Analysis of the Non-Isothermal Impaction-Spreading and Freezing of Metal Droplets
Several mathematical models are used for analysis of the spreading and freezing of droplets impacting onto a solid substrate. This study attempts to delimit the ranges of process parameters and dimensionless numbers that define distinct spreading and/or freezing regimes. In each regime, different phenomena merit consideration, and various physical models may or may not be appropriate. In addition to fluid flow (encompassing viscous and free surface effects) and crystalline solidification, glass-forming alloys with strongly temperature-dependent properties are considered. A Hadland Photonics, Inc. high-speed camera (50,000 frames/sec) was used at the Marshall Space Flight Center's Drop Tube Facility to compare experimental results with numerical predictions. This allowed the 5mm diameter molten metal droplet - traveling at a speed of 100 mph - to be captured by 10 frames of splatting imagery at the bottom of the Drop Tube. This project is being conducted through the MIT Materials Process Modeling Group in close collaboration with CALTECH and NASA. Experiments to determine the velocity and the temperature of the drop at impact have been performed and analyzed at Vanderbilt University.
The
High-speed camera and Drop Tube configuration give a view of the experimental setup.
Authors: G.Kris Schwenke, Gerardo Trapaga, Julian Szekely.
Curators: Tom Rathz /UAH tom.rathz@msfc.nasa.gov and Mike Myzska
Last Revised: February 1, 1996
