Abstract: Thermal energy delivery and oil production arrangements and methods thereof are disclosed which heat a subterranean formation (132), and which comprises positioning concentric tubing strings (220) in a wellbore (130); heating a heat transfer fluid (250) using a surface thermal fluid heater (186); flowing a liquid or feedwater (142) downward through an extremely hot innermost tubing string (248) that is inside and concentric to an outermost tubing string (252) and a casing/annulus (260), which extends below a thermal packer (156) positioned in the wellbore, and continually circulating the heat transfer fluid through the outermost tubing string and the casing/annulus above the thermal packer such that the liquid or feedwater flowing through the innermost tubing string is heated thereby and injected into the wellbore below the thermal packer and out of perforations to heat the subterranean formation to temperatures that allow for hydrocarbon production from the subterranean formation.

Abstract: Methods and systems for removing near wellbore damage in a hydrocarbon reservoir are described. In one example implementation, an antenna is positioned inside a wellbore in a location corresponding to a formation where near wellbore damage occurs. The wellbore extends from a surface of a hydrocarbon reservoir downward into the subterranean structure of the hydrocarbon reservoir. An electromagnetic (EM) wave is transmitted to the antenna. A portion of the EM wave is irradiated at the formation. The portion of the EM wave removes the near wellbore damage at the formation.

Abstract: Embodiments of a sleeve assembly, used for stimulating multiple stages in a completion string has a lower shifting sleeve and an upper shifting sleeve and stimulation ports formed therebetween. The sleeves are caused to shift by progressively larger objects pumped through a bore of the completion string and engaging seats formed thereon. The seat on the lower sleeve is a releasable seat. When shifted the lower sleeve opens the stimulation ports. The seat on the upper sleeve is sized to accept the same size object as is required to engage and shift the lower sleeve on the stage uphole therefrom to close the ports. Thereby, stimulation ports are opened and closed without increasing a number of objects required to stimulate the wellbore. Further, as the ports at each stage below the stage being stimulated are closed, the objects are not required to isolate the bore therebelow.

Abstract: A system including a rotary isobaric pressure exchanger configured to exchange pressures between a first fluid and a second fluid, and a lubrication system configured to lubricate the rotary isobaric pressure exchanger. The pump may pump a third fluid into the rotary isobaric pressure exchanger to lubricate the rotary isobaric pressure exchanger.

Abstract: A method for optimizing well spacing for a multi-well pad which includes a first group of wells and a second group of wells is provided. The method includes the steps of: creating a fracture in a stage in a first well in the first group of wells; isolating a next stage in said first well in the first group of wells from said stage; creating a fracture in said next stage in the first well in the first group after the step of isolating; measuring a pressure by using a pressure gauge in direct fluid communication with said next stage in the first well in the first group of wells; creating a fracture in one or more stages in a well in the second group of wells in a manner such that the fracture in the well in the second group of wells induces the pressure measured in the first well to change; and recording the pressure change in the next stage of the first well.

Abstract: There is provided apparatuses, and related systems, for effecting production of oil from a reservoir. A flow diverter is provided and configured to direct flow of reservoir fluids such that gases and solids are separated. A system is also provided, including the flow diverter, and is disposed within a wellbore. A pump is also provided, and disposed in fluid communication with, and downstream from, the flow diverter, for receiving reservoir fluids from which gaseous and solid material have been separated by the separator.

Abstract: A drilling apparatus including plurality of subsystems, each subsystem includes a subsystem controller, one or more sensors, and one or more actuators. Each subsystem controller is configured to determine a local subsystem state from measurements received from the one or more sensors and further configured to receive global state estimates and updated control strategies. Each subsystem controller is configured to send command signals to one or more actuators based at least in part on the local subsystem state, global state estimates, and updated control strategy. A method and system for coordinating the control of a plurality of drilling subsystems during drilling operations is provided. A method of drilling subsystem controller decision-making based on a co-player inference playing strategy is further provided.

Abstract: A cable protector can include a first side bar welded along a length of a casing section. A second side bar can be welded along the length of the casing section. The second side bar can be positioned substantially parallel to the first side bar. A cable can be positioned between the first side bar and the second side bar. The cable can be positioned while the casing section is being run-in-hole. A cover strip can be welded on top of first side bar and the second side bar. The cover strip can be welded in place while the casing section is being run-in-hole.

