Liquid-bridge flow between two slender plates: Formation and fluid mechanics

Abstract

The stable liquid-bridge flow was successfully developed in our previous work. With reasonable assumptions, the simulation model of two horizontal slender plates was successfully established in two-fluid computational fluid dynamics (CFD), and the volume of fluid (VOF) model was used to track the gas–liquid interface. The hydrodynamics experiment of helical liquid-bridge flow was also set up for verifying the accuracy of the simulation model. The experimental data were in excellent agreement with the simulation results. This work mainly investigated the influence of liquid loading, surface tension and viscosity on the formation and fluid mechanics of the liquid-bridge flow. Results show that the profile and the pressure difference between gas and liquid phases will be changed regularly when the loading, surface tension and viscosity of the liquid are varied. When the liquid loading increases from 15 ml/min to 45 ml/min, the profile of the liquid-bridge flow will gradually change from concave to flat, the neck width will increase from 0.90 mm to 1.73 mm, and the Laplace pressure will decrease from 55.29 Pa to 32.56 Pa. When the surface tension decreases from 0.0728 N/m to 0.03 N/m, the neck width will rise from 1.39 mm to 2.15 mm, while the Laplace pressure is decreased from 43.23 Pa to 6.54 Pa. Besides, the velocity distribution inside the liquid-bridge flow is presented and analyzed under different operating conditions. The increase of liquid viscosity will promote the resistance between the fluid layers, making the flow velocity of liquid bridge more slow and the velocity distribution more uniform.