The use of particle image velocimetry in the physical modeling of flow in electromagnetic or direct-chill casting of aluminum: Part I. Development of the physical model

Abstract

This article describes the development of a physical (water) model for examining flows in the liquid metal pool, at the head of an electromagnetic (EM) or direct-chill (DC) caster for aluminum, that are driven by the inflow of liquid metal. Also described is a particle image velocimetry (PIV) system developed for measuring the flows; the system dispenses with the laser usually required for PIV. Flows in the model were found to be unsteady, but ensemble averaging yielded flow patterns that conformed to expectations and velocities that can be compared to the time-averaged velocities (TAVs) of mathematical models. Some representative results are presented (with more extensive results to be included in a subsequent Part II of this article) showing that the design of the metal delivery system has a great effect on the flows.

Water Modeling Evaluation of Metal Delivery in a Twin Roll Strip Caster Using Pool Level and Residence Time Distribution Measurements.

“…This indicates that preference should be given to a Froude based model since the two predominant forces are those of inertia and gravity. Although modeling of liquid metal in continuous casting molds is more frequently carried out using two criteria, Froude-Reynolds 6,9,20,[22][23][24] or Weber-Froude, 6,[25][26][27] a single criterion, Reynolds 28,29) or Froude [30][31][32] has also been utilized. Modeling of flow in tundishes is also commonly based on the Froude number alone.…”

Evaluation of Shearing Time Sufficient for Effective Liquid Metal Processing

“…Refs. [15][16][17][18]. The HSM was immersed to about 20 mm above the bottom of the cylindrical vessel.…”

Transient Flows in Gas Stirred Vessels during Initial and Post Gas Injection Periods.

“…More details of the PIV system applied in the present study have already been described elsewhere and consequently are not re-iterated here. 5) From the PIV measurements, instantaneous volume averaged speed of bath recirculation was calculated from the measured PIV data and this formed the basis for subsequent determination of time to attain practical steady state as well as the time taken for near complete decay of motion during the post gas injection period. This instantaneous average speed of bath recirculation defined as, was estimated through volumetric averaging of the resultant velocity (based on the instantaneous axial (u i ) and radial (v i ) components of motion).…”