Turbomachine stage and method for determining a seal gap and/or an axial position of such a turbomachine stage

Abstract

A turbomachine stage, particularly a turbine stage or a compressor stage of a gas turbine, is disclosed. The turbomachine stage has a, conical in particular, housing in which is arranged a moving vane arrangement with multiple moving vanes which have an exterior shroud band with at least one radial sealing flange. The sealing flange has a recess arrangement with at least one radial recess in which, centrally in particular, a radial projection is arranged. There is arranged on the housing a sensor arrangement with at least one capacitive sensor for detecting a radial clearance to a peripheral surface of the sealing flange.

Claims

1. A turbomachine stage, comprising: a housing having an external surface; a moving vane arrangement disposed within the housing, wherein the moving vane arrangement disposed along an axial rotation axis and including at least one radially disposed vane disposed along a radial axis transverse to the axial rotation axis, the at least one vane having an exterior shroud band section including a sealing flange, the sealing flange having a recess arrangement including a radial recess and a radial projection, that together, define a peripheral surface of the sealing flange; and a sensor arrangement including a sensor having a sensing surface, the sensor arrangement being arranged on the housing so that the sensing surface of the sensor positionally converges towards or positionally diverges away in a direction relative to the radial axis in a direction that is different from the direction of the radial axis, and the converging or the diverging sensing surface of the sensor and the peripheral surface of the sealing flange, in combination, further define a radial clearance therebetween, and a radial distance of the radial clearance is detectable by the positionally converged or the positionally diverged sensor.

2. The turbomachine stage according to claim 1, wherein the turbomachine stage is a turbine stage or compressor stage of a gas turbine.

3. The turbomachine stage according to claim 1, wherein the sensor arrangement has a second sensor and a third sensor, wherein sensing surfaces of the second sensor and the third sensor form counter-directional, essentially equally sized angles with an axis of rotation of the turbomachine stage.

4. The turbomachine stage according to claim 1, wherein the peripheral surface of the sealing flange associated with the radial projection is radially spaced radially outbound from the peripheral surface of the sealing flange disposed adjacent to the radial recess.

5. The turbomachine stage according to claim 1, further comprising a processor coupled to the sensor arrangement.

6. A method for determining one or both of a radial distance and an axial position of a seal gap between a sealing flange of a moving vane arrangement and a housing in a turbomachine stage, the moving vane arrangement disposed along an axial rotation axis and having at least one vane disposed along a radial axis that is transverse to the axial rotation axis, wherein the sealing flange has a recess arrangement with a radial recess and a radial projection and wherein a sensor arrangement with a sensor has a sensing surface and is arranged on the housing so that the sensing surface of the sensor positionally converges towards or positionally diverges away in a direction relative to the radial axis that is different from the direction of the radial axis, comprising the steps of: detecting the radial recess and the radial projection of the recess arrangement by the positionally converged or the positionally diverged sensor; generating a signal swing representative of the detected radial recess and the radial projection by the positionally converged or the positionally diverged sensor; and determining the radial distance of the seal gap at least in part from the generated signal swing.

7. The method according to claim 6, further comprising the step of assigning the signal swing to the radial distance of the moving vane arrangement based on a prior calibration.

8. The method according to claim 7, further comprising the steps of: detecting a second signal swing of the sensor arrangement as a result of the radial recess and the radial projection being detected by the sensor of the sensor arrangement; and assigning the signal swing and the second signal swing to an axial position of the moving vane arrangement based on a prior calibration.

9. The method according to claim 7, further comprising the steps of: detecting a second signal swing of the sensor arrangement as a result of the radial recess or the radial projection being detected by the positionally converged or the positionally diverged sensor of the sensor arrangement; and assigning a width of the second signal swing to an axial position of the moving vane arrangement based on a prior calibration.

