1402 Bubble Nucleation Behavior in Highly Viscous Fluid during Rapid Decompression

2009 ◽  
Vol 2009 (0) ◽  
pp. 429-430
Author(s):  
Hideaki ASAI ◽  
Akiko KANEKO ◽  
Yutaka ABE
Keyword(s):  
Viscous Fluid ◽  
Bubble Nucleation ◽  
Nucleation Behavior ◽  
Rapid Decompression

Bubbles and element clusters in rock melts: A chicken and egg problem

2021 ◽  
Author(s):  
Renelle Dubosq ◽  
Pia Pleše ◽  
Brian Langelier ◽  
Baptiste Gault ◽  
David Schneider
Keyword(s):  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Growth Dynamics ◽  
Gas Bubbles ◽  
Atom Probe ◽  
Bubble Nucleation ◽  
Interface Element ◽  
Rich Cluster ◽  
Heterogeneous Distribution ◽  
Rapid Decompression

<p>The nucleation and growth dynamics of gas bubbles and crystals play a vital function in determining the eruptive behaviour of a magma. Their rate and relative timing, among other factors, are controlled by the magma’s ascent rate. Investigating the kinetics of decompression-induced degassing and crystallization processes can thus give us insight into the rheology of magmas. For example, the rapid decompression of magmas inhibits microlite crystallization and bubble nucleation during ascent leading to crystallization and degassing at shallow levels. This results in a drastic increase in viscosity and an over pressured system, which can lead to violent eruptions. Although many experiments and numerical simulations of magma decompression have been carried out, nascent and initial bubble nucleation remain poorly understood. It is widely accepted that there are two ways bubbles can nucleate within a melt: heterogeneous (on a pre-existing surface) and homogeneous nucleation (within the melt), where homogeneous nucleation requires a higher volatile supersaturation. It has since been tentatively suggested that homogeneous nucleation is simply a variety of heterogeneous nucleation where nucleation occurs on the surface of submicroscopic crystals. However, evidence of these crystals is equivocal. Thus, we have combined novel 2D and 3D structural and chemical microscopy techniques including scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) mapping, and atom probe tomography (APT) to investigate the presence of sub-nanometer scale chemical heterogeneities in the vicinity of gas bubbles within an experimental andesitic melt. The combined STEM and EELS data reveal a heterogeneous distribution of bubbles within the melt ranging between 20-100 nm in diameter, some of which have Fe and/or Ca element clusters at the bubble-melt interface. Element clusters enriched in Fe, Ca, and Na are also observed heterogeneously distributed within the melt. The reconstructed APT data reveals bubbles as low ionic density regions overlain by a Na-, Ca-, and K-rich cluster and heterogeneously distributed Fe clusters within the bulk of the melt. Based on these observations, our data demonstrate the existence of nano-scale chemical heterogeneities within the melt and at the bubble-melt interface of bubbles that were previously interpreted to be nucleated homogeneously within the melt, therefore contributing to the proposed hypothesis that homogeneous nucleation could in fact be a variety of heterogeneous nucleation. These results highlight the need to redefine homogeneous nucleation and revisit whether bubbles or crystals occur first within volcanic melts. </p>

Transient Thermal Bubble Formation on Polysilicon Micro-Resisters

2001 ◽  
Vol 124 (2) ◽  
pp. 375-382 ◽  
Author(s):  
Jr-Hung Tsai ◽  
Liwei Lin
Keyword(s):  
Bubble Formation ◽  
Bubble Nucleation ◽  
Heat Diffusion ◽  
Input Current ◽  
Transient Temperature ◽  
Nucleation Behavior ◽  
Middle Range ◽  
Macro Scale ◽  
Micro Bubble ◽  
Transient Thermal

Transient bubble formation experiments are investigated on polysilicon micro-resisters having dimensions of 95 μm in length, 10 μm or 5 μm in width, and 0.5 μm in thickness. Micro resisters act as both resistive heating sources and temperature transducers simultaneously to measure the transient temperature responses beneath the thermal bubbles. The micro bubble nucleation processes can be classified into three groups depending on the levels of the input current. When the input current level is low, no bubble is nucleated. In the middle range of the input current, a single spherical bubble is nucleated with a waiting period up to 2 sec while the wall temperature can drop up to 8°C depending on the magnitude of the input current. After the formation of a thermal bubble, the resister temperature rises and reaches a steady state eventually. The bubble growth rate is found proportional to the square root of time that is similar to the heat diffusion controlled model as proposed in the macro scale boiling experiments. In the group of high input current, a single bubble is nucleated immediately after the current is applied. A first-order model is proposed to characterize the transient bubble nucleation behavior in the micro-scale and compared with experimental measurements.

