Abstract: A blocker and swirl inducer hole configuration for use in connection with a high pressure turbine is described. In one embodiment, the blocker holes are oriented to a 45-degree tangential angle with respect to the direction of rotation of the seal, which results in pre-swirling the air before being injected into the swirl cavity. In addition, the number of blocker holes is reduced by as much as 50% of the number of blocker holes used in the known CFM56 turbine. Further, rather than injecting the air into the first swirl cavity as is known, the air is injected into a second swirl cavity. The combined effect of orienting the holes to the 45-degree tangential angle with respect to the direction of rotation of the seal, locating the holes to open into the second swirl cavity, and reducing the flow area by about 50%, results in an increase in blocker hole pressure ratio. Increasing the blocker hole pressure ratio results in a higher hole exit velocity which maximizes the cavity inlet swirl.

Abstract: A turbine rotor includes a rotor disk having a plurality of dovetail slots defining therebetween respective disk posts. Each post has a top land and a plurality of tangs spaced radially therebelow inside adjacent ones of the slots. A plurality of turbine blades each having a dovetail are mounted in respective ones of the dovetail slots for radially retaining the blades. A platform is joined integrally with the dovetail and extends circumferentially to adjoin adjacent ones of the platforms to define a radially inner flowpath. An airfoil extends integrally from the platform for extracting energy from combustion gases flowable thereover. A thermal barrier coating is fixedly bonded to each of the disk post top lands for providing thermal insulation between the platforms and the disk posts for reducing disk post temperature.

Abstract: A turbine cooling supply circuit for a gas turbine engine is disclosed in which the flow of coolant through the engine is directed to minimize temperature rise prior to discharge into the turbine. Bleed air from an impeller stage of a compressor is channeled along a backwall thereof into a cavity disposed radially inwardly of a combustor casing. The cavity is divided by a lightweight tubular member having a circumferentially uniform contour into a non-flow zone proximate the casing and a flow zone proximate a rotor. Maintenance of a high tangential flow component in the bleed flow in the flow zone facilitates discharge of the flow through apertures in a rotor into a bore portion thereof, minimizing work input and temperature rise of the coolant.

Abstract: Improved operation can be achieved from an enhanced gas turbine engine having a segmented annular shroud which radially expands and contracts to match the expansion and contraction of engine rotor blades. The segmented annular shroud is supported by a structure which includes an annular ring having two radially outwardly extending flanges, and forward and aft annular segmented brackets which attach the segmented shroud to the forward and aft side of the ring respectively. In a preferred embodiment of the invention, two circumferentially extending separate and distinct air impingement manifolds surrounds each of the outwardly extending flanges. Each manifold is provided with a valve for controlling the amount and temperature of the airflow entering each manifold. The air from each manifold then impinges upon each of the outwardly extending flanges, thereby controlling the radial movement of the corresponding shroud segments and the associated clearances with the rotor blade tips.

Abstract: The invention comprises the use of a thermal barrier coating on a member of a gas turbine engine component with one surface of the member exposed to high temperature but not exposed to high velocity gases, as an insulating material to slow the heat transfer to the substrate of the component member and allow thermal gradients within acceptable material limits between the thermal barrier coated member and the remainder of the component. In a particular application, the use of a thermal barrier coating enables making a high pressure turbine nozzle integral with a discourager seal lip, eliminating fasteners protruding into the rotor/stator cavity and split lines between segments of the prior art that allowed high temperature gas ingestion further into the cavity and caused windage losses.

Abstract: The present invention is a unique nozzle assembly for a high pressure turbine of a gas turbine engine. The nozzle assembly includes a series of circumferentially spaced vanes and a nozzle band. The nozzle band supports the vanes and includes a mounting flange extending radially from the nozzle band and adapted to be secured to the gas turbine engine. The nozzle band has an overhang portion axially downstream of the mounting flange. A pin fin bank is formed within the overhang portion for allowing cooling fluid to flow therethrough to cool the overhang portion.

Abstract: The clearances between an array of high pressure turbine blades and its surrounding high pressure turbine shroud as well as the clearances between an array of low pressure turbine blades and its associated low pressure turbine shroud are carefully controlled by a support structure which provides for evenly controlled circumferential cooling of the shroud support structure. Radial loads on the shroud support structure are reduced by counterbalancing loads imposed on the support structure by the shroud with predetermined pressure loads controlled and set through a series of cooling air cavities. The high pressure turbine shroud and low pressure turbine shroud are formed as integral segments in a segmented shroud design. Forward and aft shroud hanger members interconnect the shroud with its support so as to facilitate assembly and disassembly of the shroud segments to and from their support structure.

