Numerical Simulation of Cavitation Flow in Tandem Cascade

Abstract

Complex cavitation phenomenon in tandem cascade is investigated numerically. Three-dimensional multi-block structural mesh, Finite volume method(FVM), Shear stress transport(SST) turbulence model are employed. Single phase interface tracking model is used as the cavitation model. Flow field without cavitation involved is firstly computed as the initial field for further cavitation flow simulation. Some results are obtained through the simulation:(1) the position where cavitation occurs is near the lowest hydrofoil’s upper surface and corresponds to the trailing edge of the middle foil; (2)cavitation zone’s profile is greatly influenced by solid boundary and rotary speed, the rear profile of the cavitation zone becomes coarser with shortened distance from the impeller hub; (3)with large rotary speed, the cavitation zone’s length vertical to the main flow gets larger and coupling between cavitation zone profile and flow parameters proves to be more salient.