United Technologies Corporation

Other

Robert J Kildea

Jorge A Alcorta

Wesley D Brown

Kenneth B Hall

Robert B Richardson

Wayne D Wekenmann

Herbert R Voigt

A method for forming non-separating diffusers in a part includes fabricating at least one metering hole in a part, and fabricating at least one diffuser hole with an electrode comb in the part such that the diffuser hole intersects the metering hole at a transition region. The electrode comb includes a tooth including a nose comprised of a plurality of diffuser surfaces intersecting at a point on a tooth centerline. Each diffuser surface has a diffuser angle, and at least one of the diffuser surfaces is truncated by an offset from the tooth centerline.

Non-separating diffuser for holes produced by a two step process

The present invention relates to an improved attachment air inlet configuration for a turbine blade. It defines several modifications that reduce attachment rib concentrated stresses in highly loaded, single crystal turbine blades that cause cracking in conventional blade inlet configurations. It desensitizes rib concentrated stresses to variations in secondary crystal orientation, permitting highly loaded single crystal blades to have random secondary crystal orientation for lower cost, or seed with any secondary orientation needed to solve other blade or manufacturing problems.

Attachment air inlet configuration for highly loaded single crystal turbine blades

A seal for the aft end of a turbine blade and disk assembly of a gas turbine engine to prevent leakage of the cooling air whose main body and cross section are U-shaped that freely fits into a groove formed in the disk lug adjacent the rim of the disk on the aft side thereof. When rotating the center of the base of the U bears against the buttress of the platform of the blade and centrifugal force forces the sides of the U to deform to bear against the walls of the groove.

Turbine disk and blade assembly seal

The blade firtree bearing surface and/or the disk broached slot bearing surface is &ldquo;crowned&rdquo; to reduce the stresses at the edges thereof and more uniformly distribute the load. The width of the bearing surface is increased over the conventional flat bearing surface of the blade firtree and/or the bearing surfaces of the disk broach by judiciously moving the contact point to a discrete location.

Blade attachment configuration

A cavity judiciously dimensioned and located adjacent the tip's surface discharge port of internally cooling passage of the airfoil of the turbine blade of a gas turbine engine and extending from the pressure surface to the back wall of the discharge port guards against the contamination and plugging of the discharge port.

Tip seal and anti-contamination for turbine blades

Low angle air directing slots in the tip of an airfoil are produced by forming an elongated electrode by forming notches on opposite sides of the electrode and performing electric discharge machine with the electrode. During machining the electrode is oriented and fed at an acute angle with respect to the surface of the airfoil tip to form an opening, and then rotating the electrode to a position increasingly perpendicular to the surface of the airfoil tip.

EDM drilling of low angle holes

Spent cooling air from the internal passage(s) in a turbine blade of a gas turbine engine are judiciously located to inject air at the pressure side of the blade in proximity to or in the gap between the tip of the blade and outer air seal to reduce leakage in the gap and improve engine performance. In one embodiment, a projection at the tip of the blade on the pressure side is utilized in combination with an angled discharge passageway and in another embodiment a pair of discharge angled passages, one interconnecting an internal passage on the pressure side and the other connecting an internal passage on the suction side of the blade is utilized. A projection at the tip adjacent the pressure side may also be incorporated in the second embodiment.

Passive clearance system for turbine blades

Undersized cooling holes for air cooling a gas turbine component or the like, are formed at low cost, and are later enlarged to increase the flow rate of cooling air therethrough by blowing a mixture of abrasive grit through the holes to enlarge them. Air without the grit is thereafter passed through the holes and the resulting increased flow rate is measured to see if it is at a satisfactory level. If it is not, the process is repeated until the desired accurate flow rate is achieved.

Process for improving cooling hole flow control

The flow rate of the cooling air at the trailing edge of the airfoil of a turbine blade for a gas turbine engine is established by casting the blade to include judiciously located radially spaced projections adjacent to or in the ribs in the trailing edge which serve to meter the flow in the channels formed between the ribs. The holes for forming the projections in the core that are used to form the internal cooling passages in the trailing edge are intentionally undersized. After the core is cleaned and flashed, the blade is cast in a mold and the ceramic core is leached out. The internal cooling passages in the trailing edge are flow tested to obtain the flow rate and pressure and this data is used to resize the projection. Resizing the projection is made by reforming the core with the same die, and with the information previously obtained in the flow test, the holes that form the projections are enlarged by drilling to obtain the desired flow rate. This process is repeated until the desired flow rate for each trailing edge channel is achieved. The die may be changed at this juncture to provide the ultimate dimensioned hole in the core to provide the necessary metering of the cooling air to attain the predetermined flow rate.

Method of casting to control the cooling air flow rate of the airfoil

A method of selecting particular blades to be placed in particular slots involving an initial selection based on length and a final dedication based on weight.

Method for reducing blade tip variation of a bladed rotor

A cooled highly twisted airfoil (1) includes an integrally formed continuous warped wall (12) defined as a surface of revolution about an axis (13) with the axis determined such that the axis intersects the plane of a section along a desired centerline. Such an internal wall structure separates adjacent cooling cavities (10) and (11) and includes relatively precisely aligned impingement holes (14) for directing cooling air to the leading edge (6) of a highly twisted airfoil. Such a structure minimizes the complexity of the ceramic core and die inserts required to cast such an airfoil, thereby decreasing manufacturing costs while increasing the overall cooling efficiency of the blade.

Cooled highly twisted airfoil for a gas turbine engine

A plurality of circumferentially spaced apart oil scoops are designed to capture oil being slung from an inner shaft across an annulus to an outer shaft which rotates in a direction opposite to the inner shaft. The scoops rotate with and are a part of the outer shaft assembly. The scoops, in one embodiment, are defined by opposed spaced apart wall surfaces oriented substantially parallel to the relative velocity vector of the jets of oil as they travel outwardly from the inner shaft across the annulus. Splashing of the oil as it is picked up by the scoops is minimized by this invention.

Oil capture scoop

Concentric, counterrotating shafts include means for bringing oil from within the inner shaft across an annular gap between the two shafts into oil scoops which rotate with the outer shaft. To minimize the splashing of oil as it travels across the annular gap between the two shafts a plurality of separate, circumferentially spaced apart oil compartments are disposed around the outer circumference of the inner shaft and rotate therewith. Oil from within the inner shaft travels radially outwardly through passageways in the shaft into the oil compartments whereupon the radial velocity of the oil is reduced to zero. The oil leaves the compartment through outlets and is slung across the gap between the shafts whereupon it is captured by oil scoops and is fed to its final destination, such as to a bearing race disposed radially outwardly of the outer shaft. By reducing the radial velocity of the oil to zero after it is passed through the inner shaft and prior to its being slung across the annular gap between the shafts, the amount of splashing of the oil is reduced.

Means for feeding oil between counterrotating shafts

A thin ring fabricated from a relatively low thermal expansion material located between the engine case and the outer air seal segments and adjacent vane segments serves to seal the gap between the adjacent vane segments and outer air seal segments by virtue of deforming the ring caused by the expansion of the case.

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North Palm Beach, FL, United States of America

Robert J Kildea