NUMERICAL SIMULATION FOR FLOW OF LIQUID THROUGH A CENTRIFUGAL IMPELLER

Abstract

The CFD occupies today a very significant place in the disciplines of fluid mechanics and turbomachinery due to the great progress in the development of numerical methods and computing power. Contained within the broad field of Computational Fluid Dynamics are activities that cover the range from the automation of well-established engineering design methods to the use of detailed solutions of the Navier-Stokes equations as an additional tool along with experimental research to analyze the complex flows. The concern is over the methods designed to solve the equations of fluid motion in two dimensions. Numerical grid generation is a fairly common tool for use in the numerical solution of partial differential equations for any arbitrarily shaped region. The numerical solution of partial differential equations requires some discretization of the field into a collection of points or elemental volumes (grids). The differential equations are approximated by a set of algebraic equations on this collection, and this system of algebraic equations is then solved to produce a set of discrete values which approximates the solution of the partial differential system over the field. A numerically-generated grid is understood here to be an organized set of points formed by the intersections of the lines of a boundary-conforming curvilinear coordinate system. Structured grids and unstructured grids are two main types of the numerically generated grid. In this work, the focus is laid on structured grid generation by applying analytical transformation and algebraic grid generation techniques to discretize the problem-domain considered, which is modeled as a generalized flow passage of a centrifugal impeller. After grid generation, the two dimensional Navier-Stokes equations are solved numerically to analyze the flow field within the generalized impeller passage. The velocity field is determined for numerical model and compared with the experimental data available in the literature.