Abstract: A surface excitation ranging method includes selecting a first well with a metal casing as a target well and selecting a second well with a metal casing as a ground well. The method also includes installing a supplemental grounding arrangement for a power supply located at earth's surface, wherein the ground well and the supplemental grounding arrangement fulfill an impedance criteria or ranging performance criteria. The method also includes conveying an electrical current output from the power supply along the target well. The method also includes sensing electromagnetic (EM) fields emitted from the target well due to the electrical current. The method also includes using distance or direction information obtained from the sensed EM fields to guide drilling of a new well relative to the target well.

Abstract: A technique includes inducing a distributed temperature change along a portion of a wellbore and measuring a time varying temperature along the portion of the wellbore due to the induced change. The technique includes determining a distributed flow rate in the portion based at least in part on the measured time varying temperature before the temperature reaches equilibrium.

Abstract: A system for more accurate mechanical integrity testing of a borehole and cavity has a mechanical integrity testing tool suspended by a wireline from surface to a test depth. Distributed temperature and acoustic sensing systems respectively record distributed temperature and noise measurements along the wireline. First and second pressure sensors measure uphole and downhole pressures. The mechanical integrity testing tool has an interface detection device, which can have an Iridium-192 gamma ray source having a shorter half-life relative to conventional sources. The interface level, distributed temperature measurements, and uphole and downhole pressure measurements can be used to calculate the volume and/or mass of test fluid that has leaked out of the borehole and/or cavity over the test period. The acoustic sensing system can be used to detect and confirm the presence of a leak. The temperature and/or acoustic sensing systems can be used to identify the location of the leak.

Abstract: A method of estimating an influx profile for at least one well fluid to a producing petroleum well with two or more influx zones or influx locations to a production flow, wherein the well comprises tracer sources with distinct tracer materials in known levels of the well, at least one of said tracer sources arranged downstream and exposed to the fluids in at least one of said influx zones, wherein each said tracer source has an even release rate to said well fluid, characterised in that one or more of the tracer sources is provided in one or more delay chambers for ventilating out fluid with leaked tracer material at a time constant which is significantly longer than the diffusion rate from the tracer source to the well fluid, wherein the method further comprises: providing samples, the samples collected from the production flow at a location downstream of the tracer sources during a time period in which the tracer transient is detectable at the downstream location, analysing said samples for concentration an

Abstract: A downhole system (10, 110, 210) includes a tubular (18) having a longitudinal axis (32), and a trace (46) applied on the tubular (18). The trace (46) includes a conductive portion (60) formed from an electrically conductive material (58) and the trace (46) is configured to deliver a signal between uphole and downhole locations of the tubular (18).

Abstract: Systems and methods are presented for reducing electrical interference in measurement-while-drilling (“MWD”) data. An example may include, among other features a MWD data acquisition system including an analog data reception for receiving analog MWD data, an analog-to-digital conversion circuit, at least one isolation circuit for electrically isolating the analog data reception circuit and the analog-to-digital conversion circuit from a digital data transmission circuit. In some implementations, the data reception device may be at least partially powered by the battery.

Abstract: A downhole acoustic transmitter has a piezoelectric transducer, an enclosure in which the piezoelectric transducer is housed, a transducer preload means which applies a selected compressive force against the transducer such that a mechanical preload is applied to the 5 transducer, and an acoustic tuning element which has a first end coupled to the transducer preload means or the transducer, and an open second end. The acoustic tuning element is not coupled to anything but the transducer preload means or transducer, so the transducer preload means effectively has a second open end and thus can maintain the same preload compressive force on the transducer even when the transmitter is subjected to tension and 10 compressive forces during operation.

Abstract: A rotary pulser for transmitting information in a mud pulse telemetry system of a drilling operation. The pulser has two rotors mounted adjacent each other so that obstruction of the passages formed between the blades in one pulser by the blades of the other pulser creates pressure pulses in the drilling fluid. Each rotor is separately controlled and can be rotated continuously in one direction or oscillated. The ability to rotate each rotor separately provides flexibility in the pulser's operating mode, so as to allow more efficient generation of pulses, and also enhances the ability of the pulser to clear debris that would otherwise jam or obstruct the pulser.

