Blisk structure for reducing thermal stress of rotor
By setting arc-shaped and isosceles trapezoidal gap-filling grooves at the bottom of the blade root, combined with an arc transition design, the stress concentration problem in the blade root structure is solved, achieving the effect of reducing thermal stress and compressive stress, and improving the stability and strength of the blade root structure.
Patent Information
- Application Number
- CN202522421817.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-11-14
AI Technical Summary
In existing blade root structures, stress concentration occurs at the bottom of the blade root slots on the rotor, making them prone to damage, especially under high temperature and temperature fluctuation conditions.
The gap-filling groove is moved to the bottom of the blade root and adopts a circular arc cross section and an isosceles trapezoidal longitudinal section profile, combined with a circular arc transition design to reduce thermal stress and extrusion stress.
It effectively reduces the thermal and compressive stresses on the blade root structure, avoids damage to the blade root structure, and improves stability and strength.
Smart Images
Figure CN224679558U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a blade root structure for reducing rotor thermal stress, belonging to the field of turbine rotor design technology. Background Technology
[0002] The turbine rotor blade root is a key component connecting the moving blades and the rotor disk. Its core function is to safely and reliably transmit the enormous centrifugal force and airflow force borne by the blades to the rotor.
[0003] The function of the filler grooves in the blade root structure is to accommodate and fix the filler strips, eliminate assembly gaps, and ensure stable operation of the blade root structure under high stress and high speed conditions. In traditional blade root structures, the filler grooves are located at the bottom of the blade root slots on the rotor. This arc-shaped slotted structure faces significant thermal stress risks in the high-temperature moving blade stage in the 550-630℃ range, making the structure susceptible to damage. Especially during temperature fluctuations, the temperature differences across different rotor dimensions cause substantial thermal stress in the rotor's filler grooves. Simultaneously, the rounded edges of the blade root slots also generate significant peak stress.
[0004] In summary, due to its inherent structural characteristics, the existing blade root structure suffers from stress concentration and is prone to damage in the slotted filler strips at the bottom of the blade root grooves on the rotor. Utility Model Content
[0005] This invention aims to solve the technical problem of stress concentration and easy damage in the filler groove at the bottom of the blade root groove on the rotor due to its own structural reasons in the existing blade root structure. Therefore, it proposes a blade root structure to reduce rotor thermal stress, including a blade root intermediate body, a blade root neck, a blade root lower part and a filler groove. The intermediate body, blade root neck and blade root lower part are arranged from top to bottom. The filler groove is opened in the center of the bottom of the blade root and the cross-sectional shape of the filler groove is arc-shaped.
[0006] The blade root structure for reducing rotor thermal stress also includes a blade root groove, which is fitted on the outside of the blade root intermediate body, blade root neck, and lower part of the blade root. The blade root groove includes a blade root groove intermediate body, a blade root groove neck, and a blade root groove lower part arranged from top to bottom. The longitudinal cross-sectional profile of the lower part of the blade root groove is an isosceles trapezoid that is wider at the top and narrower at the bottom, and the four interior angles of the isosceles trapezoid are all rounded.
[0007] As another improvement of this utility model, the width dimension of the leaf root intermediate body is the same as the width dimension of the leaf root groove intermediate body.
[0008] As another improvement of this utility model, the width of the leaf root intermediate body is 58mm, and the width of the leaf root groove intermediate body is 58mm.
[0009] As another improvement of this utility model, the width of the leaf root neck is smaller than the width of the leaf root groove neck, and the length of the leaf root neck is the same as the length of the leaf root groove neck.
[0010] As another improvement of this utility model, the width of the leaf root neck is 26mm and the length of the leaf root neck is 36.5mm; the width of the leaf root groove neck is 30.6mm and the length of the leaf root groove neck is 36.5mm.
[0011] As another improvement of this utility model, the width dimension of the lower part of the blade root is smaller than the base dimension of the isosceles trapezoid in the lower longitudinal section of the blade root groove, and the height dimension of the lower part of the blade root is smaller than the height dimension of the isosceles trapezoid in the lower longitudinal section of the blade root groove.
[0012] As another improvement of this utility model, the width of the lower part of the blade root is 57.6mm, the height of the lower part of the blade root is 27mm, the base of the isosceles trapezoid in the lower longitudinal section of the blade root groove is 66.13mm, and the height of the isosceles trapezoid in the lower longitudinal section of the blade root groove is 28.5mm.
[0013] As another improvement of this utility model, the longitudinal section of the lower part of the leaf root has a rectangular shape, and all four corners of the rectangle are chamfered.
[0014] As another improvement of this utility model, the intermediate body, the blade root neck and the lower part of the blade root are forged into one piece from top to bottom.
[0015] As another improvement of this utility model, the sump groove is used to limit the position of the external sump strip.
