A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance

Abstract

The application provides a supercritical carbon dioxide turbine structure capable of adjusting a blade tip gap, comprising a main shaft, a turbine impeller, a nozzle seat and a casing which are sleeved on the main shaft, wherein the casing is arranged on the blade side of the turbine impeller, and the nozzle seat is arranged on the suction side of the turbine impeller; a dynamic-static gap is arranged between the blade side of the turbine impeller and the casing and between the turbine impeller and the nozzle seat; the nozzle seat and the casing are tightly connected; a gasket groove for mounting a gasket is arranged on the end face of the casing away from the turbine impeller and towards the nozzle seat, and the gasket groove is arranged in a circumferential direction; the blade height of the turbine impeller at the rim is greater than the original design value; the application solves the problem of easy collision and friction between the blade tip of the turbine impeller and the casing during actual operation and the problem of excessive loss of the blade tip gap.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of turbomachinery, and particularly relates to a supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance. BACKGROUND

[0002] The supercritical carbon dioxide Brayton cycle is the most concerned new power cycle at present, which has the characteristics of strong compactness, high cycle efficiency and matching various heat sources. The supercritical carbon dioxide radial turbine has high expansion ratio and excellent aerodynamic performance, and is often used as a heat power conversion component in a hundred kW level cycle.

[0003] In actual mechanical structures, there is a dynamic and static gap between the turbine blade and the casing. Excessive gap will cause serious blade tip leakage loss, affect the aerodynamic performance of the turbine, and thus reduce the cycle efficiency and output power. However, too small gap will cause the risk of rubbing between the impeller and the casing during operation, so it is very important to adjust the blade tip clearance and ensure the performance in the turbine operation. The blade tip clearance is an effective means to reduce the blade tip leakage loss. By increasing the blade height at the impeller inlet, the working medium flowing out of the nozzle is prevented from directly flowing into the impeller tip clearance, the tip clearance flow is reduced, and thus the loss is reduced. In addition, by adjusting the size of the blade tip clearance through increasing or decreasing the gasket, the risk of rubbing between the dynamic and static gaps can be avoided. However, increasing the gasket will inevitably cause the gap at the top of the nozzle blade that did not exist before, resulting in additional leakage loss. Therefore, by reserving the height allowance of the nozzle blade, the flow passage can be ensured to be continuous, and the turbine can maintain excellent aerodynamic performance while adjusting the blade tip clearance. SUMMARY

[0004] The present application aims to provide a supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance, which solves the above-mentioned deficiencies of the dynamic and static gap between the existing turbine impeller and the casing.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance, comprising a main shaft, a turbine impeller, a nozzle seat and a casing are sleeved on the main shaft, wherein the casing is arranged on the blade side of the turbine impeller, and the nozzle seat is arranged on the pressure side of the turbine impeller; a dynamic and static gap is arranged between the blade side of the turbine impeller and the casing, and between the turbine impeller and the nozzle seat; the nozzle seat and the casing are tightly connected;

[0007] A gasket groove for installing a gasket is formed on the end face of the side of the casing away from the turbine impeller and towards the nozzle seat, and the gasket groove is arranged circumferentially.

[0008] The blade height at the rim of the turbine impeller is greater than the original design value.

[0009] Preferably, the nozzle seat is provided with a plurality of nozzle blades, the height of each nozzle blade is greater than the original design value; the casing is provided with a plurality of nozzle grooves, the nozzle grooves are matched with the nozzle blades.

[0010] Preferably, the difference between the height of the nozzle blade and the original design value is the maximum height of the gasket adjustment.

[0011] Preferably, the difference between the height of the blade at the rim of the turbine wheel and the original design value is the maximum height of the gasket adjustment.

[0012] Preferably, the gasket is a plurality of gaskets with different thicknesses.

[0013] Preferably, the casing is provided with a first volute sub-flow channel, the nozzle seat is provided with a second volute sub-flow channel, the first volute sub-flow channel and the second volute sub-flow channel are connected to form a volute flow channel, and the volute flow channel is arranged close to the turbine wheel side.

[0014] Preferably, the end face of the casing towards the nozzle seat is provided with a sealing groove, the sealing groove is arranged in a circumferential direction; and an O-shaped sealing ring is installed in the sealing groove.

[0015] Preferably, the sealing groove is arranged between the gasket groove and the volute flow channel.

[0016] Preferably, the nozzle seat is connected with the main shaft through a bearing.

[0017] Preferably, the maximum height of the gasket adjustment is 10 times the tip clearance value.

