Autoignition and early flame behavior of a spherical cluster of 49 monodispersed droplets

Segawa, Daisuke; Yoshida, Masatoshi; Nakaya, Shinji; Kadota, Toshikazu

doi:10.1016/j.proci.2006.07.124

Cited by 15 publications

(5 citation statements)

References 16 publications

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“…The numerical study of Bellan and Harstad [94] concerning the autoignition of droplet clusters in convective flows indicated that ignition may occur around individual droplets or around the cluster depending on the inter-droplet spacing relative to the droplet diameter. This observation has subsequently been confirmed by experimental results for droplet clusters [96]. Dwyer et al [97] performed numerical simulations of ignition in a 3-D droplet array and observed external cluster ignition for the conditions investigated.…”

Section: Cluster Ignition and External Spray Ignitionmentioning

confidence: 54%

Single droplet ignition: Theoretical analyses and experimental findings

Aggarwal

2014

Progress in Energy and Combustion Science

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Section: Cluster Ignition and External Spray Ignitionmentioning

confidence: 54%

Single droplet ignition: Theoretical analyses and experimental findings

Aggarwal

2014

Progress in Energy and Combustion Science

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“…A numerical model for the autoignition of clusters of droplets in convective flows [204] has suggested that autoignition may be happening around individual droplets or around the cluster as a whole depending on the inter-droplet spacing relative to the droplet diameter, with some interesting experimental results from a droplet cluster recently showing similar behaviour [205]. Aggarwal [8] discussed the various droplet cluster autoignition regimes in detail and compiled data from various experiments.…”

Section: Spray Autoignitionmentioning

confidence: 99%

Ignition of turbulent non-premixed flames

Mastorakos

2009

Progress in Energy and Combustion Science

602

328

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“…Lastly, droplet size and inter-droplet distance both affect combustion behaviour [60]. Table 2 lists the mode of the inter-droplet distance S, computed as the distance to the nearest droplet in the same image, for droplets downstream of z = 25 mm (z = 25 mm was selected as the atomization was complete before this location for all experimental conditions).…”

Section: Fuel Droplet Characteristicsmentioning

confidence: 99%

Autoignition of an n-heptane jet in a confined turbulent hot coflow of air

Gupta

Markides

2020

Experimental Thermal and Fluid Science

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The autoignition of a continuous, single jet of pure liquid n-heptane injected concentrically and axisymmetrically from a water-cooled circular nozzle into a confined turbulent hot coflow (CTHC) of air at atmospheric pressure has been investigated experimentally at air temperatures up to 1150 K and velocities up to 40 m/s. The aim of this work was to examine the emergence of liquid-fuel autoignition in the presence of flow, mixture and phase inhomogeneities, to which end, the velocity, temperature and fuel-droplet fields inside the CTHC reactor were characterized in a series of dedicated measurement campaigns. Distinct phenomena were identified concerning the emergence of various regimes: no autoignition, random spots, and continuous flame. In the random spots regime, autoignition appeared in the form of well-defined, discrete localized spots occurring randomly within the reactor, similar to observations in a similar apparatus with gaseous fuels [1][2][3][4]. High-speed optical measurements of these random spots were made from which the autoignition locations/lengths were measured, and then used to infer average autoignition delay, or residence, times from injection based on the bulk air velocity. An increase in the air temperature moved the region of autoigniting spots closer to the injector nozzle, thus decreasing the autoignition length and also decreasing the autoignition delay time. Generally, autoignition moved downstream with increasing bulk air velocity, but the delay times decreased contrary to the aforementioned earlier work with pre-vaporized n-heptane in this geometry.Of interest is the finding that at the highest investigated air velocities, the autoignition length decreased as the air velocity increased, which again deviates from the same earlier work with vaporized n-heptane. Furthermore, higher liquid injection velocities also resulted in increased autoignition lengths and times.The results from this work suggest that the turbulent inhomogeneous autoignition of liquid fuels cannot be directly predicted from chemical delay times of equivalent homogeneous systems, or even from knowledge of the turbulent inhomogeneous autoignition of single-phase (gaseous) fuels in the same reactor system (flow geometry, fuel, conditions, etc.), and that the effects of evaporation and turbulent mixing must be accounted for. The data can assist the development of advanced turbulent and multiphase reacting flow models.

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Autoignition and early flame behavior of a spherical cluster of 49 monodispersed droplets

Cited by 15 publications

References 16 publications

Single droplet ignition: Theoretical analyses and experimental findings

Single droplet ignition: Theoretical analyses and experimental findings

Ignition of turbulent non-premixed flames

Autoignition of an n-heptane jet in a confined turbulent hot coflow of air

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