CN116398250A - Structure for improving low-pressure turbine blade cascade aerodynamic efficiency - Google Patents
Structure for improving low-pressure turbine blade cascade aerodynamic efficiency Download PDFInfo
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- CN116398250A CN116398250A CN202310437147.6A CN202310437147A CN116398250A CN 116398250 A CN116398250 A CN 116398250A CN 202310437147 A CN202310437147 A CN 202310437147A CN 116398250 A CN116398250 A CN 116398250A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/141—Shape, i.e. outer, aerodynamic form
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/141—Shape, i.e. outer, aerodynamic form
- F01D5/145—Means for influencing boundary layers or secondary circulations
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/147—Construction, i.e. structural features, e.g. of weight-saving hollow blades
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Abstract
The present invention provides a structure for improving aerodynamic efficiency of a low pressure turbine cascade, comprising: an end wall and a blade body; the end wall is a surface of the blade grid channel which is perpendicular to the blade body; the end wall is provided with a plurality of first concave structures, the first concave structures are positioned between two adjacent blade bodies, and the first concave structures are used for enhancing the momentum exchange between the boundary layer flow and the outside main flow, enhancing the near-wall flow kinetic energy and changing the near-wall flow direction; the blade body is provided with a blade suction surface and a blade pressure surface, the blade suction surface is an outer convex surface of the blade body, and the blade pressure surface is an inner concave surface of the blade body; the blade suction surface is provided with a plurality of second concave structures, and the second concave structures are used for inhibiting flow separation on the blade suction surface and avoiding separation vortex. The invention can obviously improve the flow of the blade cascade channels by using the concave structures on the suction surface and the end wall of the blade so as to reduce the pneumatic loss of the low-pressure turbine blade cascade and improve the pneumatic efficiency of the turbine.
Description
Technical Field
The invention relates to the technical field of aviation power equipment, in particular to a structure for improving the aerodynamic efficiency of a low-pressure turbine blade cascade.
Background
In an aviation turbofan engine, the low pressure turbine output power is used to drive the fan of the turbofan engine, which drives a large flow of air through the engine and produces the main engine thrust. Therefore, the operating efficiency and aerodynamic performance of the low pressure turbine have a significant impact on engine performance.
The development of modern aeroengines has placed demands on low pressure turbines for light weight and high efficiency, and therefore the number of blades of the low pressure turbine has to be reduced, and the load on the blades of the low pressure turbine has to be increased continuously, with the consequence that the pitch between the blades of the low pressure turbine is increased, the flow between the blades is more complex, the secondary flow losses on the end walls of the cascade are increased, and therefore the aerodynamic losses of the low pressure turbine cascade are increased, and the aerodynamic efficiency of the low pressure turbine is reduced, which reduces the through-flow capacity of the low pressure turbine, reduces the turbine energy conversion efficiency, and increases the fuel consumption of the engine.
Patent document publication No. CN105507955a discloses a high-pressure turbine transonic guide vane cascade design method, which includes the steps of: enhancing the load from the cascade channel inlet to the cascade channel geometry pre-throat region; dividing the cascade into a forward region, a throat region, and a diffusion region; improving the acceleration of the air flow in the front area and increasing the length of the diffusion area; attenuating expansion acceleration of the supersonic gas stream in the throat region; reducing the acceleration of the airflow in the diffusion area; constructing a compression wave in the diffusion region near the outlet of the channel for deceleration; and (5) completing the design of the blade cascade according to the parametric modeling method of the blade cascade 11. However, this patent document is not applicable to low pressure turbines and the technical solution is different from the present application.
Disclosure of Invention
In view of the shortcomings in the prior art, it is an object of the present invention to provide a structure for improving the aerodynamic efficiency of a low pressure turbine cascade.
According to the present invention there is provided a structure for improving aerodynamic efficiency of a low pressure turbine cascade, comprising: an end wall and a blade body; the end wall is a surface of a blade grid channel perpendicular to the blade body;
the end wall is provided with a plurality of first concave structures, the first concave structures are positioned between two adjacent blade bodies, and the first concave structures are used for enhancing momentum exchange between boundary layer flow and external main flow;
the blade body is provided with a blade suction surface and a blade pressure surface, the blade suction surface is an outer convex surface of the blade body, and the blade pressure surface is an inner concave surface of the blade body;
the blade suction surface is provided with a plurality of second concave structures, and the second concave structures are used for inhibiting flow separation on the blade suction surface and avoiding separation vortex.