[0018] Compared with the prior art, the beneficial effects of the present application are:

[0019] The supercritical carbon dioxide turbine structure provided by the present application can adjust the tip clearance, the gasket is arranged between the casing and the nozzle seat to increase the tip clearance of the turbine wheel, thereby solving the problem of easy rubbing between the tip of the turbine blade and the casing during actual operation; at the same time, there is also a problem of tip clearance loss in the supercritical carbon dioxide radial turbine, therefore, the present application increases the height of the inlet blade of the turbine wheel to avoid the working medium directly flowing into the gap, thereby solving the problem of excessive tip clearance loss.

[0020] Further, in the process of increasing the gasket, the distance between the casing and the nozzle seat will increase, by increasing the height of the nozzle blade, it is ensured that no additional gap appears at the top of the nozzle blade during the adjustment process, thereby no additional loss is generated. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1Structure diagram of the present application;

[0022] Wherein: 1 - turbine wheel, 2 - main shaft, 3 - nozzle seat, 4 - casing, 5 - O-ring seal, 6 - gasket set, 7 - bearing, 8 - locking nut. DETAILED DESCRIPTION

[0023] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, circuits, and

[0024] It is to be understood that the terminology "includes", "has", "holds", "contains" or "comprising", "comprised of" or "comprising", as used in the specification and in the following claims, indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] It is also to be understood that the terminology "and / or" as used in the specification and in the following claims, means any combination of one or more of the associated listed items and all possible combinations thereof.

[0026] As used in the specification and in the following claims, the term "if" can be interpreted as meaning "when" or "upon" or "in response to a determination" or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if detected [the described condition or event]" can be interpreted as meaning "upon determining" or "in response to determining" or "upon detecting [the described condition or event]" or "in response to detecting [the described condition or event]" depending on the context.

[0027] In addition, in the description of the specification and in the following claims, the terms "first", "second", "third", etc. are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0028] Reference to "one embodiment" or "some embodiments" or "one implementation" or "some implementations" or "one example" or "some examples" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment or implementation of the application. The appearances of the phrase "in one embodiment" or "in some embodiments" or "in one implementation" or "in some implementations" or "in one example" or "in some examples" in various places in the specification are not necessarily all referring to the same embodiment or implementation, but can refer to different embodiments or implementations, unless otherwise specifically stated.

[0029] Embodiment 1

[0030] The supercritical carbon dioxide turbine structure capable of adjusting the blade tip clearance provided by the embodiment comprises a main shaft 2, which is sleeved with a turbine wheel 1, a nozzle seat 3 and a casing 4, wherein:

[0031] The casing 4 is arranged on the blade side of the turbine wheel, and the nozzle seat 3 is arranged on the suction side of the turbine wheel 1.

[0032] The dynamic-static gap is arranged between the blade side of the turbine wheel 1 and the casing 4 and between the turbine wheel 1 and the nozzle seat 3, and the nozzle seat 3 and the casing 4 are tightly connected.

[0033] The casing 4 is away from the turbine wheel 1 on one side, and a gasket groove 6 for installing a gasket is arranged on the end face of the casing 4 towards the nozzle seat 3, and the gasket groove 6 is arranged in a circumferential direction.

[0034] The blade height of the turbine wheel 1 at the rim is greater than the original design value, so that the blade top is higher than the end face of the casing 4 towards the nozzle seat 3.

[0035] In the embodiment, the normal size of the blade tip clearance between the turbine wheel 1 and the casing 4 is constant in the initial installation state. In the actual operation process, the thickness of the gasket is adjusted according to the thermal expansion deformation of the rotor and the dynamic-static rubbing, and the maximum height of the gasket that can be adjusted is 10 times the value of the blade tip clearance. The size of the blade tip clearance between the turbine wheel and the casing is adjusted by increasing or decreasing the gasket, and the size of the blade tip clearance without the gasket is the minimum blade tip clearance, which is the initial design value.

[0036] The gasket is arranged between the casing and the nozzle seat to increase the blade tip clearance of the turbine wheel, thereby solving the problem that the blade top of the turbine wheel 1 is easy to rub against the casing 4 in the actual operation process. At the same time, there is also a problem of blade tip clearance loss in the supercritical carbon dioxide radial turbine, so the embodiment increases the blade height of the turbine inlet to avoid the working medium flowing directly into the gap, thereby solving the problem of excessive blade tip clearance loss.

[0037] Embodiment 2

[0038] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure capable of adjusting the blade tip clearance provided in the embodiment is characterized in that the difference between the blade height at the rim of the turbine wheel and the original design value is the maximum height of the gasket adjustment.

