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CN-121997475-A - Curved blade and design method thereof

CN121997475ACN 121997475 ACN121997475 ACN 121997475ACN-121997475-A

Abstract

The design method of the curved swept blade comprises the following steps of rotating the blade in the area above the tenon center of gravity of the blade around the engine axis, wherein the blade in the area from the tenon center of gravity to the 30% blade height position rotates around the engine axis towards the back direction, and an included angle is formed between the primitive-level center of gravity at the runner hub and the line connecting the engine axis and the tenon center of gravity of the blade. A swept blade is also provided. The method and the curved blade can enable the root end region of the blade to be in smooth transition with the middle and upper parts, avoid the problem of stress concentration, and realize the smooth transition from the end region in the blade runner to the tenon.

Inventors

  • YANG XIAOHE
  • CAO BO
  • LIU SHIWEN
  • LI JIBAO

Assignees

  • 中国航发商用航空发动机有限责任公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (7)

  1. 1. The design method of the sweep blade is characterized by comprising the following steps of: The blade in the area above the tenon center of gravity of the blade rotates around the engine axis, wherein the blade in the area from the tenon center of gravity to the 30% blade height position rotates around the engine axis to the blade back direction, so that an included angle is formed between the primitive level center of gravity at the runner hub and the connecting line of the engine axis and the tenon center of gravity of the blade, and the 100% blade height is the height from the runner hub to the blade tip.
  2. 2. The method of designing a swept blade as claimed in claim 1, wherein a center of gravity line of each airfoil in a region from a center of gravity of the dovetail to a 30% blade height position is offset toward the suction side.
  3. 3. The method of designing a swept blade of claim 1, further comprising the steps of: the area from the runner hub to the blade tip of the blade comprises a blade root part, a blade middle part and a blade tip part; The blade root part in the blade runner is set to be forward-swept, the blade part is set to be backward-swept, the blade tip part is set to be forward-swept, The juncture of the sweepback of the part in the blade and the sweepforward of the part in the blade is positioned at 30% -60% of the blade height, and the juncture of the sweepforward of the blade tip part and the sweepback of the part in the blade is positioned at 70% -90% of the blade height.
  4. 4. The method of designing a curved swept blade according to claim 2, wherein the relation between the curve and the sweep is made to satisfy the relation δ=σ·tan β, or the calculated deviation from δ=σ·tan β is less than ±10%, where δ is the angle of the curve, σ is the angle of the sweep, and β is the mounting angle of the blade profile.
  5. 5. The method of designing a swept blade of claim 1, wherein the primitive stage center of gravity at the runner hub forms an angle of 5 ° to 15 ° with the line connecting the engine axis and the blade tenon center of gravity.
  6. 6. The method of designing a swept blade as claimed in claim 2, wherein a centroid line of each blade profile in a region from a centroid of the tenon to a 30% blade height position is offset toward the suction surface by an angle of 0 ° to 20 °.
  7. 7. A swept blade designed by the method according to any one of claims 1 to 6.

Description

Curved blade and design method thereof Technical Field The invention relates to the field of aeroengines, in particular to the field of a design method of a swept blade. Background To achieve the economic requirement, the fuel consumption is reduced, the bypass ratio of the fan blades is increased, and the fan hub ratio is decreased. On the other hand, in order to meet the requirement of low noise, the tangential speed of the blade tip of the fan also tends to be reduced. Further, both the reduction in hub ratio and the reduction in tip tangential speed result in a reduction in tangential speed of the fan blade root. In the blade end region, the tangential velocity of the blade root is reduced, and meanwhile, in order to ensure the supercharging ratio of the root of the fan, the blade profile of the root has a larger torsion angle, and the outlet metal angle even bends over the axial direction. However, the tenons of fans, particularly composite fan blades, tend to employ straight tenons for improved molding and machining manufacturability. Therefore, the transition from the large camber profile at the root of the blade to a straight dovetail in a radially very small space is prone to localized twisting, especially in the leading edge region of the blade. The distortion of the local blade profile is unfavorable for trial production and process molding, and a high stress area is formed, so that stress concentration is caused, the local static strength or fatigue strength does not meet the strength requirement, and the service life of the blade is reduced. Disclosure of Invention The invention aims to provide a design method of a swept blade, which realizes smooth transition from an end region in a blade runner to a tenon. The design method of the curved swept blade comprises the following steps of rotating the blade in the area above the center of gravity of the tenon of the blade around the axis of the engine, wherein the blade in the area from the center of gravity of the tenon to the position of 30% of the blade height rotates around the axis of the engine towards the back direction of the blade, so that an included angle is formed between the center of gravity of the primitive stage at the runner hub and the line connecting the axis of the engine and the center of gravity of the tenon of the blade, and the blade height is 100% of the height from the runner hub to the blade tip. In one or more embodiments, the center of gravity line of each blade profile in the region of the tenon's center of gravity to 30% of the blade height position is offset toward the suction surface. In one or more embodiments, the method further comprises the steps of providing a portion of the blade root portion within the blade flowpath as forward swept, providing a portion of the blade tip portion as aft swept, providing a portion of the blade tip portion as forward swept, providing an interface between the aft swept of the portion of the blade and the forward swept of the portion of the blade at 30% -60% of the blade height, and providing an interface between the forward swept of the blade tip portion and the aft swept of the portion of the blade at 70% -90% of the blade height. In one or more embodiments, the relationship of the bend and the sweep is made to satisfy the relationship δ=σ·tan β, or the calculated deviation from δ=σ·tan β is less than ±10%, where δ is the angle of the bend, σ is the angle of the sweep, and β is the mounting angle of the blade profile. In one or more embodiments, the primary gravity center at the runner hub forms an included angle of 5-15 degrees with the line connecting the engine axis and the blade tenon gravity center. In one or more embodiments, the center of gravity line of each blade profile in the region from the center of gravity of the tenon to the 30% blade height position is offset to the suction surface by an angle of 0-20 degrees. It is a further object of the present invention to provide a swept blade designed by the above method. The method solves the problem of stress concentration of the root of the blade, rotates part of the blade body of the fan blade in the flow passage around the engine axis to a certain angle, the primary element level gravity center of the end region moves towards the blade back relative to the tenon, the deflection of the front edge of the primary element level and the tenon in the circumferential direction in the flow passage is obviously reduced, the distortion phenomenon of the front edge of the root extending section can be improved to a great extent, the blade profile gravity center is adjusted in the area from the tenon gravity center to the 30% of the blade height position, the gravity centers of the two cross-section inter-blade profiles deflect towards the suction surface, the connection with the root extending section is facilitated, and the front edge of the blade is enabled to be transited towards the pressure surface relatively quickly, so that