Preferably, the plurality of first concave structures are arranged along an arrangement line, and the arrangement line is parallel to the camber line of the blade body.
Preferably, the second concave structures are arranged in a plurality, and the depth of the second concave structures is 0-6.0 mm;
every two second concave structures are a pair of V-shaped structures, and a plurality of V-shaped structures are formed on the suction surface of the blade.
Preferably, the second concave structure is disposed near the most convex position of the blade body and is located on a distance surface 0.1 to 10 times the concave diameter d downstream of the most convex position.
Preferably, the ratio of the concave diameter d of the first concave structure to the blade pitch P of the blade body is 0.01-0.2;
the ratio of the recess depth h of the first recess structure to the recess diameter d of the first recess structure is 0.05-0.3.
Preferably, the axial arrangement spacing s of the first recess structures x The ratio of the concave diameter d of the first concave structure to the concave diameter d of the first concave structure is 1.1-1.5;
from upstream, the distance between the central point of the first concave structure on the arrangement line and the cross section of the blade grid inlet is 1.0-1.5 d;
the axial distance between the central points of the first concave structures at the head and the tail on the arrangement line is L=5-10 d, and the axial distance between the first concave structures at the tail and the section of the blade grid outlet is 0.25-0.5 times of chord length Cx.
Preferably, the first concave structures are arranged at the positions of 0.5P-0.8P in the circumferential direction in the blade grid channel, P is the blade pitch of the blade body, and the first concave structures are arranged closer to the adjacent blade pressure surfaces.
Preferably, from upstream, the first concave structure is located at a position 1.0 d-1.5 d upstream of the blade grid inlet section, and the most downstream first concave structure is located at a position 0.2-0.5 times chord length c upstream of the blade grid outlet section x Is a position of (2);
d is the concave diameter of the first concave structure, and d is 1.0-50mm; c x C is the length of the blade body in the axial direction of the blade grid x The length is 5-20 times the diameter d of the concave.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the second concave structure is arranged on the suction surface of the low-pressure turbine blade, and the first concave structure is arranged on the end wall of the turbine blade cascade, so that the motion direction of near-wall fluid is changed, the pneumatic efficiency of the low-pressure turbine blade cascade is improved, the second concave structure is arranged on the suction surface of the low-pressure turbine blade, the inner cambered surface of the second concave structure interacts with the relatively low-speed near-wall fluid, near-wall flow vortex is induced to form at the downstream of the second concave structure, the momentum exchange between the near-wall flow and the main flow is increased, meanwhile, the flow shear induced by the near-wall flow vortex promotes the near-wall flow to turn over, the capability of the near-wall fluid to overcome the reverse pressure gradient is enhanced, and finally, the laminar flow separation phenomenon on the suction surface of the blade is weakened or vanished, so that the shearing of a laminar flow separation backflow area and the main flow is reduced, and the flow wake of the blade cascade is reduced, and the blade profile loss caused by the two blade profiles is reduced;
2. according to the invention, through interaction of the first concave structure on the end wall surface of the low-pressure turbine blade grid and the secondary vortex on the end wall surface, vortex is generated, the motion energy of near-wall fluid is enhanced, the motion direction of the vortex is changed, and the accumulation of the vortex to the suction side of an adjacent blade is inhibited; the horseshoe vortex strength of the root of the front edge of the blade is weakened, so that the secondary flow vortex system strength of the blade cascade end regions such as channel vortex, angle vortex, trailing edge shedding vortex and the like which are developed and induced later is weakened, and the secondary flow loss caused by the secondary flow vortex system is reduced;
3. according to the invention, through the design that the first concave arrangement line on the surface of the end wall of the low-pressure turbine blade grid is parallel to the camber line of the blade, the transverse flow of the end wall is inhibited or weakened, the effect of horseshoe vortex on the development of secondary flow on the end wall in the blade grid channel is inhibited, and the strength of the secondary flow vortex system at the end region of the blade grid is weakened, so that the secondary flow loss caused by the horseshoe vortex is reduced;
4. the invention solves the problem of pneumatic efficiency reduction caused by secondary flow at the end wall of the low-pressure turbine blade cascade, and simultaneously has simple processing technology of the concave arrangement used by the invention, is effective under the condition of wider incoming flow Reynolds number, and particularly has obvious improvement on the pneumatic efficiency of the ultrahigh-load low-pressure turbine blade cascade.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a dimensional and structural schematic illustration of a structure for improving aerodynamic efficiency of a low pressure turbine cascade in accordance with the present invention;
FIG. 2 is a flow schematic diagram of a structure for improving aerodynamic efficiency of a low pressure turbine cascade in accordance with the present invention;
FIG. 3 is a second flow schematic of the present invention for improving aerodynamic efficiency of a low pressure turbine cascade;
FIG. 4 is a schematic drawing highlighting a second concave structure of the structure for improving aerodynamic efficiency of a low pressure turbine cascade of the present invention;
FIG. 5 is a schematic drawing highlighting a first concave structure of the structure for improving aerodynamic efficiency of a low pressure turbine cascade of the present invention.