Abstract: Methods and systems for characterizing a wellbore depth interval from rock fragments, including a method that includes converting measurements of a bulk rock fragment sample and of individual rock fragment samples to a concentration percent, computing a normalization deviation for each of the individual rock fragment samples relative to the bulk rock fragment sample (said normalization deviation being derived from the concentration percent of the bulk and individual rock fragment samples) and ranking the individual rock fragment samples based on a corresponding normalization deviation. The method further includes selecting one or more individual rock fragment samples based on a corresponding ranking, characterizing the properties of the wellbore depth interval from which the bulk and individual rock fragment samples originated using measured properties of at least some of the selected individual rock fragment samples and presenting to a user the characterized wellbore depth interval.

Abstract: Tubular stretch correction for different operational conditions is applied to determine tubular wear volume. The tubular stretch correction is applied as a function of a stretch factor comprising a varying shift factor, axial load on the tubular string, pressure effects on the tubular string, buckling of the tubular string and/or temperature effects on the tubular string. Stretch factors are taken into account to determine the correct position of wear factors along the casing string, which are ultimately used to determine the casing wear volume.

Abstract: Apparatus, computer readable medium, and program code for identifying rock properties in real-time during drilling, are provided. An example of an embodiment of such an apparatus includes a downhole sensor subassembly connected between a drill bit and a drill string, acoustic sensors operably coupled to a downhole data interface, and a surface computer operably coupled to the downhole data interface.

Abstract: A technique facilitates obtaining samples of well fluid or other fluid. A sampling tool comprises a sample chamber for collecting the fluid sample. Access to the sample chamber is controlled with a rod shiftable within the sampling tool. Additionally, a locking mechanism works in cooperation with the rod to lock the rod against undesirable movement at various stages of the sampling operation. The locking mechanism may comprise a pair of locking features which engage a groove in the rod to initially block inadvertent closure of access to the sample chamber and subsequently to block inadvertent opening of access to the sample chamber after collection of the fluid sample.

Abstract: A rock bolt system includes a fitting including a main body defining a central opening configured to receive a rock bolt and a grout body defining a space between the main body and the grout body, with the main body defining a grout opening in fluid communication with the central opening. The main body is rotatable relative to the grout body, with the grout body defining a resin port and a catalyst port. The resin port and the catalyst port are in fluid communication with the space and the grout opening of the main body. The system further includes a rock bolt defining a central opening, with the central opening of the rock bolt configured to be in fluid communication with the central opening of the fitting when the rock bolt is secured to the fitting.

Abstract: Rock anchors, inflation chucks, and inflation systems such as those described herein, allow for substantially complete draining of fluids from interior volumes of the rock anchors. In various situations, corrosive fluids may be introduced to the rock anchor, including inflating the rock anchors and during normal use, such as by groundwater intrusion. The inflation chucks described herein include multiple inflation paths for more effectively introducing and draining fluid from rock anchors during inflation processes and during general use.

Abstract: An impeller-type liquid ring compressor having a particular bearing configuration. Such a bearing arrangement may completely support the impeller as it rotates, eliminating many of the problems inherent in the prior art designs without changing the general overhung impeller design. This may allow the impeller-type liquid ring compressor to be easily retrofitted in existing use environments, such as, for example, oil and gas processing facilities, oil refineries, and petrochemical processing facilities. In some exemplary embodiments, a thrust bearing may be located on the front face of the impeller, or radial bearings may be disposed between the vanes of the impeller. A radial bearing and thrust bearing may further be disposed on the shaft side of the impeller close to the impeller itself. The compressor may be configured so that the process fluid carries heat away from each of these bearings.

Abstract: An electrodeposited nickel-chromium-aluminum (Ni—Cr—Al) composite including nickel-chromium alloy and aluminum, and alloys or compounds formed by Al, Cr and Ni applied on turbine components comprises from 2 to 50 wt % chromium, from 0.1 to 6 wt % aluminum, and a remaining balance of nickel, wherein the Ni—Cr—Al composite is heat-treated to form an aluminum compound and to restore materials lost during repair processes of the turbine components.

Abstract: A gas turbine includes: a first cavity inside a stationary body and supplied with cooling air; a second cavity between the stationary body and a rotating body; a first cooling passage between the first and second cavities and having a swirl flow guide nozzle therein by which the cooling air of the first cavity is supplied to the second cavity while being swirled along a rotation direction of the rotating body; a second cooling passage in the rotating body, in communication with the second cavity, and supplied with the cooling air of the second cavity; and a flow regulating passage, different from the first cooling passage, between the first cavity and the second cavity and through which the cooling air is supplied from the first cavity to the second cavity, wherein the flow regulating passage has a flow regulator for regulating a flow rate of the cooling air.

