Rotor of an exhaust gas turbocharger
A rotor of an exhaust-gas turbocharger includes a rotor hub and rotor blades disposed on the rotor hub. The rotor blades have a blade thickness distribution selected in such a way that the rotor blades have along their extent from a fluid inlet or leading edge to a fluid outlet or trailing edge at least one transition between a stiffness or rigidity-oriented blade thickness distribution and an inertia and stress-oriented blade thickness distribution over the height of the blade.
1. A rotor of an exhaust-gas turbocharger, the rotor comprising:
a rotor hub;
rotor blades disposed on said rotor hub, said rotor blades each having a fluid inlet edge, a fluid outlet edge, a blade root, a radial blade edge, a blade height extending in a direction radially away from said rotor hub to said radial blade edge, a blade length extending from said fluid inlet edge to said fluid outlet edge, a first side surface contour, a second side surface contour located opposite said first side surface contour, and a blade thickness distribution defined between said first side surface contour and an imaginary central line of a cross section extending between said first and second side surface contours;
said blade thickness distribution being selected to provide said rotor blades, along an extent thereof from said fluid inlet edge to said fluid outlet edge, with at least one transition between a first thickness distribution extending over said blade height and a second thickness distribution extending over said blade height;
wherein said blade thickness distribution at said fluid inlet edge is said second thickness distribution extending over said blade height and said blade thickness distribution at said fluid inlet edge merges into said first thickness distribution at a location disposed away from said fluid inlet edge;
wherein said first thickness distribution requires said first side surface contour to have a curvature change region in which said first side surface contour changes from a convex profile to a concave profile as said first side surface contour extends in a radially outwardly extending direction; and
wherein said second thickness distribution requires said first side surface contour to have a concave profile causing a blade thickness to decrease degressively over the blade height as said first side surface contour extends in the radially outwardly extending direction.
2. The rotor according to claim 1 , wherein said curvature change region is between said blade root and said radial blade edge.
3. The rotor according to claim 2 , wherein said first side surface contour has one straight or one curved first transition region between said blade root and said curvature change region.
4. The rotor according to claim 3 , wherein said first side surface contour has one straight or one curved second transition region between said radial blade edge and said curvature change region.
5. The rotor according to claim 1 , wherein said concave profile of said first thickness distribution is between said blade root and said radial blade edge and said concave profile of said second thickness distribution is between said blade root and said radial blade edge.
6. The rotor according to claim 5 , wherein said concave profile of said second thickness distribution merges, in a direction toward said radial blade edge, into a profile being inclined toward said imaginary central line or being parallel to said central line, forming a transition region having a trapezoidal taper in a radially outward direction or a uniform thickness, in said cross section of the rotor blade.
7. The rotor according to claim 1 , wherein said first side surface contour also has a multiplicity of straight-running contour sections in a radially outward direction in an area of said first thickness distribution and in an area of said second thickness distribution.
8. The rotor according to claim 1 , wherein said rotor blades each have a suction side and a pressure side with identical blade thickness distributions on said suction side and on said pressure side, and said first and second side surface contours of said respective rotor blades run symmetrically relative to one another about said imaginary central line.
9. The rotor according to claim 1 , wherein said rotor blades each have a suction side and a pressure side with different blade thickness distributions on said suction side and on said pressure side, and said first and second side surface contours have different contour profiles relative to said imaginary central line.