Anti-deposition turbine blade with self-excited oscillation air film hole

Abstract

The present application relates to the field of turbine blade cooling technology of an aero-engine, and particularly relates to a turbine blade with self-excited oscillation film holes and capable of resisting deposition, which comprises a blade body, the blade body comprises a pressure surface, a suction surface, a leading edge and a trailing edge, and three rows of self-excited oscillation film holes capable of resisting deposition are arranged in the front part of the pressure surface; the three rows of self-excited oscillation film holes are arranged in a forked manner, two adjacent rows of hole positions are staggered with each other along the blade span direction, and the outlet of the rear row of self-excited oscillation film holes corresponds to the span direction region between the two adjacent film holes of the front row; the present application is provided with three rows of forked self-excited oscillation film holes in the peak deposition area of the pressure surface, and mature conventional film holes are used in the remaining positions, which belongs to a local improvement scheme and reduces the difficulty of modification design. The three rows of film holes are arranged in a forked manner, the oscillation swept film holes are mutually overlapped in the span direction, the film blank between the holes is eliminated, and the film coverage rate of the high deposition area of the pressure surface is improved under the condition that the total equivalent cold gas flow area is unchanged.

Description

Technical Field

[0001] This invention relates to the field of aero-engine turbine blade cooling technology, specifically to an anti-deposition turbine blade with self-excited oscillating film perforations. Background Technology

[0002] During actual service, particles such as sand and ash from the intake environment enter the engine with the air and are carried into the turbine region by the high-temperature mainstream airflow. After colliding with the outer surface of the turbine blades, some particles adhere to the blade surface and gradually accumulate to form a deposition layer. The deposition distribution of particles on the outer surface of the blades is usually significantly non-uniform. Influenced by factors such as the pressure gradient on the blade surface, the mainstream velocity, particle inertia, and the film jet, the degree of particle collision and adhesion varies considerably at different locations. In particular, the leading-middle region of the pressure surface is prone to forming a high deposition zone with a significantly higher particle deposition rate than the surrounding areas.

[0003] Existing turbine blades generally employ conventional cylindrical film cooling orifices. These orifices have a fixed jet direction for the cooled gas, resulting in limited lateral coverage per orifice and potential film coverage blind spots between orifices and rows. To improve film coverage in high deposition zones, traditional methods typically involve simply increasing the cooled gas supply and densifying the orifice arrangement, which leads to a surge in cooled gas consumption, increased blade aerodynamic drag, and decreased overall turbine efficiency.

[0004] In summary, existing conventional film-cooled turbine blades suffer from severe localized particle deposition on the pressure surface and insufficient lateral coverage of conventional film-cooled pores, necessitating the design of a novel anti-deposition turbine blade. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-deposition turbine blade with self-excited oscillating film perforations, which improves the film coverage of the high-deposition region on the pressure surface and inhibits particle adhesion and deposition on the blade surface without increasing the total equivalent cooling air flow area of ​​the three rows of perforations. This solves the technical problems in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an anti-deposition turbine blade with self-excited oscillating film perforation, comprising a blade body, wherein the blade body includes a pressure surface, a suction surface, a leading edge, and a trailing edge, characterized in that:

[0007] Three rows of anti-deposition self-excited oscillating film pores are arranged in the front part of the pressure surface; the three rows of self-excited oscillating film pores are arranged in a staggered manner, with the positions of two adjacent rows of pores staggered along the blade span, and the outlet of the latter row of self-excited oscillating film pores corresponds to the spanwise region between two adjacent film pores in the former row.

[0008] The blade body is provided with a front cooling chamber and a rear cooling chamber; the front cooling chamber and the rear cooling chamber are separated by an internal partition; of the three rows of self-excited oscillating film holes, the two rows near the leading edge are connected to the front cooling chamber, and the row near the trailing edge is connected to the rear cooling chamber.

[0009] Furthermore, with the leading edge of the blade as the starting point of the axial chord length and the trailing edge as the ending point of the axial chord length, the axial chord length is defined as Cx, and the centers of the expansion outlets of the three rows of self-excited oscillating film holes are respectively set at x / Cx=0.32, 0.48 and 0.60.

[0010] Furthermore, the self-excited oscillating film air hole is opened inside the pressure surface wall, and the channel obliquely penetrates the pressure surface wall of the blade; the height of the flow channel of the self-excited oscillating film air hole perpendicular to its own planar structure direction is 0.3mm.