Abstract: A system is provided, including an airfoil. The airfoil includes a first suction portion of a nominal airfoil profile substantially in accordance with Cartesian coordinate values of X, Y, and Z of a suction side as set forth in TABLE I to a maximum of three decimal places, wherein the X and Y values of the suction side are coordinate values that couple together to define suction side sections of the first suction portion of the nominal airfoil profile at each Z coordinate value, the suction side sections of the first suction portion of the nominal airfoil profile are coupled together to define the first suction portion, the airfoil includes an airfoil length along a Z axis, the first suction portion comprises a first portion length along the Z axis, the first portion length is less than or equal to the airfoil length, and the Cartesian coordinate values of X, Y, and Z are non-dimensional values convertible to dimensional distances.

Abstract: An impeller comprises a hub and blades extending therefrom. The blades include splitter blades interspersed between full blades. First flow channels are defined between pressure sides of the splitter blades and suction sides of the full blades. Second flow channels are defined between suction sides of the splitter blades and pressure sides of the full blades. A width of the first flow channels at leading edges of the splitter blades and at the hub is less than a width of the second flow channels at the leading edges of the splitter blades and at the hub. The width of the first flow channels at the leading edges of the splitter blades and at the tips is more than the width of the second flow channels at the leading edges of the splitter blades and at the tips.

Abstract: The invention relates to a radially compressible and expandable rotor (13, 13a, 13b) for a pump having at least one impeller blade (20, 22, 36, 36a, 36b, 36c, 36d, 36e, 36f, 36g, 37, 37a, 37b, 37c, 37d, 37e, 37f, 74, 88, 89, 90), wherein the impeller blade has an impeller blade body whose material is elastically deformable as well as at least one stiffening strut (25, 26, 27, 30, 31, 32, 52, 53, 57, 58, 62, 63, 67, 95) which is at least partially embedded in the material of the impeller blade body. The struts are designed suitably in size, shape and arrangement and are integrated in suitable hollow spaces of the impeller blade body for stabilizing the impeller blade. Elements with tensile strength can additionally be provided.

Abstract: A turbomachine airfoil element includes an airfoil that has pressure and suction sides spaced apart from one another in a thickness direction and joined to one another at leading and trailing edges. The airfoil extends in a radial direction a span that is in a range of 0.75-0.85 inch (19.1-21.6 mm). A chord length extends in a chordwise direction from the leading edge to the trailing edge at 50% span and is in a range of 0.56-0.66 inch (14.2-16.8 mm). The airfoil element includes at least two of a first mode with a frequency of 2740±10% Hz, a second mode with a frequency of 5956±10% Hz, a third mode with a frequency of 6554±10% Hz and a fourth mode with a frequency of 31959±10% Hz.

Abstract: A method for producing turbine rotor blades or the base bodies thereof includes a) providing the base body, which has, following one another along a longitudinal axis, a blade root, a blade platform and a blade airfoil, b) sensing a value of at least one parameter of the base body, at least one of the parameters representing a vibrational property of the base body, c) comparing the sensed value with a predetermined target interval, d) if the sensed value lies outside the target interval, reducing the mass of the base body, wherein the reduction of the mass takes place at the blade root and/or on the blade platform by introducing at least one recess and/or by reducing a dimension below the corresponding target value.

Abstract: A blade for a gas turbine is described, the blade comprising a trailing edge and a trailing edge cooling channel extending from a first upstream end to a second downstream end, in which the width of the trailing edge cooling channel in the direction perpendicular to the camber line of the blade varies and the narrowest width in the trailing edge cooling channel is at the first upstream end, so as to provide a blade where the trailing edge can be removed with a minimal change or no change in the cooling flow capacity through the trailing edge cooling channel. Related methods are also described.

Abstract: A turbine stator vane or turbine rotor vane has a body, a channel being adapted for leading a cooling fluid through the body, and a flow adaption feature protruding from the body to the channel in such a manner as to reduce a cross-sectional area of the channel.

Abstract: A turbine blade for a gas turbine employs film cooling to enhance cooling performance. The turbine blade includes an outer surface; and at least one film cooling hole formed in the outer surface, each film cooling hole including a cooling channel extending inside the turbine blade to guide cooling air toward the outer surface, an outlet communicating with one end of the cooling channel to discharge cooling air to the outer surface, and a plurality of protrusions formed on an inside surface of the outlet and arranged along a longitudinal direction of the outlet. The protrusions protrude inwardly to a predetermined height from the inside surface of the outlet and extend from the cooling channel to the outer surface, in an arrangement of at least one protrusion formed on an inside wall of the outlet or on each of two opposing inside walls of the outlet.

