A Critical Review on the Application of Computational Fluid Dynamics in Centrifugal Turbomachines

Centrifugal turbomachines are the popular type of power absorbing machines especially used in many industrial applications. In these devices the energy from the rotating impeller is transferred to the fluid to increase its pressure energy. The flow phenomena in these machines is very complex because of the presence of adverse pressure gradients in the flow passages. The level of complexity of turbomachinery flow fields is directly influenced by flow-path geometry and component blade geometry. Hence there is a dire need of advanced flow modelling techniques to understand and capture the fluid characteristics in these flow devices. To design such flow domains, advanced Computational Fluid Dynamics (CFD) tools are required that are capable of accurately modelling the complex flows encountered in turbomachinery applications. These models reflect the full three-dimensional, turbulent, transonic, and often unsteady nature of the actual flows. In addition, they must allow analyses to be performed in reasonable amounts of time that can be accommodated within a typical design cycle. With the development of fast and validated numerical methods, and the continuous improvement in clock speed of computer processors, highly complex problems are now being solved using CFD methods even more economically and quickly. This article focusses the efficacy of CFD tools in turbomachinery applications and various parametric methodologies pertaining to efficiency improvement of turbomachines in detail.