BUBBLE FORMATION FROM ELASTIC HOLES

The elastic membrane sparger is studied by observing bubble formation at a single hole centered in a circular membrane. Two types of models are developed to forecast intrinsic properties of the elastic bubble generator: (i) flow rate as a function of pressure change (ii) bubble size as a function of flow rate. In the former, certain properties relating to the changing hole size are revealed, and in the second, the dominant bubble regime is delineated. Comparison of theory and experiment suggests the rubber sparger operates as a linear area device, that is, hole area appears to increase linearly with increasing pressure. This behavior has certain advantages over a fixed-hole sparger, for example the retardation of the onset of jetting. We next show certain modifications of the classical analysis can predict quite adequately the bubble sizes emanating from the flexible hole. © 1987, Gordon and Breach Science Publishers S.A.