阅读说明：本技术 压气机叶片及其调频槽口尺寸的确定方法、压气机和燃气轮机 (Compressor blade, method for determining size of frequency modulation notch of compressor blade, compressor and gas turbine ) 是由 尹诗彧 安鑫 魏泽明 何柳 于 2021-08-23 设计创作，主要内容包括：本发明提供了一种压气机叶片,包括叶片本体,叶片本体包括叶身、缘板和榫头,缘板的上端与叶身相连,缘板的下端与榫头相连,其中榫头包括与缘板相连的第一部分和与第一部分相连的第二部分,榫头还包括在周向方向上开设的调节频率的调频槽口,调频槽口改变榫头的径向面积实现调频。设置调频槽口即可改变榫头的径向面积以实现对叶片的准确调频,又可有效的减少叶片的重量。本发明还提供了上述调频槽口尺寸的确定方法及含有该压气机叶片的压气机和燃气轮机。(The invention provides a compressor blade which comprises a blade body, wherein the blade body comprises a blade body, a flange plate and a tenon, the upper end of the flange plate is connected with the blade body, the lower end of the flange plate is connected with the tenon, the tenon comprises a first part connected with the flange plate and a second part connected with the first part, the tenon also comprises a frequency modulation notch which is arranged in the circumferential direction and is used for adjusting the frequency, and the frequency modulation notch changes the radial area of the tenon to realize frequency modulation. The radial area of the tenon can be changed by arranging the frequency modulation notches so as to realize accurate frequency modulation on the blade, and the weight of the blade can be effectively reduced. The invention also provides a method for determining the size of the frequency modulation notch, and a compressor and a gas turbine comprising the compressor blade.)

1. The utility model provides a compressor blade, includes the blade body, the blade body includes blade body, flange and tenon, the upper end of flange links to each other with the blade body, the lower extreme of flange with the tenon links to each other, wherein the tenon include with the flange first portion that links to each other and with the second portion that the first portion links to each other, its characterized in that: the tenon also comprises a frequency modulation notch which is arranged in the circumferential direction and is used for adjusting the frequency, and the frequency modulation notch changes the radial area of the tenon to realize frequency modulation.

2. The compressor blade of claim 1 wherein the sum of the length of the tuned slot in the axial direction and the length of the second portion in the axial direction is a first axial length and the length of the platform in the axial direction is a second axial length, the first axial length being less than the second axial length.

3. The compressor blade of claim 2 wherein the first portion has a length in the axial direction that is a third axial length, and wherein the first axial length is less than or equal to the third axial length.

4. The compressor blade of claim 3 wherein the second axial length, the third axial length, and the first axial length decrease sequentially.

5. The compressor blade of claim 1 wherein the top surface of the second portion is a second top surface and the top surface of the tuned slot is a third top surface, the third top surface having a height in the radial direction that is greater than or equal to the height of the second top surface in the radial direction.

6. The compressor blade according to claim 5, wherein the top surface of the first portion is a first top surface, and the height of the third top surface in the radial direction is greater than the height of the second top surface in the radial direction and less than or equal to the height of the first top surface in the radial direction.

7. The compressor blade according to any one of claims 1 to 6 wherein the slots of the frequency modulated slots are defined by: and determining a safety factor K1 of the initial peak stress according to the structure of the compressor, and determining the position of the frequency modulation notch in the axial direction of the tenon according to the safety factor K1.

8. The compressor blade according to any one of claims 1 to 6 wherein the slots of the tuned slots are dimensioned: determining a frequency modulation order and a frequency modulation amount, determining a size parameter of the frequency modulation notch according to the position of the frequency modulation notch in the axial direction of the tenon, the frequency modulation order and the frequency modulation amount, and determining the size of the slot according to the size parameter.

9. The compressor blade according to any one of claims 1 to 6 wherein the iterative checking of the slot size of the frequency modulated slots comprises: re-determining a safety coefficient K2 of peak stress according to the slot size, determining an updating order and a corresponding updating frequency, and determining a frequency modulation result according to a difference value between the updating frequency and the initial frequency and the safety coefficient K2 so as to check the slot size; and repeating the steps to carry out iterative checking.

10. The compressor blade of any one of claims 1 to 6 wherein the tuned notch is located on a side of the dovetail facing away from the platform in a radial direction.

11. The compressor blade according to any one of claims 1 to 6, wherein the frequency-modulated slots are through-slots and/or non-through-slots that extend in the circumferential direction.

12. The compressor blade according to any one of claims 1 to 6, wherein the tuning notches are located in the middle and/or on both sides in the axial direction of the dovetail.

