The shape transformation to a circular form of a fluid jet exiting a non-circular orifice of a nozzle

Sammanfattning: Nozzles are used in a wide range of applications. Nevertheless, the geometric of non-circular orifices have not been widely studied. This project has examined fluid jets exiting through a non-circular orifice, in the gravitational direction. Furthermore, its transformation to a circular cross-section due to a surface tension forces. How the length to a circular cross-section changes with the nozzles geometry and bath depth of the tundish was the main focus of this studied. A water model and high-speed camera was used to capture the profile of the fluid jet. Four different nozzles were attached one by one to five different tundishes with different bath depths. The result showed that with deeper bath depths the circular cross-section occurred further down from the nozzles orifice. The length to the circular cross-section also depended on the orifice area, a larger area gave a longer distance than a smaller area. It was shown that the length to circular cross-section followed a quadratic function, when the measured values were analyzed based on the Weber number. The profile of the fluid jet was dependent on the material of the nozzle, the geometries of the orifice, the bath depth and the surface tension.