Computer Simulation and Optimization of Stirrer Hydrodynamics at High Reynolds Numbers pp. 493-510
Authors: (O. Ugur, K. Yapici, Y. Uludag, B. Karasozen, Institute of Applied Mathematics, Middle East Technical University, Ankara, Turkey, and others)
Abstract: Computational fluid dynamics (CFD) is a powerful tool for solving problems as- sociated with flow, mixing, heat and mass transfer and chemical reaction. Hence they are useful alternatives to experimental techniques that are expensive and time consum- ing in the simulation of mixing processes. In this chapter, computational analysis of turbulent flow field in a mixing tank and a numerical approach for the optimization of stirrer configuration parameters are presented. Velocity field and power requirement are obtained using the FASTEST, a CFD package, which employs a fully conservative finite volume method for the solution of the Navier-Stokes equations. The inheritably time-dependent geometry of stirred vessel is simulated by clicking mesh method. In the simulation of the turbulent flow field in a mixing tank with six bladed Rush- ton turbine, the effects of impeller clearance and disc thickness on the power number are determined and it is found that the power number decreases with decreasing clear- ance and increasing disc thickness. The results are comparable with those of well established measurement techniques in terms of time-averaged velocity field, turbu- lent kinetic energy, dissipation rate, and power number.