EP2052133B1 - Arrangement for optimising the running clearance for turbomachines - Google Patents

Description

The invention relates to an arrangement for optimizing the running gap for at least sections of axial-type turbomachinery by controlling or regulating the run-gap-relevant inner diameter of at least one stator blade surrounding a rotor blade ring.

In professional circles, the designations for this technology most "active clearance control control" or "learance A ctive C C ontrol CACC)" is used. The known constructive solutions are generally based on the principle that housing areas or stator elements defined with air of lower temperature, ie with cooling air, are flown in order to influence the running gap by thermal contraction of these components. A reduction or interruption of the cooling air flow causes the components to expand again. The effect is the more effective, the greater the temperature difference between the component and cooling air. Preferably, a hot turbine stator is charged with relatively cool compressor air. Such an arrangement is for example in the US Pat. No. 6,454,529 B1 protected. The development also goes with compressors to the active fission attitude control. A thermal influence of the housing or stator comes especially in the compressor due to low temperature differences to their limits. Thus, more responsive and more powerful systems are in demand.

From the document DE 102 33 881 A1 an arrangement for running gap optimization for turbomachines is known which has an adapting to changing thermal conditions stator structure. This consists of a closed outer ring, a concentric closed inner ring and a plurality of distributed over the circumference, relative to the radial direction in the circumferential direction inclined, the outer with the inner ring hingedly connecting webs. At different thermal expansion of the rings, the pivotable webs keep the rings always concentric to each other. The diameter of the inner ring is thus only via thermal measures, ie relatively slow, changeable.

The document GB 2 108 591 A relates to an arrangement for running gap optimization, in which over the circumference a plurality of interrupted, ie segmented, inner ring via lever mechanisms with actuators in the diameter is variable. At any deviation from the design diameter of the inner ring deviates from the ideal circular shape, ie polygonized.

From the document FR 2 458 676 A an arrangement for running gap optimization is known, which is a segmented inner ring on bellows-type, pneumatic actuators in diameter variable. Again, there is the disadvantage of polygonizing.

In view of the known solutions, the object of the invention is to propose an arrangement for running-gap optimization for at least sections of axial-type turbomachinery, which is fast-reacting as well as powerful and reliable.

This object is achieved by the features characterized in claim 1, in conjunction with the generic features in the preamble. The arrangement comprises a stator structure having an inner ring, an outer ring concentric with the latter and radially spaced and a plurality of webs integrally connecting the rings in a novel manner on. All webs are inclined relative to the radial direction by the same angle in the circumferential direction. Furthermore, the arrangement comprises an adjusting device for rotating the inner ring relative to the outer ring under elastic change of the running gap-relevant inner diameter. Thus, it is a mechanical arrangement, which, starting from a zero adjustment "center position" depending on the direction of rotation allows both a compression and expansion of the inner ring under elastic, reversible deformation. The reaction rate of the arrangement depends primarily on the speed of the selected adjustment. Since the invention is not dependent on thermally induced deformations, speed improvements can be achieved, for. B. by hydraulic, pneumatic or piezoelectric force generator. This also has the advantage that no or at least no relevant process gas flow has to be taken from the engine for the adjustment.

Preferred embodiments of the arrangement are characterized in the subclaims.

• Figur 1 einen Teilquerschnitt durch eine Anordnung zur Laufspaltoptimierung,
• Figur 2 einen Teillängsschnitt durch einen Verdichter mit zwei Anordnungen zur Laufspaltoptimierung, und
• Figur 3 einen Teilquerschnitt durch eine Anordnung zur Laufspaltoptimierung im Bereich eines Sensors zur Laufspalterfassung.

The invention will be explained in more detail with reference to the drawings. In a simplified, not to scale representation:

• FIG. 1 a partial cross section through an arrangement for running gap optimization,
• FIG. 2 a partial longitudinal section through a compressor with two arrangements for running gap optimization, and
• FIG. 3 a partial cross section through an arrangement for running gap optimization in the region of a sensor for Laufspalterfassung.

