Speed-controlled conditioning valve for high pressure compressor

A rotor for a gas turbine engine has: a first rotor disk; an interstage flange that extends from the first rotor disk to a flange end portion that has an axial end surface and first radial outer and inner surfaces; a circumferential groove, formed in the flange end portion and extending from the axial end surface toward the first rotor disk; radial outer and inner slots formed in the first radial outer and inner surfaces along the circumferential groove and extend through the first radial outer and inner surfaces; and a valve member disposed within the circumferential groove and is secured within the circumferential groove when the flange end portion is connected to a second rotor disk, wherein the valve member deflects from rotor rotational speeds to seal or unseal the radial outer slot.

BACKGROUND

Exemplary embodiments pertain to the art of valves and more specifically to a speed-controlled conditioning valve for high pressure compressor of a gas turbine engine.

During engine accelerations, compressive stress conditions may be induced in outer rim features of rotors due to rapid temperature change. These conditions may exist in both bladed rotor configurations, i.e., where blades are attached to rotors, and integrated blade rotor (“IBR”) configurations. Gas path temperatures may increase faster than the rotor can absorb the temperatures, and heat conducted in the rotor may cause a temperature gradient between the gas path and the rest of the rotor, which may reduce a total life of the rotor. Stress conditions can also be induced in an opposite direction, if the rotor rim is cooling faster than the bores. This may happen during a fast deceleration of the engine, when the engine is in a high power state and goes to idle state.

Gas path air may be used to mitigate the thermal gradient between a rotor outer dimeter (“OD”) rim and a rotor body by flowing gas path air into rotor inner dimeter (“ID”) cavities, adjacent to rotor bores and blade webs. In known flow metering systems, such as that used for controlled cooling of turbine blades, actuation of a valve member may be performed using a relatively large device (such as a Bellville washer). In addition, in known conditioning flow systems, air can flow constantly through the engine cycle. During maximum temperature conditions, such as that which occurs during peak engine output, the constant cooling flow can have negative impacts on the creep properties of the rotor webs, degrading the life of the parts. A constant flow condition also has negative impacts on the performance parameters of the engine, efficiency, thrust.

BRIEF DESCRIPTION

Disclosed is a rotor for a gas turbine engine, including: a first rotor disk; an interstage flange that extends in an axial direction from the first rotor disk to a flange end portion, the flange end portion having an axial end surface and first radial outer and inner surfaces; a circumferential groove, formed in the flange end portion and extending axially from the axial end surface toward the first rotor disk; radial outer and inner slots are respectively formed in the first radial outer and inner surfaces along the circumferential groove, respectively radially extending through the first radial outer and inner surfaces; and a valve member disposed within the circumferential groove, the valve member being secured within the circumferential groove when the flange end portion is connected to a second rotor disk, when the rotor is rotating below a predetermined speed, the valve member is in a first deflected state, the radial outer and inner slots being unsealed when the valve member is in the first deflected state, and when the rotor is rotating above the predetermined speed, the valve member is in a second deflected state, the radial outer slot being sealed by the valve member when the valve member is in the second deflected state.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the valve member includes deflectable and stationary valve portions respectively located thereon; and the valve member is located in the circumferential groove so that the deflectable valve portion engages the radial outer and inner slots.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the circumferential groove defines a first shape between the first radial outer and inner surfaces, and the stationary valve portion is formed with a second shape defined by second radial outer and inner surfaces that is complementary to the first shape; and the deflectable valve portion is formed with a third shape defined by third radial outer and inner surfaces, wherein the third shape is formed to taper in a radial direction toward a circumferential end of the valve member.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the second radial outer surface defines a first radius having a first radial center, and the third radial outer surface defines a second radius having a second radial center, wherein the first and second radial centers are in different locations; and the second and third radial inner surfaces define a same radius as each other and have a same radial center location as each other.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the second radius is smaller than the first radius.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, an effective circumferential length of the deflectable valve portion decreases with deflection of the deflectable valve portion during rotation of the rotor, and wherein a resonant frequency of the deflectable valve portion is defined by

