The Generation and Movement of Gas Bubbles in Liquid Metals Under Low Gravity Conditions

1994 ◽  
Vol 33 (3) ◽  
pp. 233-241
Author(s):  
F. Weinberg ◽  
C. Mui
Keyword(s):  
Liquid Metals ◽  
Gas Bubbles ◽  
Low Gravity

Liquid-Metal Foams – Feasible In Situ Experiments under Low Gravity

2006 ◽  
Vol 508 ◽  
pp. 275-280 ◽  
Author(s):  
N. Babcsán ◽  
F. Garcia-Moreno ◽  
D. Leitlmeier ◽  
John Banhart
Keyword(s):  
Liquid Metal ◽  
Metal Foam ◽  
Liquid Metals ◽  
Gas Bubbles ◽  
Metal Foams ◽  
Solid Particles ◽  
Low Gravity ◽  
X Ray ◽  
In Situ Experiments

Metal foams are quite a challenge to materials scientists due to their difficult manufacturing. In all processes the foam develops in the liquid or semiliquid state. Liquid-metal foams are complex fluids which contain liquid metals, solid particles and gas bubbles at the same time. An X-ray transparent furnace was developed to monitor liquid metal foam evolution. Aluminium foams - similar to the commercial Metcomb foams - were produced by feeding argon or air gas bubbles into an aluminium composite melt. The foam evolution was observed in-situ by X-ray radioscopy under normal gravity. Drainage and rupture were evaluated during the 5 min foam decay and 2 min solidification. Argon blown foams showed significant drainage and cell wall rupture during the first 20 s of foam decay. Air blown foams were stable and neither drainage nor rupture occurred. We demonstrated the feasibility of experiments during parabolic flight or drop tower campaigns. However, the development of a foam generator for low gravity is needed.

Distorted gas bubbles at large Reynolds number

1974 ◽  
Vol 62 (1) ◽  
pp. 163-183 ◽  
Author(s):  
M. El Sawi
Keyword(s):  
Surface Tension ◽  
Weber Number ◽  
Liquid Metals ◽  
Gas Bubbles ◽  
Joint Effect ◽  
Large Reynolds Number ◽  
Recent Experimental Data ◽  
Approximate Theory ◽  
Axis Ratio ◽  
Comparison Of The Results

The distortion of a gas bubble rising steadily in an inviscid incompressible liquid of infinite extent under the action of surface tension forces is investigated theoretically using an appropriate extension of the tensor virial theorem. A convenient parameter for distinguishing the bubble shape is the Weber numberW. The virial method leads to an expression relatingWand the axis ratio χ, of the transverse and longitudinal axes of the bubble. To first order inW, this relation agrees with the linear theory established by Moore (1959). Also, comparison of the results with his (1965) approximate theory reveals similar features and excellent agreement up to χ = 2. In particular, it confirms his prediction of the existence of a maximum Weber number. Although the present work does not consider the stability of these bubbles, it is interesting to note that the maximum value of 3.271 attained byWdiffers only by about 2.8% from the critical Weber number obtained by Hartunian & Sears (1957) for the onset of instability.An approximate method for the study of slightly distorted spheroidal gas bubbles is also formulated and the resulting boundary-value problem solved numerically. The theory is then extended to include gravity. The joint effect of surface tension as well as gravitational forces has not been included in earlier theories. The shapes of the bubbles are traced and compared with the unperturbed spheroids. Comparisons for the velocity of bubble rise are made between the present predictions and some experimental results. In particular the results are compared with recent experimental data for the motion of gas bubbles in liquid metals.

Nucleation of Carbon Monoxide Gas Bubbles in Electromagnetically Levitated Molten Iron Drops

2015 ◽  
Vol 15 (1) ◽  
pp. 23-28
Author(s):  
David G. C. Robertson
Keyword(s):  
Computer Simulation ◽  
Carbon Monoxide ◽  
Liquid Metal ◽  
Liquid Metals ◽  
Experimental Studies ◽  
Gas Bubbles ◽  
Electromagnetic Levitation ◽  
Bubble Nucleation ◽  
Gas Bubble ◽  
Electromagnetically Levitated

AbstractDr El-Kaddah used the electromagnetic levitation technique in a number of experimental studies on gas–liquid metal reactions and “containerless melting”. He also studied the electromagnetic levitation process itself, using computer simulation. This paper will discuss two phenomena that Dr El-Kaddah worked on that are still unresolved today – gas bubble nucleation in liquid metals and the degree of mixing in levitated drops.

A novel probe for detecting gas bubbles in liquid metals

2006 ◽  
Vol 37 (3) ◽  
pp. 333-337 ◽  
Author(s):  
M. Schneider ◽  
J. W. Evans
Keyword(s):  
Liquid Metals ◽  
Gas Bubbles

Propagation of Pressure Waves, Caused by a Thermal Shock, in Liquid Metals Containing Gas Bubbles

2005 ◽  
Author(s):  
K. Okita ◽  
Y. Matsumoto ◽  
S. Takagi
Keyword(s):  
Thermal Shock ◽  
Void Fraction ◽  
Pressure Wave ◽  
Cavitation Erosion ◽  
Liquid Metals ◽  
Bubble Radius ◽  
Gas Bubbles ◽  
Pressure Waves ◽  
Lower Natural Frequency ◽  
Small Bubbles

Propagation of pressure waves caused by a thermal shock in liquid metals containing gas bubbles is performed by a numerical simulation. The present study examined the influences of bubble radius and void fraction on the absorption of thermal expansion of liquid metals and attenuation of pressure waves. As the result of the calculation, since the large bubbles which have a lower natural frequency than the small bubbles cannot respond to the heat input, the peak pressure at the heated region increases with increasing bubble radius. Especially, when the bubble radii are around 500 μm, the pressure wave propagates through the mixture not with the sonic speed of the mixture but with that of liquid mercury. On the other hand, decreasing the void fraction makes behavior of bubbles nonlinear and a collapse of bubble produces a high pressure wave. However, the calculation shows that the method of introducing micro gas bubbles into liquid metals is effective to prevent cavitation erosion on the wall.

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