Self-triggering of small-scale fuel-coolant interactions: I. Experiments

Dullforce, T. A.; Buchanan, D. J.; Peckover, R S

doi:10.1088/0022-3727/9/9/006

Cited by 80 publications

(30 citation statements)

References 10 publications

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“…This allows the molten metal to break up into small droplets before it solidifies. Tin may therefore break up into beads if it starts out at much higher temperatures, as suggested by Dullforce et al [24]. The nature of the debris size distribution changes from one with a local peak, to an exponential one, when the metal temperature becomes higher, which increases the number and strength of the vapor explosions.…”

Section: Discussionmentioning

confidence: 92%

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Formation of microbeads during vapor explosions of Field's metal in water

Kouraytem

Thoroddsen

2016

Phys. Rev. E

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We use high-speed video imaging to investigate vapor explosions during the impact of a molten Field's metal drop onto a pool of water. These explosions occur for temperatures above the Leidenfrost temperature and are observed to occur in up to three stages as the metal temperature is increased, with each explosion being more powerful that the preceding one. The Field's metal drop breaks up into numerous microbeads with an exponential size distribution, in contrast to tin droplets where the vapor explosion deforms the metal to form porous solid structures. We compare the characteristic bead size to the wavelength of the fastest growing mode of the Rayleigh-Taylor instability.

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Section: Discussionmentioning

confidence: 92%

“…The break-up of this layer allows vapor and liquid to penetrate into the molten metal and the water boils in a rapid thousand-fold expansion producing a vapor explosion [20][21][22][23]. Such explosions become more violent at higher metal temperatures [24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Formation of microbeads during vapor explosions of Field's metal in water

Kouraytem

Thoroddsen

2016

Phys. Rev. E

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“…Without applying a trigger, spontaneous explosions did not occur, in contrast to drops of molten tin and other low-melting metals released into water at similar melt temperatures (for example, Dullforce et al 1976, F l o r y et al 1969, Shoji andTakagi 1983). When triggered, the interactions of the aluminum drops normally would initially form a small bubble that collapsed after a few milliseconds, followed by a moderate second bubble, the volume of which did not exceed about 1 L. Sometimes a third or even a fourth smaller bubble formed after the second and largest bubble collapsed.…”

Section: Comparisons Withearlier Workmentioning

confidence: 99%

Thermal and ignition type steam explosions of single drops of molten aluminum

Nelson

Duda²,

Hyndman

et al. 1995

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“…Perhaps more interesting is the observation mentioned before that increasing the temperature of the molten material (say from 300 to 900 ~ sharply decreases the propensity for explosion and for high enough temperatures of the melt, no explosions are seen regardless of the temperature of the water. For water temperatures above ~ 80 ~ no explosions have been observed in the laboratory regardless of the melt temperature (e.g., Dullforce et al, 1976;Witte et al, 1970).…”

Section: Implication Of Quench Supersaturation As the Cause Of The Exmentioning

confidence: 99%

The mechanism of the Mt. St. Helens eruption and speculations regarding Soret effects in planetary dynamics

Rice

1985

Geophysical Surveys

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Abstract. Steady heat flux through a double diffusive layered convecting system demands each layer have the same Rayleigh number. If double diffusive convective layering occurs in a gaseous rotating proto-solar system nebula of uniform composition, this Rayleigh number criterion sets the distances from the centre of the nebula to each boundary layer of the convecting layers and these distances are given by the Titius-Bode law. In a layer of nebula convection, outgoing plumes will he retrograde, ingoing plumes prograde, such that where these plumes impinge on a boundary layer, vortices can be set up in the boundary layer with rotation along the same axis as the total cloud. Soret convection may serve to segregate the cloud isotopically, elementally and chemically.With regard to the failure of the north slope on Mt. St. Helens, 18th May, 1980, civil engineering criteria rule out gravitational failure and leave ambiguous the possibility the slide was seismically induced. P arrival and S wave magnitudes from the 18th May eruption along with characteristics of blasting excavation indicates the north slope failure to have been induced by explosion at depth. A review of industrial experience with steam explosions indicates it unlikely the Mt. St. Helens blast was the result of loss of overburden and vapor flashing. Quench cooling, however, may yield vapor super-saturations to 104 atmospheres. Once exsolution was initiated, vapor mass transport would be massive and strip the melt dry of other volatiles, this based on explosive exsolution experience in steel making industries.Further appeal to industrial solidifying melt literature indicates marginal border groups and cryptic variation to be analogs of microsegregation (solute banding) and macrosegregation. Fractional crystallization in the sense of micro and macrosegregation sets up the zonation in a mafic magma chamber necessary to establish double diffusive convective layering and attendent Soret segregation of minerals. Theoretically, rollover, i.e. homogenization of stratified or zoned chambers can occur in marie or andesitic environments. In the andesitic environment, zonation of the chamber from silicic to marie melt with depth indicates that the mafic portions could be explosively supercharged with vapor during the quench attending rollover, i.e., it would 'pop' like popcorn but on a more impressive scale.KNO 3 and NaNO 3 aqueous solutions have negative Soret coefficients which explain peculiar density build-ups in the bottom of experimental tanks. These experiments were designed to model magma chambers but they do not replicate solidifying melts because they lack dynamic similitude: pertinent dimensionless parameters differ by up to 7 orders of magnitude. Scaling crystal size in these experiments indicates that crystals a kilometer across should be found in magma chambers. These experiments also advance a mechanism for picritic intrusions in oceanic crust for which horizontal layering is required. However, ophiolites show essentially arcuate banding and picrites ...

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Self-triggering of small-scale fuel-coolant interactions: I. Experiments

Cited by 80 publications

References 10 publications

Formation of microbeads during vapor explosions of Field's metal in water

Formation of microbeads during vapor explosions of Field's metal in water

Thermal and ignition type steam explosions of single drops of molten aluminum

The mechanism of the Mt. St. Helens eruption and speculations regarding Soret effects in planetary dynamics

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