A new method to dynamically measure the surface tension, viscosity, and density of melts

Abstract

A new formulation has been developed to describe the fluid dynamics of a liquid draining through an orifice under the influence of gravity. The model relates experimental quantities of head and flow rate, with surface tension, viscosity, and density, facilitating the calculation of all three properties. Experiments performed with molten aluminum at temperatures from 937 to 1173 K indicate that surface tension (N/m) and density (kg/m 3 ) are [0.871 Ϫ 0.155 ϫ 10 Ϫ3 (T Ϫ T liq )] and [2390 Ϫ 0.15 (T Ϫ T liq )], which is within 6.5 and 2.5 pct, respectively, of values reported in the literature. The viscosity has been determined to be 5.2 ϫ 10 Ϫ4 Nsm Ϫ2 , which is significantly less than data reported from other sources. The method is unique because the measurements are performed under highly dynamic conditions.

A Comparison of Surface Tension, Viscosity, and Density of Sn and Sn–Ag Alloys Using Different Measurement Techniques

“…The model developed can be used to calculate these physical properties from only one experiment at a desired temperature. It was reported in Roach and Henein [4,5] that for liquid Al, the values of surface tension and density are reasonable, but the value of the viscosity differed from published values by nearly an order of magnitude. It was hypothesized that this may have been due to the fact that in the gravity flow method, the fluid flow is under turbulent conditions; therefore, the measured viscosity may be related to a turbulent dynamic viscosity.…”

“…The capillary was then immersed to a specified depth, and the apparatus was thermally equilibrated for an hour. Next the 4 Viscosity of tin versus temperature using MC method compared with average data from Chhabra and Sheth [11] (dashed line), and with Gebhardt et al [12] [11,12]. The viscosity as a function of temperature is expressed by an Arrhenius equation, and the results are shown in Table 1.…”

“…Roach and Henein [3,4] have developed a new method enabling the simultaneous measurement of surface tension, viscosity, and density in one run for fluids, herein referred to as the RH method. The method is based on a fluid exiting a crucible as a stream flowing under gravity.…”

A Broad Literature Review of Density Measurements of Liquid Cast Iron

“…The draining crucible method has been developed and used for light metals, i.e., aluminium and magnesium [46,47]. It has the advantage that it is possible to obtain values on surface tension, viscosity, and density from the same measurement.…”

“…The diameter of the orifice must be known accurately in order not to result in significant errors in the property values [46,47]. It is also important that the material at the orifice is non-wetting with regard to the evaluated melt.…”