13. The compressor blade of claim 12 wherein the interface of the top surface and the side surface of the tuned slot is arcuate.

14. The compressor blade of claim 12 wherein the arc is mirror symmetric with respect to a vertical bisecting plane of the dovetail.

15. The compressor blade as in claim 12, wherein an axial width L of the midmost fm slot is greater than a radius R1 of the arc of the midmost fm slot.

16. The compressor blade as in claim 15, wherein the axial width L of the midmost fm slot is greater than 2 times the radius R1 of the arc of the midmost fm slot.

17. The compressor blade as in claim 12, wherein the radius of curvature R2 of the tuned notch on both sides is greater than a fourth axial length that is half the difference between the second axial length and the axial length of the second portion of the dovetail.

18. The compressor blade of claim 1 wherein the dovetail is inverted T-shaped in cross-section.

19. The compressor blade of claim 18 wherein a cross-section of the first and second portions of the dovetail forms an inverted T-shape in a radial direction.

20. The compressor blade of claim 19 wherein said first portion has a cross-sectional width less than a cross-sectional width of said second portion.

21. The compressor blade according to claim 1, wherein the number of frequency modulated slots is 1 to 3.

22. A method of determining the size of a tuned slot in a compressor blade according to any one of claims 1 to 21, comprising the steps of:

determining a safety coefficient K1 of initial peak stress according to the structure of the compressor, and determining the position of a frequency modulation notch in the axial direction of the tenon according to the safety coefficient K1 so as to determine the slotting mode of the frequency modulation notch;

determining the frequency modulation order and the frequency modulation quantity of the compressor blade, and determining the slotting size corresponding to the frequency modulation order and the frequency modulation quantity of the compressor blade according to the position of the frequency modulation notch in the axial direction of the tenon;

and performing iterative checking on the slotting size.

23. The method of claim 22, wherein the slotting comprises slotting in the axial middle and/or sides of the tenon and obtaining frequency-modulated slots in the circumferential direction for adjusting the frequency.

24. The method of determining of claim 22, wherein iteratively checking the slot size comprises:

according to the size of the slot, determining a safety factor K2 of the peak stress again;

updating each order frequency;

calculating each order frequency difference value of each updated order frequency and each order initial frequency, and checking according to the safety coefficient K2 of the peak stress and each order frequency difference value;

if the calibration is passed, determining the size of the slot; and if the checking fails, resetting the slotting size and repeating the steps for iterative checking.

25. The method of claim 24, wherein the criteria for passing is: the safety factor K2 of the peak stress and the frequency difference of each order meet the design requirement.

26. A compressor comprising a rotor including a disk and the compressor blade of claim 1 mounted on the disk.

27. A gas turbine engine comprising a compressor according to claim 26.

Technical Field

The invention relates to a gas turbine, in particular to a compressor blade and a method for determining the size of a frequency modulation notch of the compressor blade, a compressor and the gas turbine.

Background

The compressor generally includes a wheel disc and blades arranged on the wheel disc, and the wheel disc rotates to drive the blades to rotate, so that the blades compress air to do work. Because the blade sets up on the rim plate, when the weight of blade is great, will lead to the load of rim plate heavier, and then influence the rotation of rim plate to fixed the difficulty that brings the blade. When the compressor is designed, the resonance of each order of frequency of the blades of the compressor is ensured not to be generated, and the danger brought by the resonance is avoided. Therefore, when the blade structure is designed initially, the frequency is usually adjusted. In designing the blade, it is necessary to reduce the weight of the blade as much as possible, and to adjust the frequency of the blade to avoid resonance.

There are proposals to provide a frequency modulated structure on the blade to vary the blade frequency. For example, patent CN208900416U discloses a compressor blade for heavy-duty gas turbine, which comprises a blade body, wherein the blade body comprises a blade body, a rim and a tenon, the bottom of the tenon is provided with a blind adjusting hole for adjusting frequency, the bottom of the rim is provided with a notch, and a damping ring is installed in the notch. Wherein, a plurality of blind adjusting holes are needed to be arranged at the bottom of the tenon, and the depths of the blind adjusting holes are different. This patent is through seting up the regulation blind hole that is used for the frequency modulation, and then can change the graduation of blade quality and rigidity to realize the frequency modulation, avoid the blade to take place resonance phenomenon. However, this patent does not disclose how the size and shape of the blind holes are determined. That is, the patent only proposes the concept of setting the adjusting blind hole on the blade to adjust the frequency, but does not give the specific size of how to set the blind hole, and in addition, the influence of the adjusting blind hole on the rigidity properties of the blade body and the tenon is small, that is, the frequency of the blade cannot be accurately adjusted through the blind hole. Meanwhile, a plurality of blind holes are required to be formed in the method, so that the mechanism is troublesome in design, quantitative estimation can not be carried out in the design stage, the frequency modulation amount can only be determined through experiments and multiple experiences, and accurate frequency modulation can not be realized in the design stage. In the aspect of weight reduction, the blind holes are generally small in size, and the weight of the blade cannot be effectively reduced.