F=Kn2⁢π⁢E*Iq*L4
where E=Young's Modulus, I=an area of inertia of the deflectable valve portion, L=the effective circumferential length of the deflectable valve portion, q=a distribution of mass of the deflectable valve portion, Kn=a modal constant for the deflectable valve portion, and F=a frequency of response for the deflectable valve portion.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the flange end portion has connector holes; and the radial outer and inner slots are circumferentially offset from the connector holes.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the circumferential groove is an annular groove; and the valve member is a conical ring, or a plurality of layered conical rings, having a radial smaller end and a radial larger end, when the rotor is at rotating above the predetermined speed, the radial smaller end of the valve member is deflected radially outward, the radial outer slot being sealed by the valve member when the radial smaller end of the valve member is deflected radially outward.

In addition to one or more of the above disclosed features for the rotor, or as an alternate, the circumferential groove is a first circumferential groove, and wherein the rotor comprises: the second rotor disk, the second rotor disk including first and second axial outer surfaces that are axially opposite to each other on the second rotor disk and a second circumferential groove extending axially from the first axial outer surface toward the second axial outer surface, wherein the first and second circumferential grooves are radially aligned when the first and second rotor disks are connected to each other, and wherein the valve member has a valve member axial length that is longer than the first circumferential groove so that the valve member extends between the first and second circumferential grooves when the first and second rotor disks are secured to each other.

Further disclosed is a gas turbine engine, including: a rotor that includes: a first rotor disk; an interstage flange that extends in an axial direction from the first rotor disk to a flange end portion, the flange end portion having an axial end surface and first radial outer and inner surfaces; a circumferential groove, formed in the flange end portion and extending axially from the axial end surface toward the first rotor disk; radial outer and inner slots are respectively formed in the first radial outer and inner surfaces along the circumferential groove, respectively radially extending through the first radial outer and inner surfaces; and a valve member disposed within the circumferential groove, the valve member being secured within the circumferential groove when the flange end portion is connected to a second rotor disk, and when the rotor is rotating below a predetermined speed, the valve member is in a first deflected state, the radial outer and inner slots being unsealed when the valve member is in the first deflected state, and when the rotor is rotating above the predetermined speed, the valve member is in a second deflected state, the radial outer slot being sealed by the valve member when the valve member is in the second deflected state.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the valve member includes deflectable and stationary valve portions; and the valve member is located in the circumferential groove so that the deflectable valve portion engages the radial outer and inner slots.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the circumferential groove defines a first shape between the first radial outer and inner surfaces, and the stationary valve portion is formed with a second shape defined by second radial outer and inner surfaces that is complementary to the first shape; and the deflectable valve portion is formed with a third shape defined by third radial outer and inner surfaces, wherein the third shape is formed to taper in a radial direction toward a circumferential end of the valve member.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the second radial outer surface defines a first radius having a first radial center, and the third radial outer surface defines a second radius having a second radial center, wherein the first and second radial centers are in different locations; and the second and third radial inner surfaces define a same radius as each other and have a same radial center location as each other.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the second radius is smaller than the first radius.

In addition to one or more of the above disclosed features for the engine, or as an alternate, an effective circumferential length of the deflectable valve portion decrease with deflection of the deflectable valve portion during rotation of the rotor, and wherein a resonant frequency of the deflectable valve portion is defined by

F=Kn2⁢π⁢E*Iq*L4
where E=Young's Modulus, I=an area of inertia of the deflectable valve portion, L=the effective circumferential length of the deflectable valve portion, q=a distribution of mass of the deflectable valve portion, Kn=a modal constant for the deflectable valve portion, and F=a frequency of response for the deflectable valve portion.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the flange end portion has connector holes; and the radial outer and inner slots are circumferentially offset from the connector holes.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the circumferential groove is an annular groove; and the valve member is a conical ring, or a plurality of layered conical rings, having a radial smaller end and a radial larger end, when the rotor is at rotating above the predetermined speed, the radial smaller end of the valve member is deflected radially outward, the radial outer slot being sealed by the valve member when the radial smaller end of the valve member is deflected radially outward.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the circumferential groove is a first circumferential groove, and wherein the rotor comprises: the second rotor disk, the second rotor disk including first and second axial outer surfaces that are axially opposite to each other on the second rotor disk, a second circumferential groove extending axially from the first axial outer surface toward the second axial outer surface, wherein the first and second circumferential grooves being radially aligned when the first and second rotor disks are connected to each other, and wherein the valve member has a valve member axial length that is longer than the first circumferential groove so that the valve member extends between the first and second circumferential grooves when the first and second rotor disks are secured to each other.

