A double-wall blade with helical ribs on the cold air passage wall surface for suppressing sand dust deposition

Abstract

The application discloses a sand ash deposition inhibiting double-layer wall blade with spiral ribs on cold air passage wall surfaces, belongs to the technical field of turbine blade design of an aero-engine, and solves the technical problem that high flow resistance and small scale vortices cannot effectively capture sand ash. The application comprises an impact plate, a target plate and a spoiler column. A plurality of partitions are arranged in the cavity of the impact plate to divide the cavity of the impact plate into a plurality of cold air passages. Spiral ribs are arranged on the inner wall of the cold air passages in a circumferential direction. After passing through the spiral ribs, gas forms large scale vortices in the cold air passages. The spiral ribs are left-handed or right-handed. The spiral ribs make full use of the wall surfaces of the cold air passages, so that large scale vortices are formed in the cold air passages. The sand ash existing in the vortices is thrown to the roots of the spiral ribs due to centrifugal force. Most of the sand ash will be deposited on the surfaces of the ribs, so that the amount of sand ash entering the gap between the plates is significantly reduced, and the cooling attenuation of the wall surfaces caused by sand ash deposition is alleviated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of turbine blade design of an aero-engine, and particularly relates to a double-wall blade with a cold-gas passage wall surface provided with a spiral rib and capable of inhibiting sand ash deposition. BACKGROUND

[0002] In a high-performance aero-engine, since the turbine inlet gas temperature far exceeds the bearing limit of the turbine blade material, effective cooling measures must be taken to ensure the reliable operation of the turbine blade in a high-temperature, high-pressure and high-speed environment. At present, the main solution is to use a double-wall structure blade to reduce the blade surface temperature and improve the ability of the blade to resist high-temperature gas impact. When the aircraft using the double-wall blade is in the take-off and landing stage or passes through a volcanic ash cloud, the aero-engine will inevitably suck in sand ash. The rotor turbine blade can use centrifugal force to throw out the sand ash from the dust removal hole at the blade top, but the stator turbine blade has no clear dust removal design. The sand ash is deposited in the stator turbine blade, which may cause the gas film hole to be blocked, thereby reducing the blowing ratio. Since the thermal conductivity of the sand dust deposited on the surface is less than that of the turbine blade structure, heat is accumulated in the inner wall of the target plate, thereby accelerating the attenuation of the cooling performance of the stator turbine blade.

[0003] Patent CN111425263B Double-wall stator turbine blade with corrugated impact plate, 2022-03-25, has the following disadvantages: the corrugated plate forms small-scale vortices in the airflow entering the cold gas passage. Compared with the large-scale vortices formed by the spiral rib structure, the small-scale vortices formed by the corrugated plate have limited ability to intercept sand ash. Moreover, the corrugated structure is arranged on the impact plate and does not utilize the cold gas passage interwall surface for sand ash inhibition structure design. Compared with the spiral rib structure, the cold gas passage internal space is not fully utilized.

[0004] Patent CN110821573B Turbine blade for slowing down cooling effect degradation by regulating internal dust deposition position, 2022.03.01, has the following disadvantages: the vortices formed by the airflow induced by the cold gas passage internal baffle structure are still small-scale vortices. Compared with the large-scale vortices formed by the spiral rib structure, the small-scale vortices formed by the baffle structure can regulate the air in the entire cold gas passage. The effect of the small-scale vortices formed by the baffle structure on inhibiting sand ash deposition to the inside of the target plate is still limited. SUMMARY

[0005] In view of the high flow resistance and the small-scale vortices that cannot efficiently capture sand ash in the prior art, the application provides a double-wall blade with a cold-gas passage wall surface provided with a spiral rib and capable of inhibiting sand ash deposition.