[0039] Embodiment 3

[0040] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure capable of adjusting the blade tip clearance provided in the embodiment is characterized in that the nozzle seat 3 is provided with a plurality of nozzle blades, and the height of each nozzle blade is greater than the original design value; the casing 4 is provided with a plurality of nozzle grooves 9, and the shape of the nozzle groove 9 matches the nozzle blade.

[0041] The depth of the nozzle groove 9 is consistent with the difference between the height of the nozzle blade and the original design value.

[0042] In the embodiment, the distance between the casing 4 and the nozzle seat 3 increases in the process of increasing the gasket, and the height allowance of the nozzle blade is increased to ensure that no additional gap occurs at the top of the nozzle blade during the adjustment process, thereby avoiding additional loss.

[0043] Embodiment 4

[0044] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure capable of adjusting the blade tip clearance provided in the embodiment is characterized in that the difference between the height of the nozzle blade and the original design value is the maximum height of the gasket adjustment.

[0045] Embodiment 5

[0046] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure capable of adjusting the blade tip clearance provided in the embodiment is characterized in that the gasket is a plurality of gaskets with different thicknesses, which are used to adjust the size of the blade tip clearance according to the actual operation.

[0047] Embodiment 6

[0048] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure capable of adjusting the blade tip clearance provided in the embodiment is characterized in that the casing 4 is provided with a first volute sub-flow passage, the nozzle seat 3 is provided with a second volute sub-flow passage, the first volute sub-flow passage and the second volute sub-flow passage are connected in a butt joint manner to form a volute flow passage, and the volute flow passage is arranged close to the turbine wheel.

[0049] The split plane between the first volute sub-flow passage and the second volute sub-flow passage is based on the blade tip plane of the basic design height of the nozzle blade.

[0050] The end face of the casing 4 towards the end of the nozzle seat is provided with a sealing groove 5, which is arranged circumferentially; an O-shaped sealing ring is installed in the sealing groove to prevent the supercritical carbon dioxide working medium in the main flow channel from leaking outwards.

[0051] Embodiment 7

[0052] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure provided in this embodiment is capable of adjusting the blade tip clearance, and a bearing 7 is arranged between the nozzle seat 3 and the main shaft 2.

[0053] Embodiment 8

[0054] On the basis of Embodiment 1, the supercritical carbon dioxide turbine structure provided in this embodiment is capable of adjusting the blade tip clearance, and a locking nut 8 is further arranged on the main shaft, which is located in front of the turbine impeller and is used for axial positioning of the turbine impeller.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance, characterized in that, The device includes a main shaft, on which a turbine impeller, a nozzle seat, and a casing are mounted. The casing is located on the blade side of the turbine impeller, and the nozzle seat is located on the back side of the turbine impeller. Dynamic and static clearances are provided between the blade side of the turbine impeller and the casing, and between the turbine impeller and the nozzle seat. The nozzle seat and the casing are tightly connected. The casing has a gasket groove for mounting a gasket on the end face away from the turbine impeller and facing the nozzle seat. The gasket groove is arranged circumferentially. The blade height at the rim of the turbine impeller is greater than its original design value.

2. The supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 1, characterized in that, The nozzle holder is provided with multiple nozzle blades, each of which has a height greater than its original design value; the casing is provided with multiple nozzle grooves, which cooperate with the nozzle blades.

3. The supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 2, characterized in that, The difference between the height of the nozzle blade and the original design value is the maximum adjustable height of the shim.

4. The supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 1, characterized in that, The difference between the blade height at the rim of the turbine impeller and the original design value is the maximum adjustable height of the shim.

5. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 1, characterized in that, The gasket consists of a set of multiple gaskets of different thicknesses.

6. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 1, characterized in that, The casing has a first volute sub-channel, and the nozzle seat has a second volute sub-channel. The first volute sub-channel and the second volute sub-channel are connected to form a volute flow channel, which is arranged near the turbine impeller.

7. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 6, characterized in that, A sealing groove is provided on the end face of the casing facing the nozzle seat, and the sealing groove is arranged circumferentially; an O-ring is installed in the sealing groove.

8. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 7, characterized in that, The sealing groove is positioned between the gasket groove and the volute flow channel.

9. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 1, characterized in that, The nozzle seat is connected to the main shaft via a bearing.

10. A supercritical carbon dioxide turbine structure capable of adjusting blade tip clearance according to claim 1, characterized in that, The maximum adjustable height of the shim is 10 times the blade tip clearance value.

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