An improved turbulence model for separation flow in a centrifugal pump

For the stable and reliable operation of centrifugal pump, the transient flow must be studied and the separation region should be avoided. Three-dimensional, incompressible, steady, and transient flows in a centrifugal pump at specific speed within 74 were numerically studied using shear stress transport k-omega turbulence model, and an improved explicit algebraic Reynolds stress model-rotation-curvature turbulence model was proposed by considering the effects of rotation and curvature in the impeller passages in this work. Steady and transient computations were conducted to compare with the experiments. The comparison of pump hydraulic performance showed that the explicit algebraic Reynolds stress model-rotation-curvature turbulence model was better than the original model, especially between 0.6Q(BEP) and 1.2Q(BEP); the improved model could enhance the head prediction of pump by about 1%-7% than that with the original model. Then, the visualization of the vortex evolution was observed to validate the unsteady simulations. Good agreement was investigated between calculations and visualizations. It is indicated that the explicit algebraic Reynolds stress model-rotation-curvature model can successfully capture the separation flow.