[0006] In order to achieve the above object, the present application adopts the following technical scheme: a sand and ash deposition inhibiting double-wall blade with spiral ribs on the wall surface of a cold air passage, comprising an impact plate, a target plate and a spoiler column, the impact plate and the target plate form a plate gap, the spoiler column is located in the plate gap, the impact plate has a cavity, a plurality of partitions are arranged in the cavity to divide the cavity into a plurality of cold air passages, a plurality of impact holes are formed in the wall surface of the impact plate, each cold air passage corresponds to a part of the impact holes, a plurality of air film holes are formed in the wall surface of the target plate, spiral ribs are arranged along the inner wall of the cold air passage in the circumferential direction, and the gas entering the cold air passage from the spiral axis direction of the spiral rib forms a large-scale vortex in the cold air passage after passing through the spiral rib, and the spiral rib is a left-handed spiral rib or a right-handed spiral rib.

[0007] In the embodiment of the present application, the ratio of the plate gap spacing to the impact plate thickness is (1-1.5):1;

[0008] In the embodiment of the present application, the ratio of the diameter of the spoiler column to the diameter of the impact hole is (0.5-0.8):1;

[0009] In the embodiment of the present application, the ratio of the thickness of the target plate to the thickness of the impact plate is (1-2):1;

[0010] In the embodiment of the present application, the ratio of the diameter of the air film hole to the diameter of the impact hole is (0.4-0.6):1;

[0011] In the embodiment of the present application, the ratio of the height of the spiral rib to the thickness of the impact plate is (0.8-1):1;

[0012] In the embodiment of the present application, the included angle between the spiral rib and the chord line of the blade is 30-45°;

[0013] In the embodiment of the present application, the number of spiral ribs is 1-5, and the pitch of a single spiral rib is 5-35mm;

[0014] In the embodiment of the present application, the cross-sectional shape of the spiral rib is one of a circle, a polygon, an ellipse and a sector, and the ratio of the cross-sectional area of a single spiral rib to the minimum cross-sectional area of the impact hole is (3-5):1.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] 1. The present application increases the spiral rib structure on the inner wall of the impact plate of the turbine blade, reduces the amount of sand and ash deposition on the inner wall of the target plate, and reduces the cooling attenuation of the turbine blade.

[0017] 2. The spiral rib makes full use of the cold gas passage wall surface, so that large-scale vortex is formed in the cold gas passage, and the ash in the vortex is thrown to the root of the spiral rib due to the centrifugal force, most of which will be deposited on the rib surface, thereby significantly reducing the amount of ash entering the inter-plate gap, and thus relieving the cooling attenuation of the wall surface caused by ash deposition.

[0018] 3. The gas flow entering the impact hole is rotated, the turbulence degree of the gas flow impacting the inner side of the target plate is enhanced, the acting area of the cooling gas flow on the inner side of the target plate is increased, and thus the convective heat exchange capacity of the inter-plate gap of the double-wall structure is enhanced, and the surface of the blade impacted by the main flow of gas is better protected from ablation.

[0019] 4. The turbine blade of the application increases the contact area of the cold gas passage and the impact gas flow by increasing the spiral rib structure, and blocks the dust in the impact gas flow, so that more dust is deposited on the spiral rib of the impact plate. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a partial sectional view of a conventional smooth structure blade;

[0021] Figure 2 is a whole sectional view of a conventional smooth structure blade;

[0022] Figure 3 is a partial sectional view of a spiral rib blade;

[0023] Figure 4 is a whole sectional view of a spiral rib blade;

[0024] Figure 5 is a schematic view of embodiment one;

[0025] Figure 6 is a schematic view of embodiment two;

[0026] Figure 7 is a schematic view of embodiment three.