In the current patent, for example, CN111156196A, an intermediate metal plate is disposed in a blade body, and a blade cavity is formed by the intermediate metal plate, a skin is disposed at an edge of the blade body, and the skin is connected to the intermediate metal plate; the tenon comprises a first tenon tooth surface pair and a second tenon tooth surface pair, the first tenon tooth surface pair and the second tenon tooth surface pair are symmetrically arranged, and a tenon cavity is arranged between the opposite inner tenon tooth surfaces of the first tenon tooth surface pair and the second tenon tooth surface pair; the blade body with the tenon is connected, just the tenon cavity with the blade cavity intercommunication. Namely, the weight of the blade is reduced by designing the blade body and the tenon into a hollow structure. I.e. all the way to reduce the weight of the blade, nothing is mentioned about how to adjust the frequency of the blade. In summary, there is a need for a solution that can not only accurately adjust the frequency of the blade, but also effectively reduce the weight of the blade.

The present invention has been made in view of the above problems.

Disclosure of Invention

The invention mainly aims to provide a compressor blade to solve the problem that the frequency of the blade cannot be accurately adjusted and the mass of the blade cannot be effectively reduced in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a compressor blade comprising a blade body including a blade body, a rim plate, and a tenon, wherein an upper end of the rim plate is connected to the blade body, and a lower end of the rim plate is connected to the tenon, wherein the tenon includes a first portion connected to the rim plate and a second portion connected to the first portion, and the tenon further includes a frequency modulation notch opened in a circumferential direction to adjust a frequency, and the frequency modulation notch changes a radial area of the tenon to implement frequency modulation. The radial area of the tenon can be changed by arranging the frequency modulation notch so as to realize accurate frequency modulation on the blade, and the weight of the blade can be effectively reduced.

Further, the axial length of the frequency modulation notch needs to satisfy the following relationship: the sum of the length of the frequency-adjusting notch in the axial direction and the length of the second part in the axial direction is a first axial length, the length of the flange plate in the axial direction is a second axial length, and the first axial length is smaller than the second axial length.

Further, the length of the first part in the axial direction is a third axial length, and the first axial length is smaller than or equal to the third axial length. The tenon narrows from the first portion to the second portion and is tapered for insertion into a bucket slot for mounting the bucket.

Further, the second axial length, the third axial length and the first axial length decrease in sequence. Along the downward direction, the first part, the second part of listrium, tenon narrow in proper order, do benefit to the tenon grafting in above-mentioned blade groove to do benefit to the listrium butt at the fixed blade in the top of blade groove.

Further, the height of the frequency modulation notch should satisfy the following condition: the top surface of the second portion is a second top surface, the top surface of the frequency modulation notch is a third top surface, and the height of the third top surface in the radial direction is larger than or equal to the height of the second top surface in the radial direction.

Further, the top surface of the first portion is a first top surface, and the height of the third top surface in the radial direction is greater than the height of the second top surface in the radial direction and is less than or equal to the height of the first top surface in the radial direction. The frequency-modulated notch must not be higher than the first portion in the radial direction.

To achieve the above object, according to one aspect of the present invention, there is provided a method of notching a frequency-modulated notch, comprising: and determining a safety factor K1 of the initial peak stress according to the structure of the compressor, and determining the position of the frequency modulation notch in the axial direction of the tenon according to the safety factor K1.

Further, the iterative checking of the slotting size of the frequency-modulated slot comprises: re-determining a safety coefficient K2 of peak stress according to the slot size, determining an updating order and a corresponding updating frequency, and determining a frequency modulation result according to a difference value between the updating frequency and the initial frequency and the safety coefficient K2 so as to check the slot size; and repeating the steps to carry out iterative checking. Further, the iterative checking of the slotting size of the frequency-modulated slots comprises: determining a safety coefficient K2 for updating the peak stress according to the size of the slot to determine an updating order and a corresponding updating frequency, and determining a frequency modulation result according to a difference value between the updating frequency and the initial frequency and the safety coefficient K2 to check the size of the slot; and repeating the steps to carry out iterative checking.

