NUMERICAL SIMULATION AND EXPERIMENTAL INVESTIGATION OF THE GUIDE - VANE FLOW AND THE INFLUENCE FROM THE LEAKAGE FLOW

摘要

This paper presents numerical and experimental results of the flow in the tip clearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations were employed to model the flow in end clearance region of guide vane cascade, the Reynolds stress differential model was used for turbulence closure, and the body-fitted curvilinear coordinates and the SIMPLE! algorithm were adopted. The governing equations were discretized with the non-staggered grids by means of the finite volume method. Detailed comparison of hydrodynamical characteristics of guide vane in hydraulic turbine with or without tip gap was made. Special attention was paid to the influence of leakage flow on the main flow and to the movement of tip leakage flow in the end guide vane. The position and strength of the roll-vortex on the sides of guide vane in were determined. The numerical solutions agree with the experimental results obtained by particle image ve-locimetry. The results help to clarify the loss, wear and cavi-tation erosion between the guide vane and rings, especially for those used in the Yellow River which has a high sediment content.