[0027] In the drawings, 1 is an impact hole, 2 is an impact plate, 3 is an inter-plate gap, 4 is a spiral rib, 5 is a film hole, 6 is a spoiler column, 7 is a target plate, 8 is cooling gas, 9 is high-temperature gas, 10 is a cold gas passage, and 11 is a partition plate. DETAILED DESCRIPTION

[0028] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0029] As Figure 1 shown, a partial sectional view of a conventional smooth structure turbine blade is shown, in which Figure 1As can be seen, when the cooling gas 8 flows in the cooling gas passage, a part of the cooling gas 8 flows through the impact holes 1 on the impact plate 2, the plate gap 3 between the impact plate 1 and the target plate 7, the spoiler column 6 and the film holes 5 on the target plate 7 in turn, and the cooling gas 8 can absorb the heat from the high-temperature gas 9 transferred to the blade when flowing through the plate gap 3, and a cooling film can be formed on the outer wall surface of the target plate 7 after the cooling gas 8 is sprayed from the film holes 5, so that the temperature of the outer wall surface of the target plate 7 is reduced, and the overall cross-sectional view is as shown in Figure 2 However, since the heat transfer coefficient and the temperature difference of the impact plate 2 are relatively small, the heat transfer amount of the impact plate 2 has limited contribution to the cooling effect, and the temperature difference between the high-temperature gas 9 and the cooling gas 8 on both sides of the target plate 7 is large, so that the heat transfer process of the target plate 7 plays a decisive role in the cooling effect.

[0030] Therefore, it is necessary to improve the dust removal capacity of the stator turbine blade to reduce the amount of dust and ash deposited on the inner wall surface of the target plate 7, thereby slowing down the degradation of the cooling performance of the blade, and finally improving the cooling effect of the blade.

[0031] At present, in order to improve the dust removal capacity of the stator turbine blade, the technical personnel has considered adding a screen on the cooling pipeline of the aero-engine to intercept the dust and ash, but the addition of the screen will cause the flow resistance of the cooling gas to increase rapidly, thereby causing the cooling gas flow to be insufficient, which will affect the cooling effect of the blade. And there are also inventions that increase a baffle inside the impact plate, so that the dust and ash in the cooling gas passing through the cooling gas passage is deposited on the baffle, so as to reduce the flow of dust and ash into the plate gap and then deposited on the inner side of the target plate. This baffle structure makes the passing airflow form a small vortex to cause the dust and ash to be deposited near the baffle, but the size of the small vortex is small relative to the cooling gas passage, and it cannot efficiently capture the passing dust and ash for the whole cooling gas passage. And the above structure does not use other cooling gas passage walls that have not arranged the baffle structure to set the baffle structure, so as to maximize the dust and ash capture efficiency.

[0032] The present application is based on this direction to propose a spiral rib structure, which makes up for the shortcomings of the previous one, further improves the dust and ash interception capacity inside the impact plate, and reduces the adverse effects of the dust and ash flowing to the inner side of the target plate on the cooling efficiency.

[0033] As Figures 1-2As shown, the sand ash deposition inhibiting double wall blade with spiral rib on the cold gas passage wall surface of the present application comprises an impact plate 2, a target plate 7 and a spoiler column 6, the target plate 7 is sleeved on the impact plate 2 and forms a plate gap 3 between the impact plate 2 and the target plate 7, the spoiler column 6 is located in the plate gap 3, the two ends of the spoiler column 6 are respectively abutted and fixed on the outer wall surface of the impact plate 2 and the inner wall surface of the target plate 7, the impact plate 2 has a cavity, three partitions 11 are arranged in the cavity of the impact plate 2 to divide the cavity of the impact plate 2 into four cold gas passages 10, a plurality of impact holes 1 are formed on the impact plate 2, each cold gas passage 10 corresponds to a part of the plurality of impact holes 1, and a plurality of film holes 5 are formed on the wall surface of the target plate 7; the impact holes 1 and the film holes 5 are respectively communicated with the plate gap 3.

[0034] When the cooling gas 8 flows in the cold gas passage 10, a part of the cooling gas 8 flows through the impact holes 1 on the impact plate 2, the plate gap 3 between the impact plate 1 and the target plate 7, the spoiler column 6 and the film holes 5 on the target plate 7 in sequence, and the cooling gas 8 can absorb the heat of the high-temperature gas transferred to the blade in the process of flowing through the plate gap 3, and a cooling gas film can be formed on the outer wall surface of the target plate 7 after the cooling gas 8 is sprayed out of the film holes 5, so as to finally achieve the effect of reducing the temperature of the outer wall surface of the target plate 7.

