High Yielding Microbubble Production Method

Figure 5

The nitrogen gas-liquid compound jet behaviour in the different flow regimes and the resulting microbubble population. (a) (i, ii) Due to insufficient air pressure, the liquid-nitrogen gas cone contacts the bottom surface of the chamber before flowing out through the orifice. (iii) The large bubbles grow and burst outside the orifice, (iv) to produce large diameter bubbles. (b) (i, ii) In intermediate air regime, the compound jet drips from the inner capillary and emits through orifice (iii) as intermittent sprays. Resulting microbubble population is shown in (iv). (c) (i, ii) At the optimised pressure regime, a stable gas-liquid cone is disintegrated into (iii) fine spray-mist outside the orifice. (iv) The microbubbles with 2.6 μm mean diameter and polydispersity index of 16% were produced. Scale bar for all images represents 50 μm.