[0011] Furthermore, the self-excited oscillating film air hole includes an air inlet, a power nozzle, a self-excited oscillating chamber, and an expansion outlet arranged sequentially along the cooling air flow direction;

[0012] The air inlet is located at the air inlet end of the self-excited oscillation film orifice; the air inlet is connected to the power nozzle; after the cooling air enters from the air inlet, it passes through the power nozzle and enters the self-excited oscillation chamber; two sets of feedback channels are symmetrically arranged on both sides of the self-excited oscillation chamber; an expansion outlet is provided at the air outlet end of the self-excited oscillation film orifice.

[0013] Furthermore, the air inlet has a horn-shaped structure; the width of the connection between the air inlet and the power nozzle is 0.5mm, and the sidewall of the air inlet tapers inward with a taper angle of 30°.

[0014] Furthermore, the expansion outlet is a fan-shaped structure that gradually widens along the exhaust direction; the expansion angle of the sidewall of the expansion outlet is 70°.

[0015] Furthermore, a trailing edge slit is provided on the trailing edge of the blade, with a width of 1.4 mm.

[0016] Beneficial effects

[0017] This invention incorporates three rows of staggered self-excited oscillating gas film pores in the peak zone of particle deposition on the pressure surface, allowing the structural improvement to directly target the area most in need of anti-deposition protection. The staggered arrangement of the three rows of pores ensures that the oscillating and sweeping gas films overlap longitudinally, eliminating gaps between the pores. Under the condition that the total equivalent cold air flow area remains unchanged, the gas film coverage in the high deposition area of ​​the pressure surface is increased.

[0018] This invention features a front cooling chamber and a rear cooling chamber with separate air supply structures. It supplies air to three rows of self-excited oscillating air film holes at different chordal positions, matching the external mainstream static pressure differences at different positions. This allows for the separate adjustment of the pressure difference and blowing ratio before and after each group of holes, ensuring that all three rows of holes can maintain a stable jet self-excited oscillation effect and avoiding the problem of partial hole row oscillation failure under unified air supply conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 This is a schematic diagram of the air film hole arrangement on the pressure surface of the turbine blade of the present invention;

[0021] Figure 2 This is a schematic diagram of the internal structure of the turbine blade of the present invention;

[0022] Figure 3 This is a schematic diagram of the turbine blade AA section and a partially enlarged structure at position B of the present invention;

[0023] Figure 4 This is a planar structural dimension diagram of a single anti-deposition self-excited oscillation air film pore of the present invention.

[0024] Explanation of reference numerals in the attached diagram: 1. Pressure surface; 2. Suction surface; 3. Leading edge; 4. Trailing edge; 5. Self-excited oscillating film gas hole; 6. Conventional film gas hole; 7. Front cooling chamber; 8. Rear cooling chamber; 9. Internal partition; 10. Trailing edge slit; 51. Air inlet; 52. Power nozzle; 53. Self-excited oscillating chamber; 54. Feedback channel; 55. Expansion outlet. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To achieve the above objectives, the present invention provides the following technical solutions, such as... Figure 1-4As shown, an anti-deposition turbine blade with self-excited oscillating film cooling holes is provided. The blade body is composed of a pressure surface 1, a suction surface 2, a leading edge 3, and a trailing edge 4. A front cooling chamber 7 and a rear cooling chamber 8 are provided inside. After the cooling air enters the front cooling chamber 7 and the rear cooling chamber 8, it is injected into the external mainstream through the film cooling holes of the pressure surface 1 and the suction surface 2, and forms a low-temperature film cooling on the blade surface to reduce the heat exchange intensity between the high-temperature mainstream and the blade wall.

[0027] See Figure 1 The pressure surface 1 has multiple air film vents, including self-excited oscillating air film vents 5 and conventional air film vents 6. Based on the particle deposition distribution outside the pressure surface 1 under design conditions, three rows of anti-deposition self-excited oscillating air film vents 5 are arranged in the particle deposition peak zone at the front of the pressure surface 1. With the leading edge point 3 as the starting point of the axial chord length and the trailing edge point 4 as the ending point of the axial chord length, and defining the axial chord length as Cx, in this embodiment, the center of the expansion outlet 55 of the three rows of self-excited oscillating air film vents 5 is located at x / Cx = 0.32, 0.48, and 0.60, that is, after the dense region of conventional air film vents 6 at the leading edge 3 and before the region at the trailing edge 4. The three rows of air film vents are arranged in a staggered manner, with adjacent rows of vents offset from each other in the blade spanwise direction, so that the outlet of the later row of vents corresponds to the spanwise region between two adjacent vents in the previous row. In this way, the transversely swept air film formed by the self-excited oscillating air film vents 5 can overlap between adjacent rows, reducing the gaps in the coverage between vents and forming a more continuous air film protection for the high deposition zone of the pressure surface 1.