[0035] As shown in Figures 3-4 , a spiral rib 4 is arranged along the inner wall of the cold gas passage 10, and the gas entering the cold gas passage 10 from the spiral line axis direction of the spiral rib 4 forms a large-scale vortex in the cold gas passage 10 after passing through the spiral rib 4, and the sand ash existing in the vortex is thrown to the root of the spiral rib 4 due to the centrifugal force, most of which is deposited on the surface of the rib, thereby significantly reducing the amount of sand ash entering the plate gap, and thus relieving the cooling attenuation of the wall surface caused by sand ash deposition.

[0036] As shown in Figure 3 , the cooling gas 8 enters the cold gas passage 10 from the spiral line axis direction of the spiral rib 4, enters the plate gap 3 through the impact hole 1, flows out of the film hole 5, and mixes with the high-temperature gas 9. The cooling gas 8 is converted into a rotational flow after passing through the spiral rib 4, and the sand ash particles in the cooling gas 8 are impacted on the wall surface of the cold gas passage 10 due to the centrifugal force, a part of the particles are captured by the wall surface, and the number of particles entering the plate gap 3 through the impact hole 1 is reduced, and the overall sectional view is as shown in Figure 4 .

[0037] The spiral rib 4 is provided as a left-hand spiral direction rib or a right-hand spiral direction rib, and the number of spiral ribs is 1-5;

[0038] Embodiment one: as shown in Figure 5As shown, the spiral rib 4 has a left-handed spiral direction with a step size of 10 mm. The ratio of the plate gap 3 to the thickness of the impact plate 2 is 1:1. The ratio of the diameter of the turbulence column 6 to the diameter of the impact hole 1 is 0.5:1. The ratio of the thickness of the target plate 7 to the thickness of the impact plate 2 is 1:1. The ratio of the diameter of the film gas hole 5 to the diameter of the impact hole 1 is 0.4:1. The ratio of the height of the spiral rib 4 to the thickness of the impact plate 2 is 0.8:1. The angle between the spiral rib 4 and the blade chord is 30°. There is one spiral rib. The ratio of the cross-sectional area of ​​a single spiral rib 4 to the minimum cross-sectional area of ​​the impact hole 1 is 3:1.

[0039] Example 2: Figure 6 As shown, the spiral rib 4 has a right-handed spiral direction with a step size of 10 mm. The ratio of the plate gap 3 to the thickness of the impact plate 2 is 1.3:1; the ratio of the diameter of the turbulence column 6 to the diameter of the impact hole 1 is 0.6:1; the ratio of the thickness of the target plate 7 to the thickness of the impact plate 2 is 1:1; the ratio of the diameter of the film gas hole 5 to the diameter of the impact hole 1 is 0.5:1. The ratio of the height of the spiral rib 4 to the thickness of the impact plate 2 is 0.9:1; the angle between the spiral rib 4 and the blade chord is 35°; there is one spiral rib; and the ratio of the cross-sectional area of ​​the spiral rib 4 to the cross-sectional area of ​​the impact hole 1 along the wall normal direction is 4:1.

[0040] Example 3: Figure 7 As shown, two helical ribs 4 are arranged with a rib spacing of 5.6 mm. The helical direction of each helical rib 4 is a right-handed helix with a step size of 30 mm. The ratio of the plate gap 3 to the thickness of the impact plate 2 is 1.5:1; the ratio of the diameter of the turbulence column 6 to the diameter of the impact hole 1 is 0.8:1; the ratio of the thickness of the target plate 7 to the thickness of the impact plate 2 is 2:1; the ratio of the diameter of the film gas hole 5 to the diameter of the impact hole 1 is 0.6:1. The ratio of the height of the helical rib 4 to the thickness of the impact plate 2 is 1:1; the angle between the helical rib 4 and the blade chord is 45°; there are 5 helical ribs; and the ratio of the cross-sectional area of ​​the helical rib 4 to the cross-sectional area of ​​the impact hole 1 along the wall normal direction is 5:1.

