Unsteady flow in a gas bubble plume
Fahrenthold, Eric P.
Beckmann, Herbert K.
Master of Science
The characteristics of a gas bubble plume produced by the discharge of gas from a submerged orifice at high flowrates is investigated. Flow of the gas and liquid mixture into the plume has been found to develop pulsations at high gas flowrates, resulting in a plume structure different from that produced by uniform bubble flow. The plume is modeled as a column of gas bubble "clouds." The frequencies of the flow pulsations in the plume are obtained by evaluation of the forces acting on a bubble cloud forming at the discharge nozzle. The vertical current in the plume is investigated by consideration of the wake produced by bodies of revolution traveling in line. Expressions for the drag force on cylinders (two-dimensional), spheres, and disks arranged in line are determined. Available experimental data on flow fluctuations in gas bubble plumes and drag forces on cylinders, spheres, and disks arranged in line are used to evaluate the derived expressions.