In addition to one or more of the above disclosed features for the engine, or as an alternate, the engine includes a low pressure compressor and a high pressure compressor, wherein the rotor is a high pressure compressor rotor.

Further disclosed is a method of directing conditioning air through a rotor of a gas turbine engine, including: rotating the rotor below a predetermined speed so that a valve member located in a circumferential groove formed in the rotor is in a first deflected state, and radial outer and inner slots respectively formed in first radial outer and inner surfaces surrounding the circumferential groove are unsealed; and rotating the rotor above the predetermined speed so that the valve member is in a second defected state and the radial outer slot is sealed by the valve member.

DETAILED DESCRIPTION

The exemplary engine20generally includes a low speed spool30and a high speed spool32mounted for rotation about an engine central longitudinal axis A (engine radial axis R is also illustrated inFIG. 1) relative to an engine static structure36via several bearing systems38. It should be understood that various bearing systems38at various locations may alternatively or additionally be provided, and the location of bearing systems38may be varied as appropriate to the application.

As shown inFIG. 2A, in the high pressure compressor52of the engine20, a conditioning flow90of gas path air may be used to condition an inner diameter (ID) cavity100of the rotor stack (rotor)110. The conditioning flow will heat or cool engine cavities depending on when the air is flowing in the engine cycle. The disclosed embodiments, discussed in greater detail below, enable reducing the conditioning flow90during maximum engine operating conditions, when such conditioning flow90could be damaging to engine components. As a result, the disclosed embodiments increase the life of the engine parts. The disclosed embodiments also provide a compact form factor for a rotor bolted flange or rotor snap interface. The disclosed embodiments also provides means to improve engine efficiency and thrust-specific fuel consumption (TSFC) compared to open flow condition.

As shown inFIGS. 2A and 2B, the rotor110includes a first rotor disk130A. An interstage flange140extends in the axial direction A from the first rotor disk130A to a flange end portion160. The flange end portion160having an axial end surface190and first radial outer and inner surfaces201A,201B.

Also shown inFIG. 2Ais a blade112axially surrounded by a pair of vanes114A,114B. Another interstage flange116connects with the interstage flange140and a second rotor disk130B supporting the blade112via a bolt connector120. Additional outer diameter interstage flanges122A,122B connect via snap flanges124A,124B to a rim126of the blade112. Each of the outer diameter interstage flanges122A,122B may include knife seals127A,127B. A case structure128supports the vanes114A,114B and blade outer air seals129.

As shown inFIGS. 3A-3D, a (first) circumferential groove210A is formed in the flange end portion160and extending axially from the axial end surface190toward the first rotor disk130A. Radial outer and inner slots220A,220B are respectively defined in the first radial outer and inner surfaces201A,201B along the circumferential groove210A, extending radially through the respective first radial outer and inner surfaces201A,201B. The radial outer and inner slots220A,220B allow a path flow for the conditioning flow90. The radial outer and inner slots220A,220B, are formed (or cut) circumferentially between flange connector (bolt) holes230A,230B connecting the first and second rotor disks130A,130B.

A valve member240is disposed within the circumferential groove210A. The valve member240is secured within the circumferential groove210A when the flange end portion160is connected to the second rotor disk130B. The rotor110is rotating below a predetermined speed (e.g., measured in rotations per minute, or RPM), the valve member240is in a first deflected state. From this configuration the radial outer and inner slots220A,220B are unsealed. When the rotor110is rotating above the predetermined speed, the valve member240is in a second deflected state. In this configuration, the radial outer slot220A is sealed. Thus, the disclosed embodiments provide for passively actuating the valve member240to deflect, elastically, with rotational speed of the compressor rotor (rotor)110(e.g., the valve member240is speed-controlled), to restrict conditioning flow90.

