An existing Navier-Stokes solver to simulate the turbulent transonic flow using block-structured grids has been used to optimize the guide vanes of radial inflow turbines. The code has been extended to calculate the flow in the rotating parts of turbomachines and is now used to simulate the turbulent flow through the rotor of a radial inflow turbine.

The results of three calculations are presented (inviscid and viscous flow without tip clearance, viscous flow with tip clearance). The flowfield is investigated at design conditions where a large incidence angle exists at the entrance of the rotor. Unsteady effects are neglected.

The comparison of the results of the inviscid and viscous simulations shows the strong influence of the viscous forces. Strong secondary flow patterns are found in the vicinity of the blades and the walls. Special attention has been paid to the analysis of the flow through the gap between the casing and the blades. The determination of the mass flow rate through the gap shows that mass is transported from the suction towards the pressure side of the blade at the beginning of the blade (6.1% of the blade length). Thereafter, the mass flow through the gap changes its direction.

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