10. The method according to claim 7, further comprising the step of detecting a rubbing on the housing opposite from the sealing flange.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts a part of a turbomachine stage according to an embodiment of the present invention in a view in the axial direction;

(2) FIG. 2 depicts a part of the turbomachine stage of FIG. 1 along line II-II in FIG. 1;

(3) FIG. 3A depicts a signal of a sensor of the turbomachine stage of FIG. 1 for an axial position and a radial distance of a moving vane arrangement of the turbomachine stage;

(4) FIG. 3B depicts a signal of the sensor in an illustration corresponding to FIG. 3A for a different axial position;

(5) FIG. 3C depicts a signal of the sensor in an illustration corresponding to FIG. 3A for a different radial distance;

(6) FIG. 4 depicts a top-down view in a radial direction from the outside to a part of a turbomachine stage of FIG. 1;

(7) FIG. 5 depicts a part of a turbomachine stage according to another embodiment of the present invention in an illustration corresponding to FIG. 4; and

(8) FIG. 6 depicts a signal of a sensor of the turbomachine stage of FIG. 4 in an illustration corresponding to FIG. 3A.

DETAILED DESCRIPTION OF THE DRAWINGS

(9) FIGS. 1, 2, and 4 depict in a view in the axial direction (FIG. 1), a meridional cut (FIG. 2), or an unrolled top-down view in a radial direction of a part of a turbomachine stage according to an embodiment of the present invention. The turbomachine stage can be, for example, a turbine or compressor stage of a gas turbine, preferably of an aircraft engine.

(10) It has a moving vane arrangement with multiple moving vanes 1 adjoining each other in the peripheral direction. The moving vane arrangement is arranged in a conical housing 2.

(11) The moving vane arrangement has a conical exterior shroud band 1.1, which is formed of multiple exterior shroud band sections, to which one or more moving vanes are each connected.

(12) Radially outward on the exterior shroud band, there are arranged in a spaced apart manner two radial sealing flanges 1.2, 1.3 in an axial or flow direction (horizontal from left to right in FIGS. 2 and 4), which extend strut-like radially outward (see FIGS. 1, 2) as well as in the peripheral direction (see FIGS. 1, 4).

(13) The present invention is explained in greater detail below in reference to the left sealing flange 1.2 in FIGS. 2, 4. The embodiments can be applied identically to the right sealing flange 1.3 in FIGS. 2, 4.

(14) Sealing flange 1.2 is formed by multiple sealing flange sections that are integrally constructed with the respective exterior shroud band section and of which in FIG. 1 two are labeled with 1.2 and 1.2 for the sake of better differentiation.

(15) Sealing flange 1.2 has a recess arrangement with four radial recesses 4, of which one is depicted in FIG. 1. Each of the identical recesses has two opposing arms (left, right in FIG. 1) that extend essentially in a radial direction. Between the arms extends a recess bottom that has a cylindrical peripheral surface, so that recess 4 is constructed in a U-shaped manner.

(16) There is arranged in recess 4 a radial projection 4.1, which extends from the recess bottom radially outward and has a cylindrical ring-shaped peripheral surface. Radial projection 4.1 is, when seen in a peripheral direction, centrally arranged in recess 4. Recess 4 with projection 4.1 arranged in it is constructed symmetrically.

(17) There is arranged on housing 2 a sensor arrangement 3 with six capacitive sensors for detecting a radial distance to a peripheral surface of the sealing flange, of which one is depicted in FIGS. 1, 2, and of which two sensors 3.1, 3.2 are depicted in FIG. 4.

(18) When a sensor is passed over by a recess 4, the radial distance changes: first it increases as soon as the sensor detects the recess bottom. Subsequently, the radial distance decreases when the sensor detects the projection. Subsequently, it increases again as soon as the sensor detects the recess bottom on the opposite side of the projection in the peripheral direction. Lastly, the radial distance decreases again to the starting value when it detects the peripheral surface of the sealing flange next to the recess.

(19) In this way, when a recess rotates past a sensor, there results a general W-type signal sequence with four alternating, counter-directional signal swings. FIG. 3A depicts such a signal sequence for the two adjacent sensors 3.1, 3.2 when the same recess 4 rotates past sensors 3.1, 3.2 one after the other. In doing so, the horizontal axis can equally represent an angle of rotation of the rotor arrangement or the time, since both can be mutually converted into the other via the speed of rotation of the rotor arrangement.

