Author(s): Steven F. Daly; Samuel C. Colbeck
Linked Author(s): Steven F. Daly
Keywords: No Keywords
Abstract: In a series of recent experiments, the dynamic size distribution and concentration of frazil ice crystals were measured in the U. S. Army Cold Regions Research and Engineering Laboratory (CRREL) refrigerated flume facility. These data were found using a crystal imaging system developed at CRREL. The imaging system consists of a circular fiber-optic strobe light, a microscope, and either a high-resolution television camera and monitor or a 35 mm camera. The system can observe crystal sizes ranging from 30 micrometers to several millimeters. This system was attached to a movable carriage mounted on the flume. A series of experiments were performed. In each experiment, the size distribution of the frazil crystals was measured as it developed along the length of the flume. The slope of the flume and the bottom roughness of the flume were varied to provide a range of hydraulic conditions. Supercooling levels of 0.01°C to 0.04°C were achieved in the flume and held constant for several hours. The room temperature was typically -12°C. The crystal Images were stored on 35 mm slides and analyzed using standard digitizing techniques. From the recorded data such information as the size-dependent growth rates and secondary nucleation rates of the crystals can be determined as a function of the fluid turbulence conditions. This information can be used in development of models of frazil ice dynamics.
Year: 1986