinder natural gas engine. Measurements were conducted at a constant engine speed of 1400 l/min and include intake air temperatures in the range of 150–175°C and relative air-fuel ratios ([Formula: see text]) from 2.0 to 2.8. Results show that the HSI system enables combustion under conditions, which do not allow for pure HCCI operation. Moreover, the combustion timing can be actively controlled within certain limits by changing the HSI temperature. Increasing cycle-to-cycle variations limit stable operation at lower temperatures, while a transition to pure HCCI is found at intake temperatures beyond 170°C. The applicable [Formula: see text] range is limited by knocking or uncontrolled combustion toward the rich side and instable operation toward the lean side. Loss analysis points out that wall heat flow and imperfect combustion represent the dominant loss mechanisms. Heat release analysis reveals two pronounced phases, indicating initial flame propagation and subsequent auto-ignition similar to spark assisted compression ignition (SACI).

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Experimental and numerical study of the ignition of hydrogen-air mixtures by a localized stationary hot surface

Cited by 21 publications

References 39 publications

Theoretical analysis on the ignition of a combustible mixture by a hot particle

Theoretical analysis on the ignition of a combustible mixture by a hot particle

Effect of Lateral Airflow on Initial HSI and Flame Behavior of Marine Fuel in a Ship Engine Room: Experiment and Analysis

Experimental study on controlled hot surface assisted compression ignition (HSACI) in a naturally aspirated single cylinder gas engine

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