液体金属中浸漬オリフィス出口における吹き込みガスの挙動

抄録

Nitrogen (0.054 500 cm³/s) was injected into a mercury bath through an orifice of 0.10.4 cm in diameter located at the transparent vessel bottom. The highest gauge pressure supplied to the system was 20 kgf/cm². Behavior of gas jets at the orifice was observed directly through the bottom plate by using a high speed cinecamera.
At gas-flow rates lower than the critical rate described below, the jet is shown to expand immediately upon discharging and form seemingly discrete bubbles of various sizes. This behavior is called "bubbling". With increased gas-flow rates, an apparent coincidence between the bubble base diameter and the orifice diameter begins to occur over various time ranges. It is presumed that in these time ranges a continuous gas jet forms at the orifice. This phenomenon is called "jetting". It is found that the value of the critical gas-flow velocity at which the transition from bubbling to jetting begins to occur is independent of the diameter of the orifice and a little bit higher than but very close to the sonic velocity. With increasing gas-flow rate jetting fraction increases and bubbling fraction decreases.