A locally air-injected impulse turbine rotor and assembly method

Abstract

The application discloses a partial air inlet impulse turbine rotor and an assembling method, and relates to the technical field of rocket engines, and aims at solving the problems of a large cyclic stress amplitude at the blade root, easy high-frequency fatigue damage and a short service life. The partial air inlet impulse turbine rotor comprises a rotor shaft, a plurality of blades and a girdle, the plurality of blades are uniformly arranged on the circumferential side of the rotor shaft, the root of each blade is fixedly connected with the rotor shaft, and the top of each blade is provided with a groove; the girdle is in a circular ring structure, the girdle is clamped in the groove of each blade, and the girdle is fixedly connected with each blade. The assembling method of the partial air inlet impulse turbine rotor is used for assembling the above-mentioned partial air inlet impulse turbine rotor. The partial air inlet impulse turbine rotor and the assembling method are used for reducing the cyclic stress amplitude at the turbine blade root, and then the fatigue life of the turbine rotor is improved.

Description

Technical Field

[0001] This invention relates to the field of rocket engine technology, and in particular to a partial air intake impingement turbine rotor and its assembly method. Background Technology

[0002] In the design of turbopumps for open-cycle liquid rocket engines, the turbine generally adopts a localized intake impingement turbine rotor. The rotor generally includes a rotor shaft and multiple blades, with the multiple blades fixedly arranged on the periphery of the rotor shaft.

[0003] During operation, the turbine rotor rotates at high speed under the blowing of the high-temperature working medium. Because it is a local air intake structure, each blade of the rotor will be blown by the turbine nozzle once in turn for every revolution of the turbine. The load on the turbine rotor blades exhibits obvious periodic characteristics. Therefore, the fatigue failure of the turbine rotor blades of open-cycle liquid rocket engines is generally manifested as high-frequency fatigue failure.

[0004] The blade is a cantilevered force-bearing structure with its root fixed on the rotor shaft and its top suspended in the air. When the rotor blades are blown by the turbine nozzles in sequence, only the rotor shaft provides support for the blade root. This results in stress concentration at the blade root, which makes the cyclic stress amplitude at the blade root large, easily causing high-frequency fatigue failure and resulting in a short service life. Summary of the Invention

[0005] The purpose of this invention is to provide a localized intake impact turbine rotor and its assembly method, which reduces the cyclic stress amplitude at the turbine blade root and thereby improves the fatigue life of the turbine rotor.

[0006] To achieve the above objectives, the present invention provides a partial intake impingement turbine rotor, comprising:

[0007] Rotor shaft;

[0008] Multiple blades are evenly arranged around the rotor shaft, and the root of each blade is fixedly connected to the rotor shaft. Each blade has a groove on its top.

[0009] The guard belt has a circular structure and is fitted into the groove of each blade, with each blade fixedly connected to the guard belt.

[0010] Compared to existing technologies, this invention provides a partial inlet impingement turbine rotor including a ferrule. The ferrule is engaged in a groove in each blade and fixedly connected to each blade. When the turbine nozzle blows the high-temperature working medium onto the blades fixedly connected to the rotor shaft, the ferrule, being fixedly connected to the blade tip, provides a supporting force opposite to the blade's direction of movement when the blade is under stress. This reduces stress concentration at the blade root and consequently reduces the cyclic stress amplitude at the blade root. Based on this, the partial inlet impingement turbine rotor provided by this invention includes a ferrule, which provides a supporting force opposite to the blade's direction of movement to the blade tip. This reduces the displacement at the blade tip, decreases stress concentration at the blade root, and thus reduces the cyclic stress amplitude at the blade root, improving the turbine rotor's service life. Furthermore, the ferrule is engaged in a groove in each blade, and the width of the ferrule is smaller than the width of the groove, meaning the width of the ferrule is smaller than the width of each blade. Therefore, adding the ferrule does not affect the original turbine rotor's outer width.

