Experimental Investigation of Bubble Formation from a Nozzle and an Orifice. 2nd Report: Effects of the Orientation of Gas Injection and Turbulence Transition in Nozzle Flow on the Frequency of Bubble Formation.

Gas was injected into a bath through a nozzle attached to an immersed top lance. The injection angle was changed from zero (upward injection) to π/2 (horizontal injection) to investigate the effect of injection angle on the frequency of bubble formation. In the case of upward injection, the direction of the inertia force of injected gas and that of the buoyancy force acting on the injected gas is the same, while in the case of horizontal injection, the two directions are perpendicular to each other. The frequency of bubble formationfB was significantly influenced by the injection angle. It increased monotonically as the injection angle increased from 0 to π/2. An empirical equation was derived for correlating measuredfB data. In addition, the effect of turbulence transition in nozzle flow on the frequency of bubble formation was discussed.