The figure shows:
first concave structure 201 of blade body 1
Second concave structure 1011 camber line 4
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
Example 1:
as shown in fig. 1 to 4, the present embodiment provides a structure for improving aerodynamic efficiency of a low-pressure turbine cascade, comprising: the blade comprises an end wall 2 and blade bodies 1, wherein the end wall 2 is a blade grid channel surface perpendicular to the blade bodies 1, a plurality of first concave structures 201 are arranged on the end wall 2, the plurality of first concave structures 201 are located between two adjacent blade bodies 1, the first concave structures 201 are used for enhancing momentum exchange between boundary layer flow and external main flow and changing the near wall flow direction, a blade suction surface 101 and a blade pressure surface 102 are arranged on the blade bodies 1, the blade suction surface 101 is an outer convex surface of the blade bodies 1, the blade pressure surface 102 is an inner concave surface of the blade bodies 1, the blade suction surface 101 is provided with a plurality of second concave structures 1011, and the second concave structures 1011 are used for inhibiting flow separation on the blade suction surface 101 and avoiding generating separation vortex.
The leading edge of the blade body 1 is tangential to the cascade inlet section 5 and the trailing edge of the blade body 1 is tangential to the cascade outlet section 6.
The number of the second concave structures 1011 is plural, the depth of the second concave is 0-6.0 mm, every two second concave structures 1011 are a pair of V-shaped structures, and a plurality of V-shaped structures are formed on the suction surface 101 of the blade. The second recess 1011 is located near the most convex position of the blade body 1 and is located on a distance surface 0.1 to 10 times the recess diameter d downstream of the most convex position.
The first recess structures 201 are disposed along an arrangement line 3, and the arrangement line 3 is parallel to the camber line 4 of the blade body 1.
The axial arrangement spacing s of the first recess structures 201 x Recess diameter d with first recess structure 201The ratio is 1.1-1.5, from the upstream, the distance between the center point of the first concave structure 201 on the arrangement line 3 and the blade grid inlet section is 1.0-1.5 d, the axial distance between the center points of the first concave structures 201 at the head and the tail on the arrangement line 3 is L=5-10 d, and the axial distance between the first concave structure 201 at the tail and the blade grid outlet section 6 is 0.25-0.5 times of chord length Cx.
The ratio of the recess diameter d of the first recess structure 201 to the blade pitch P of the blade body 1 is 0.01 to 0.1, and the ratio of the recess depth h of the first recess structure 201 to the recess diameter d of the first recess structure 201 is 0.05 to 0.3.
From upstream, the first concave structure 201 is located at a position 1.0 d-1.5 d upstream of the cascade inlet section 5, and the most downstream first concave structure 201 is located at a position 0.2-0.5 times chord length c upstream of the cascade outlet section 6 x D is the concave diameter of the first concave structure 201, d is 1.0-50mm, c x C is the length of the blade body 1 in the axial direction of the blade row x The length is 5-20 times the diameter d of the concave.
The first concave structures 201 are arranged at the positions of 0.5P-0.8P in the circumferential direction in the cascade channels, wherein P is the blade pitch of the blade body 1, and the first concave structures 201 are arranged closer to the adjacent blade pressure surfaces.
The embodiment can reduce the secondary flow loss of the low-pressure turbine cascade end region, improve the aerodynamic efficiency of the low-pressure turbine cascade, inhibit the secondary flow vortex system of the low-pressure turbine cascade end region, or weaken the strength of the secondary flow vortex system, reduce the secondary flow loss of the cascade end region, and improve the aerodynamic efficiency of the low-pressure turbine cascade.
