Steam explosions of molten iron oxide drops: easier initiation at small pressurizations

Nelson, Lloyd S.; Duda, P.M.

doi:10.1038/296844a0

Cited by 11 publications

(1 citation statement)

References 10 publications

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“…In the current tests, at 9 m/s the water cannon produced a pressure pulse with a peak pressure of 1.3 MPa and a rise time of 2 ms. From the radiographs and high-speed photographs of the current tests it is not possible to determine if this causes the initial vapour film to collapse or just compress. Although this peak pressure is well above the minimum shock pressure of 0.4 MPa that was found to be required to collapse the vapour film in experiments by Nelson and Duda [24], the risetime is two orders of magnitude greater than that reported by Nelson and Duda. Inoue et al [25] experimentally and analytically studied the effect of pressure pulse magnitude and risetime on the collapse of a vapour film on a heated platinum ribbon.…”

Section: Figure 14mentioning

confidence: 50%

Fragmentation of a molten metal droplet in an ambient water flow

Cunningham

Frost

2023

Front. Phys.

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The influence of an ambient fluid flow on the fragmentation of hot molten tin droplets (initially at 800°C) and cold low melting point alloy droplets (initially at 70°C) in water is investigated with high-speed photography and flash radiography. The water is accelerated using a converging nozzle to a constant speed of up to 30 m/s using a double piston arrangement designed to eliminate the formation of a shock wave that is present in most earlier studies. At low flow velocities, the fragmentation of hot droplets is governed by thermal effects and vapour formation, growth, and collapse. At high flow velocities, vapour formation is suppressed and the droplet fragmentation is determined by hydrodynamic effects in which hydrodynamic instabilities (Rayleigh-Taylor and Kelvin-Helmholtz) and wavecrest stripping all play a role in the droplet breakup. At intermediate flow velocities, both thermal and hydrodynamic effects play a role. Quantitative image analysis of the radiographs is used to determine the spatial distribution of the droplet mass during the fragmentation process. Comparison with earlier work in which the ambient flow is preceded by a strong shock wave indicates that the transition from thermal to hydrodynamic breakup is strongly dependent on the pressure field.

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Section: Figure 14mentioning

confidence: 50%

Fragmentation of a molten metal droplet in an ambient water flow

Cunningham

Frost

2023

Front. Phys.

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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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Fragmentation and solidification of fuel–coolant interaction of columnar molten iron and water

Chen

Liu

et al. 2023

J Therm Anal Calorim

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Steam explosions of molten iron oxide drops: easier initiation at small pressurizations

Cited by 11 publications

References 10 publications

Fragmentation of a molten metal droplet in an ambient water flow

Fragmentation of a molten metal droplet in an ambient water flow

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

Fragmentation and solidification of fuel–coolant interaction of columnar molten iron and water

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