Numerical Investigation Of Flows In Centrifugal Pump Impeller Considered Effects Of Rotation And Curvature

At present, the nuclear electricity in China is developing rapidly but the domestic de-mands for nuclear reactor coolant pump (RCP) still rely on imports. The RCP is becoming a bottleneck to the independent development for nuclear power, which seriously hampered China's nuclear power development and its localization process. The RCP, as one of the most important rotating equipment in first loop of the nuclear power station, long-term safely ser-vices in a condition of high temperature, high pressure and high radioactivity. So it requires an extremely high technical for hydraulic design and manufacturer.When turbulent flow within a centrifugal impeller undergoes system rotation, the resulting Coriolis and centrifugal accelerations are responsible for strong effects to the development of boundary layers and the secondary flow field, and then greatly affect the wall friction coeffi-cient. These phenomena caused by the rotation and curvature are particularly important for the understanding of flow field and losses generation mechanism of centrifugal and mixed-flow pump. In order to find out the flow law in the RCP impeller, especially the effects of rotation and streamline curvature to the flow field, a numerical investigation on centrifugal impeller internal flow is carried out.First of all, the SST k-ωturbulence model based on the open source code OpenFOAM is applied to calculate the rotational flow field in a straight rectangular duct and a 90°bend duct. Part of present numerical results are compared with the experimental and numerical data from available literatures. The comparison shows a well agreement, indicating that the simulation is accurate and reliable. The software and turbulence model used in this problem show a good applicability to predict the flow influenced by rotation and curvature.Based on the theory derived from former study on the ducts, numerical simulation of the flow in the RCP impeller is conducted by calculating a single flow passage in several different flow-rate conditions. The velocity distribution and static pressure of the axial medial section and span wise sections as well as secondary flow problem in impeller flow field and the causes of these flow characteristics are analyzed. The investigation of flow characters in the RCP impeller and consequently the analysis of the losses generation mechanism should give valu-able reference to an optimized design of the RCP.