Abstract: A turbine blade for use in a high temperature environment and with low cooling flow. The blade includes a dual serpentine flow cooling circuit with a 5-pass serpentine circuit located along the leading edge and the tip section of the blade. A 3-pass serpentine circuit is formed within the 5-pass serpentine circuit with a third leg located along the trailing edge of the blade. A showerhead arrangement of film cooling holes on the leading edge is supplied by the first leg of the 5-pass serpentine circuit. Tip cooling holes are connected to the 5-pass serpentine circuit at the tip turns. The fifth leg of the 5 pass serpentine circuit discharges cooling air through film cooling holes on the pressure side wall and through the tip section. The inner legs of each of the dual serpentine circuits do not discharge cooling air through rows of film holes in order to provide for the low cooling flow.

Abstract: A bearing lubrication system for a high temperature bearing, such as in a small gas turbine engine for a UAV, in which the bearing and lubricant requires a long shelf life, where the bearing includes a solid lubricant movable within a chamber formed within a housing and located adjacent to the bearing. The solid lubricant is biased by a spring toward the bearing and abuts against a runner that rotates along with the rotor shaft during engine operation. A cooling air passage opens into a space formed between the bearing and the solid lubricant to supply cooling air through the bearing. When the engine operates, heat is transferred through the runner to the solid lubricant to melt the lubricant. Rubbing of the runner against the biased solid lubricant will also melt the lubricant. The melting lubricant is carried by the cooling air through the bearing to provide both cooling and lubrication for the bearing.

Abstract: A turbine rotor blade with a 3-pass serpentine flow cooling channel having a first leg located at the leading edge of the airfoil and a third leg located adjacent to the trailing edge of the airfoil and connected to a row of exit slots, and in which a second leg includes three separate channels in parallel with inlet metering holes to regulate a cooling air flow and pressure in each separate channel. The blade includes a blade tip channel connected to the first leg of the serpentine and which supplies the cooling air to the second leg channels through the separate metering holes. Because the metering holes can be sized individually, the hottest part of the mid-chord region of the airfoil can be supplied with more cooling air flow and the pressure ratio across the trailing edge can be reduced so that the exit slots can be larger or more numerous.

Abstract: A turbine rotor blade with an airfoil cooling circuit and a platform cooling circuit formed integral with each other such that only one cooling flow is used. The airfoil cooling circuit includes a 5-pass aft flowing serpentine circuit with a first leg located adjacent to the leading edge region. The platform includes a mid section platform cooling circuit and an aft section platform cooling circuit. Cooling air from the second leg flows into the mid section platform cooling circuit and then into the third leg, turns at the blade tip and flows from the fourth leg into the aft section platform cooling circuit, and then into the fifth leg and up toward the blade tip. Cooling air from the fifth leg is bled off through rows of multiple impingement holes in the trailing edge and then discharged through exit holes or slots formed along the trailing edge.

Abstract: A turbine blade with a squealer tip having a cooling circuit formed from a number of rows of multiple impingement cavities that extend across the blade tip from the pressure side wall to the suction side wall. One of the impingement cavities (main impingement cavity) in each row is connected to a cooling pressure supply channel through a main metering and impingement hole. The remaining impingement cavities in the row is either a pressure side impingement cavity or a suction side impingement cavity, and each are connected to the main impingement cavity through secondary metering and impingement holes. The impingement cavities located on the ends and adjacent to the side walls of the blade tip are connected top film cooling holes.

Abstract: A turbine blade with a single tip rail extending along the mid-chord section of the blade tip from the trailing edge and around the leading edge region offset from the leading edge wall and ending just before the pressure side wall of the airfoil. The tip rail includes a forward side with a concave shaped cross section to form a vortex flow of cooling air on the side of the tip rail. A row of cooling holes discharge cooling air into the vortex flow formed along the concave forward side of the tip rail the tip rail also includes an aft side that is slanted downward to also form a vortex flow. The pressure side wall of the airfoil includes a concave shaped slot extending along the pressure side wall just below the tip corner, and a row of cooling holes to discharge film cooling air upward toward the tip corner.

