Numerical Simulation Of Bubble Plume

Bubble plume is complex two-phase flow. Bubbly unconfined jets and plumes havereceived considerable attention, but most of them focus on experimental study. Thenumerical simulations of bubbly jets and plumes have seldom been reported to ourbowledge. Numerical simulation of the round plume in still environment is achieved inthis paper. Detailed work is listed as fOllows:1. Based on the analysis of the development of bubble plume, a conclusion is drawn thatcalculating water flows using turbulence models is a new tendency. Turbulencemodels can simulate fiow-field accurately, which will help well understanding theproperties of bubbly movements and provide scientific bases for the theoreticaldeve1opment.2. Tboulence models are reviewed and commented briefly. A variety of turbulencemodels are compared. In practice, standard two-equation k-ε model is employed topredict field characteristics of round bubble plume in a uniform still environment.3. Bubble diffusion equation is deduced using separately diffusion theories and two-phase ftuid dynamics theories, and its applicable conditions, thereby establishing thediffusion equation for describing the properties of bubbly movements.4. Boussinesq and the boundary layer approximations are employed to improve standardk-ε model. Governing equations for bubble plume flows are set up in pillaraxisymmetric coordinates. A method using integral form of the governing equationsin an arbittar control volume for the discretization of the scalar transport, whichaecounts for possible discontinuities in the diffusivities, is described in details. Alldiscretized equations in computational space are obtained and boundary conditionsat built. In view of the properties of the flows, single equation is solved usingTDMA method. A general compater program to solve equations governing bubbleplume in axisymmetric coordinates is built. Numerical simulation of round bubbleplwne in still uniform environment is performed and the results show favorableagreement with the experimental observations.