[0028] Besides the three rows of self-excited oscillating film cooling holes 5, all other film cooling holes on pressure surface 1 are conventional film cooling holes 6 with a diameter of 0.5 mm. The conventional film cooling holes 6 maintain the original cooling design, undertaking the film cooling task for most of the blade area; the self-excited oscillating film cooling holes 5 are concentrated in the most severely deposited local areas, representing a localized improvement design, without altering the overall coolant distribution or external aerodynamic shape of the blade. This localized improvement approach maintains the original blade's cooling air distribution and overall structural form as much as possible, while concentrating the more complex self-excited oscillating film cooling holes 5 in the areas where the film coverage and anti-deposition capabilities are most needed.

[0029] See Figure 1 and 3 Inside the blade wall, a front cooling chamber 7 and a rear cooling chamber 8 are provided for the three rows of self-excited oscillating film holes 5. The front cooling chamber 7 and the rear cooling chamber 8 are isolated within the air supply area by the internal partition wall 9. The two rows of self-excited oscillating film holes 5 near the leading edge 3 are connected to the front cooling chamber 7, and the row of self-excited oscillating film holes 5 near the trailing edge 4 is connected to the rear cooling chamber 8.

[0030] The three rows of holes are located at different chordal positions, resulting in differences in the external mainstream static pressure and the pressure difference before and after the holes. Therefore, the air supply required for the three rows of holes to achieve the target blowing ratio and stable oscillation is not entirely consistent. By supplying air to the front and rear chambers, the air supply conditions of the corresponding hole rows can be adjusted separately, avoiding the simplification of treating the three rows of holes as having an equal air supply. The front cooling chamber 7 and the rear cooling chamber 8 are separated from each other within the air supply area of ​​the aforementioned hole rows. It should be noted that the cooling flow paths at other locations on the blades can be interconnected according to the overall cooling design, as long as the air supply areas corresponding to the three rows of self-excited oscillating film holes 5 are separated by the internal partition 9, the structural requirements of this invention are met.

[0031] See Figure 2 Conventional film cooling holes 6 are opened on the suction surface 2, and self-excited oscillating film cooling holes 5 are not arranged, thus retaining the original cooling structure of the suction surface 2; a trailing edge slit 10 is provided on the trailing edge 4, and the rear cooling chamber 8 is connected to the trailing edge slit 10; the width of the slit is set to 1.4mm to achieve cooling of the trailing edge 4 region.

[0032] See Figure 3 and Figure 4 The self-excited oscillating film air hole 5 is located inside the wall of the pressure surface 1. Its inner side is connected to the internal cooling channel of the blade, and its outer side opens on the outer surface of the pressure surface 1 and is arranged obliquely along the local wall surface. Figure 3 The magnified structure in the image shows the arrangement of the film cooling holes along the wall thickness direction. The self-excited oscillating film cooling hole 5 has a flow channel design height of 0.3 mm in the direction perpendicular to its planar structure. Cooling air can directly enter the self-excited oscillating film cooling hole 5 from the internal cooling channel of the blade, and then be ejected from the orifice of pressure surface 1.

[0033] like Figure 4 As shown, the planar structure of a single anti-deposition self-excited oscillating film air hole 5 has a total length of 4.3 mm and a total width of 2.4 mm. An air inlet 51, a power nozzle 52, a self-excited oscillation chamber 53, and an expansion outlet 55 are sequentially arranged along the cooling air flow direction. The air inlet 51 is located at the air inlet end of the self-excited oscillating film air hole 5; the air inlet 51 is connected to the power nozzle 52; cooling air enters from the air inlet 51, passes through the power nozzle 52, and enters the self-excited oscillation chamber 53; two sets of feedback channels 54 are symmetrically arranged on both sides of the self-excited oscillation chamber 53; an expansion outlet 55 is provided at the air outlet end of the self-excited oscillating film air hole 5.

[0034] The air inlet 51 has a trumpet-shaped structure; the width of the connection between the air inlet 51 and the power nozzle 52 is 0.5mm, and the side wall of the air inlet 51 is constricted inward with a constriction angle of 30°.