(20) By a processing means 5, the signal swings of the sensor arrangement are detected as a result of the recesses of the recess arrangement and their projections being detected by sensors of the sensor arrangement.

(21) Signal swings d, which result due to the clearance change between the recess bottom and the projection and between the projection and the recess bottom, are assigned to a radial distance of the moving vane arrangement on the basis of a prior calibration. FIG. 3C shows the signal sequence of FIG. 3A for another radial distance between moving vane arrangement 1 and sensor arrangement 3 or housing 2. One can see that signal swings d differ for these various radial distances. Accordingly, signal swing d or d can be assigned to a certain radial distance on the basis of a prior calibration.

(22) The sensors of the sensor arrangement and their sensing surfaces form counter-directional, equally sized angles of 15 with an axis of rotation of the turbomachine stage (see FIG. 4).

(23) By these sensing surfaces inclined against the axis of rotation of the turbomachine, an axial position of the moving vane arrangement can be detected. Concerning this, FIG. 3B depicts the signal sequence of FIG. 3A for another axial position of vane arrangement 1: initially signal swings d of the sensor arrangement are detected as a result of a recess of the recess arrangement and the projection in this recess being detected by a sensor 3.1 of the sensor arrangement (left in FIGS. 3A, 3B).

(24) By the rotor continuing to rotate to the other sensor 3.2, subsequently additional signal swings (right in FIGS. 3A, 3B) of the sensor arrangement are detected as a result of this recess and the projection in this recess being detected by the other sensor 3.2 of the sensor arrangement. The time or angle of rotation interval of these signal swings, indicated in FIGS. 3A, 3B by the interval T or T of the middle peaks, can then be assigned, in processing means 5, to an axial position of the moving vane arrangement on the basis of a prior calibration. In looking at FIG. 4, one can see that for the sensing surfaces, converging from left to right, of sensors 3.1, 3.2, the interval of the signal swings decreases the further the sealing flange is displaced from left to right.

(25) Likewise, as precedingly explained for the signal between recess bottom 4 and projection 4.1 or projection 4.1 and recess bottom 4, a signal swing D or D (see FIGS. 3A, 3C) also results when entering or exiting a recess into or out of the sensing surface of a sensor. The signal swing is used in processing means 5 to detect an abrasion of sealing flange 1.2: the greater the abrasion, the smaller signal swing D or D is. Correspondingly, signal swings of the sensor arrangement are detected as a result of a recess of the recess arrangement and a sealing flange peripheral surface adjoining this recess, particularly positioned ahead or after in the direction of rotation, being detected by a sensor of the sensor arrangement and these signal swings are assigned to an abrasion of the sealing flange on the basis of a prior calibration.

(26) The seal gap between the sealing flange and housing, particularly an inlet coating of the housing, can depend on the radial distance of the sealing flange to a housing-affixed sensor and any abrasion of the sealing flange as well as a rubbing 2.1 on the housing, as indicated in FIG. 2. Correspondingly, a rubbing of housing 2 opposite the sealing flange, particularly of the housing 2 inlet coating opposite the sealing flange, is periodically detected and taken into consideration, in particular added to a radial distance and an abrasion of the sealing flange, by processing means 5 when detecting the seal gap.

(27) In FIG. 1, one can see that the peripheral surface of radial projection 4.1 is radially depressed in recess 4 and that recess 4 and projection 4.1 extend across the contact surface of two adjoining moving vanes. Concerning this, sealing flanges 1.2, 1.2 of two adjoining exterior shroud band sections are radially depressed in relation to sealing flange 1.2 of the exterior shroud band sections connecting to them (see FIG. 1), so that recess 4 extends across both entire exterior shroud band sections 1.2, 1.2. Radial projection 4.1 is arranged on the mutually facing contact surfaces of this adjoining exterior shroud band section 1.2, 1.2.