In the structure of this embodiment, the first concave structures 201 are arranged on the end wall 2, the arrangement curves of the first concave structures 201 are parallel to the blade camber line 4, as shown in fig. 2 and 3, when the airflow a flows through the end wall 2 and impacts the root of the front edge of the blade body 1, the boundary layer flow forms a multi-layer horseshoe vortex structure at the root of the front edge of the blade due to low flow velocity in the boundary layer, the horseshoe vortex will develop into a channel vortex B of oblique flow, and the angle vortex at the root of the suction surface 101 of the adjacent blade and the shedding vortex D of the trailing edge of the blade are induced, and these vortex structures are called as blade grid end region secondary flow vortex systems.
In the structure of this embodiment, the first recess structure 201 on the wall surface of the end wall 2 can enhance the momentum exchange between the boundary layer flow and the external main flow, and the kinetic energy of the boundary layer flow near the wall surface can be enhanced. As the secondary flow from the blade pressure face 102 passes over the first concave structure 201 on the end wall 2, it will rush into the interior of the first concave structure 201 and interact with the curved wall surface of the first concave structure 201, the first concave structure 201 changes the flow direction of the near-wall vortex, causing the near-wall vortex to flow into the main flow and gaining energy for downstream flow, which reduces the accumulation and intrusion of this secondary flow with low energy flow near the adjacent blade suction face 101, thus reducing the end wall 2 cross flow, inhibiting or reducing horseshoe vortex structure and vortex strength, and thus reducing the cascade end region secondary flow vortex system and its resultant secondary flow losses.
In the structure of the present embodiment, the second concave structures 1011 are arranged on the turbine blade suction surface 101, the second concave structures 1011 are arranged in pairs in a V-shape on the blade suction surface 101, the second concave structures 1011 have an inclination angle β with respect to the air flow, and generally, the second concave structures 1011 are arranged in the vicinity of the downstream of the most convex position of the blade suction surface 101. The second recess is oblong or spherical in shape.
In the structure of this embodiment, the second concave structure 1011 on the blade suction surface 101 plays a role in suppressing flow separation on the blade suction surface 101 and avoiding generation of separation vortex, and reduces aerodynamic loss due to the separation vortex, and also plays a role in suppressing entrainment of the separation vortex on the blade suction surface 101 to the channel vortex B, reducing aerodynamic loss, remarkably improving flow of the cascade channels, and improving aerodynamic efficiency of the turbine.
Specific geometrical parameters of the preferred concave nodes when applied on an ultra-high load low pressure turbine cascade:
a. relative diameter d/P of the concave structures (concave structure diameter/blade pitch) = 0.077,0.01 to 0.1;
b. the depth-to-diameter ratio h/d of the concave structure (concave structure depth/concave structure diameter) = 0.15,0.1 to 0.2;
c. relative arrangement spacing s of concave structures in axial direction x /d (concave junction)Construct axial arrangement pitch/recess diameter) =1.2;
d. the relative arrangement spacing s of the concave structures in the circumferential direction θ P (pitch of circumferential arrangement of concave structures/pitch of blades) =0.1;
e. for the first concave structures 201, the first concave structures 201 are 1.2d from the cascade inlet cross-section, calculated as the center point of the upstream first concave;
f. for the first concave structures 201, the axial length of the arrangement of the first concave structures 201 is 7.2d calculated by the distance between the center points of the head and tail concave structures;
g. the first concave structures 201 are arranged at positions of 0.6P circumferentially in the cascade channels, and are closer to the pressure side;
h. the alignment curve of the first recess structure 201 is parallel to the blade camber line 4.
Example 2:
the present embodiment can be understood by those skilled in the art as a specific description of embodiment 1.
As shown in fig. 1, a row of second recess structures 1011 is arranged on the suction side 101 of the blade and a row of first recess structures 201 is arranged on the end wall 2. The first second recess 1011 is spaced from the cascade inlet section 5 by a cascade axial distance x b . For the first concave structures 201, the diameter of each first concave structure 201 is d, and the spacing between adjacent first concave structures 201 in the axial direction of the blade cascade is s x . The row of first recess structures 201 has a total length l=7.2d in the axial direction of the cascade, and a length L upstream from the cascade inlet section 5.