The valve member240includes deflectable (or actuatable) and stationary valve portions260A,260B. The valve member240is located in the circumferential groove210A so that the deflectable valve portion260A engages the radial outer and inner slots220A,220B.

The circumferential groove210A defines a first shape between the first radial outer and inner surfaces201A,201B. The stationary valve portion260B is formed with a second shape defined by second radial outer and inner surfaces202A,202B, that is complementary to the first shape. The deflectable valve portion260A is formed with a third shape defined by third radial outer and inner surfaces203A,203B. The third shape is formed to taper in a radial direction toward a circumferential end270of the valve member240.

The second radial outer surface202A defines a first radius280A having a first radial center280B. The third radial outer surface203A defines a second radius290A having a second radial center290B. The first and second radial centers280B,290B are disposed in different locations. The second and third radial inner surfaces202B,203B define a same radius as each other and have a same radial center location as each other. In one embodiment, the second radius290A is smaller than the first radius280A.

The second and third radial outer surfaces202A,203A of the deflectable and stationary valve portions260A,260B are tangent to each other where they meet. As indicated, a shape and curvature of the deflectable valve portion260A is such that it deflects against the radial outer slot220A at a desired rotational speed to enable an increase in engine efficiency and a decrease in rotor stress.

With the disclosed embodiments, the stationary valve portion260B is fixed in the circumferential groove210A to prevent circumferential motion of the valve member240relative to the circumferential groove210A. The deflectable valve portion260A has a shape that is tuned or optimized to provide valve actuation at pre-determined engine speed ranges.

A radial height of the valve member240may be, e.g., 0.250 in (inches). The height would be dictated by the stiffness needed to accomplish the correct valve actuation (deflection) in the deflectable valve portion260A. A flow area through the radial outer and inner slots220A,220B, is less than five percent (5%), and as low as one percent (1%) of engine core flow. A circumferential span of the radial outer and inner slots220A,220B and/or a number of the slots may be selected to achieve the desired conditioning flow.

As shown inFIG. 3B, as the deflectable valve portion260A deflects, the effective circumferential length of the deflectable valve portion260A changes. This is due to a change in the second radius290A of the third radial outer surface203A during deflection of the deflectable valve portion260A. For example the effective circumferential length is L1when of the deflectable valve portion260A is against the radial inner slot220B, e.g., when the engine20is not running. This is shown as a non-deflected state D0inFIG. 3B. When the engine is running at a max output, and the deflectable valve portion260A is against the radial outer slot220A, and effective circumferential length is L2, which differs from L1. This is shown as a second deflected state D2inFIG. 3B. At low speeds or intermediate speeds, between idle and the maximum output, the effective circumferential length of the deflectable valve portion260A is L3. That is, L3is variable between L1and L2and is a function of the speed of the engine20and design characteristics of the valve member240. This is shown as a first deflected state D1inFIG. 3B. InFIG. 3B, the leader lines for L1-L3touch upon the third inner radial surface203B for the deflectable valve portion260A in each respective deflected state D1-D3.

The deflection response of the deflectable valve portion260A can be adjusted by design of the valve member240to provide the conditioning flow90for the engine20. That is, by design, below a threshold rotational speed, the first deflected state D1of the valve member240allows conditioning flow90through the radial outer and inner slots220A,220B. Above the threshold, the valve member240is in the second deflected state D2that results in closing off the radial outer slot220A, preventing the further flow of the condition flow90. Thus, the disclosed configuration meters conditioning air based on rotational speed of the compressor52.

The conditioning flow may be most effective at a low power condition for the engine20. Thus, as shown inFIG. 4A, as the high pressure compressor52increases in speed, the conditioning flow90is reduced and eventually closed off, due to the deflection of the valve member240. The flow curve4A1shows flow around the deflectable valve portion260A when the engine is at idle and the deflectable valve portion260A is in the first deflected state D1(FIG. 3B), and conditioning flow will be at a relative maximum.

The flow curve4A2shows flow around the deflectable valve portion260A when the engine is operating in a speed range of between idle and maximum engine output. During this engine operational state, the deflectable valve portion260A will also be in the first deflected state D1(FIG. 3B), though the deflection of the deflectable valve portion260A will increase as engine output, and compressor rotation, increases. That is, during this middle-range engine rotational speed (between idle and a maximum engine output), the valve member240may deflect (or bend) toward the radial outer slot220A, limiting conditioning flow through it.