The arrangement 1 for running gap optimization comprises two essential functional units, firstly an integral, elastically deformable stator structure 3 and secondly an adjusting device with at least one lever 10, at least one actuator 16 and at least one sensor 18 for running splitter detection. The stator structure 3 consists essentially of a circular, self-contained inner ring 5, of a concentric to this radially spaced circular outer ring 7 and a plurality of distributed over the circumference of the stator 3, the inner ring 5 and the outer ring 7 integral The webs 8 are inclined at a defined angle α relative to the radial direction in the circumferential direction, so that a relative rotation of the inner ring 5 and the outer ring 7 a reversible compression or widening of the inner ring 5 and thus a change of the running clearance relevant inner diameter D entails. The inner ring 5 has in relation to the outer ring 7 has a thinner cross-section, is thus much more flexible. This ensures that the desired change in diameter essentially results from the deformation of the inner ring 5. The radially inner and radially outer ends of the webs 8 are integrally connected to the inner ring 5 and the outer ring 7 and designed as elastic solid joints. It can be seen that the webs 8 are contoured over their radial length, wherein the radially central region 9 is thickened relative to the ends and thus stiffened. Thus, the webs 8 behave over the majority of their radial length rigid body-like, which amplifies the change in diameter of the inner ring 5 at a given relative rotation. The webs 8 may also be contoured with respect to their axial extent. Their axial depth can be greater on the outer ring 7 than on the inner ring 5, with a conical taper between them. At high axial stiffness so the adjustment can be reduced. This contouring is not shown. The outer ring 7 is rotationally held in a housing-like support 29, so that it forms the truly static element of the stator structure 3. The possibly with - in FIG. 1 not shown - Rotor blade coming into contact inner ring 5 is provided radially inside with a friction-tolerant Anstreifbelag 17, the inside of the running gap-relevant inner diameter D predetermines. The Anstreifbelag 17 follows the elastic deformation (compression, expansion) of the inner ring. 5

Beyond the stator structure 3 FIG. 1 still essential elements of the adjustment. The relative rotation causing force transmission between the inner ring 5 and the outer ring 7 takes place mechanically. For this purpose, a pivoting movements about an axis parallel to the axis of rotation of the turbomachine axis permitting storage 13 for a lever 10 is disposed on the outer ring 7 at least one point of its circumference. The inner ring 5 is a corresponding recess, which together with a nose-like end of the lever 10 is a positive, play-free and low-friction Joint 15 forms. The connecting line from the hinge 15 to the bearing 13 (center to center) extends at an angle β to the radial direction. Since no supporting web 8 is present at this point, the adjusting kinematics, including the angle β, are designed so that the local run-gap-relevant deformation of the inner ring 5 corresponds optimally to the deformation in the region of a web 8. The angle β is generally different from the angle α. The angles α and β are here - arbitrarily - set in such a way that the longitudinal center line of a web 8 and the connecting line from the bearing 13 to the joint 15 (center to center) are each strung with the running gap relevant inside diameter D, respectively a connecting line of the Rotary axis of the turbomachine to the intersection S1, S2 is placed, and then the acute angle between the respective connecting line "rotation axis intersection" and the longitudinal center line "web" and the connecting line "bearing joint" are determined. The angles are comparable only if the relevant intersection points S1, S2 lie on the same diameter, but which does not necessarily have to be the inner diameter D. The lever 10 is angled to save space, with its long lever arm 12 is adapted to the circular cylindrical outer contour of the outer ring 7 and its support 29 and still extends within the housing 27 of the turbomachine. The passage of the lever 10 through the outer ring 7 in the region of the bearing 13 is provided with a lip-like or seal 14, whereby the interior of the stator 3 is separated from the radially outer environment, unless there is a connection over at least one Front side of the stator structure 3. At the end of the long lever arm 12, an actuator 16 engages, which is largely arranged on the outside of the housing 27 of the turbomachine. The actuator 16 is preferably designed as a double-acting, ie pressure and tensile forces generating, power cylinder whose power supply can be pneumatic, hydraulic or electrical / electronic. Due to the arrangement on the long lever arm 12, the Aktuatorkräfte and thus also its weight, etc. are reduced. Only the required Aktuatorhub thereby increases. In FIG. 1 Bottom right another gap without bridge 8 with a bearing and a yoke for another lever 10 (not shown) recognizable. With even distribution over the circumference so here four actuator / lever kinematics would be provided. Theoretically, a kinematics for the stator structure would suffice. With a view to the most uniform possible deformation of the inner ring 5 and on a redundant system you will probably install two or more kinematics.