The first concave structures 201 are arranged along an arrangement line 3, the arrangement line 3 is parallel to the blade camber line 4, and the distance between the arrangement line 3 and the blade camber line 4 in the circumferential direction of the blade grid is p. The arrangement pitch of the blade bodies 1 in the circumferential direction of the blade row is P, and the length of the blade bodies 1 in the axial direction of the blade row is c x . The blade body 1 is tangential to the blade leading edge with the blade cascade inlet section 5 and the blade body 1 is tangential to the blade trailing edge with the blade cascade outlet section 6.
The first concave structures 201 arranged on the wall surface of the end wall 2 induce interaction of the main flow and generate near-wall spiral vortex, promote momentum exchange of near-wall boundary layer low-speed fluid and main flow high-speed fluid, strengthen near-wall fluid kinetic energy to resist transverse pressure gradient in the blade grid channel, reduce deflection of the near-wall fluid to the suction side, reduce flow converging to the suction side horseshoe vortex of the blade, and weaken strength of the suction side horseshoe vortex.
The alignment line 3 of the first concave structure 201 is parallel to the blade camber line 4, and the near-wall spiral vortex formed by the alignment line blocks the cross flow from the pressure side to the suction side, so that the near-wall fluid is promoted to flow along the direction of the blade camber line 4, and the flow organization structure of the near-wall area is improved.
The spreading position of the arrangement of the first concave structures 201 just intercepts the weak point of the pressure side horseshoe vortex, and the internal flow of the pressure side horseshoe vortex is flushed into the first concave structures 201 and interacted with the wall surface of the first concave structures 201 to generate vortex, so that the kinetic energy of the pressure side horseshoe vortex is diffused, and the strength of the pressure side horseshoe vortex is weakened.
The effect on the flow organization structures of the suction side water chestnut vortex, the pressure side water chestnut vortex and the near wall area finally weakens the strength of secondary flow vortex systems such as channel vortex, reduces unnecessary flow shearing, finally reduces secondary flow loss, improves the flow speed, flow direction distribution and flow passage performance in the blade grid channel, and improves the efficiency of the low-pressure turbine.
The first concave structures 201 arranged in an array extend from the blade grid inlet section 5, and influence the flow of the boundary layer at the position where the front boundary layer is thinner, so that the capability of forming a near-wall spiral vortex is stronger, the cross flow on the end wall 2 can be blocked to a greater extent, and the trend of collision of fluid on the near-wall area of the end wall 2 to the suction side is restrained.
The first concave structure 201 is a concave structure, the concave depth is close to the thickness of the near-wall boundary layer, the concave depth does not invade the high-speed main flow area, only the fluid in the near-wall boundary layer is influenced, the flow speed of the main flow is not influenced, no additional shape resistance is generated, and the concave structure has obvious advantages compared with the traditional convex structure.
The length of the first concave structures 201, the 1 st first concave structure 201 is positioned at the position of 1.0 d-1.5 d upstream of the blade grid inlet section 5, and the most downstreamThe first concave structure 201 is located upstream of the cascade outlet section 6 by a chord length c of 0.2-0.5 times x Is a position of (c). The alignment line 3 of the first concave structures 201 on the end wall 2 is parallel to the cascade camber line 4, and the first concave structures 201 are aligned across the convexity of the alignment line 3. Since the near-wall boundary layer develops a thickening downstream of the cascade channels, the channel vortices have approached the suction side and gradually lifted off the end wall 2, the first concave structure 201 of the end wall 2 downstream of the cascade channels will not have an effect on the thicker boundary layer and the secondary flow vortices away from the end wall 2, and will increase the flow losses due to self-induced turbulence.
The wall shape of the first recess structure 201 is spherical or conical, and the shape of the first recess structure 201 may be oblong, for example, the first recess structure 201 is oblong, and the direction of the oblong recess is along the direction of the arrangement line 3.
The first concave structures 201 are arranged on the end wall 2 of the cascade channel, the distance between the arrangement line 3 of the first concave structures 201 and the camber line 4 is 0.5P-0.8P, the arrangement line 3 of the first concave structures 201 is closer to the pressure side of the adjacent blade, and as shown in fig. 1, the arrangement line 3 of the first concave structures 201 is closer to the blade pressure surface 102 of the upper blade body 1.
The invention uses the concave structures on the suction surface and the end wall of the blade, can obviously improve the flow of the blade grid channel and improve the aerodynamic efficiency of the turbine.
In the description of the present application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements being referred to must have a specific orientation, be configured and operated in a specific orientation, and are not to be construed as limiting the present application.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without affecting the spirit of the invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily without conflict.