Further, the tuning notches are located on a side of the tenon that is remote from the platform in the radial direction. Avoid the frequency modulation notch to influence the intensity of listrium.

Further, the frequency modulation notches are through grooves penetrating in the circumferential direction and/or non-penetrating notches.

Furthermore, the frequency modulation notches are positioned in the middle and/or on two sides of the axial direction of the tenon.

Furthermore, the junction of the top surface and the side surface of the frequency modulation notch is in a circular arc shape. The arc shape avoids scratching the hand.

Furthermore, the circular arc is mirror-symmetrical relative to the vertical median plane of the tenon.

Further, the axial width L of the fm notch at the middle is greater than the radius R1 of the arc of the fm notch at the middle.

Further, the axial width L of the fm notch at the middle portion is greater than 2 times the radius R1 of the arc of the fm notch at the middle portion.

Further, the circular arc radius R2 of the fm notch on both sides is larger than the fourth axial length, which is half the difference between the second axial length and the length of the second part of the tenon in the axial direction.

Furthermore, the cross-section of tenon is the type of falling T.

Further, the first portion has a cross-sectional width that is less than a cross-sectional width of the second portion.

Further, the number of frequency modulation notch is 1 ~ 3.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for determining a size of a frequency modulation notch in a compressor blade as above, comprising the steps of:

determining a safety coefficient K1 of the initial peak stress according to the structure of the compressor, and determining the position of the frequency modulation notch in the axial direction of the tenon according to the safety coefficient K1 so as to determine the slotting mode of the frequency modulation notch;

determining the frequency modulation order and the frequency modulation quantity of the compressor blade, and determining the slotting size corresponding to the frequency modulation order and the frequency modulation quantity of the compressor blade according to the position of the frequency modulation notch in the axial direction of the tenon;

and (5) performing iterative checking on the size of the slot.

Further, the slotting mode includes slotting in the middle and/or two sides of the tenon in the axial direction and obtaining a frequency modulation slot for adjusting the frequency in the circumferential direction.

Further, the iterative checking of the size of the slot includes:

according to the size of the slot, re-determining the safety coefficient K2 of the peak stress;

updating each order frequency;

calculating each order frequency difference value of each order frequency and each order initial frequency after updating, and checking according to the safety coefficient K2 of the peak stress and each order frequency difference value;

if the calibration is passed, determining the size of the slot; and if the check is not passed, resetting the slotting size and repeating the steps for iterative check.

Further, the passing criteria of the check are: the safety factor K2 of the peak stress and the frequency difference of each order meet the design requirement.

To achieve the above object, according to one aspect of the present invention, there is provided a compressor including a rotor including a disk and the above compressor blades mounted on the disk.

In order to achieve the above object, according to one aspect of the present invention, there is provided a gas turbine including the compressor as above.

By applying the technical scheme of the invention, the frequency of the blade can be adjusted by arranging the frequency modulation notch on the tenon of the blade, and the radial area can be accurately adjusted by changing the position and the size of the frequency modulation notch, so that the precise adjustment of the frequency of the blade is realized. The frequency modulation notch is arranged on the tenon of the blade, so that the weight of the blade can be effectively reduced, and the bearing of the supporting device can be reduced.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows an isometric view of a blade and blade slot with a frequency tuning notch disposed in the middle according to the present invention; and

FIG. 2 shows a schematic front view of a frequency tuning slot according to the present invention positioned in the center of the blade and blade slot; and

FIG. 3 shows a schematic side view of a frequency tuning notch positioned in the center blade and blade slot according to the present invention; and

FIG. 4 illustrates an isometric view of a dovetail and platform of a blade with a frequency tuning slot disposed in the middle according to the present invention; and

FIG. 5 shows a schematic front view of a dovetail and platform of a blade with a frequency tuning slot disposed in the middle according to the present invention; and

FIG. 6 shows a schematic side view of a dovetail and platform of a blade with a frequency tuning slot disposed in the middle according to the present invention; and

FIG. 7 shows an isometric view of a blade and blade slot with frequency modulated notches disposed on both sides according to the present invention; and

FIG. 8 shows a schematic front view of a blade and blade slot with frequency modulated notches on both sides according to the present invention; and

FIG. 9 shows a schematic side view of a blade and blade slot with frequency modulated notches on both sides, according to the present invention;

FIG. 10 shows an isometric view of a dovetail and platform of a blade with tuned slots on both sides, in accordance with the present invention, and;

FIG. 11 shows a schematic front view of a dovetail and platform of a blade with tuned slots on both sides, in accordance with the present invention, and;

FIG. 12 shows a schematic side view of a dovetail and platform of a blade with frequency tuning slots on both sides according to the present invention.

