MEASUREMENTS OF THERMOPHYSICAL PROPERTIES OF LIQUID-METALS RELEVANT TO MARANGONI EFFECTS

Marangoni convection is caused by a gradient in the surface tension al ong a free liquid surface. The dimensionless Marangoni number, which c ontrols the strength of this convection, contains additional thermophy sical parameters. For liquid metals, these quantities are best measure d under containerless conditions using electromagnetic levitation and non-contact diagnostic tools. In microgravity, small electromagnetic f ields are sufficient to position a liquid sample. Some experiments can only be performed in such an environment, most others greatly benefit from microgravity and lead to results of higher precision. This paper reports on both terrestrial and microgravity measurements of thermoph ysical properties of undercooled liquid metals, including specific hea t, density, surface tension, viscosity and electrical conductivity.