Claims (8)
1. A structure for improving aerodynamic efficiency of a low pressure turbine cascade, comprising: an end wall (2) and a blade body (1); the end wall (2) is a surface of a blade grid channel perpendicular to the blade body (1);
the end wall (2) is provided with a plurality of first concave structures (201), the first concave structures (201) are positioned between two adjacent blade bodies (1), the first concave structures (201) are used for enhancing the momentum exchange between the boundary layer flow and the outside main flow, enhancing the near-wall flow kinetic energy and changing the near-wall flow direction;
the blade body (1) is provided with a blade suction surface (101) and a blade pressure surface (102), the blade suction surface (101) is an outer convex surface of the blade body (1), and the blade pressure surface (102) is an inner concave surface of the blade body (1);
the blade suction surface (101) is provided with a plurality of second concave structures (1011), and the second concave structures (1011) are used for inhibiting flow separation on the blade suction surface (101) and avoiding generating separation vortex.
2. Structure for improving aerodynamic efficiency of a low pressure turbine cascade according to claim 1, characterized in that several of the first recess structures (201) are arranged along an alignment line (3), which alignment line (3) is parallel to the camber line (4) of the blade body (1).
3. The structure for improving aerodynamic efficiency of a low pressure turbine cascade according to claim 1, characterized in that the second recess structure (1011) is provided in plurality, the depth of the second recess is 0-6.0 mm;
every two second concave structures (1011) are a pair of V-shaped structures, and a plurality of V-shaped structures are formed on the suction surface (101) of the blade.
4. A structure for improving aerodynamic efficiency of a low pressure turbine cascade according to claim 1, characterized in that the second recess structure (1011) is arranged close to the most convex position of the blade body (1) and on a distance surface downstream of the most convex position 0.1-10 times the recess diameter d.
5. The structure for improving aerodynamic efficiency of a low pressure turbine cascade according to claim 1, characterized in that the ratio of the recess diameter d of the first recess structure (201) to the blade pitch P of the blade body (1) is 0.01-0.1;
the ratio of the recess depth h of the first recess structure (201) to the recess diameter d of the first recess structure (201) is 0.05-0.3.
6. The structure for improving aerodynamic efficiency of a low pressure turbine cascade according to claim 5, characterized in that the first recess structure (201) has an axial arrangement spacing s x The ratio of the concave diameter d of the first concave structure (201) to the concave diameter d of the first concave structure is 1.1-1.5;
the distance between the central point of the first concave structure (201) on the arrangement line (3) and the cross section of the blade grid inlet is 1.0-1.5 d from the upstream;
the axial distance between the central points of the first concave structures (201) at the head and the tail on the arrangement line (3) is L=5-10 d, and the axial distance between the first concave structures (201) at the tail and the blade grid outlet section (6) is 0.25-0.5 times of chord length Cx.
7. The structure for improving aerodynamic efficiency of a low pressure turbine cascade according to claim 6, characterized in that the first concave structures (201) are arranged at positions of 0.5P-0.8P in the circumferential direction in the cascade channels, P being the pitch of the blades of the blade body (1), the first concave structures (201) being arranged closer to the adjacent blade pressure surfaces.
8. For increasing low pressure according to claim 1The aerodynamic efficiency structure of the turbine cascade is characterized in that, from upstream, the first one of the first concave structures (201) is located at a chord length c of 0.05-0.3 times upstream of the cascade inlet section (5) x The most downstream first concave structure (201) is located at the upstream of the blade grid outlet section (6) by 0.2-0.5 times of the chord length c x Is a position of (2);
d is the concave diameter of the first concave structure (201), and d is 1.0-50mm; c x C is the length of the blade body (1) in the axial direction of the blade grid x The length is 5-20 times the diameter d of the concave.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310437147.6A CN116398250A (en) | 2023-04-21 | 2023-04-21 | Structure for improving low-pressure turbine blade cascade aerodynamic efficiency |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310437147.6A CN116398250A (en) | 2023-04-21 | 2023-04-21 | Structure for improving low-pressure turbine blade cascade aerodynamic efficiency |
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| CN116398250A true CN116398250A (en) | 2023-07-07 |
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| CN202310437147.6A Pending CN116398250A (en) | 2023-04-21 | 2023-04-21 | Structure for improving low-pressure turbine blade cascade aerodynamic efficiency |
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