Wherein the figures include the following reference numerals:

1. a leaf body; 2. a flange plate; 3. a tenon; 31. a first portion of a tenon; 32. a second portion of the tenon; 4. a frequency modulation notch; 5. a blade groove; 6. a wheel disc.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

The present invention is described in further detail below with reference to specific examples, which are not to be construed as limiting the scope of the invention as claimed. The term "comprising" when used indicates the presence of a feature but does not preclude the presence or addition of one or more other features.

The compressor generally comprises a wheel disc 6 and blades arranged on the wheel disc 6, and the rotating wheel disc 6 drives the blades to rotate, so that the blades compress air. Therefore, when the blade is designed, the blade needs to meet the design requirement of hydrodynamics, and the frequency of the blade needs to be adjusted, so that the blade can not generate resonance at different orders of frequency, and the danger is avoided. When the blades are designed, the weight of the blades is reduced as much as possible, the bearing of the supporting device is reduced, and the phenomenon that the rotation of the wheel disc 6 is influenced by the overweight of the blades is avoided. Especially for heavy duty gas turbines, the blades are relatively large, and more care should be taken in design to tune the frequency and reduce weight. The technical scheme of the compressor blade design provided by the invention not only can accurately realize the frequency adjustment of the blade, but also can effectively reduce the weight of the blade.

A compressor blade generally includes a blade body including a body 1, a platform 2, and a dovetail 3. The blade body 1 is a main body for compressing air, the tenon 3 is a part of the blade for being inserted on the wheel disc 6, and the flange plate 2 is a position limiting part which is abutted against the top end of the blade groove 5 for inserting the blade on the wheel disc 6 after the blade is inserted on the wheel disc 6. The connection relationship among the three is as follows: the flange plate 2 is arranged in the middle, the upper end of the flange plate 2 is connected with the blade body 1, and the lower end of the flange plate 2 is connected with the tenon 3. The tenon 3 comprises a first part 31 connected with the flange 2 and a second part 32 connected with the first part 31, namely, the tenon 3 is divided into the first part 31 and the second part 32 according to the change of the cross-sectional shape.

The invention provides that a frequency modulation notch 4 which is arranged along the circumferential direction of a wheel disc 6 is arranged on a tenon 3, and the radial area of the tenon 3 is changed through the frequency modulation notch 4 so as to realize frequency modulation. And the change of the position of the frequency modulation notch 4 arranged on the tenon 3 and the change of the size of the frequency modulation notch 4 can adjust the radial area of the tenon 3, thereby realizing the accurate adjustment of the frequency of the blade.

The invention has reasonable design that the frequency modulation notch 4 is arranged on the tenon 3 of the blade. The provision of the frequency-modulated slots 4 in the blade airfoil 1 of the blade would likely disrupt the profile of the airfoil 1 and thereby affect the gas flow at the airfoil 1. If the frequency-modulated notches 4 are provided in the platform 2, the abutting effect between the platform 2 and the blade groove 5 will be affected, and the fixation of the blade may be affected. Therefore, the scheme that the frequency modulation notch 4 is arranged at the position of the tenon 3 is more reasonable, and the fixing and the operation of the blade cannot be influenced.

The shape structure of the frequency modulation notch needs to meet the following conditions:

the frequency-adjusting notch 4 can be arranged at any position on the tenon 3, and the axial extension length of the frequency-adjusting notch 4 at any position meets the following conditions: the sum of the length of the frequency-modulated notch 4 in the axial direction and the length of the second portion 32 in the axial direction is a first axial length, and the length of the flange 2 in the axial direction is a second axial length, and the first axial length is smaller than the second axial length. That is, as described above, the platform 2 should have an abutting and limiting effect on the vane groove 5, and therefore the axial length of the platform 2 should be greater than the axial length of the second portion 32 of the dovetail 3 and the tuned slot opening 4. The edge plate 2 serves to receive the blade body 1, so that the edge plate 2 should be relatively long. If the second portion 32, the tuned slot 4, extends axially longer, it will also affect the insertion of the dovetail 3 into the blade slot 5.

Preferably, the length of the first portion 31 in the axial direction is a third axial length, and the first axial length is less than or equal to the third axial length. That is, the tenon 3 is narrowed from the first portion 31 to the second portion 32 in the axial direction, so that the integral tenon 3 is tapered in the axial direction, and thus the shape of the tenon 3 is convenient for being inserted and fixed in the blade groove 5. Further preferably, the second axial length, the third axial length and the first axial length decrease in this order. I.e. the rim plate 2, the first part 31 and the second part 32 of the locking head are successively narrowed in the axial direction, which facilitates the stabilization of the blade body 1 and facilitates the insertion of the above-mentioned tenon 3 in the blade groove 5.

