Parametric study on liquid and surface properties affecting meniscus dynamics during bubble formation in capillaries- Applications to frying

Abstract

A parametric study was conducted to understand the effect of orifice diameter, and liquid and surface properties on meniscus formation between subsequent bubbles for a submerged orifice. Parameters studied were liquid viscosity and surface tension, and wettability of the capillary surface. Pressure in the orifice chamber and high-speed video of the meniscus motion were recorded. Meniscus behavior was characterized using the Weber number (We): single bubbles (We < 1), or jetting (We > 1). Bond number (Bo) characterized meniscus motion: capillary driven (Bo < 1), meniscus oscillations (Bo ~1), or gravity weeping (Bo ≫ 1). Viscosity increase up to 60 times that of water, was not shown to influence meniscus dynamics. Surface tension and wettability were the primary parameters controlling the depth of meniscus entry and position of pinch-off. Meniscus dynamics in oil was similar in behavior to solutions of water with sodium n-dodecyl sulfate. In processes such as frying, oil absorption during immersion stage occurs as a result of meniscus entry into the capillary. Thus, understanding of properties affecting meniscus dynamics can help understand mechanisms that control oil absorption during this stage.