The flow curve4A3shows flow around the deflectable valve portion260A when the engine20is near or at a maximum engine output. During this engine operational state, the deflectable valve portion260A will be in the second deflected state D2(FIG. 3B), shutting off the conditioning flow90.

Turning toFIG. 4B, during operation of the engine, an undamped (resonant or first mode) response may occur in the deflectable valve portion260A of the valve member240as labeled in curve4B1. This may cause damage to the valve member240. That is, the deflectable valve portion260A functions as a cantilevered beam, and a frequency of response is therefore determined by a frequency response formula:

In the frequency response formula, E=Young's Modulus, I=an area of inertia of the deflectable valve portion, L=the effective circumferential length of the deflectable valve portion, q=a distribution of mass of the deflectable valve portion, Kn=a modal constant for the deflectable valve portion, and F=a frequency of response for the deflectable valve portion. Thus, the frequency of response is tied to the effective circumferential length and changes as a function of the engine speed. Therefore, the vibration mode of the deflectable valve portion260A also changes based on engine speed. To address unwanted vibrations, the second radius290A or the second radial center290B of the deflectable valve portion260A may be shifted, or its shape may be modified to provide the desired frequency response and damp out the vibrations.

Turning toFIGS. 5A and 5B, in another embodiment, a first ring300A, having a full hooped (annular) conical shape, is utilized for the valve member240. The first ring300A has a radial smaller end310A and a radial larger end310B. When the rotor110is rotating above the predetermined speed, the radial smaller end310A is deflected radially outward. In this configuration, the radial outer slot220A is sealed by the valve member240.

The first ring is placed in the circumferential groove210A, which may also be a full hoop (annular) groove. The first ring300A may have a conical angle, length, and thickness that define its stiffness. The first ring300A may have an axial length that may be sufficient to fully cover the radial outer slot220A when the first ring300A is deflected (or passively actuated) during peak operating output conditions. The first ring300A may be tuned (or formed) so that a deflection response of the first ring300A changes in the axial direction A (FIG. 2A), conical angle and wall thickness for the ring.

Harmonic responses of the valve member240may be mitigated with a plurality of layered (conical) rings, including the first ring300A and a second ring300B. The first and second rings300A,300B, may be tuned (formed) to have different natural frequency from each other. Any delta (or difference) in the frequency response may generate friction absorbing vibratory energy.

In one embodiment, the second rotor disk130B includes first and second axial outer surfaces320A,320B that are axially opposite to each other on the second rotor disk130B. A second circumferential groove210B extends axially from the first axial outer surface320A toward the second axial outer surface320B. The first and second circumferential grooves210A,210B are radially aligned when the first and second rotor disks130A,130B are connected to each other.

The valve member240in this embodiment, which may be a combination of the first and second rings300A,300B, may have an axial length that is longer than the first circumferential groove210A. Thus, the valve member240overlaps the first and second circumferential grooves210A,210B when the first and second rotor disks130A,130B are secured to each other.

The utilization of the second ring300B and the second circumferential grove210B may make it easier for the valve member240to fully restrict the conditioning air flow due manufacturing tolerances between the first circumferential groove210A and the first ring300A. With the first and second circumferential grooves210A,210B extending axially into both rotor disks130A,130B, the tolerances can be absorbed.

Turning toFIG. 6, further disclosed is a method of directing conditioning air through a rotor of a gas turbine engine. As shown in block600, the method includes rotating the rotor110below a predetermined speed. In this operational state, the valve member240, which is located in the circumferential groove210A formed between first radial outer and inner surfaces201A,201B of the flange end portion160of the first rotor disk130A, is in the first deflected state. Additionally, in this operational state, radial outer and inner slots220A,220B, respectively formed in the first radial outer and inner surfaces201A,201B, are unsealed. As shown in block610, the method includes rotating the rotor110above the predetermined speed. In this operational state, the valve member240is in a second defected state and the radial outer slot220A is sealed by the valve member240.