As shown in fig. 1-12, the radial height of the tuning notch 4 should also satisfy the following condition: the top surface of the second portion 32 is a second top surface, and the top surface of the frequency-modulated notch 4 is a third top surface having a height in the radial direction greater than or equal to the height of the second top surface in the radial direction. The radial height of the frequency modulation notch 4 is larger than that of the second part 32, so that the frequency modulation notch 4 has a certain radial height, and the effect of effective weight reduction can be achieved.

Further preferably, the top surface of the first portion 31 is a first top surface, and the height of the third top surface in the radial direction is greater than the height of the second top surface in the radial direction and is less than or equal to the height of the first top surface in the radial direction. When the height of the fm slot 4 is greater than the radial height of the first top surface, it may cause the fm slot 4 to communicate with the rim plate 2, thereby affecting the structure of the rim plate 2. This is to avoid the tuning notches 4 from affecting the stability of the tongue 3 and the flange 2 due to their high radial extension.

As shown in fig. 1-12, the intersection of the top surface and the side surface of the frequency-adjusting notch 4 is in the shape of a circular arc. The arc shape can play a role in stable transition and avoid hurting hands in the process of blade installation and processing. Preferably, the circular arc is mirror-symmetrical relative to the vertical median plane of the rabbet 3, which is convenient for design and has beautiful appearance. For the solution in which the fm notch 4 is arranged in the circumferential middle of the rabbet 3: the axial width L of the frequency modulation notch 4 is larger than the radius R1 of the circular arc of the frequency modulation notch 4 positioned in the middle; the axial width L of the fm notch 4 in the middle is greater than 2 times the radius R1 of the circular arc of the fm notch 4 in the middle. I.e. to ensure that the axial width of the frequency-modulated notch 4 is at least greater than the sum of the axial widths of the two arcs. For the solution in which the fm notches 4 are provided on both sides of the circumference of the tenon 3: the radius R2 of the arc of the tuning notch 4 is greater than a fourth axial length, which is half the difference between the second axial length and the length of the second part 32 of the tenon 3 in the axial direction.

As shown in particular in fig. 1-12, the cross-section of the tenon 3 may be of an inverted T-shape. The second portion 32 of the tenon 3 is narrowed toward the first portion 31 in the radial direction, and the first portion 31 and the second portion 32 of the tenon 3 form an inverted T-shape in the radial direction in cross section. That is, the first portion 31 of the tenon 3 constitutes a narrower "I" portion of the inverted T-shaped structure in the radial direction, and the second portion 32 of the tenon 3 constitutes a wider "one" portion of the T-shaped structure. It is further preferred that the cross-sectional width of the first portion 31 is smaller than the cross-sectional width of the second portion 32. In the radial direction, the second portion 32 is wider than the first portion 31, so that the structure of the integral tenon 3 is more stable.

In fact, any number of frequency modulation notches 4 can be arranged on the tenon 3, but in order to avoid difficulty in design and avoid the influence of the more frequency modulation notches 4 on the strength of the tenon 3, the frequency modulation notches 4 are preferably 1-3 in number.

According to the scheme of the compressor blade, the effect of adjusting the frequency of the blade can be achieved by arranging the frequency-adjusting notch 4 on the tenon 3 of the blade to adjust the radial area of the tenon 3, and the effect of reducing the weight of the blade can be achieved by arranging the frequency-adjusting notch 4 on the tenon 3.

Design of frequency modulation notch:

the above discusses the condition that the shape of the fm slot 4 needs to satisfy at the time of design, and the following will discuss how to design the fm slot 4 in detail. When designing the frequency modulation notch 4, firstly, the grooving mode of the frequency modulation notch 4 needs to be determined, and then the specific size of the frequency modulation notch 4 is designed.

Step one, determining a slotting mode:

the slotting mode comprises: the specific position of the frequency-adjusting notch 4 on the tenon 3 is designed, for example, the frequency-adjusting notch 4 can be arranged in the middle or at the outer edge of the tenon 3. The slotted mode also includes the type of the frequency-modulated slots 4, for example, the frequency-modulated slots 4 may be provided as through slots or slots with closed ends. The slotting method also includes the shape of the specific frequency-modulation slot 4, for example, the frequency-modulation slot 4 is set to be a long circular slot or an arc slot, etc.

