Ü Stator | Blade properties

 

In principle, the same features are available as for the blade properties of impellers.

 

The outlet angles αTE are input values for most of the blade types according to the desired change of flow direction. Slip models are not available for stators. Some angle oversizing should be considered if necessary.

 

 

Two additional special blade shapes are available for "Radial diffuser" type stators (see Main dimensions):

 

1. Log. Spiral + Straight 2D

The inlet section of the vanes without overlapping is noneffective and configured as a logarithmic spiral (similar to spiral casing).

The diffuser part in the overlapping area is straight. The transition point between these areas can be moved along the logarithmic spiral curve (see mean line).

 

2. Circular + Free-form 2D

The inlet section of the vanes without overlapping is configured as a circular arc with the boundary conditions inlet radius r3, inlet angle α3 and ideal throat width a3.

The diffuser part in the overlapping area is designed by a Bezier spline with optionally 2 (straight), 3 or 4 Bezier points (selectable by context menu). The transition point between these areas can be moved along the circular arc curve (see mean line).

 

Calculation of throat width a3 can be done using the conservation of angular momentum (const. swirl) or a specific deceleration ratio alternatively:

a) Const. swirl

Throat width corrsponds to the dimensioning in accordance with the conservation of angular momentum, whereat the deceleration is increased by using the factor fa3 (1.1...1.3).

b) Deceleration

Alternatively one can use the deceleration ratio c3q/c2 (0.7...0.85) for throat width calculation.

 

Trailing edge angle αTE is a result of mean line design for these special blade shapes and therefore cannot be specified explicitly ("var.").

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