Method for rotor blade tip clearance control and rotor blade manufactured by the method

Abstract

A rotor blade tip clearance control method and a rotor blade manufactured using same. The control method includes: coinciding, along an axial direction of an aircraft engine, a center of gravity of a rotor blade with a center of gravity of a rotor wheel disk supporting the rotor blade; rotating the rotor wheel disk to measure a leading edge deformation amount of the rotor blade; measuring a trailing edge deformation amount of the rotor blade; comparing the deformation amounts; and adjusting the center of gravity of the rotor wheel disk until the leading edge deformation amount tends to be approximately equal to the trailing edge deformation amount. The method can effectively improve or even solve the problem of inconsistent radial displacements of a leading edge and a trailing edge during the operation.

Claims

1. A method for controlling rotor blade tip clearances in an aeroengine, comprising: setting a center of gravity of a rotor blade to be overlapped with a center of gravity of a rotor disk in an axial direction of the aeroengine; rotating the rotor disk; measuring a leading edge deformation amount of a leading edge of the rotor blade; measuring a trailing edge deformation amount of a trailing edge of the rotor blade; comparing the leading edge deformation amount and the trailing edge deformation amount when a difference between the leading edge deformation amount and the trailing edge deformation amount is larger than a specified range; and adjusting the center of gravity of the rotor disk based on the comparison of the leading edge deformation amount and the trailing edge deformation amount, until the leading edge deformation amount and the trailing edge deformation amount tends to be approximately the same, wherein adjusting the center of gravity of the rotor disk comprises offsetting the center of gravity of the rotor disk towards one of the leading edge and the trailing edge which has a smaller deformation amount by a predetermined offset amount.

2. The method of claim 1, wherein the predetermined offset amount depends on a rotating speed of the rotor disk.

3. The method of claim 1, wherein: for blade heights of less than 20 mm, the specified range is 0.5%-1.5% of a height of the rotor blade; for blade heights between 20 mm and 40 mm, the specified range is 0.25%-2% of the height of the rotor blade; for blade heights between 40 mm and 100 mm, the specified range is 0.2%-1% of the height of the rotor blade; and for blade heights greater than 100 mm, the specified range is 0.2%-0.6% of the height of the rotor blade.

4. The method of claim 1, wherein the rotor blade is part of a booster compressor.

5. The method of claim 1, wherein the leading edge deformation amount of the leading edge of the rotor blade and the trailing edge deformation amount of the trailing edge of the rotor blade are measured by a deformation modulus tester.

6. An aeroengine comprising a rotor blade, wherein the aeroengine is configured to: set a center of gravity of the rotor blade to be overlapped with a center of gravity of a rotor disk in an axial direction of the aeroengine; rotate the rotor disk; measure a leading edge deformation amount of a leading edge of the rotor blade; measure a trailing edge deformation amount of a trailing edge of the rotor blade; compare the leading edge deformation amount and the trailing edge deformation amount when a difference between the leading edge deformation amount and the trailing edge deformation amount is larger than a specified range; and adjust the center of gravity of the rotor disk based on the comparison of the leading edge deformation amount and the trailing edge deformation amount, until the leading edge deformation amount and the trailing edge deformation amount tends to be approximately the same, wherein adjusting the center of gravity of the rotor disk comprises offsetting the center of gravity of the rotor disk towards one of the leading edge and the trailing edge which has a smaller deformation amount by a predetermined offset amount.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to further illustrate the method for controlling the rotor blade tip clearance according to the present invention and the rotor blade manufactured by the method, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

(2) FIG. 1 is a partial cross section diagram of the rotor disk with a single rotor blade mounted thereon, without offsetting the center of gravity of the rotor disk;

(3) FIG. 2 is an enlarged schematic diagram of the rotor blade mounted on the rotor disk shown in FIG. 1;

(4) FIG. 3 is similar to FIG. 1, but with offsetting the center of gravity of the rotor disk; and

(5) FIG. 4 is an enlarged schematic diagram of the rotor blade mounted on the rotor disk shown in FIG. 3.

DETAILED DESCRIPTION

(6) The steps of the method for controlling rotor blade tip clearance according to the present invention, and the structure and effects of the rotor blade manufactured by the method are described below with reference to the accompanying drawings, wherein the same components are denoted by the same reference signs.

