Submerged Entry Nozzle
This glowing hot SEN has just been removed from an operating continuous casting mold. It is still attached to the tundish (above) and is dripping steel and slag from its two ports. Typical nozzle geometry.

Flow through the nozzle is controlled by a throttling plate (slide gate), which restircts the pipe cross section

Model simulation of fluid flow through the nozzle. The light regions are molten steel, while the dark regions are where gas pockets collect.