[0016] The beneficial effects of this utility model are:
[0017] This invention modifies the common rotor filler groove to the bottom of the blade root. Due to the small size of the blade root (only 27mm in total height at the bottom), it quickly reaches a relatively uniform temperature when facing a temperature gradient. Therefore, the groove here does not bear excessive thermal stress, thus avoiding the problem of excessive thermal stress in the original rotor filler groove. The groove uses a calculated filler groove arc that reduces thermal and compressive stress, without excessively occupying blade root space, avoiding a potential significant reduction in blade root strength. Simultaneously, the lower rounding of the blade root groove is enlarged, and the four interior corners of the isosceles trapezoid are all rounded, effectively reducing stress at the rounded area of the blade root groove. Attached Figure Description
[0018] Figure 1 It is a structural diagram of the leaf root intermediate body, leaf root neck, lower part of leaf root and gap filling groove.
[0019] Figure 2 This is a schematic diagram of the leaf root groove structure. Detailed Implementation
[0020] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. All embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.
[0021] Specific implementation method one: Combining Figure 1 and Figure 2 This embodiment describes a blade root structure for reducing rotor thermal stress. It includes a blade root intermediate body 1, a blade root neck 2, a blade root lower part 3, and a gap-filling groove 4. The intermediate body, blade root neck 2, and blade root lower part 3 are arranged from top to bottom. The gap-filling groove 4 is located at the center of the bottom of the blade root. The cross-sectional shape of the gap-filling groove 4 is arc-shaped. The radius of the arc is 5mm, and the distance from the apex of the arc to the lower surface of the blade root is 4mm.
[0022] The blade root structure for reducing rotor thermal stress also includes a blade root groove, which is fitted on the outside of the blade root intermediate body 1, the blade root neck 2, and the blade root lower part 3. The blade root groove includes a blade root groove intermediate body 11, a blade root groove neck 22, and a blade root groove lower part 33 arranged from top to bottom. The longitudinal section of the blade root groove lower part 33 is an isosceles trapezoid that is wider at the top and narrower at the bottom, and the four interior corners of the isosceles trapezoid are all rounded.
[0023] The intermediate body is 58mm wide, the blade root neck is 26mm wide and 36.5mm long, and the lower part of the blade root is 57.6mm wide and 27mm high. The slotted section is located in the center of the lower part of the blade root and uses a calculated arc to reduce thermal and compressive stress. The blade root groove consists of the intermediate body, the neck, the lower part, and the arc. The intermediate body is 58mm wide, the neck is 30.6mm wide and 36.5mm long, and the lower part is 66.13mm wide and 28.5mm high. The four interior corners of the isosceles trapezoid in the lower part of the blade root groove are rounded.
[0024] The blade root neck has four rounded corners, each 3mm in size. The three chamfered corners on the inlet side are 0.3mm, 0.8mm, and 7.6mm from top to bottom, respectively. The three chamfered corners on the outlet side are 0.3mm, 1.2mm, and 8mm from top to bottom. The rounded corners of the blade root groove, from top to bottom, are: 0.3mm in the middle, 5mm on the top side of the lower part, and 11mm on the bottom side of the lower part. The four chamfered corners at the blade root groove neck are 1mm in size.
[0025] The structure is reasonable, avoiding excessive thermal stress in the original rotor slots and reducing stress in the lower part of the blade root slots.
[0026] Specific Implementation Method Two: Combining Figure 1 and Figure 2 This embodiment differs from Specific Embodiment 1 in that the width of the leaf root intermediate body 1 is the same as the width of the leaf root groove intermediate body 11. Other components and connection methods are the same as in Specific Embodiment 1.
[0027] Specific implementation method three: Combining Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the width of the blade root intermediate body 1 is 58mm, and the width of the blade root groove intermediate body 11 is also 58mm. This design meets the assembly requirements of the blade root structure. Other components and connection methods are the same as in specific embodiment one or two.
[0028] Specific implementation method four: Combination Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the width of the blade root neck 2 is smaller than the width of the blade root groove neck 22, while the length of the blade root neck 2 is the same as the length of the blade root groove neck 22. This design satisfies the assembly requirements of the blade root structure. Other components and connection methods are the same as any one of specific embodiments one to three.
[0029] Specific Implementation Method Five: Combining Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the width of the blade root neck 2 is 26mm and the length is 36.5mm; the width of the blade root groove neck 22 is 30.6mm and the length is 36.5mm. This design meets the assembly requirements of the blade root structure. Other components and connection methods are the same as any one of specific embodiments one to four.
[0030] Specific Implementation Method Six: Combination Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the width of the lower part 3 of the blade root is smaller than the base of the isosceles trapezoid in the longitudinal section of the lower part 33 of the blade root groove, and the height of the lower part 3 of the blade root is smaller than the height of the isosceles trapezoid in the longitudinal section of the lower part 33 of the blade root groove. This design meets the assembly requirements of the blade root structure. Other components and connection methods are the same as any one of specific embodiments one to five.
[0031] Specific implementation method seven: Combining Figure 1 and Figure 2This embodiment differs from specific embodiment one in that the width of the lower blade root 3 is 57.6 mm, the height is 27 mm, the base of the isosceles trapezoid in the longitudinal section of the lower blade root groove 33 is 66.13 mm, and the height is 28.5 mm. This design meets the assembly requirements of the blade root structure. Other components and connection methods are the same as any one of specific embodiments one to six.
