Relation of chemical and physical processes in two-phase detonations

Lu, Pai-Lien; Slagg, Norman; Fishburn, B.; Ostrowski, Piotr

doi:10.1016/0094-5765(79)90071-7

Cited by 43 publications

(3 citation statements)

References 12 publications

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“…Explosive character of aerosol combustion, consisting of a series of local micro-explosions, was revealed in experimental studies of the detonation wave structure in mono-dispersed keroseneoxygen mixtures [12,33] and also by Lu etal. [6], who pointed out an important relation of chemical and physical processes in aerosol detonation. The suggestion expressed in [13,38] is that the explosive character of aerosol combustion is necessary to support the leading front because of the lengthy combustion zone.…”

Section: Finding the Aerosol Detonation Regimes (A) Fulfilment Of Zeldovich's Necessary Conditionmentioning

confidence: 99%

“…However, from the very beginning, it was well established [3][4][5] that the aerosol drop breakup by the wake stream behind the detonation front is a key process, which considerably intensifies fuel transition into gas phase and thereby the rate of chemical energy release, which supports the leading shock front. Therefore, the detonability of aerosols is affected by both physical and chemical kinetics rates [6]. Calculations [7] showed that the parent drop atomization behind shock wave generates a mist of finest daughter droplets, which increases the total liquid surface by two to three orders greatly intensifying evaporation.…”

Section: Introductionmentioning

confidence: 99%

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Self-sustained regimes of liquid aerosol detonation

Girin¹

2019

Proc. R. Soc. A.

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Main problem of detonation theory, self-sustained regimes finding, is solved for liquid aerosols. Combustion modelling is performed at two scale levels, where the irreversible processes such as aerosol atomization, daughter droplets' evaporation and chemical energy release kinetics are represented at the lower scale. Instability of flow in conjugated boundary layers at drop surface is adopted as mechanism of aerosol atomization. Vapour mixing with oxidizer forms combustible moles, whose chemical induction times are calculated individually, so that the moles are stack-ordered. At the upper scale, equations of overall motion of two-velocity, two-temperature, five-component reacting medium are composed. Two key aspects of the main problem are considered: (i) detonation wave structure in stationary zone is calculated and analysed and (ii) self-sustained regime velocities are determined. The first reveals the existence of two mixture burning modes: explosive kinetic and smooth diffusive, which are separated by conclusive micro-explosion. The second shows the existence of only two front velocity values in aerosol system, at which the interphase processes provide fulfilment of Zeldovich's necessary condition. Explanation is found for incomplete burnout regime: it stands on specific balance between the rate ratio of physical-to-chemical processes, which is reached at such front velocity, when sonic state is attained exactly after the conclusive micro-explosion.

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Section: Finding the Aerosol Detonation Regimes (A) Fulfilment Of Zeldovich's Necessary Conditionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self-sustained regimes of liquid aerosol detonation

Girin¹

2019

Proc. R. Soc. A.

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“…For example, the work of Dabora et al 3 and Ragland et al 4 dealt with the properties and structure of spray detonations as manifested in a constant-area tube, whereas Nicholls et al 5 and Bar-Or et al 6 were concerned with cylindrical detonations. Lu et al 7 were concerned with the effects of chemical and physical processes on the detonation, finding that certain additives to the fuel can affect the establishment of detonations. More recent reviews of spray detonations can be found in articles by Dabora^ and Sichel 9 .…”

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confidence: 99%

Lean Detonation Limit of Sensitized Kerosene Sprays in Air

1991

Dynamics of Detonations and Explosions: Detonations

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A shock-tube technique was used to determine the lean detonability limit of kerosene sprays in air when the kerosene is sensitized by either propyl nitrate (PN) or butyl nitrite (BN). The technique accounts for the initiation energy and its rate, or power. Monodisperse sprays having droplet diameter of 780 [im are tested in a 5-cm-square tube, 2.7 m in length. An initiation energy of 50 J/cm 2 at a rate of 160 Kw/cm 2 is used, and three equivalence ratios (<()) namely, 0.59, 0.44, and 0.3, are tested. The kerosene is mixed with 10% or 20% of either PN or BN. The results indicate that the addition of PN reduces the limiting (j) so that, for 10% PN, it is between 0.44 and 0.3 and below 0.3 for 20% PN. Erratic behavior was detected when 10% BN was used. However, when 20% BN is mixed with the kerosene, the limiting § is found to be below 0.3. NomenclatureA = driven section area aj = speed of sound of gas in driven section d = drop diameter E = energy E* = critical initiation energy f = droplet shedding frequent /4 = driver length M = Mach number M = initial Mach number

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Spray Detonation

Zhang¹

2009

Shock Wave Science and Technology Reference Library

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Relation of chemical and physical processes in two-phase detonations

Cited by 43 publications

References 12 publications

Self-sustained regimes of liquid aerosol detonation

Self-sustained regimes of liquid aerosol detonation

Lean Detonation Limit of Sensitized Kerosene Sprays in Air

Spray Detonation

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