[0011] Alternatively, in the aforementioned partial intake impingement turbine rotor, the ferrule is welded to each blade.

[0012] Optionally, in the above-mentioned partial intake impingement turbine rotor, the width of the groove is 70% to 80% of the width of the blade.

[0013] Optionally, in the aforementioned partial intake impingement turbine rotor, the groove depth is equal to the thickness of the ferrule.

[0014] Optionally, in the above-mentioned partial intake impingement turbine rotor, the thickness of the protective belt is 1mm to 1.5mm.

[0015] Optionally, in the aforementioned partial intake impingement turbine rotor, the material of the shroud is GH3128 nickel-based alloy or GH4169 nickel-based alloy.

[0016] The present invention also provides a method for assembling a partial inlet impingement turbine rotor, for assembling the above-mentioned partial inlet impingement turbine rotor, comprising:

[0017] A groove is made at the top of each blade;

[0018] The blades are sequentially fixedly connected to the rotor shaft;

[0019] The strip is rolled into a round shape and then sequentially clamped into the groove of each blade. Electron beam welding is used to weld the strip to the top of each blade to form the first weld. The butt joints at both ends of the strip are then fused together to form the second weld, thus forming the saber strip.

[0020] The assembly method of the local intake impact turbine rotor provided by the present invention can fix a guard belt at the top of the blade. The guard belt provides a support force to the top of the blade in the opposite direction of the blade movement, thereby reducing the displacement generated at the top of the blade, reducing the stress concentration at the blade root, and thus reducing the cyclic stress amplitude at the blade root, and improving the service life of the turbine rotor.

[0021] Optionally, in the above-described assembly method of the partial inlet impingement turbine rotor, after creating a groove at the top of each blade, the strip is rolled into a round shape and sequentially snapped into the groove of each blade. Electron beam welding is then used to weld the strip to the top of each blade to form a first weld. The butt joints at both ends of the strip are then fused together to form a second weld. Before forming the protective strip, the above-described assembly method of the partial inlet impingement turbine rotor further includes:

[0022] Select the strip material based on the coefficient of thermal expansion of the blade material;

[0023] The strip is processed according to the distance from the bottom of the groove to the rotation axis of the rotor shaft and the width of the groove, so that the width of the strip is less than the groove and the length is greater than 2π times the vertical distance from the bottom of the groove to the rotation axis of the rotor shaft.

[0024] Optionally, in the above-described assembly method of the partial inlet impingement turbine rotor, after rolling the strip into a circle, sequentially snapping the strip into the groove of each blade, welding the top of each blade using electron beam welding, and fusion welding the two ends of the strip together to form a ferrule, the above-described assembly method of the partial inlet impingement turbine rotor further includes:

[0025] Ultrasonic inspection was performed on the first weld between the blade and the saber.

[0026] The second weld of the mating interface of the sanitary belt was inspected by X-ray. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 This is a schematic diagram of the structure of a partial intake impingement turbine rotor provided in an embodiment of the present invention;

[0029] Figure 2 This is a partial schematic diagram of the blades, the protective belt, and the connection point of a partially inlet impingement turbine rotor provided in an embodiment of the present invention.

[0030] Figure 3A cross-sectional view of the connection between the blades and the ferrule of a partial intake impingement turbine rotor provided in an embodiment of the present invention;

[0031] Figure 4 A flowchart illustrating an assembly method for a partially inlet impingement turbine rotor provided in an embodiment of the present invention;

[0032] Figure 5 A flowchart illustrating another method for assembling a partial intake impingement turbine rotor, provided as an embodiment of the present invention.