[0035] The expansion outlet 55 is a fan-shaped structure that gradually widens along the exhaust direction; the width of the connection between the expansion outlet 55 and the self-excited oscillation cavity 53 is 0.4 mm, the axial length of the expansion outlet 55 section is 0.7 mm, and the expansion angle of the sidewall of the expansion outlet 55 is 70°.

[0036] In operation, cooling air enters through inlet 51, passes through power nozzle 52 to form a high-velocity, concentrated main jet, and then enters self-excited oscillation chamber 53. Feedback channels 54 are located on both sides of self-excited oscillation chamber 53, transmitting pressure changes in the downstream region to the vicinity of power nozzle 52. Under the effect of wall adhesion, the main jet initially deflects to one side and adheres to that side wall. At this point, part of the airflow enters the corresponding feedback channel 54, forming pressure feedback, causing the main jet to detach from its original attachment side and switch to the other side; subsequently, the other side generates feedback in the same manner. This feedback process alternates between the two sides, enabling the main jet to form stable periodic transverse oscillations without any mechanical moving parts.

[0037] The aforementioned self-excited oscillation process is equivalent to using the airflow within the orifice to automatically reverse direction. The main jet initially deflects to one side, and the feedback channel 54 then transmits the pressure change back upstream, pushing the jet to the other side. This process repeats, thus eliminating the need for valves, motors, or other moving parts. While the jet direction of a conventional film gas orifice 6 is relatively fixed, the outlet jet of the self-excited oscillating film gas orifice 5 can sweep back and forth on both sides of the orifice, allowing the same film gas orifice to cover a wider blade surface within one oscillation cycle.

[0038] After the main jet passes through the expansion outlet 55, the 70° fan-shaped structure along the blade span provides a larger lateral expansion space for the jet, and its expansion direction is consistent with the left and right sweeping direction of the self-excited oscillating jet. The self-excited oscillation cavity 53 is responsible for generating the periodic left and right oscillation of the main jet, while the spanwise expansion outlet 55 is equivalent to providing a wider discharge window for the already oscillating jet, allowing the jet to leave the orifice more smoothly at both extreme deflection positions, avoiding the narrow outlet from re-constraining the sweeping width. As a result, the time-averaged spanwise coverage of a single orifice is further increased; combined with the three-row staggered arrangement, the coverage areas of adjacent orifices and adjacent rows can overlap, thereby improving the overall gas film coverage of the high-particle deposition area on pressure surface 1.

[0039] The working principle and process are as follows:

[0040] During the operation of the aero-engine, after the cooling air enters the interior of the blade, part of the cooling air enters the front cooling chamber 7, part enters the rear cooling chamber 8, and the remaining cooling air is delivered to the other cooling channels of the blade, supplying the conventional film cooling holes 6 of the pressure surface 1 and the suction surface 2, and simultaneously supplying the trailing edge slit 10.

[0041] The front cooling chamber 7 supplies air to two rows of self-excited oscillating film air holes 5 near the leading edge 3, and the rear cooling chamber 8 supplies air to one row of self-excited oscillating film air holes 5 near the trailing edge 4. The three rows of staggered self-excited oscillating film air holes 5 each output a periodically sweeping jet of cold gas. The time-averaged film air of the jets overlaps with each other along the spanwise direction, forming a continuous cold gas shielding layer in the high deposition zone of the pressure surface 1.

[0042] The self-excited oscillating film pore structure reduces particle deposition primarily through three aspects: First, the periodic sweeping jet alters the instantaneous velocity direction and vortex structure in the near-wall region, subjecting particles to time-varying aerodynamic forces. This causes some particles to deviate from the wall's trajectory, thus reducing the impact probability. Second, the sweeping jet enhances and periodically alters the local wall shear, making it difficult for particles to form stable deposits near the wall. Third, for particles that have just contacted the wall or have low adhesion strength, strong instantaneous shear and scouring can cause them to detach from the wall and re-enter the mainstream. Intuitively, this structure can both remove some particles from their original impact path before they reach the wall and repeatedly scour particles that have already contacted but not yet firmly deposited.

[0043] Compared to simply increasing the cooling air volume or significantly increasing the number of film cooling holes, this invention primarily expands the film cooling coverage and improves anti-deposition capabilities by altering the unsteady organization of the cooling jet in the target area. The three-row staggered arrangement concentrates the self-excited oscillating film cooling holes 5 on the high deposition area of ​​the pressure surface 1, while the remaining rows still use conventional film cooling holes 6. Therefore, it can balance cooling air utilization, structural complexity, and overall blade aerodynamic performance.