When the grooving mode of the frequency modulation notch 4 is specifically designed, the grooving mode is mainly determined according to the structure of the blade. When blade self intensity was stronger promptly, it is less to its influence to set up frequency modulation notch 4 on tenon 3, can not produce the risk that blade intensity is not enough, so can set up frequency modulation notch 4 in the great position of intensity influence, for example the position of the axial middle part of well tenon 3 to frequency modulation notch 4 can set up to workable, nevertheless to the great logical groove of intensity influence. When the strength of the blade itself is poor, it is necessary to set the frequency-modulated notch 4 at a position that has less influence on the strength, such as the outer edge of the tenon 3.

The safety factor of peak stress K1 is only segmented with the structure of the material itself, and the safety factor of peak stress K1 can reflect the strength of the blade. The stronger the strength of the blade, the easier it is to ensure safety when the blade is subjected to peak stress, i.e. the greater the safety factor K1 for the peak stress of the blade. Therefore, the slotting mode of the frequency modulation slot 4 is determined as follows: and determining a safety factor K1 of initial peak stress according to the structure of the compressor, and determining the position of the frequency modulation notch 4 in the axial direction of the tenon 3 according to the safety factor K1 so as to determine a slotting mode. More specifically, the notch is formed in the axial middle or other positions of the tenon 3 according to the safety factor K1 of the peak stress. When the safety coefficient K1 of the initial peak stress is larger, the frequency modulation notch 4 is arranged at the axial middle part of the tenon 3; when the safety factor K1 of the initial peak stress is small, the frequency-modulated notch 4 is set at a position that has a small influence on the strength of the tenon 3.

Two embodiments are described below to illustrate specific grooving methods.

Slotted embodiment example 1

When the safety factor K1 for the initial peak stress is > 1.75, the tuned notch 4 is arranged in the axial middle of the tenon 3, as shown in fig. 1 to 6. Since the safety factor K1 of the initial peak stress is greater than 1.75, it is considered that the strength of the blade itself is high, so the frequency-modulated notch 4 can be provided at the middle position of the tenon 3 where the stress is large. And the frequency modulation notch 4 is arranged to be a through groove which is easier to machine and is arranged along the circumferential direction of the tenon 3. Specifically, the frequency modulation notch 4 is of a structure similar to a cuboid, and round chamfers with relatively large radiuses are arranged at two vertex angles of the top of the frequency modulation notch 4. The shape of the frequency-modulated notch 4 of this structure is convenient for processing.

Slotted mode embodiment 2

When the safety factor K1 of the initial peak stress is larger than 1.75, which indicates that the strength of the blade is weak, the frequency-modulated notch 4 is arranged on the tenon 3 at the two side positions with small influence on the strength. As shown in fig. 7 to 12 in particular, the frequency-modulated notches 4 are provided on both sides of the outer periphery of the tenon 3 in the circumferential direction. The frequency modulation notches 4 on the two sides are arranged to be symmetrical about the axial center line of the tenon 3, and the two frequency modulation notches 4 are arc-shaped structures with openings pointing out of the tenon 3.

Second, determining the slotting size through the steps, the slotting mode is determined, and then the specific slotting size needs to be determined. When the slotting size is determined, the slotting size is required to be preset firstly, then the set slotting size is modified through iterative checking until the checked slotting size meets the design requirement, and then the slotting size is determined.

Namely, the step of determining the size of the slot comprises the following steps:

1. presetting the slotting size of the frequency modulation slot 4:

when the grooving size of the frequency modulation notch 4 is preset, the setting is mainly carried out according to the shape and experience of the frequency modulation notch 4.

Preset Slot sizing EXAMPLE 1

When the frequency-modulated notch 4 is provided in the axial middle of the tenon 3 as shown in fig. 1 to 6, the value R, L, H shown in the drawing is preliminarily preset first. The preset value of L can be determined according to the functional relation with the peak stress safety factor K1, the preset value of H is determined by the size of the blade root and is set according to the conditions that the rounding structure of the tenon 3 cannot be damaged and the like, and a larger value is preset for R.

Preset grooving size example 2

When the fm notches 4 are provided on both sides of the tenon 3 in the axial direction as shown in fig. 6 to 12, the values of α, H shown in the drawings are preliminarily preset first.

