Improvement in the design of a centrifugal impeller for an oil cooling blower system using computational fluid dynamics

This article presents the computational flow analysis of an axial-centrifugal flow system used for transformer oil cooling in WAP-5 and WAP-7 electric locomotives of Indian Railways. The commercial computational fluid dynamics code 'FLUENT' was used for the numerical simulation of the flow system. A standard k-epsilon turbulence model was employed for turbulence modelling. The flow field through the impeller was analysed to investigate the effect of blade twists and to determine the forces on the blades. A modified impeller design is suggested whose diameter is less than the existing one, which helps in reducing the centrifugal forces. The flow field analysis of the modified impeller shows improvement in the flow through the impeller channels with better performance and reduction in forces on the blades.