This document discusses numerical modeling of flow in centrifugal pumps using computational fluid dynamics (CFD). It describes the key components and working mechanism of centrifugal pumps. It then introduces the use of 3D CFD simulations to model flow fields within centrifugal pump impellers and impeller-volute assemblies. The document reports on simulations conducted using various turbulence models and evaluates their impact on predicted pump head, velocity fields, and pressure distributions. It concludes that CFD provides an effective tool for optimizing centrifugal pump design by capturing important internal flow characteristics.