Formation of Gas Bubbles in aA Stagnant Liquid Examined for the Technological Application of Metal Foam

A study of different shapes of gas bubbles rising in stagnant liquid experimentally. A testing facility with the high-speed camera was designed. The results obtained are presented in terms of dimensionless parameters i. e. Reynold's, Morton's and Eötvös. Factors varied to test their dependencies such as nozzle diameter (3 – 5 mm), rate of flow rate (15 and 130 l/h), viscosity, surface tension, and density were changed in order to see their effect on the shape of the bubble, its velocity in the liquid, surface tension force, drag force and buoyancy force. In order to vary such parameters, a water-ethanol mixture was used in the tank. Results showed at surface tension valued at 32 [N/m] it was not possible to trap air bubbles under the surface for the application of creating Foam, while 72 [N/m] it was possible, while for the tested flow rates most of Eötvös values were below one, which indicates that surface tension force dominates shape of the bubble when compared to gravitational force influence.