Abstract: A turbine blade having a root and a tip and an airfoil with a core section made of composite material and a protective sheath or layer joined to the composite core at a location or locations exposed to erosion is described with the composite core of the airfoil being continuous from a location in vicinity of the root to a location in vicinity of the tip of the blade and including a section which widens with distance from the rotational axis along the length of the airfoil and which ends at the location in vicinity of the tip of the blade. The protective sheath or layer is secured by interference fit with widening section of the core.

Abstract: The invention relates to sheath for a blade that has a uniform assembly direction over the radial height of the sheath whether the blade has a straight or curved trajectory. This is achieved by the a sheath formed around the edge, having a first inner surface wherein a first tangential vector projected tangentially to the first inner surface in a direction away from the head portion in an longitudinal plain forms a first angle with the rotational axis that does not vary over the radial height of the sheath while a second tangential vector projected tangentially from any point of the second inner surface of the sheath in a direction towards the head portion intersects the first tangential vector.

Abstract: A turbine blade having a root and a tip and an airfoil with a core section made of composite material and a protective sheath or layer joined to the composite core at a location or locations exposed to erosion is described with the composite core of the airfoil being continuous from a location in vicinity of the root to a location in vicinity of the tip of the blade and including a section which widens with distance from the rotational axis along the length of the airfoil and which ends at the location in vicinity of the tip of the blade. The protective sheath or layer is secured by interference fit with widening section of the core.

Abstract: The invention relates to sheath for a blade that has a uniform assembly direction over the radial height of the sheath whether the blade has a straight or curved trajectory. This is achieved by the a sheath formed around the edge, having a first inner surface wherein a first tangential vector projected tangentially to the first inner surface in a direction away from the head portion in an longitudinal plain forms a first angle with the rotational axis that does not vary over the radial height of the sheath while a second tangential vector projected tangentially from any point of the second inner surface of the sheath in a direction towards the head portion intersects the first tangential vector.

Abstract: A method of replacing rotating metal blades of a steam turbine inserted into a rotor having one or more existing grooves for inserting root sections of the metal blades is described, the method including the steps of providing replacement blades having radially inwards directed root sections of fiber-reinforced composite material, changing the shape of the one or more grooves in the rotor to form a cavity for the insertion of the root sections of fiber-reinforced composite material and inserting the replacement blades into the rotor.

Abstract: A turbine blade having a root and a tip and an airfoil with a core section made of composite material and a protective sheath or layer joined to the composite core at a location or locations exposed to erosion is described with the composite core of the airfoil being continuous from a location in vicinity of the root to a location in vicinity of the tip of the blade and including a section which widens with distance from the rotational axis along the length of the airfoil and which ends at the location in vicinity of the tip of the blade. The protective sheath or layer is secured by interference fit with widening section of the core.

Abstract: A turbomachine includes a turbine stage having a plurality of blades including a first and a second blade disposed adjacent to each other, each blade having a radial longitudinal axis and a blade tip and configured to twist around the radial longitudinal axis in an operating state in a twist direction, wherein the first and the second blades are pretwisted in a direction of twist in a non-operating state, and wherein a connecting element interconnects the first and the second blades to each other in a circumferential direction in a region of the respective blade tip so as to maintain the pretwisting.

Abstract: A method of replacing rotating metal blades of a steam turbine inserted into a rotor having one or more existing grooves for inserting root sections of the metal blades is described, the method including the steps of providing replacement blades having radially inwards directed root sections of fiber-reinforced composite material, changing the shape of the one or more grooves in the rotor to form a cavity for the insertion of the root sections of fiber-reinforced composite material and inserting the replacement blades into the rotor.

Abstract: A rotating blade row is provided for the final stage of a steam turbine has blades with an integrated shroud. The shroud of each blade has a projection in the axial direction, in each case on its pressure side, which prevents droplets in the working fluid of the steam turbine from reaching the shroud fillet of the respective subsequent blade in the flow direction. The shroud fillet is therefore protected against erosion damage caused by droplets impact erosion. The projection is positioned and of such a size that mass equilibrium is ensured between the suction side and the pressure side of the shroud, and stress equilibrium is ensured between the projection on the pressure side and the suction-side shroud. The projection furthermore has a recess between its greatest axial extent and the leading edge.

Abstract: A turbine blade having a root and a tip and an airfoil with a core section made of composite material and a protective sheath or layer joined to the composite core at a location or locations exposed to erosion is described with the composite core of the airfoil being continuous from a location in vicinity of the root to a location in vicinity of the tip of the blade and including a section which widens with distance from the rotational axis along the length of the airfoil and which ends at the location in vicinity of the tip of the blade. The protective sheath or layer is secured by interference fit with widening section of the core.

Abstract: A rotating blade row is provided for the final stage of a steam turbine has blades with an integrated shroud. The shroud of each blade has a projection in the axial direction, in each case on its pressure side, which prevents droplets in the working fluid of the steam turbine from reaching the shroud fillet of the respective subsequent blade in the flow direction. The shroud fillet is therefore protected against erosion damage caused by droplets impact erosion. The projection is positioned and of such a size that mass equilibrium is ensured between the suction side and the pressure side of the shroud, and stress equilibrium is ensured between the projection on the pressure side and the suction-side shroud. The projection furthermore has a recess between its greatest axial extent and the leading edge.

Abstract: A turbomachine includes a turbine stage having a plurality of blades including a first and a second blade disposed adjacent to each other, each blade having a radial longitudinal axis and a blade tip and configured to twist around the radial longitudinal axis in an operating state in a twist direction, wherein the first and the second blades are pretwisted in a direction of twist in a non-operating state, and wherein a connecting element interconnects the first and the second blades to each other in a circumferential direction in a region of the respective blade tip so as to maintain the pretwisting.