[0044] The pressure surface 1 and the other conventional film cooling holes 6 and suction surface 2 continuously spray out steady-state cooling film to complete the thermal protection of the rest of the blade; the trailing edge slit 10 sprays out cooling airflow to cool and protect the trailing edge 4 of the blade.

[0045] In this embodiment, the total equivalent cooling air flow area of ​​the three rows of self-excited oscillating film cooling holes 5 is equal to that of the original three rows of conventional film cooling holes 6 that were replaced, without consuming additional cooling air. Under numerical calculation conditions of blade cascade pressure ratio of 2.1, mainstream temperature of 1500K, and mainstream to cooling airflow temperature ratio of 2.5, compared with traditional blades that use all conventional film cooling holes 6, this embodiment increases the film coverage of the high deposition zone on the pressure surface 1 by about 30%; reduces the number of particles at the peak particle deposition position by about 70%; and increases the overall blade flow resistance by only 1.32%.

[0046] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A self-excited oscillating film gas hole anti-deposition turbine blade, comprising a blade body, the blade body including a pressure surface (1), a suction surface (2), a leading edge (3), and a trailing edge (4), characterized in that: Three rows of anti-deposition self-excited oscillating film holes (5) are arranged in the front part of the pressure surface (1); the three rows of self-excited oscillating film holes (5) are arranged in a staggered manner, with the positions of two adjacent rows of holes staggered along the blade span, and the outlet of the latter row of self-excited oscillating film holes (5) corresponds to the spanwise region between two adjacent film holes in the former row; a front cooling chamber (7) and a rear cooling chamber (8) are provided in the blade body; the front cooling chamber (7) and the rear cooling chamber (8) are separated by an internal partition (9); the two rows of self-excited oscillating film holes (5) near the leading edge (3) are connected to the front cooling chamber (7), and the row near the trailing edge (4) is connected to the rear cooling chamber (8).

2. The anti-deposition turbine blade with self-excited oscillating film gas holes according to claim 1, characterized in that, With the leading edge (3) of the blade as the starting point of the axial chord length and the trailing edge (4) as the ending point of the axial chord length, the axial chord length is defined as Cx. The centers of the expansion outlets (55) of the three rows of self-excited oscillating film holes (5) are respectively set at x / Cx=0.32, 0.48 and 0.

60.

3. The anti-deposition turbine blade with self-excited oscillating film gas holes according to claim 2, characterized in that, The self-excited oscillating film air hole (5) is opened inside the pressure surface (1) wall, and the hole channel obliquely penetrates the pressure surface (1) wall of the blade; the height of the self-excited oscillating film air hole (5) perpendicular to its own planar structure direction is 0.3mm.

4. The anti-deposition turbine blade with self-excited oscillating film gas holes according to claim 3, characterized in that, The self-excited oscillating air film hole (5) includes an air inlet (51), a power nozzle (52), a self-excited oscillation chamber (53), and an expansion outlet (55) arranged sequentially along the cooling air flow direction; the air inlet (51) is located at the air inlet end of the self-excited oscillating air film hole (5); the air inlet (51) is connected to the power nozzle (52); after the cooling air enters from the air inlet (51), it passes through the power nozzle (52) and enters the self-excited oscillation chamber (53); two sets of feedback channels (54) are symmetrically arranged on both sides of the self-excited oscillation chamber (53); the air outlet end of the self-excited oscillating air film hole (5) is provided with an expansion outlet (55).

5. The anti-deposition turbine blade with self-excited oscillating film gas holes according to claim 4, characterized in that, The air inlet (51) has a trumpet-shaped structure; the width of the connection between the air inlet (51) and the power nozzle (52) is 0.5 mm, and the side wall of the air inlet (51) contracts inward with a contraction angle of 30°.

6. The anti-deposition turbine blade with self-excited oscillating film gas holes according to claim 5, characterized in that, The expansion outlet (55) is a fan-shaped structure that gradually widens along the exhaust direction; the expansion angle of the sidewall of the expansion outlet (55) is 70°.

7. The anti-deposition turbine blade with self-excited oscillating film perforation according to claim 1, characterized in that, The trailing edge (4) of the blade is provided with a trailing edge slit (10), and the width of the trailing edge slit (10) is 1.4mm.

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