Effects of immersion depth on flow turbulence of liquid steel in a slab mold using a nozzle with upward angle rectangular ports

Fluid flow of liquid steel in a slab mold influenced by a submerged entry nozzle (SEN) with ports of high aspect ratio and upward angle of 100 was studied using a water modeling approach and experimental techniques including tracer injection, particle image velocimetry and ultrasound velocimetry. Fluid dynamics near the ports indicate that the discharging jet is subdivided into upper and lower jets when the SEN is at its deep position (185 mm) forming a double roll flow (DRF). At the shallow position (115 mm) the tendency to form two jets decrease with a general trend to form a single jet and a single roll flow (SRF) pattern. These flows are attributed to the difference of the hydrostatic pressures between both submergences. Both, the upper flow in the DRF and the upper flow in the SRF induce free shear flows near the free bath surface that give origin to vortexes and unstable meniscus dynamics. Therefore, nozzle ports with upward angles create small pressure gradients which, in spite of their small magnitudes, have profound effects on fluid flow patterns of the fluid in the whole working mold volume. The results indicate that this nozzle works with less turbulence in the shallow position.