Abstract: A row of mix-tuned rotor blades for use in a turbomachine in which the first mode vibratory frequency of each of the blades falls into either of two distinct groups. The blades from the first group alternate with the blades from the second group so that no two adjacent blades have the same frequency, thereby inhibiting the onset of stall flutter. The blades are made by forging a forging blank between upper and lower die halves. The orientation of the upper die half relative to the lower die half when the die is fully closed is different depending on whether blades are being made for the first or second group, the difference being an offset in the position of the upper die half. As a result, the airfoils of the blades in the first and second groups have slightly different shapes, thereby resulting in the difference in resonant frequency.

Abstract: A steam turbine blade is provided in which the geometry of the blade airfoil is configured to reduce the weight of the blade while maintaining adequate thermodynamic performance. The blade has a high camber angle to increase its stiffness and an airfoil portion having pressure and suction surfaces. The curvature of the portion of the pressure surface between the base and 75% blade height has a point of inflection in an area adjacent the leading edge so that the curvature switches sign. The curvature upstream of the point of inflection is concave, while the curvature downstream of the point of inflection is convex.

Abstract: A steam turbine blade is provided in which the geometry of the blade airfoil is configured to reduce the weight of the blade while maintaining adequate thermodynamic performance. The blade has a high camber angle to increase its stiffness and an airfoil portion having pressure and suction surfaces. The curvature of the portion of the pressure surface between 25% and 75% blade height has a point of inflection in an area adjacent the leading edge so that the curvature switches sign. The curvature upstream of the point of inflection is concave, while the curvature downstream of the point of inflection is convex.

Abstract: A high performance steam turbine blade is provided in which the geometry of the blade airfoil is configured to minimize energy loss through the row of blades and control the radial distribution of the degree of reaction. The velocity of the steam over the blade surface is minimized to reduce friction losses, rapid deceleration of the steam velocity as it expands toward the trailing edge is avoided to prevent boundary layer separation and the reaction distribution is adjusted so that a relatively high reaction occurs at the base of the airfoil, thereby reducing secondary flow, and a relatively low reaction occurs at tip of the airfoil, thereby minimizing tip leakage. Specifically, the radial reaction distribution is such that in the hub region at least 20% of the stage pressure drop occurs in the blade row and in the tip region less than 50% of the stage pressure drop occurs in the blade row.

Abstract: A method and apparatus are provided for determining the amount and type of permanent deformation experienced by a turbomachine blade. According to the invention, small holes are drilled in at least three blades of the blade row. One hole is drilled in the inlet face of the blade shroud and another hole is drilled in the inlet face of the blade root. In addition, third and fourth holes are drilled in the exit face of the shroud and a sixth hole is drilled in the exit face of the root. Measurements are taken between the shroud holes on the middle blade and the root holes on the outer blades in the row on both the inlet and exit faces. The measurements are use to form triangles indicating the blade geometry. By comparing the changes in these triangles after substantial operating time, both the type and amount of permanent deformation can be determined.

Abstract: A steam turbine stationary blade diaphragm consisting of steam turbine blades with inner and outer rings which are integral with the blades to form a diaphragm structure of a particular design that avoids steam separation by selection of the blade parameters so as to cause a substantially continuous velocity increase over the major extent of the suction surface of the blade.

Abstract: A stationary blade of a steam turbine having a rotor and an inner cylinder for mounting the stationary blade in a row with plural identical stationary blades, comprising an airfoil having a leading edge, a trailing edge, a pressure-side concave surface and suction-side convex surface extending between the leading and trailing edges. A stagger angle being defined by as an angle of a chord between the leading and trailing edges to a longitudinal axis of the rotor; an outer ring for connecting a proximal end of the airfoil to the inner cylinder; an inner ring connected to a distal end of the airfoil; and a seal assembly carried by the inner ring and sealingly engaging the rotor; wherein the stagger angle ranges from about 42.degree. at the distal end of the airfoil to about 52.degree. at the proximal end.

Abstract: A tapered twisted rotating blade for the fourth rotating blade row of a BB71 and BB471 turbine has a shroud segment integrally formed on the tip of the airfoil portion such that the shroud is dimensionalized according to materials used so that the tuned frequencies remain the same regardless of materials used, based on changes in Young's modulus due to use of different materials. The blade also has a pitch to chord ratio that increases linearly with length of the blade.

Abstract: A stationary blade for a steam turbine includes an airfoil portion having an inner diameter end and an outer diameter end; an inner ring portion integrally formed at the inner diameter end of the airfoil portion; and an outer ring portion integrally formed at the outer diameter end of the airfoil portion, the airfoil, inner ring and outer ring portions being envelope forged from a single bar stock, and each blade being welded together with an adjacent, substantially identical blade with welds provided at the inner and outer ring portions, the inner ring portion welds comprising a first, upstream weld and a second, downstream weld which is lower than the upstream weld.

Abstract: An integral shroud blade comprising a root portion for mounting the blade in a row on a turbine rotor; a platform portion; an airfoil portion extending upwardly from the platform portion and having a leading edge, a trailing edge, and a tip; a shroud formed on the tip of the airfoil portion and having two opposite tangential side surfaces and a top surface; and at least one pair of holes extending into the shroud, each of the two tangential sides having one hole of each pair being formed therein.

Abstract: A steam turbine of the type employing a plurality of axial entry, integral shroud blades comprises spring means resident in a slot machined in at least one face of each shroud. The spring means urge against the adjacent shroud and reduce relative motion between adjacent blades.

Abstract: A steam turbine of the type employing a plurality of axial entry blades has a first annular plate juxtaposed one side of the disc that overlays the grooves in the disc and faces of the platforms of the blades. If desired, a second similar annular plate may be provided on the other side of the disc. The annular plates reduce windage and leakage.

Abstract: A method is provided for forming a circular array of rotatable blades from blades having an integral shroud with a leading planar surface and a trailing planar surface, the leading planar surface being generally parallel to an axial radial plane passing through the center of the root of the blade and the trailing surface, if extended, intersecting the axial radial plane passing through the center of the root of the blade to form an angle generally equal in degrees to 360 divided by the number of blades forming the circular array. Strict radial alignment is provided by assembling the complete blade row such that all blade center lines coincide with the groove center lines, with the shroud mating surfaces in complete contact and in tangential compression.

Abstract: A locking system for attaching a circular array of side entry steam turbine blades to a rotor disc utilizing a circumferential groove in the outer periphery of the disc and a notch in one side of a blade platform to form an opening for receiving a pin which prevents the blade from sliding in the side entry slots in the disc and the next blade installed on the rotor captures a pin in the preceding blade except the last blade assembled in the array or closing blade has a kerf in the platform which registers with the circumferential groove in the disc and a locking key fitting into the kerf and groove to hold the last blade in place and the locking key being captured in the kerf and groove by a strip of metal passing through a slit in the locking key and an opening formed in the platforms.