Bubbles from submerged orifices

Another method of direct determination of emulsion density has been developed based on the pressure necessary to form gas bubbles below a liquid surface (2,4). The densitometer involves the use of two submerged orifices of equal radii, but mounted at unequal depths below the liquid surface. Figure 3 shows a drawing of the prototype instrument. A sensitive differential pressure transducer is connected to pressure on the two orifices. Compressed nitrogen is bubbled from each orifice at a slow rate. 

Sparging is the introduction of gas bubbles into a liquid through fine orifices. In a flotation cell the size of the air bubbles introduced near the impeller is important. The size of bubbles produced at a submerged orifice can be estimated by assuming that, at the moment of bubble release from the orifice, the buoyancy and surface tension forces are equal. This produces the following approximate equation [281] for the bubble size ... 

In the case of gas emerging from a simple submerged orifice at very low flow rates, bubbles periodically form at the orifice, grow to a certain size, and break away. For media with a reasonably low viscosity, bubble diameter is a function of the interfacial tension and density as indicated below ... 

Tsuge H, Hibino S. Bubble formation from an orifice submerged in liquids. Chem Eng Comm 22 63-79, 1983. 

Tsuge H, Nakajima Y, Terasaka K. Behavior of bubbles formed from a submerged orifice under high system pressure. Chem Eng Sci 47 3273-3280, 1992. 

GAS DISPERSION BUBBLE BEHAVIOR. In a quiescent liquid a single bubble issuing from a submerged circular orifice will be a sphere if the flow rate is small. Under these conditions the bubble diameter can be calculated as follows, by... 

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