[0033] Figure label:

[0034] 1-Rotor shaft; 2-Blade; 3-Warrior belt; 4-First weld; 5-Second weld. Detailed Implementation

[0035] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0036] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0038] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] In the design of turbopumps for open-cycle liquid rocket engines, the turbine typically employs a locally inlet impingement turbine rotor. The rotor generally consists of a rotor shaft and multiple blades, all fixedly mounted around the rotor shaft. During operation, the turbine rotor rotates at high speed under the influence of a high-temperature working medium. Due to the locally inlet structure, each blade is sequentially agitated by the turbine nozzles with each revolution of the turbine. This results in a distinct cyclic load on the turbine rotor blades, leading to fatigue failure in open-cycle liquid rocket engine turbine rotor blades, which is generally characterized by high-frequency fatigue failure. The blades are cantilevered structures with their roots fixed to the rotor shaft and their tops suspended. When the rotor blades are sequentially agitated by the turbine nozzles, only the rotor shaft provides support at the blade roots, causing stress concentration at the blade roots. This results in a large cyclic stress amplitude at the blade roots, making them prone to high-frequency fatigue failure and a shorter service life.

[0041] To resolve the above issues, please refer to Figure 1 and Figure 2 This invention provides a partial intake impact turbine rotor, including a rotor shaft 1, multiple blades 2 and a guard belt 3. The multiple blades 2 are evenly arranged on the periphery of the rotor shaft 1, and the root of each blade 2 is fixedly connected to the rotor shaft 1. Each blade 2 has a groove on its top. The guard belt 3 has a circular structure and is engaged in the groove of each blade 2. The guard belt 3 is fixedly connected to each blade 2.

[0042] In the specific working process, the turbine nozzle blows the high-temperature working medium onto several blades 2 that are fixedly connected to the rotor shaft 1. After the blades 2 are subjected to force, all the blades 2 and the rotor shaft 1 rotate together. After the position of the blades 2 changes, the turbine nozzle blows the high-temperature working medium onto the blades 2 corresponding to the nozzle position. This cycle is repeated so that each blade 2 is subjected to force in a cycle, thereby controlling the rotation of the rotor.

[0043] As can be seen from the structure and specific working process of the partial intake impact turbine rotor provided by the embodiments of the present invention, the partial intake impact turbine rotor provided by the embodiments of the present invention includes a guard belt 3, which is engaged in the groove of each blade 2 and fixedly connected to each blade 2. When the turbine nozzle blows the high temperature working medium onto several blades 2 fixedly connected to the rotor shaft 1, since the guard belt 3 is fixedly connected to the top of the blade 2, when the blade 2 is under force, the guard belt 3 will provide a supporting force to the top of the blade 2 in the opposite direction of the blade 2's movement, thereby reducing the stress concentration at the root of the blade 2 and thus reducing the cyclic stress amplitude at the root of the blade 2. Compared to existing technologies, the present invention provides a partial intake impact turbine rotor including a guard belt 3. The guard belt 3 provides a supporting force to the top of the blade 2 in the opposite direction of the blade 2's movement, reducing the displacement generated at the top of the blade 2 and reducing the stress concentration at the root of the blade 2, thereby reducing the cyclic stress amplitude at the root of the blade 2 and improving the service life of the turbine rotor. In addition, the guard belt 3 is inserted into the groove of each blade 2, and the width of the guard belt 3 is smaller than the width of the groove, that is, the width of the guard belt 3 is smaller than the width of each blade 2. Therefore, the addition of the guard belt 3 does not affect the original outer width of the turbine rotor.

[0044] Specifically, in the aforementioned partial-intake impingement turbine rotor, the ferrule 3 is welded to each blade 2. The welded connection is relatively stable, ensuring the connection strength between the ferrule 3 and the blade 2. Each blade 2 is fixedly connected to the ferrule 3, and the ferrule 3 can provide significant support for each blade 2.

[0045] Specifically, please refer to 3. In the aforementioned partial intake impingement turbine rotor, the ferrule 3 is welded to the two sidewalls and the bottom of the groove of each blade 2 on three sides. This three-sided welding further ensures the connection strength between the ferrule 3 and the blade 2.