Abstract: An improved system provides cooling air to the turbine blades of a gas turbine engine. The improved system includes the combination of an inducer to receive pressurized cooling air from the compressor and then to direct this cooling air in a substantially tangential direction to a radial flow impeller which includes an air seal. Cooling air is directed to the turbine blades which are mounted on the rim of the rotating first turbine disk. In a preferred embodiment of the invention, a second portion of the cooling air from the inducer is conveyed through a deswirler to introduce the cooling air into a circumferential channel surrounding the rotor shaft. The cooling air is then directed to a second inducer means which is mounted on the higher pressure turbine disk. The cooling air is then directed to a second annular impeller mounted on the lower pressure turbine disk to convey this portion of cooling air to the lower pressure turbine rotor blades.

Abstract: An improved gas turbine engine is disclosed. The engine includes counterrotating first and second turbine rotors without an intervening nozzle. Disclosed also are means for obtaining pitch relative outlet velocity greater than pitch absolute inlet velocity for at least one of the rotors. In one embodiment, the reaction of at least one of the rotors is greater than a reference reaction effecting peak efficiency of the one turbine. Advantages include improved overall engine efficiency and decrease in weight, reduced cooling flow and complexity of the engine.

Abstract: Disclosed are a cooling air modulation apparatus for and method of operation for a gas turbine engine which are effective for increasing engine operating efficiency. According to one embodiment of the invention, the apparatus includes a first inducer means effective for channeling a first portion of cooling air to a rotor component during both first and second modes of operation of the engine. A second inducer means is also provided and is effective for channeling a second portion of the cooling air to the rotor component. Valve means are provided for selectively modulating the amount of cooling air flowing through the second inducer for preventing flow therethrough during the first mode of operation and for allowing unrestricted flow therethrough during the second mode of operation.

Abstract: A seal structure between first and second relatively moveable members for preventing gas flow in the space between the members and transverse to their general direction of motion is disclosed. The seal structure includes a plurality of substantially parallel strips within 30.degree. of normal to the radial plane generally containing these first and second relatively moveable members. The strips are thin and closely spaced and arranged so that one strip edge is attached to the first member and another edge is free to resiliently deflect when in rubbing contact with the second member.

Abstract: An air modulation apparatus, such as for use in modulating cooling air to the turbine section of a gas turbine engine. The apparatus includes valve means disposed around an annular conduit, such as a nozzle, in the engine cooling air circuit. The valve means, when in a closed position, blocks a portion of the conduit, and thus reduces the amount and increases the velocity of cooling air flowing through the nozzle. The apparatus also includes actuation means, which can operate in response to predetermined engine conditions, for enabling opening and closing of the valve means.

Abstract: A turbine shroud includes a ceramic sealing layer secured to a metal substrate. In one form, the metal substrate includes a plurality of pegs extending therefrom. Intermediate bonding layers are disposed on the peg-metal substrate structure. A ceramic sealing layer of zirconium oxide with about 20 weight percentage magnesium oxide is disposed, e.g., plasma sprayed, on the intermediate bonding layers. The ceramic sealing layer includes an ordered pattern of very fine cracks therein which reduce the thermal stress in the ceramic sealing layer. A method of constructing a turbine shroud structure is also disclosed.

Abstract: A gas turbine engine having a compressor and an air-cooled turbine is provided with a cooling system for decreasing the temperature of the turbine cooling air. A compact heat exchanger, rotatable with the compressor, receives a portion of the pressurized air which is bled from the compressor. Relatively cool engine lubrication oil is pumped through the heat exchanger into heat exchange relationship with the pressurized air, thereby cooling the air and heating the lubrication oil. The cooled air is then routed to and circulated through the turbine blades to provide improved internal cooling thereof. The heated lubrication oil is collected from the heat exchanger and routed to a second heat exchanger wherein it is placed in heat exchange relationship with engine fuel to recover the heat extracted from the compressor bleed air and to return the heat to the engine operating cycle. The cooling system is designed to contain the lubricant in the unlikely event of a leak developing in the heat exchanger.