Faik Hamad
Teesside University, UK
Title: Drop/bubble formation and coalescence from submerged nozzle
Biography
Biography: Faik Hamad
Abstract
A general two-stage model of the drop diameter prediction in liquid-liquid systems without use of experimental constant as utilized in previous models has been formulated. The force balance analysis includes the forces of buoyancy, momentum, surface tension, drag and inertia to predict in both stages. The results from the model have been compared with kerosene drop formation in water. The Bubble formation was also studied using Ansys Fluent. A single bubble formation process through an orifice in a rectangle domain is modelled to study the bubble formation characteristics using the volume of fluid (VOF) with the continuum surface force (CSF) method. The effect of gas inlet velocities, Ug ~ 0.1 - 0.3 m/s on bubble formation stages (i.e., expansion, elongation and pinch off), bubble contact angle, dynamics and static pressure, bubble departure diameter etc. was investigated through an orifice diameter of 1 mm. The method was also used to study the effect of Reynolds number, Reμ ~ 1.32 - 120 on bubble formation when all other parameters were kept constant. Bubble coalescences have been also investigated. The effects of Bond number ranges, Bo ~ 4.09 - 50 (variation of the surface tension) and Reynolds number range, Re ~ 0.98 - 120 (variation of the liquid viscosity) were investigated. Significant effects were observed in the process of bubble coalescence on the shape of bubbles, when the viscosity ratio (μr) and density ratio (ρr) were kept constant.