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On page Dimensions, panel Shaft/ hub, the required shaft diameter is computed and the hub diameter is determined by the user.

¢ Shaft/Hub


The main dimensions of a designed runner  - inlet and outlet diameters dS1, dH1, and dS2, dH2, and inlet width b1 - can be seen on Main dimensions panel. They can be recomputed by pressing the Calculate-button. The computation is based on "Euler's Equation of Turbomachinery", on the continuity equation and the relations for the velocity triangles as well as on the parameters and parameter ratios given in the tab sheets Setup and Parameters.

Individual main dimensions can be calculated separately using the button inside the value field.

You may accept the proposed values or you can modify them slightly, e.g. to meet a certain normalized diameter.

In case the checkbox Automatic is activated a new calculation will accomplished after any change of parameter. Then the manual alteration of the main dimensions is not possible.

Neighboring components

In specific cases the dimensions of the neighboring components at inlet and/ or outlet can be used to get exactly matching geometry.

This feature is available only for explicitly uncoupled components or side-by-side impellers.


In the right panel of any tab sheet an information panel is situated, which holds the computed variables in accordance to the actual state of design, the resulting Meridional section as well as the Cordier-Diagram with the location of the best point. These three sections can be chosen by the appropriate soft buttons in the heading.

In the Value section the following variables are displayed for information which result from calculated or determined main dimensions:

Work coefficient

Flow coefficient

Meridional flow coefficient

Specific diameter

Inlet velocity

Inlet velocity (net)

Outlet velocity

Outlet velocity (net)

Outlet width ratio

Meridional velocity ratio


The Meridional preview is until now based on the main dimensions only.


The Cordier diagram can be used for checking the impeller diameter d2.

See Cordier.

The Velocity triangles are the result of a mid-span calculation and are based on the design point and the main dimensions.