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# Axial Turbine

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# Axial Turbine

► Rotor | Main dimensions

The Main Dimensions menu item is used to define main dimensions of the axial rotor. Main Dimensions are forming the most important basis for all following design steps.

 The real flow in the rotor is turbulent and  three-dimensional. Secondary flows, separation and reattachment in boundary layers, transient recirculation areas and other features may occur. Nevertheless it is useful - and it is common practice in the turbine design theory - to simplify the realistic flow applying representative streamlines for the first design approach. Employing 1D-streamline theory the following cross sections are significant in particular: just before leading edge (index 0), at the beginning (index 1) and at the end of the blade (index 2), behind the trailing edge (index 3) and at the outlet (index 4). Details

## Possible warnings

Problem

Possible solution

Inlet boundary conditions do not fit previous component.

If a stator is located prior the rotor, boundary conditions for the determination of the main dimensions will be calculated on the basis of the thermodynamic state at its outlet. In case of an undefined thermodynamic state at this location the inlet boundary conditions (i.e. total pressure and temperature) will be taken from the global setup.

Adjust the stator geometry (dimensions or blade angles) or change the Global setup (e.g. decrease mass flow).

Inlet static pressure is smaller than the outlet static pressure.

If a vaned stator is located prior the rotor, its blade angles might yield a very high circumferential velocity and therefore a comparable small static pressure. In case this pressure, which is the inlet static pressure of the rotor, is smaller than the estimated static outlet pressure, an reasonable expansion cannot be established.

Adjust the precursor stator trailing edge blade angles and decrease herewith the circumferential velocity component.