β Blade angle
The blade is designed by means of a blade angle distribution with the help of Bezier curves.
The x-values of the Bezier control points are defined with respect to certain x-axis definitions. These definitions can be selected below the design mode selection and will determine the x-axis definition in the design diagram too.
The endpoints of the curves are completely fixed by their meridional coordinate specified in the Meridional contour design step and the blade angles βB1 (leading edge) and βB2 (trailing edge) specified in the Blade properties design step.
The inner Bezier points can be moved without any restrictions.
In the area Angular positions the stacking position can be defined. Only at this position the tangential coordinate ϕ can be specified directly, all other points along the meanline are calculated automatically. Therefore, the blade wrap angle of each span is a result of the given blade angle progression.
The context menu of the curves contains additional options:
•Bezier curve/ Add/ Remove Bezier point:
The number of Bezier points can be modified, which provides high flexibility.
•Bezier curve/ Constant βB1 (βB2) near leading (trailing) edge:
An additional control point at leading and/ or trailing edge is added, which defines a horizontal line and hence a region with constant βB1/ βB2.
The exact position can be defined by the point context window as r, z, or m value.
•Polyline/ Load curve:
After switching the curve mode to polyline, a user-defined polyline can be loaded.
The visibility of the inner mean lines can be toggled via "Inner spans".