Numerical simulation of impeller-volute interaction in a centrifugal turbomachinery

Generally, an impeller of centrifugal turbomachinery is designed at isolated condition without considering the presence of a volute. But when the impeller is operating with its volute, the performance of impeller could be different. This is largely caused by the interaction between the impeller and volute flow fields. The magnitude of distortion is increased as the operating point is away from the design point and, as a result, the interaction between the impeller and volute is stronger. The computational method is developed for the calculation of impeller-volute flowfield. In the method the flow is assumed to be quasi-steady across the interface between the volute and impeller flowfield. Although the flow within the impeller and the volute is naturally unsteady, the steady three-dimensional incompressible time averaged N-S equations with standard k -ε turbulent model is solved for the flowfield. The calculation results are compared with the experimental results obtained for an industrial fan and the good agreement is demonstrated.