Abstract: An airfoil may comprise an airfoil body having a leading edge, a trailing edge, an inner diameter end wall and an outer diameter end wall. A first cooling structure may be disposed within the airfoil body. The first cooling structure may comprise a first rib extending between the inner diameter end wall and the outer diameter end wall and may define a first radial passage configured to conduct a cooling airflow in a radial direction through the airfoil body. A second cooling structure may be disposed within the airfoil body. The second cooling structure may comprise a first baffle defining an axial passage configured to conduct the cooling airflow in an axial direction toward the trailing edge of the airfoil body.

Abstract: An airfoil includes a leading edge and an opposing trailing edge. The airfoil includes a pressure sidewall and an opposing suction sidewall. A leading edge cavity is defined between the pressure sidewall and the suction sidewall. The leading edge cavity has a first end opposite the leading edge and a second end defined at a rib. The airfoil includes at least one pin structure defined in the leading edge cavity between the first end and the second end. The at least one pin structure includes a main body and a first branch. The main body is coupled to the second end and extends toward the first end. The first branch extends from the main body toward the first end.

Abstract: A blade for a turbomachine bladed wheel having N blades. At one end, the blade presents a platform that is formed integrally with an airfoil of the blade. Over a portion of the axial extent of the blade, a section through the platform wall on a plane perpendicular to the axis (X) of the wheel is constituted mainly by two first straight line segments arranged respectively on the two sides of the airfoil. Each of these segments forms an angle of 90°-180°/N relative to the radial direction on either side of the airfoil.

Abstract: An unshrouded turbomachine impeller is disclosed. The impeller comprises a hub and a plurality of sequentially arranged blades. Each blade extends from a blade root at the hub to a blade tip and is comprised of a first blade edge and a second blade edge. A flow vane is formed between each pair of neighboring blades. A connection member extends across each flow vane between neighboring blades and rigidly or monolithically connects a first modal displacement region of a first one of the pair of neighboring blades to a second modal displacement region of a second one of the pair of neighboring blades.

Abstract: Method and apparatus are provided for electroplating a surface area of an internal wall defining a cooling cavity present in a gas turbine engine component.

Abstract: An aerofoil structure (26) for a gas turbine engine (10), the aerofoil structure comprising a carbon composite aerofoil portion (38) and a tip portion (48), wherein the tip portion comprises a tip surface (60) configured to face a corresponding casing structure (30), the tip portion further comprising a ridge line (62) extending along at least a portion of the tip surface, wherein the tip surface comprises a first surface (64) and a second surface (66) provided either side of the ridge line, the ridge line being defined by the intersection of the first and second surfaces, wherein the ridge line is configured to cut into the casing structure during an interaction between the aerofoil structure and casing structure.

Abstract: A nickel-chromium (Ni—Cr) alloy and a method for electrodepositing the Ni—Cr alloy on a turbine engine component for dimensionally restoring the engine component are described. The engine component is restored by re-building wall thickness with the Ni—Cr alloy including from 2 to 50 wt % chromium balanced with nickel. The turbine component coated with the Ni—Cr alloy is heat-treated at a high temperature to homogenize composition of the alloy to mimic the base alloy and to restore materials lost during repair of the turbine component.

Abstract: Fixing set for securely assembling and locking a blade shaped element, for instance a turbine blade, on a support, for instance a turbine rotor. The blade shaped element is adapted to be inserted into a groove of the external surface of the support and the fixing set includes first, second and third locking elements adapted to be inserted into the groove, between the lower end surface of the root portion of the blade shaped element and the groove base surface. The first, second and third locking elements are adapted to securely lock the blade shaped element on the support and are further adapted to allow easy and simple installation by an operator with no need of additional working and extra machining.

Abstract: Aerial vehicles may be equipped with propellers having pivotable blades that are configured to rotate or fold when the propellers are not rotating under power. A pivotable blade may rotate about an axis of a propeller with respect to a hub in the presence of wind flow until the pivotable blade is coaligned with a fixed blade, in a direction opposite to the wind flow. A pivotable blade may also fold over a hub of a propeller in the presence of wind flow, with the pivotable blade and a fixed blade being oriented in directions opposite to the wind flow. A center of mass of the pivotable blade may be caused to be on the same side of an axis as a center of mass of a fixed blade, even where the axis is not normal to the wind flow, thereby reducing an amount of drag generated by the propeller.