(7) FIG. 1 shows a rotor disk 10 without an offset center of gravity, which is provided with a plurality of rotor blades 20. For the convenience of illustration, only one rotor blade 20 is shown in the figure.

(8) It is known that a rotating body supported by a bearing during high-speed rotation is called a rotor, and rotor is the main rotating component in the field of power machinery such as electric motor, generator, gas turbine, turbocompressor and compressor. The rotor can rotate around its axis, the extending direction of the axis is called an axial direction of the rotor, and the direction perpendicular to and extending radially outward from the axis is called a radial direction of the rotor. In the compressor, the rotor disk of the rotor supports a plurality of rotor blades, which are evenly distributed along the circumferential direction of the rotor disk. The rotor blade can be generally separated into three parts: a blade root, a blade body and a blade tip, where the blade root is mounted or integrally formed on the rotor disk, the blade body extends along the radial direction of the rotor with a certain space curvature, and the blade tip is located at the outermost side of the rotor blade.

(9) During the operation of the rotor, the rotor blade 20 perform a circular motion around the axis together with the rotor and the rotor disk 10. Although not shown in the figures, those skilled in the art should understand that a casing, as a casing component covering the outside of the rotor, is mainly used to form an airflow channel. The casing is generally cast or forged from metal or metal alloy, and a certain radial gap is left between the blade tip and the inner wall of the casing, which is a blade rotor tip clearance.

(10) The method for controlling rotor blade tip clearance according to the present invention comprises the following steps: (i) In the thermal design, a center of gravity G.sub.B of the rotor blade 20 overlaps with a center of gravity G.sub.D of the rotor disk 10 in the axial direction of the aeroengine. As shown in FIG. 1, the dotted line connecting the center of gravity G.sub.B of the rotor blade 20 and the center of gravity G.sub.D of the rotor disk 10 is the radial direction D of the aeroengine. (ii) After the rotor blade 20 and the rotor disk 10 complete the tumble cooling, during the high-speed rotation of the rotor disk 10 together with the rotor blade 20 thereon, a leading edge 21 and a trailing edge 22 of the rotor blade 20 will have different radial displacement due to centrifugal force. At this time, a leading edge deformation amount ?.sub.1 of the leading edge 21 of the rotor blade 20 and a trailing edge deformation amount ?.sub.2 of the trailing edge 22 of the rotor blade 20 are measured.

(11) As shown in FIG. 2, the rotor blade 20 is mounted on the rotor disk 10 shown in FIG. 1, wherein the dashed line shows the position of the rotor blade 20 at a stationary state, and the solid line shows the position of the rotor blade 20 at a rotating state. The leading edge deformation amount ?.sub.1 of the leading edge 21 and the trailing edge deformation amount ?.sub.2 of the trailing edge 22 can be measured by a deformation measuring device known in the art, such as a deformation modulus tester available in the market. (iii) When the difference between the leading edge deformation amount?.sub.1 and the trailing edge deformation amount?.sub.2 measured is larger than a specified range, the leading edge deformation amount?.sub.1 and the trailing edge deformation amount?.sub.2, the leading edge deformation amount?.sub.1 and the trailing edge deformation amount?.sub.2 would be compared to figure out which one of the leading edge 21 and the trailing edge 22 has a smaller amount of deformation.

(12) It should be noted that the specified range mentioned above is specified as follows: For a blade with a blade height less than 20 mm, the specified range is 0.5%-1.5% of the blade height; For a blade with a blade height between 20 mm to 40 mm, the specified range is 0.25%-2% of the blade height; For a blade with a blade height between 40 mm to 100 mm, the specified range is 0.2%-1% of the blade height; For a blade with a blade height greater than 100 mm, the specified range is 0.2%-0.6% of the blade height. (iv) Adjust the center of gravity G.sub.D of the rotor disk 10 according to the results after comparing, until the leading edge deformation amount ?.sub.1 and the trailing edge deformation amount?.sub.2 tends to be approximately the same. Similar to FIG. 2, the dashed line in FIG. 4 shows the position of the rotor blade 20 at the stationary state, and the solid line shows the position of the rotor blade 20 at the rotating state. At this time, the variation of the rotor blade tip clearance reaches the design objective.