[0041] This invention employs a double-walled stator turbine blade on an impact plate 2 with a spiral rib 4 structure on the wall of the cold air passage. The invention adds a spiral rib 4 structure to the inner wall of the impact plate 2, including the wall of the cold air passage 10, thereby creating a large-scale vortex in the passing cold air within the cold air passage 10. Centrifugal force causes sand and ash particles to deposit on the wall of the cold air passage 10, reducing the amount of sand and ash entering the inter-plate gap 3. This controls the deposition position of the sand and ash, effectively reducing the amount of sand and ash deposited on the inner wall of the target plate 7, thereby improving the flow capacity of the cooling gas 8 within the inter-plate gap 3 between the impact plate 2 and the target plate 7, and further improving the film efficiency of the outer wall of the target plate 7.

[0042] The spiral rib 4 structure starts from one end of the cold air channel 10 and ends at the other end of the cold air channel 10. Compared with the baffle structure provided only on one wall of the cold air channel 10, the spiral rib 4 structure makes full use of the wall of the cold air channel 10 to more efficiently achieve the effect of intercepting sand dust. The bottom end of the spiral rib 4 is completely attached to the wall of the cold air channel 10. If the spiral rib 4 covers the impact hole 1, the position of the spiral rib 4 covering the impact hole 1 needs to be punched according to the original impact hole 1 radius, so that the airflow can enter the inter-plate gap 3 from the covered impact hole 1. The spiral rib 4 structure also causes the airflow entering the impact hole 1 to change into a rotational flow. Compared with the impact plate 2 on the traditional smooth structure blade, the rotational flow entering the inter-plate gap 3 from the impact hole 1 has stronger convective heat transfer capacity.

[0043] The scheme in the embodiment is not used to limit the patent protection scope of the application. Any equivalent implementation or change without departing from the application is included in the patent scope of the application.

Claims

1. A double-walled blade with spiral ribs on the wall of a cold air passage to suppress sand and ash deposition, comprising an impact plate, a target plate, and a turbulence column, characterized in that: The shock plate and the target plate form a plate gap, the spoiler column is located in the plate gap, the shock plate has a chamber, the chamber is divided into multiple cold gas passages by multiple partitions, multiple through holes are formed on the wall of the shock plate, each cold gas passage corresponds to a part of the through holes, multiple gas film holes are formed on the wall of the target plate, and a spiral rib is arranged along the inner wall of the cold gas passage in a circumferential direction, so that the gas entering the cold gas passage from the spiral line axis direction of the spiral rib forms a large-scale vortex in the cold gas passage, thereby reducing the amount of sand ash entering the plate gap through the through holes, and the spiral rib is a left-handed spiral rib or a right-handed spiral rib.

2. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold gas passage wall surface according to claim 1, characterized in that: The ratio of the plate gap to the thickness of the shock plate is (1-1.5):

1.

3. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The ratio of the diameter of the spoiler column to the diameter of the through hole is (0.5-0.8):

1.

4. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold gas passage wall surface according to claim 1, characterized in that: The ratio of the thickness of the target plate to the thickness of the shock plate is (1-2):

1.

5. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The ratio of the diameter of the gas film hole to the diameter of the through hole is (0.4-0.6):

1.

6. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The ratio of the height of the spiral rib to the thickness of the shock plate is (0.8-1):

1.

7. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The angle between the spiral rib and the chord line of the blade is 30-45 degrees.

8. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The number of spiral ribs is 1-5, and the pitch of a single spiral rib is 5-35 mm.

9. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The cross-sectional shape of the spiral rib is circular, polygonal, oval or sector.

10. The sand-deposition-inhibiting double-walled vane with spiral ribs on the cold-gas-passage wall surfaces according to claim 1, characterized in that: The ratio of the cross-sectional area of the spiral rib to the cross-sectional area of the through hole in the normal direction of the wall is (3-5):1.

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