Abstract: A mid-turbine frame (MTF”) for a jet engine is disclosed and comprises a duct that extends between a high pressure turbine (“HPT”) and a low pressure turbine (“LPT”), the duct comprising a plurality of segments that together form an outer annular structure and an inner annular structure, the inner annular structure situated radially inward of the outer annular structure, and/or a plurality of vanes that extend radially outward from the inner annular structure toward the outer annular structure, each vane comprising a channel. Each segment may be coupled to an adjacent segment by a seal.

Abstract: When cold and in the non-coated state, the aerodynamic profile is substantially identical to a nominal profile determined by the Cartesian coordinates X,Y, Zadim given in Table 1, in which the coordinate Zadim is the quotient D/H where D is the distance of the point under consideration from a first reference plane P0 situated at the base of the nominal profile, and H is the height of said profile measured from the first reference plane to a second reference plane P1. The measurements D and H are taken radially relative to the axis of the turbine, while the X coordinate is measured in the axial direction of the turbine.

Abstract: The invention relates to an intermediate case for a twin spool turbomachine for an aircraft, comprising at least one lubricant passage and piece (88a) associated with at least one of its vanes (24), comprising a lubricant passage (98a) extending along a passage axis (134a) and opening up into the lubricant duct (55a). The passage axis (134a) and the orifice axis (140a) are also at a spacing from each other along a circumferential direction (91), and a connection piece (125a) through which a connection conduit (142a) passes is firstly partially housed in the vane root (34) so as to create a communication between the connection duct (142a) and the lubricant passage orifice (124a), and secondly is partially housed in an end-piece support device (108a) or in the lubricant passage end-piece (88a), such that the connection conduit (142a) communicates with the lubricant passage (98a) in the end-piece.

Abstract: An insulated seal seat assembly comprises a shaft configured and arranged to rotate about an axial axis, a seal seat that is secured to the shaft, and a thermal insulator configured and arranged radially between the shaft and the seal seat.

Abstract: Flow discouragers, flow path assemblies, and methods for assembling flow path assemblies are provided. For example, a discourager for discouraging fluid flow between adjacent first and second components comprises a first contact surface in contact with the first component; a second contact surface in contact with the second component; and a body connecting the first and second contact surfaces that includes a pocket for receipt of a retention member and a plurality of apertures defined therethrough between the first and second contact surfaces. An exemplary flow path assembly comprises adjacent first and second components and a flow discourager that includes first and second contact surfaces in contact with the first and second components, respectively. The first and second contact surfaces each have a three-dimensional geometric shape to maintain contact with the first and second components. Each discourager may be formed from a ceramic matrix composite material.

Abstract: This disclosure provides a cross key anti rotation spacer for use in a gas turbine engine. A compressor disk assembly can have a cross key ring having a plurality of keys, teeth, or castellations, alternating with a plurality of gaps to form a cross key surface. The keys or teeth of the cross key surface can mesh with corresponding teeth formed on a spacer of a compressor rotor assembly. The spacer teeth, in connection with the teeth or keys of the cross key ring can prevent rotation between the spacer and compressor disk. This is particularly beneficial during transient operations, such as startup and shutdown of the gas turbine engine.

Abstract: There is provided a seal structure to suppress a leak flow of a working fluid from a gap between a rotating structure and a stationary structure, the rotating structure being configured to rotate in a prescribed direction about an axial center line, the stationary structure facing an outer periphery of the rotating structure in a radial direction with the gap inbetween, wherein the stationary structure has a cavity in which the rotating structure is accommodated, an inner peripheral surface of the cavity is provided with a seal fin that extends toward the axial center line and a plurality of stationary-side recesses arranged along a flow direction of the leak flow, and as compared with a first stationary-side recess disposed on a most upstream side, a second stationary-side recess disposed on an immediately downstream side of the first stationary-side recess is set to have a smaller depth dimension.

Abstract: A gas turbine engine includes a coupling and an air seal attachment. The annular coupling extends along a centerline and has coupling teeth that extend axially rearward. The annular air seal attachment includes an air seal at an axially rearward end and air seal attachment teeth at an axially forward end that extend axially forward to interlock with the coupling teeth such that the air seal attachment teeth and the coupling teeth alternate in a circumferential direction.