Measurements of Bubble Nucleation Characteristics in Pool Boiling of a Wetting Liquid on Smooth and Roughened Surfaces

2008 ◽  
Author(s):  
John P. McHale ◽  
Suresh V. Garimella
Keyword(s):  
High Speed ◽  
Electrical Discharge Machining ◽  
Bubble Diameter ◽  
Pool Boiling ◽  
Ccd Camera ◽  
Terminal Velocity ◽  
Nucleation Site ◽  
Bubble Nucleation ◽  
Working Fluid ◽  
Nucleation Behavior

Quantitative measurements are obtained from high-speed visualizations of pool boiling at atmospheric pressure from smooth and roughened surfaces, using a perfluorinated hydrocarbon (FC-77) as the working fluid. The boiling surfaces are fabricated from aluminum and prepared by mechanical polishing in the case of the smooth surface, and by electrical discharge machining (EDM) in the case of the roughened surface. The roughness values (Ra) are 0.03 and 5.89 micrometers for the polished and roughened surfaces, respectively. The bubble diameter at departure, bubble departure frequency, bubble terminal velocity, and active nucleation site density are measured from the monochrome movies, which are recorded at 8000 frames per second with a digital CCD camera and magnifying lens. Results are compared to predictions from existing models of bubble nucleation behavior in the literature. Wall superheat, heat flux, and heat transfer coefficient are also reported.

scholarly journals Bubble Forming Behavior of High Viscous Fluid under Rapid Decompression

2008 ◽  
Vol 28 (5) ◽  
pp. 27-32
Author(s):  
Hitoshi FUJII ◽  
Akiko FUJIWARA ◽  
Nobuyuki WAKABAYASHI ◽  
Yutaka ABE
Keyword(s):  
Viscous Fluid ◽  
Rapid Decompression ◽  
High Viscous Fluid

Kinetics of gas bubble nucleation and growth in magmatic melt at its rapid decompression

2014 ◽  
Vol 26 (11) ◽  
pp. 116602 ◽  
Author(s):  
A. A. Chernov ◽  
V. K. Kedrinsky ◽  
A. A. Pil'nik
Keyword(s):  
Nucleation And Growth ◽  
Bubble Nucleation ◽  
Gas Bubble ◽  
Rapid Decompression ◽  
Kinetics Of

Flashing Inception in Water During Rapid Decompression

1993 ◽  
Vol 115 (1) ◽  
pp. 231-238 ◽  
Author(s):  
E. Elias ◽  
P. L. Chambre´
Keyword(s):  
Homogeneous Nucleation ◽  
Nucleation And Growth ◽  
Bubble Nucleation ◽  
Probable Error ◽  
Thermodynamic Conditions ◽  
Rapid Decompression ◽  
Data Points ◽  
Effect Of Impurities ◽  
Inception Point ◽  
Energy Equations

A phenomenological model is presented for predicting the thermodynamic conditions at the onset of flashing in liquid undergoing a static or flow depressurization transient. It is shown that at extremely high rates of decompression (pulse expansion), a liquid may reach the homogeneous nucleation limit of superheat before appreciable phase transition occurs. A criterion for pulse expansion is derived by an asymptotic solution of the mass and energy equations in conjunction with the equation for spontaneous bubble nucleation and growth near the flashing inception point. The effect of impurities and dissolved gases is considered by an empirically defined heterogeneous nucleation coefficient. The model predicts the minimum pressure at the flashing point with a probable error of less than 11 percent, using 83 experimental data points.

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