Abstract: A turbine rotor blade made from the spar and shell construction in which the shell formed from a plurality of shell segments each being a thin wall shell segment made from a high temperature resistant material that is formed by a wire EDM process, and where the shell segments are each secured to the spar separately using a retainer that is poured into retainer occupying spaces formed in the shell segments and the spar, and then hardened to form a rigid retainer to secure each shell segment to the spar individually. The spar includes a number of radial extending projections each with a row of cavities that form the retainer occupying spaces in order to spread the loads around. The retainer can be a bicast material, a transient liquid phase bonding material, or a sintered metal. An old shell can be easily removed and replaced with a new shell by removing parts of the retainer and re-pouring a new retainer with a new shell in place.

Abstract: A split ring wedge bearing friction damper for an aero engine that allows the engine to operate without an oil tank, a pump, and a lubricant cooler, the friction damper having a damper ring and a wedge ring that both have wedge surfaces in contact so that an axial load can be applied to the bearing outer race to provide damping to the bearing, and so that the damper ring can also have a radial displacement to produce a radial load on the damper ring against the stator bearing support surface in which the axial load provides the friction damping and the radial load eliminates lost motion for maximum damping.

Abstract: An turbine airfoil and a process for near wall cooling of a turbine airflow with low flow in which the airfoil is formed by a main spar that forms the support structure for the airfoil and forms a series of cooling air collecting chambers extending from the leading edge region to the trailing edge region of the airfoil. A thermal skin forms an outer airfoil surface and also forms a series of pressure side and suction side impingement chambers along the airfoil walls. A cooling air supply chamber is formed by the spar in the leading edge region and supplies the cooling air for the airfoil. A series of leading edge impingement chambers are formed along the leading edge and carry the cooling air from the supply chamber to the series of collection chambers and impingement chambers downstream. The spent cooling air is then collected in a trailing edge collecting chamber and discharged through a row of exit holes.

Abstract: A turbine rotor blade and stator vane assembly in which the rotor blades include a cooling air discharge slot formed within the blade platform to discharge cooling air toward a surface of the adjacent vane to prevent formation of a vortex flow over the region of the vane where the vane airfoil and the inner endwall merges around the fillet. The rotor blade includes a row of exit holes to discharge cooling air from an impingement cavity to provide cooling for the trailing edge. The platform injection cooling air ejection slot is connected to the impingement cavity and provides cooling for the platform and injection of cooling air to break down the formation of the vortex on the vane endwall region.

Abstract: A turbine rotor blade with a leading edge region cooled by a series of impingement cooling cavities that repeats from near the platform to the blade tip to provide impingement cooling for the leading edge without a loss of cooling air flow volume. A cooling supply cavity delivers cooling air to a series of impingement cavities located on the pressure side, the leading edge and the suction side of the airfoil in a series flow. The spent cooling air from the series then flows up into the next series of impingement cavities to provide impingement cooling to the next section of the leading edge. The cooling air flows through multiple series of impingement cooling cavities until the blade tip, which then discharges the spent impingement cooling air through tip cooling holes.

Abstract: A turbine airfoil with a relatively thick TBC applied over the airfoil surface. The airfoil has a surface contour on the trailing edge region with a forward end having a large amount of taper and a rearward end with less taper such that a substantially constant wall thickness is formed in the rearward end. The TBC is applied over the airfoil surface and tapers off at the trailing edge ends on the pressure side and the suction side walls to produce an ideal surface contour on the airfoil. In another embodiment, the airfoil surface includes a tapered section at the trailing edge region, and the TBC is applied over the taper so that an over-coating is formed. The TBC over-coating is then removed and a smooth and ideal surface contour is produced along the airfoil surface. Small raised bumps each having a height of the desired thickness of the TBC to be applied over the respective bump is used to control the finished thickness of the TBC.

Abstract: A turbine airfoil such as a turbine stator vane used in an industrial gas turbine engine, the vane including a trailing edge region having a thin wall cooling channel arrangement of mini cooling channels formed by a series of rows of elongated flow blockers that form the mini cooling channels between adjacent flow blockers. The adjacent row of flow blockers are offset from the each other such that the inlet and the outlet flow of cooling air is discharged directly onto the flow blocker in order to produce impingement cooling. The mini cooling channels have a spacing to hydraulic diameter ratio of less than 4.0 and a mini channel length to hydraulic diameter ratio of 5.0 of less in order to maintain a high flow velocity within the mini channels. In one embodiment, the flow blockers have a progressively decreasing length in the flow direction of the cooling air.

