Patent ID: 7066713
Filing Date: 2006-06-27
Classification: F01D,F05D,Y02T

Abstract:
1. A rotor blade for a rotary machine having a flowpath for working medium gases, the rotor blade having an inner end which includes a base which adapts the rotor blade to be joined to a rotatable structure, an outer end having a laterally extending, outwardly facing surface which is disposed circumferentially about an axis Ar and having a radius of curvature about the axis Ar, an airfoil having a leading edge, a trailing edge, and a suction side and a pressure side which each extend chordwise from the leading edge to the trailing edge, and a tip region which includes the outer end, which comprises: a plurality of airfoil sections disposed spanwise about and perpendicular to a stacking line for defining the surfaces of the airfoil, the stacking line of the airfoil extending spanwise in a radial direction, and each airfoil section having a tip shroud for the rotor blade disposed in the tip region, the tip shroud including wings which extend from the sides of the airfoil, the wings including a transition zone formed from said transition zone portions of the wings and of the beam, the transition zone extending from a junction with the suction side of the airfoil and a junction with the pressure side of the airfoil to provide a flow path surface of the shroud which has a smooth contour; wherein the rotor blade has a reference normal sectioning plane P passing through a point at the junction of the transition zone to the airfoil that contains a first line perpendicular to the side of the airfoil section at that junction point and a second line passing through that junction point that is perpendicular to the first line and parallel to the stacking line of the airfoil; wherein a transition line is the line of intersection of the plane P with the transition zone at a junction point and defines the surface contour of the transition zone at a particular location; wherein each transition line has an offset distance A from the airfoil which is the distance of the projection of the transition line along the first line of the plane P perpendicular to the side of the airfoil section, has an offset distance B from the shroud which is the distance of the projection of the transition line along the second line of the sectioning plane parallel to the stacking line, and has an offset ratio which is the ratio of the offset distance A from the airfoil divided by the offset distance B from the shroud; wherein each transition line has a first end at the junction point and a second end at the point the transition zone terminates, the transition lines being smoothly recessed from a straight line connecting the ends of each transition line; wherein on at least one of said sides of the airfoil those transition lines that extend under the beam have greater bending away from the airfoil at a region closer to the airfoil on the transition line than at a region closer to the side of the shroud such that the average of offset ratios Rb of transition lines that extend under the beam are greater than one and are greater than the average of offset ratios Rw of transition lines that extend only under the rear portion of the wings.