(28) FIG. 5 depicts in an illustration corresponding to FIG. 4 a top-down view in a radial direction from the outside to a part of a turbomachine stage according to another embodiment of the present invention. Congruent elements are identified by identical reference signs so that reference is made to the remaining description and subsequently only the differences to the embodiment according to FIGS. 1-4 are addressed.

(29) The sensor arrangement of the embodiment according to FIG. 5 has a sensor 3.3 for detecting a radial clearance to a peripheral surface of the sealing flange, whose hatched sensing surface in FIG. 5 converges in an axial direction (from left to right). As one can see in FIG. 5, the sensing surface is thereby designed in a bi-radial manner, which can be represented for example by a V-shaped capacitive sensor.

(30) When this sensor is passed over by a recess 4, whose recess bottom in FIG. 5 is shown in a dark color, the radial distance changes: first it increases, as soon as the sensor detects the recess bottom. Subsequently, the radial distance decreases when the sensor detects the projection 4.1. Subsequently, it increases again as soon as the sensor detects the recess bottom on the opposite side of the projection in the peripheral direction. Lastly, the radial distance decreases again to the starting value, when the sensor detects the peripheral surface of the sealing flange next to the recess.

(31) In this way, when a recess rotates past a sensor, a generally W-type signal sequence results with four alternating, counter-directional signal swings. FIG. 6 depicts such a signal sequence in an illustration corresponding to FIG. 3A.

(32) Due to the bi-radial sensing surface, the signal swings thereby each have plateaus: if the recess is rotated into the one sensing surface, the signal decreases in a tapering manner. Then, when the recess is rotated also into the other sensing surface, the signal decreases further in a tapering manner. Correspondingly, the signal increases step-wise in a tapering manner as soon as the projection is rotated into the sensing surfaces or the projection is rotated out of the sensing surfaces.

(33) Due to the converging sensing surface, width B of the signal swings or edges changes: the sensing surface is wider at left in FIG. 5 in the peripheral direction (vertical in FIG. 5) than on the right. Correspondingly, a greater twisting of sealing flange 1.2 is required until its recess or projection is detected to a maximum degree or not at all by sensor 3.3. In this way, a width B of signal swing D increases as a result of sensor 3.3 detecting recess 4 when transitioning between the peripheral surface of sealing flange 1.2 next to recess 4 (bottom in FIG. 5) and the recess. This width B can be assigned to an axial position of sealing flange 1.2 relative to sensor 3.3 on the basis of a two-dimensional calibration.

(34) Width B can, for example, be determined between a point 1, at which the sensor signal C exceeds a preset value for the first time, and a another point 2, at which sensor signal C falls below a preset smaller value for the first time. Similarly, width B can be determined between two points 1, 2 at which sensor signal C has the same gradient dC/d , for example half of a maximum gradient. In this way, width B can be determined independently from an absolute magnitude of sensor signal C. Instead of signal swing D, signal swing d can be used as a result of detecting recess 4 and its projection 4.1.

(35) Even though in the preceding description, sample embodiments were explained, it is pointed out that a plurality of variations are possible. In addition, it is pointed out that the sample embodiments only pertain to examples that are in no way intended to restrict the protective scope, applications, and the structure. Rather, a person skilled in the art is given by means of the preceding description a guideline for implementing at least one of the sample embodiments, wherein diverse changes, particularly in regard to the function and arrangement of the described components, may be undertaken without departing from the protective scope, as emerges from the claims and these equivalent combinations of features.

LIST OF REFERENCE CHARACTERS

(36) 1 Moving vane (arrangement) 1.1 Exterior shroud band (section) 1.2, 1.3 Sealing flange 1.2, 1.2 Sealing flange section 2 Housing 2.1 Rubbing 3 Sensor arrangement 3.1, 3.2, 3.3 (Sensing surface of a) sensor 4 Recess 4.1 Radial projection 5 Processing means

(37) As also discussed above, the foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.