Abstract: A film cooling hole for a turbine airfoil. the first embodiment is a film cooling hole aligned with the stream-wise direction of the hot gas flow over the hole and includes a metering section followed by a diffuser section. The diffuser section includes a left side wall and a right side wall both having a curvature facing outward and at about the same radius of curvature. The diffuser section also includes a top side wall and a bottom side wall which both have a curvature in the stream-wise direction, and in which the radius of curvature of the top side wall is greater than the radius of curvature of the bottom side wall. A second embodiment is a film cooling hole offset from the stream-wise direction of flow and includes the four walls with a curvature, but in which the left side wall has a greater radius of curvature than the right side wall due to the stream-wise offset of the hole.

Abstract: A turbine blade for use in a gas turbine engine having an internal serpentine flow cooling circuit with pin fins and trip strips to promote heat transfer for obtaining a thermally balanced blade sectional temperature distribution. The serpentine flow cooling circuit forms a 7-pass serpentine flow circuit from the leading edge, along the pressure side, through the trailing edge region, and then along the suction side. The serpentine flow circuit of the present invention is formed by a printing process without the need for a ceramic core and casting, and where the pin fins for all of the channels can be aligned perpendicular to the airfoil surface. The metallic and ceramic printing process can be used to form a single piece airfoil with all of the internal cooling passages and features as a single piece.

Abstract: A gas turbine engine with a floating air seal to form a seal between a rotor disk and an adjacent stator vane segment shroud and allow for both axial and radial shifting of the rotor disk with respect to the stator while maintaining the sealing capability. The floating air seal includes an annular piston that slides within an annular groove formed within the stator in an axial direction. The annular piston includes an annular groove on the rotor disk side to form an air cushion against the rotor disk, a pressure buffer surface on the opposite end, and a central passage to supply the air cushion chamber with pressurized fluid from the buffer pressure chamber. A balancing force on the annular piston is formed between the air cushion formed and the pressure force acting to push the annular piston toward the rotor surface.

Abstract: A turbine rotor blade with a single tip rail on the suction side of the blade tip, and in which the pressure side tip edge includes a row of trench film slots that each having side walls that are open on the pressure side wall and extend onto the tip floor and have side walls with a curvature toward the trailing edge of the blade tip. The trench film slots also have a curved inboard surface and a curved outboard surface in which the inboard surface curvature is less than the outboard surface curvature. The tip rail includes a slot opening onto the top surface and extending the length of the tip rail with a row of metering and cooling holes opening into the slot. The metering and cooling holes have a curvature toward the pressure side edge of the tip floor to increase a heat transfer rate form the metal.

Abstract: An apparatus and a process for determining the mass required for a wire damper ring to produce the maximum amount of damping in a certain rotary machine. The testing apparatus includes a test piece with an inward facing annular groove and a plurality of expander segments each with the top or outer half of a wire damper ring segment secured to and extending outward to fit within the annular groove. A mandrel with an outer surface having a slight slope is passed through a central opening of the expander segments and displaces the ring segments radially outward and into the annular groove at varying loads. The apparatus is set to vibrating and a piece of the test piece is observed for vibrations. The load applied to the damper ring segments is varied until the vibration is at a minimum. The applied load can now be correlated with the mass required for the damper ring to produce similar damping capability.

Abstract: A turbine blade with a pressure side wall having a plurality of radial extending near wall cooling channels to provide near wall cooling, where each radial channel includes a converging channel with an opening that discharges cooling air out from the blade tip in a direction offset toward an on-coming hot gas flow to reduce leakage. A plurality of radial cooling channels extends along the pressure side wall and a concave shaped depression formed in the pressure side wall adjacent to the radial channels provides a deflecting surface for the flow on the pressure side wall surface. If the blade tip forms a squealer pocket, then the suction side tip rail can also include radial extending channels with converging channels formed within the tip rail to discharge cooling air toward the leakage at the suction side tip rail.

Abstract: A turbine rotor blade with a series of 3-pass serpentine flow near wall cooling circuits that extend along the airfoil to provide low flow cooling for the blade. the 3-pass serpentine circuits include a first channel positioned along the pressure side wall to provide near wall cooling, a third channel positioned along the suction side wall to provide near wall cooling, and a second or middle channel located between the two near wall channels in the cooler section of the airfoil. The two near wall radial extending cooling channels flow in a direction toward the blade tip so that the centrifugal force developed due to blade rotation will aid in driving the flow while the second channel is without trip strips and has a larger flow area to minimize flow loss. The first channel with cooler air provides near wall cooling to the hotter sections of the airfoil while the third channel uses the heated air to provide cooling to the cooler sections of the airfoil.