Simulation of gas-liquid and gas-solid two-phase flows

Gas-liquid flows and gas-solid flows are common features in many important industrial processes. Fully understanding the behaviors of such flows is usually critical in the design of those processes.; In this study, a multiphase hydrodynamic model based on the laws of mass conservation and momentum conservation is applied to model gas-liquid phase separation in different T-junction systems and gas-solids two phase flow in CFB risers. Since two flow systems have different features, the research work will be given in two separate parts.; In the first part, the simulations of the gas-liquid two phase flow in two different T-junctions, namely a branching tee and an impacting tee, are presented. Chapter I gives the background information of the research work being done in this part. Chapter II discusses the simulation of gas-liquid two phase flow in a horizontal branching tee. A set of empirical correlations of saturated steam properties has been introduced into the mathematical model in accomplishing the simulation of the steam-water system. Chapter III addresses the simulation of the gas-liquid two phase flow in an impacting tee. The results show that even mixture dividing is restricted to a certain range in an impacting tee, although it was originally invented to correct the undesirable phase separation in a branching tee. The numerical solutions using the current mathematical model have been found to be consistent with the experimental data.; In the second part, the research work on the gas-solids two phase flow in a CFB riser is presented. Chapter IV gives the description of the background of this work. Chapter V describes the simulation of a challenging problem--benchmark modeling a CFB riser unit. The results show an unusual phenomenon of this system, which is consistent with the experimental measurements even though it has not yet been recognized in the CFB community. Chapter VI discusses the kinetic theory approach of the gas-solids mixture simulation.; Summaries of this research work are given in Chapter VII. Some recommendations are also presented in this chapter.; This study shows that the current mathematical model has a promising future in modern industrial applications. With further development, the model will be a very powerful design tool some day.