FIG. 2 shows as a concrete application example a multi-stage compressor 26 in axial construction with two arrangements 1, 2 according to the invention for Laufspaltoptimierung in partial longitudinal section. Above you can see the multi-part housing 27 of the compressor 26 with flange. Down in FIG. 2 the flow channel of the compressor with a plurality of rotor and vane rings and a part of the rotor 34 is shown. The - not reproduced - rotation axis would run horizontally below the representation. The flow through the compressor 26 is from left to right, see the white arrows. The arrangements 1, 2 are in the radial planes of the blade rings 30, 31, wherein the axial distance is such that even a vane ring with vane ring segments 33 between the assemblies 1, 2 place fits. Concentric with a radial distance, a common carrier 29 for the two stator structures 3, 4 is present within the housing 27 and fastened to the housing 27 via a flange connection. The lever 10, 11 passing through the carrier 29 and the two pedestals for the actuators not shown here can be seen on the outside, here above, on the housing 27. The inner ring 5 of the left, upstream stator structure 3 is kinematically coupled on both sides with guide vane segments 32, 33. The inner ring 6 of the right stator structure 4 is kinematically coupled on one side with the vane ring segments 33. In this way, the assemblies 1, 2 affect not only the running gaps of the blade rings 30, 31, ie the outer airseal, but also the gaps between the rotor 34 and the vane ring segments 32, 33, ie the Inner Airseal. Due to the two-sided coupling with the inner rings 5 and 6, the vane ring segments 33 are optimally moved. The vane ring segments 32 coupled only on one side to the inner ring 5 are not moved to the same extent, but still advantageously.

The prerequisite for a control or regulation in the sense of an optimization is that the actual, instantaneous running gap is recorded at adjusted time intervals and processed in terms of control or regulation. For more steady-state operating conditions, there may be larger time intervals between the measurements, for highly transient operating conditions you will carry out measurements in short time intervals up to a continuous data acquisition. For reasons of redundancy, at least two sensors should be present for the run splitter detection. With multiple levels, redundancy works across levels. With several sensors on the circumference it is also possible to detect quasi-static eccentricities of the rotor relative to the stator. FIG. 3 shows in the partial cross section the range of such a sensor 18 within an arrangement for running gap optimization. The sensor 18 is fixed relative to the inner ring 5 immediately surrounding a blade ring. For this purpose, a sleeve-like holder 20 is integrated into the inner ring 5, in which the sensor 18 is radially inserted from the outside against the stop and again pulled out. The authoritative radially inner sensor end is approximately flush with the inner surface of the squealer pad 17. By slightly resetting radially outward, it is ensured that the sensor 18 is not damaged when the blade tips are rubbed against it. In any case, the Anstreifbelag must have a "window", ie a breakthrough in the region of the sensor 18. Depending on the distance of the webs 8 in the circumferential direction, if necessary, at least one web 8 may be omitted in order to make space for the sensor 18 together with the holder 20. Since the inner ring 5 is rotated for gap optimization together with the sensor 18 relative to the outer ring 7, in the latter a passage 21 is provided with sufficient clearance in the circumferential direction to the sensor shaft. To seal the passage 21, a slidable on the outer diameter of the outer ring 7, sliding sealing ring 22 is arranged, which is loaded via a spring washer 23 radially from the outside. Between the housing 27 of the compressor 26 and the outer ring 7, a bellows 24 extends radially, which forms an elastic, open channel for a flexible connecting line 19 of the sensor 18. The bellows 24 is also used to hold the sensor 18 in its operating position by exerting a defined radial force. The bellows 24 is in turn connected to a cover 25 which is attached to a flange 28 of the housing 27 releasably and sealed, preferably screwed. The connection line 19 leads to electrical or electronic components, which are attributable to the control or regulation system of the gap optimization ultimately exporting, at least one actuator 16.