[0046] Specifically, in the aforementioned partial intake impact turbine rotor, the width of the groove is 70% to 80% of the width of the blade 2; for example, the width of the groove is 70%, 72%, 75%, 78%, 80%, etc., of the width of the blade 2.

[0047] Specifically, in the aforementioned partial intake impingement turbine rotor, the groove depth is equal to the thickness of the guard belt 3. With this configuration, the outer periphery of the guard belt 3 is flush with the outer periphery of the blade 2, and the addition of the guard belt 3 does not affect the maximum diameter of the original turbine rotor.

[0048] Specifically, in the aforementioned partial intake impact turbine rotor, the thickness of the guard belt 3 is 1mm to 1.5mm; for example, the thickness of the guard belt 3 is 1mm, 1.2mm, 1.4mm, 1.5mm, etc. Reducing the thickness of the guard belt 3 while ensuring its structural strength reduces its mass, facilitating rotor rotation and also making the processing of the guard belt 3 easier.

[0049] In some embodiments, in the aforementioned partial-intake impingement turbine rotor, the material of the ferrule 3 is GH3128 nickel-based alloy or GH4169 nickel-based alloy. GH3128 and GH4169 nickel-based alloys possess high plasticity, high creep strength, good oxidation resistance, and good stamping and welding properties, ensuring the performance of the ferrule 3 and meeting the operating temperature and load requirements of the turbine rotor. Furthermore, the turbine blade 2 is primarily made of nickel-based alloys. The coefficients of thermal expansion of GH3128 and GH4169 nickel-based alloys are comparable to those of the blade 2 material, preventing breakage at the weld between the blade 2 and the ferrule 3 due to differences in their coefficients of thermal expansion.

[0050] Please see Figure 1 , Figure 2 , Figure 3 and Figure 4 The present invention also provides a method for assembling a partial inlet impingement turbine rotor, for assembling the above-mentioned partial inlet impingement turbine rotor, comprising:

[0051] S101, A groove is made on the top of each blade 2; specifically, a groove of the same size is made on the top of each blade 2 by means of a lathe.

[0052] S102. Fix the blades 2 to the rotor shaft 1 in sequence;

[0053] S103. Roll the strip into a circle and then sequentially clamp the strip into the groove of each blade 2. Use electron beam welding to weld the strip to the top of each blade 2 to form the first weld 4. Then, weld the butt joints at both ends of the strip to form the second weld 5, thus forming the saber strip 3.

[0054] The assembly method of a partial intake impact turbine rotor provided by the present invention can fix a guard belt 3 on the top of the blade 2. The guard belt 3 provides a support force to the top of the blade 2 in the opposite direction of the blade 2's movement, thereby reducing the displacement generated at the top of the blade 2, reducing the stress concentration at the root of the blade 2, and thus reducing the cyclic stress amplitude at the root of the blade 2, and improving the service life of the turbine rotor.

[0055] Please see Figure 1 , Figure 2 , Figure 3 and Figure 5 The present invention also provides another method for assembling a partial inlet impingement turbine rotor, for assembling the above-mentioned partial inlet impingement turbine rotor, comprising:

[0056] S201. A groove is made on the top of each blade 2; specifically, a groove of the same size is made on the top of each blade 2 by means of a lathe.

[0057] S202. Fix the blades 2 to the rotor shaft 1 in sequence;

[0058] S203. Select the strip material according to the coefficient of thermal expansion of the blade 2 material; for example, when the turbine blade 2 material is a nickel-based alloy, the material of the strip 3 is GH3128 nickel-based alloy material or GH4169 nickel-based alloy material.

[0059] S204. Process the strip according to the distance from the bottom of the groove to the rotation axis of the rotor shaft 1 and the width of the groove, so that the width of the strip is less than the groove and the length is greater than 2π times the vertical distance from the bottom of the groove to the rotation axis of the rotor shaft 1.