(13) More specifically, it is found after simulation experiments that when the center of gravity G.sub.D of the rotor disk 10 is offset towards the side close to the leading edge 21 of the rotor blade tip relative to the center of gravity G.sub.B of the rotor blade 10, the leading edge deformation amount ?.sub.1 of the leading edge 21 of the rotor blade tip is larger than the trailing edge deformation amount ?.sub.2 of the trailing edge 22 of the rotor blade tip. Conversely, when the center of gravity G.sub.D of the rotor disk 10 is offset towards the side close to the trailing edge 22 of the rotor blade tip relative to the center of gravity G.sub.B of the rotor blade 10, the leading edge deformation amount ?.sub.1 of the leading edge 21 of the rotor blade tip is smaller than the trailing edge deformation amount ?.sub.2 of the trailing edge 22 of the rotor blade tip. Therefore, in the (iv) step mentioned above, the center of gravity G.sub.D of the rotor disk 10 can be adjusted by offsetting the center of gravity G.sub.D of the rotor disk 10 towards one of the leading edge and the trailing edge which has a smaller deformation amount by a predetermined offset amount.

(14) As shown in FIG. 3, the rotor disk 10 with offset of the center of gravity G.sub.D is shown. It can be seen that the center of gravity G.sub.D of the rotor disk 10 was located in the axial direction of the engine originally. After offsetting the center of gravity G.sub.D, the center of gravity G.sub.D has been shifted onto the direction of a line connecting the centers of gravity after the offset, and the offset amount is shown by an arrow in FIG. 3. The problem of inconsistent radial displacement of the leading edge 21 and the trailing edge 22 during the operation of rotor blade tip can be improved or even solved by the offset adjustment mentioned above.

(15) Since a relative offset amount w between the center of gravity G.sub.D of the rotor disk 10 and the center of gravity G.sub.B of the rotor blade 10 and/or the rotor speed affect the difference in radial displacement between the leading edge 21 and the trailing edge 22 of the rotor blade 20 comprehensively during the operation of aeroengine, a suitable relative offset amount w between the center of gravity G.sub.D of the rotor disk 10 and the center of gravity G.sub.B of the rotor blade 10 can be chosen based on the range of rotor speed, and the desired difference in radial displacement between the leading edge 21 and the trailing edge 22 of the rotor blade 20 can be obtained, thereby the radial deformation amount ?.sub.1 and ?.sub.2 of the leading edge 21 and the trailing edge 22 tends to be approximately the same during the operation of rotor blade tip.

(16) It should be noted that the term approximately the same used herein does not mean that the numerical values have to be equal in the strict sense, but the numerical values have the same order of magnitude and are substantially close to each other within an allowable uncertainty range. In other words, as long as the numerical values are substantially close to each other within the allowable uncertainty range, it can be considered that the deformation amount ?.sub.1 and ?.sub.2 tends to be approximately the same.

(17) A plurality of rotor blades 20 for aeroengine can be manufactured by the control method mentioned above. The rotor blades 20 are provided on the rotor disk 10, which has a feature of center of gravity offset, along the circumferential direction of the rotor.

(18) The feature of center of gravity offset is achieve by at least one of the following methods: (i) a predetermined offset amount w is provided between the center of gravity G.sub.D of the rotor disk 10 and the center of gravity G.sub.B of the rotor blade 20 in the axial direction D of the aeroengine; (ii) a centerline of symmetry of the rotor disk 10 is substantially perpendicular to the axial direction D of the aeroengine, that is, the centerline of symmetry of the rotor disk 10 is not strictly perpendicular to the axial direction of the engine, but rather presents an acute angle or obtuse angle close to 90?; (iii) an asymmetric feature of the rotor disk 10.

(19) Although the method for controlling rotor blade tip clearance of the invention and the rotor blade manufactured by the method have been described above with reference to the preferred embodiments, those skilled in the art should understand that the above embodiments are only for illustration, but not as a limitation of the invention. Therefore, modifications and variations of the present invention can be made within the essential spirit of the claims, and these modifications and variations will fall within the scope of protection as claimed in the claims of the invention.