Claims (13)

1. An arrangement (1, 2) for optimizing the running clearance for turbomachines that at least in sections are of the axial construction type, such as, for example, turbocompressors, gas turbines and steam turbines, in particular for compressors of stationary gas turbines, by controlling or regulating the inside diameter (D), which is relevant to the running clearance, of at least one stator structure (3, 4) surrounding a rotor-blade ring (30, 31), wherein the arrangement (1, 2) comprises the stator structure (3, 4), wherein the stator structure (3, 4) has a closed circular inner ring (5, 6), a circular outer ring (7) that is concentric to the inner ring (5, 6) and radially spaced therefrom, and also a plurality of webs (8) which connect the inner ring (5, 6) to the outer ring (7), are inclined at a defined angle (α) to the radial direction in the circumferential direction and are distributed over the circumference of the stator structure (3, 4),
   characterised in that
   the webs (8) integrally connect the inner ring (5, 6) to the outer ring (7), and in that the arrangement (1, 2) comprises an adjusting device for turning the inner ring (5, 6) relative to the outer ring (7) with elastic modification of the inside diameter (D), which is relevant to the running clearance, of the inner ring (5, 6).
2. An arrangement according to claim 1,
   characterised in that
   the adjusting device comprises at least one lever (10, 11), which is pivoted on the outer ring (7) and is connected in a form-closing and also articulated manner to the inner ring (5, 6), and at least one actuator (16) that moves the lever (10, 11).
3. An arrangement according to claim 2,
   characterised in that
   the at least one lever (10, 11) is angled, adapted over the greater part of its length to the outside diameter of the outer ring (7) and sealed in the region of its bearing (13) on the outer ring (7).
4. An arrangement according to claim 2 or 3,
   characterised in that
   the at least one actuator (16) is constructed as a force cylinder and acts at the end of the long lever arm (12) of the lever (10, 11) outside the outer ring (7).
5. An arrangement according to one of claims 1 to 4,
   characterised in that
   at least one sensor (18), which detects the running clearance, is secured to the inner ring (5, 6).
6. An arrangement according to claim 5,
   characterised in that
   the outer ring (7) has at least one sealed feedthrough (21) for the connecting line (19) of the at least one sensor (18) and also for the installation and removal of the at least one sensor (18) through the outer ring (7).
7. An arrangement according to claim 5 or 6,
   characterised in that
   the at least one sensor (18) is integrated into a control circuit for the actuation of the at least one actuator (16).
8. An arrangement according to one of claims 1 to 7,
   characterised in that
   the inner ring (5, 6) is constructed so as to be thinner in cross section and thus easier to deform than the outer ring (7).
9. An arrangement according to one of claims 1 to 8,
   characterised in that
   the webs (8) are constructed so as to be contoured, being thicker in the radially central region (9) between the inner ring (5, 6) and the outer ring (7).
10. An arrangement according to one of claims 2 to 9,
    characterised in that
    the inclination of the at least one lever (10, 11) between its bearing (13) on the outer ring (7) and its connection to the inner ring (5, 6) at a defined angle (β) to the radial direction is selected with regard to optimum roundness of the inner ring (5, 6) by way of the adjusting movement and is different from the inclination of the webs (α) relative to the radial direction.
11. An arrangement according to one of claims 1 to 10,
    characterised in that
    the inner ring (5, 6) of the at least one stator structure (3, 4) is kinematically coupled to guidevane-ring segments (32, 33) on at least one side and thus also influences their running clearance towards the rotor.
12. An arrangement according to one of claims 1 to 11,
    characterised in that
    the at least one stator structure (3, 4) is designed for a reduction in the inside diameter (D), which is relevant to the running clearance, by approximately -0.2 % by compression of the inner ring (5, 6), and for an enlargement in the inside diameter (D), which is relevant to the running clearance, by approximately +0.2 % by expansion of the inner ring (5, 6).
13. An arrangement according to one of claims 1 to 12,
    characterised in that
    the webs (8) have a greater depth in the axial direction on the outer ring (7) than on the inner ring (5, 6) and taper conically from the outer ring (7) to the inner ring (5, 6).

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