Numerical Simulation Of Bubbling Dynamics In Gas-liquid Columns With Volume Of Fluid Method

The gas-liquid bubble column has a several advantages, such as sufficient inter-phase contact, uniformly inter-phase mixing, excellent mass and heat transfer, equally temperature distribution, et al. As a result, it is widely used in a variety of industries ranging from chemical to petroleum engineering, form bioengineering to environment engineering. This paper focuses on the three-dimension (3D) numerical simulation of bubble dynamics in a gas-liquid flow based on the precious work, which could give a guidance on the design, scale-up, optimal operation and control of bubble columns. This work also lays a base for the further study of a gas-liquid-solid three phase flow.In this paper, Euler-Euler method was applied, with FLUENT 6.3 as a simulation platform, using Volume of Fluid model to tracing the interface of gas phase and liquid phase, to study the single-nozzle, two-nozzle, four-nozzle bubbling hydrodynamics, such as bubble formation, growth, detachment and movement, and to discuss the influence factors from fluid physical properties, such as surface tension, liquid viscosity and density to operation conditions, such as orifice bubble velocity and orifice diameter.The practical space is three dimensional, thus the simulation study of physical movement in a two dimension is unilateralism. Three-dimension numerical simulation on the bubble dynamic behavior can give us valuable results. Some computer programs were written in order to simulate the bubbles'movement in three-dimension. CMOS high speed photograph system was used to obtain the gas-liquid flow images.It can be vividly seen by the investigations of 3D dimension numerical simulation that the bubble's rise track is a combination of spiral, flexuous and straight line. In the rising process bubbles appear dissimilar shapes, for instance, near-spherical, near-ellipsoidal, near-skirt shapes, due to different bubble diameter, bubble rise velocity, liquid surface tension and velocity, et al. Within the range of investigated conditions, the bubble diameter enlarges with the enlargement of orifice gas velocity (ranging from 0.05m/s to 3m/s), decreases with the increase of liquid velocity (ranging from 0m/s to 0.1m/s), increases with the amplification of surface tension (ranging from 0.01456N/m to 0.728N/m). Bubble diameter has little relation to do with liquid viscosity (ranging from 0.001Pa·s to 0.0117Pa-s) and density (ranging from 959.1kg/m3 to 998.2kg/m3). Bubble detachment time decreases with the increase of orifice diameter, orifice gas velocity, liquid velocity, while increases with the increase of surface tension. Liquid viscosity and density has a negligible impact on the bubble detachment time.