[0032] Specific implementation method eight: Combination Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the longitudinal cross-sectional shape of the lower part 3 of the blade root is rectangular, with all four corners chamfered. The four rounded corners of the blade root neck are 3mm in size, and the three chamfered corners on the steam inlet side are 0.3mm, 0.8mm, and 7.6mm respectively from top to bottom. The three chamfered corners on the steam outlet side are 0.3mm, 1.2mm, and 8mm respectively from top to bottom. This design meets the assembly requirements of the blade root structure. Other components and connection methods are the same as any one of specific embodiments one through seven.
[0033] Specific Implementation Method Nine: Combining Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the intermediate body, the blade root neck 2, and the lower blade root 3 are forged into a single piece from top to bottom. Other components and connection methods are the same as any one of specific embodiments one through eight.
[0034] Specific Implementation Method Ten: Combining Figure 1 and Figure 2 This embodiment differs from specific embodiment one in that the grouting groove 4 is used to limit the movement of the external grouting strip. Other components and connection methods are the same as any one of specific embodiments one through nine.
[0035] Combination Figure 1 and Figure 2 Explanation of the working principle of this utility model:
[0036] This invention modifies the common rotor filler groove to the bottom of the blade root. Due to the small size of the blade root (only 27mm in total height at the bottom), it quickly reaches a relatively uniform temperature when facing a temperature gradient. Therefore, the groove here does not bear excessive thermal stress, thus avoiding the problem of excessive thermal stress in the original rotor filler groove. The groove uses a calculated filler groove arc that reduces thermal and compressive stress, without excessively occupying blade root space, avoiding a potential significant reduction in blade root strength. Simultaneously, the lower rounding of the blade root groove is enlarged, and the four interior corners of the isosceles trapezoid are all rounded, effectively reducing stress at the rounded area of the blade root groove.
[0037] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A blade root structure for reducing rotor thermal stress, characterized in that... It includes a leaf root intermediate body (1), a leaf root neck (2), a leaf root lower part (3) and a gap-filling groove (4). The intermediate body, the leaf root neck (2) and the leaf root lower part (3) are arranged from top to bottom. The gap-filling groove (4) is opened at the center of the bottom of the leaf root. The cross-sectional shape of the gap-filling groove (4) is arc-shaped. The blade root structure for reducing rotor thermal stress also includes a blade root groove, which is fitted on the outside of the blade root intermediate body (1), the blade root neck (2) and the lower part of the blade root (3). The blade root groove includes a blade root groove intermediate body (11), a blade root groove neck (22) and a blade root groove lower part (33) arranged from top to bottom. The longitudinal section profile of the lower part of the blade root groove (33) is an isosceles trapezoid that is wider at the top and narrower at the bottom. The four interior corners of the isosceles trapezoid are all rounded.
2. The blade root structure for reducing rotor thermal stress according to claim 1, characterized in that, The width dimension of the leaf root intermediate body (1) is the same as the width dimension of the leaf root groove intermediate body (11).
3. The blade root structure for reducing rotor thermal stress according to claim 2, characterized in that, The width of the leaf root intermediate body (1) is 58mm, and the width of the leaf root groove intermediate body (11) is 58mm.
4. The blade root structure for reducing rotor thermal stress according to claim 1, characterized in that, The width of the leaf root neck (2) is smaller than the width of the leaf root groove neck (22), and the length of the leaf root neck (2) is the same as the length of the leaf root groove neck (22).
5. The blade root structure for reducing rotor thermal stress according to claim 4, characterized in that, The width of the leaf root neck (2) is 26 mm and the length of the leaf root neck (2) is 36.5 mm; the width of the leaf root groove neck (22) is 30.6 mm and the length of the leaf root groove neck (22) is 36.5 mm.
6. The blade root structure for reducing rotor thermal stress according to claim 1, characterized in that, The width of the lower part of the leaf root (3) is smaller than the base of the isosceles trapezoid in the longitudinal section of the lower part of the leaf root groove (33), and the height of the lower part of the leaf root (3) is smaller than the height of the isosceles trapezoid in the longitudinal section of the lower part of the leaf root groove (33).
7. The blade root structure for reducing rotor thermal stress according to claim 6, characterized in that, The width of the lower part of the blade root (3) is 57.6 mm, the height of the lower part of the blade root (3) is 27 mm, the base of the isosceles trapezoid in the longitudinal section of the lower part of the blade root groove (33) is 66.13 mm, and the height of the isosceles trapezoid in the longitudinal section of the lower part of the blade root groove (33) is 28.5 mm.
8. The blade root structure for reducing rotor thermal stress according to claim 1, characterized in that, The longitudinal section of the lower part of the leaf root (3) is rectangular, and all four corners of the rectangle are chamfered.
9. The blade root structure for reducing rotor thermal stress according to claim 1, characterized in that, The intermediate body, the leaf root neck (2), and the lower part of the leaf root (3) are forged together from top to bottom.
10. The blade root structure for reducing rotor thermal stress according to claim 1, characterized in that, The sprue groove (4) is used to limit the position of the external sprue.