Study on hydrodynamic characteristics of splitter cascade

In order to realize the miniaturization of water jet axial-flow pump, the project selected splitter cascade based on NACA4412 hydrofoil to explore the feasibility of splitter cascade in water axial-flow pump. The project involved an extensive numerical study of 2-D geometries, and the flow field was determined by solving two-dimensional incompressible Navier-Stokes equations while the effects of turbulence were accounted for by SST (Shear-Stress Transport) k-w model. The hydrodynamic characteristics between traditional cascade and splitter cascade were compared. Pertinent external conditions including the angles of attack and Reynolds were set to analyze the optimum operating condition of splitter cascade. In addition, it's important part of predicting the effect trends of axial length ratio on performance of splitter cascade. The results show that the load on large hydrofoil reduce after small hydrofoil is added, and angle of attack has an obvious influence on the pressure distribution of large hydrofoil, the lowest pressure on the upper surface of the hydrofoil moves forward with angle of attack increasing. Besides, the smaller the axial length ratio is, the easier the boundary layer separates; on the contrary, it causes deterioration in the flow capacity of splitter cascade.