[0060] Based on this, it can be ensured that the strip can be locked in the groove and that the strip can wrap around the top of each blade 2 once.

[0061] S205. Roll the strip into a circle and sequentially snap the strip into the groove of each blade 2. Use electron beam welding to weld the strip to the top of each blade 2 to form the first weld 4. Then, weld the butt joints at both ends of the strip to form the second weld 5, thus forming the saber strip 3.

[0062] Specifically, after the strip is wrapped around the top of each blade 2, if there is still excess strip, the excess strip is cut off first, and then the butt joints at both ends of the strip are fused together to form a second weld 5, forming the saber strip 3.

[0063] S206. Perform ultrasonic inspection on the first weld 4 between blade 2 and saber 3.

[0064] Specifically, the weld fusion width between the first weld seam 4 and the blade tip is checked by ultrasonic testing to see if it is greater than the preset width. The preset width is the minimum weld fusion width required to ensure the connection strength between the blade 2 and the guard strip 3.

[0065] S207. Perform X-ray inspection on the second weld 5 of the mating interface of the sanitary belt 3.

[0066] Specifically, the internal quality of the second weld 5 at the mating interface of the sanitary belt 3 is inspected using X-rays to determine whether it meets the standard requirements.

[0067] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A partial intake impingement turbine rotor, characterized in that, include: Rotor shaft; Multiple blades are evenly arranged around the rotor shaft, and the root of each blade is fixedly connected to the rotor shaft. Each blade has a groove on its top. The guard belt has a circular structure and is fitted into the groove of each blade, and is fixedly connected to each blade. The groove depth is equal to the thickness of the sanitary tape.

2. The partial intake impingement turbine rotor according to claim 1, characterized in that, The ferrule is welded to each of the blades.

3. The partial intake impingement turbine rotor according to claim 1, characterized in that, The width of the groove is 70% to 80% of the width of the blade.

4. The partial intake impingement turbine rotor according to claim 1, characterized in that, The thickness of the guard belt is 1mm to 1.5mm.

5. The partial intake impingement turbine rotor according to claim 1, characterized in that, The material of the sanitary belt is GH3128 nickel-based alloy or GH4169 nickel-based alloy.

6. A method for assembling a partially inlet impingement turbine rotor, characterized in that, For assembling the partial inlet impingement turbine rotor according to any one of claims 1-5, comprising: A groove is made at the top of each blade; The blades are sequentially fixedly connected to the rotor shaft; The strip is rolled into a round shape and then sequentially snapped into the groove of each blade. Electron beam welding is used to weld the strip to the top of each blade to form a first weld. The butt joints at both ends of the strip are then fused together to form a second weld, thus forming a sanitary strip.

7. The assembly method of the partial intake impingement turbine rotor according to claim 6, characterized in that, After creating a groove at the top of each blade, the strip is rolled into a round shape and sequentially snapped into the groove of each blade. Electron beam welding is then used to weld the strip to the top of each blade to form a first weld. The butt joints at both ends of the strip are then fused together to form a second weld. Before forming the satellite strip, the assembly method of the partial intake impingement turbine rotor further includes: Select the strip material based on the coefficient of thermal expansion of the blade material; The strip is processed according to the distance from the bottom of the groove to the rotation axis of the rotor shaft and the width of the groove, such that the width of the strip is smaller than the groove and the length is greater than 2π times the vertical distance from the bottom of the groove to the rotation axis of the rotor shaft.

8. The assembly method of the partial intake impingement turbine rotor according to claim 6, characterized in that, After rolling the strip into a round shape, sequentially snapping the strip into the grooves of each blade, welding the strip to the top of each blade using electron beam welding, and fusion welding the two ends of the strip together to form a ferrule, the assembly method of the partial intake impingement turbine rotor further includes: Ultrasonic inspection was performed on the first weld between the blade and the saber. The second weld of the mating interface of the sanitary belt was inspected by X-ray.

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