2. Iteratively checking the size of the slotting and finally determining the size of the slotting

The iterative checking of the slot size of the frequency-modulated slot 4 comprises: and determining a safety factor K2 for updating the peak stress according to the size of the slot, and determining an updating order and a corresponding updating frequency. Specifically, after the tenon 3 is slotted according to the preset slotting size, the structure of the slotted blade changes, and the safety coefficient of the peak stress is the updated safety coefficient K2 of the peak stress, and the frequencies corresponding to different steps of the blade also change. And recalculating the safety factor K2, the updating order and the corresponding updating frequency of the updated peak stress according to the new structure of the blade. And then checking according to the difference between the updated frequency of each step and the initial frequency and the updated peak stress safety factor K2. If the check is passed, slotting according to the preset slotting size, if the check is not passed, resetting the size of the frequency modulation slot 4, and repeating the steps for iterative check. And determining the size of the frequency modulation notch 4 until the checking is passed.

When the check is not passed every time, the size of the frequency modulation notch 4 is reset according to the formula.

Resizing the tuning notch 4 example 1:

for the solution of providing the fm notch 4 in the middle of the tenon 3 in the axial direction as shown in fig. 1 to 6, a new preset Ln is Ln-1 Δ F/Δ fn, where Ln is the latest preset fm notch 4 axial width, Ln-1 is the last preset fm notch 4 axial width, Δ F is the total required fm, and Δ fn is the change of this frequency. And the new radial height Hn of the frequency modulation notch 4 and the new value of the chamfer Rn are reset by matching with the preset axial width Ln of the frequency modulation notch 4. And the checking is carried out again according to the newly preset values of Ln, Hn and Rn.

Resizing the tuning notch 4 example 2:

for the solution of providing the fm notches 4 on both axial sides of the rabbet 3 as shown in fig. 7-12, the circumferential grooving angle α of the new fm notch 4 preset again is Ln/Lwhole α whole, where Lwhole is the total circumferential length of the circumferential contact surface of the rabbet 3, α whole is the total circumferential angle inclination angle of the rabbet 3, and Ln is the circumferential length of the contact surface of the new fm notch 4; h should be designed as large as possible under the condition of ensuring the integrity of the flow path. Similarly, the above-mentioned check is performed again according to the values of the circumferential grooving angle α and the radial height H of the reset frequency-modulated notch 4. The size of the frequency-modulated notch 4 can be determined by iterative checking until the checking passes.

The standard of the check pass is as follows: and the safety coefficient of the peak stress calculated according to the current blade structure and the difference value between each order of frequency and the initial frequency meet the design requirement. The safety coefficient of the peak stress represents the strength of the blade, and the safety coefficient of the peak stress meets the design requirement, so that the strength of the blade is sufficient; the difference between each order frequency and the initial frequency represents the frequency change amount, and the frequency change amount should be equal to the required frequency modulation amount delta F, which proves that the frequency modulation target is achieved as required.

In the checking process, when the safety coefficient of each order of frequency and peak stress is obtained after the model of the blade is adjusted, calculation checking can be carried out according to one dimension or three dimensions. The three-dimensional calculation is mainly carried out in a finite element simulation mode, a model of the blade does not need to be actually processed, and the safety factors of frequency, strength and peak stress of each order under the corresponding structure can be obtained only according to the three-dimensional model of the blade, so that the effect of reducing the design cost is achieved.

According to the method for determining the size of the frequency modulation notch 4, the finally obtained specific size of the frequency modulation notch 4 can realize the effect of accurately modulating the frequency of the blade in a continuous iteration checking mode, and the final blade structure meets various design requirements. The method for determining the size of the frequency modulation notch 4 provided by the invention does not need to actually process a blade model for many times, and can reduce the processing cost and shorten the design period mainly by means of simulation and iterative checking.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

1. according to the scheme of arranging the frequency modulation notch on the tenon of the compressor blade, the radial area of the tenon can be changed through the frequency modulation notch, and the effect of modulating the frequency of the blade is further achieved; and in turn, the weight of the blade may be reduced by the provision of frequency modulated notches.

2. The size and the shape of the frequency modulation notch designed on the tenon provided by the invention need to meet the conditions, so that the stability of the blade can not be influenced after the frequency modulation notch is designed on the tenon, and the installation and the use of the blade are not influenced.

3. According to the method for determining the size of the frequency modulation notch, the specific size of the finally obtained frequency modulation notch can be ensured to realize the effect of accurately modulating the frequency of the blade in a continuous iteration checking mode, and the final blade structure meets various design requirements such as strength.

4. The method for determining the size of the frequency modulation notch does not need to process the blade for multiple times, is mainly determined in the modes of analog simulation and iterative checking, and can save cost and shorten design period.

5. The invention also provides a compressor and a gas turbine with the compressor blade.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.