Numerical Simulation of 3D Unsteady Flow in Centrifugal Pump by Dynamic Mesh Technique

Abstract

The 3-D Dynamic Meshing technique is applied for numerical simulation of unsteady flow fields in a centrifugal pump using the Fluent software. The surface motion of the impeller computational domain was defined by the Profile file in Fluent software, in which the rotational direction and speed of the impeller were specified. The simulation results are also compared with those derived from the widely used Sliding Mesh technique to illustrate superior computational efficiency of the Dynamic Mesh method. In the Dynamic Mesh technique, all the computational domains, considered as stationary, were defined in an inertial reference frame, while the topological relationship between previous and current mesh nodes were retained to ensure a good precision and time coherency. Three methods, namely the spring-based smoothing, dynamic layering and local re-meshing were used to achieve mesh deformations. Comparisons of solutions with those obtained using the Sliding Mesh technique considering identical computational model, meshes, and initial and boundary conditions revealed that both the methods converge to comparable solutions within five revolutions of the impeller. The iterative speed of the Dynamic Mesh method, however, was almost three times that of the Sliding Mesh method. The results thus suggest that the Dynamic Mesh technique for flow simulation in centrifugal pumps, defined in an inertial reference frame, yields substantially greater computing efficiency than the Sliding Mesh method involving comprehensive data transfer among multiple reference frames.