Blade top casing structure and preparation method thereof

Abstract

The invention provides a blade top casing structure and a preparation method thereof, and the preparation method comprises the steps: building a first non-axisymmetric concave-convex end wall model and a second non-axisymmetric concave-convex end wall model according to a control function; establishing a model of a blade top and a model of a casing; coupling the first non-axisymmetric concave-convex end wall model and the model of the blade top to obtain a first model, and coupling the second non-axisymmetric concave-convex end wall model and the model of the casing to obtain a second model; and preparing the blade top and the casing according to the first model and the second model. According to the blade top casing structure and the preparation method thereof, the blade top and the casing can reduce the fluid pressure difference of the gap through the non-axisymmetric concave-convex structure, then secondary flow velocity distribution is affected, formation and development of channel vortexes are delayed, and therefore the strength of the channel vortexes is reduced, secondary flow losses are reduced, and the service life of the blade top casing structure is prolonged. And therefore, the efficiency of the turbine is effectively improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of turbine engines, and particularly to a tip casing structure and a preparation method thereof. Background Art

[0002] Gas turbine engines are widely used in real life, involving multiple fields such as aviation, power generation, and industry. Advanced gas turbine engines integrate various advanced technologies such as high efficiency, low noise, and low emissions, and can participate in the power generation process with cleanliness, high quality, and high stability. In a gas turbine engine, the small gap between the blade and the casing is called the tip clearance, which is one of the main reasons for reducing the turbine efficiency. The heat loss caused by the tip clearance accounts for up to one-third of the total loss of the turbine passage.

[0003] The tip clearance usually brings two types of losses. One is that due to the pressure difference between the suction surface and the pressure surface of the moving blade, some airflows flow along the suction surface side, resulting in a reduction in the overall work done. The other loss is the mixing loss caused by the change in the flow direction of the mainstream in the gap. When the thermal load of the turbine blade increases, due to the influence of the secondary flow, the leakage airflow has an axial component velocity. Then the leakage airflow encounters the oncoming flow on the suction surface side and then separates, simultaneously forming a vortex. And as the airflow flows out of the gap, the vortex will gradually expand, causing an increase in the secondary flow rate in the cascade passage, thereby resulting in a large aerodynamic loss.

[0004] In order to output as much mechanical energy as possible per unit volume of the device under the same thermodynamic parameters, it is necessary to improve the efficiency of the turbine. Summary of the Invention

[0005] The present disclosure aims to solve at least one of the technical problems in the related art to some extent.

[0006] To this end, the purpose of the present disclosure is to provide a tip casing structure and a preparation method thereof.

[0007] To achieve the above object, the first aspect of the present disclosure provides a preparation method of a tip casing structure, including: establishing a first non-axisymmetric concave-convex end wall model and a second non-axisymmetric concave-convex end wall model according to a control function; establishing a model of the tip and a model of the casing; coupling the first non-axisymmetric concave-convex end wall model and the model of the tip to obtain a first model, and coupling the second non-axisymmetric concave-convex end wall model and the model of the casing to obtain a second model; preparing the tip and the casing according to the first model and the second model.

[0008] Optionally, the method further includes: applying a first sine function in the radial and axial directions along the profile of the tip, and establishing the first non-axisymmetric concave-convex end wall model according to the deformation of the first sine function.

[0009] Optionally, the method further includes: arranging a first number of first axial control lines along the profile of the blade tip; arranging a second number of radial control lines along the profile of the blade tip, and causing the first number of first axial control lines and the second number of radial control lines to be cross-distributed to form a third number of first cross control points; applying a first sine function in the radial and axial directions along the profile of the blade tip, and deforming the first sine function at the first cross control points to establish the first non-axisymmetric concave-convex end wall model.

[0010] Optionally, the first non-axisymmetric concave-convex end wall model has a smooth deformed surface at the first cross control points.

[0011] Optionally, the peak of the first sine function is close to the pressure surface of the blade, and the trough of the first sine function is close to the suction surface of the blade.

[0012] Optionally, the method further includes: applying a second sine function in the circumferential and axial directions along the profile of the casing, and establishing the second non-axisymmetric concave-convex end wall model according to the deformation of the second sine function.

[0013] Optionally, the method further includes: arranging a fourth number of second axial control lines along the profile of the casing; arranging a fifth number of circumferential control lines along the profile of the casing, and causing the fourth number of second axial control lines and the fifth number of circumferential control lines to be cross-distributed to form a sixth number of second cross control points; applying a second sine function in the circumferential and axial directions along the profile of the casing, and deforming the second sine function at the second cross control points to establish the second non-axisymmetric concave-convex end wall model.

[0014] Optionally, the second non-axisymmetric concave-convex end wall model has a smooth deformed surface at the second cross control points.

[0015] A second aspect of the present disclosure provides a blade tip casing structure, including: a blade tip and a casing; the inner walls of the blade tip and the casing are arranged opposite to each other and provided with a gap, and the blade tip is provided with a first non-axisymmetric concave-convex structure, and the inner wall of the casing is provided with a second non-axisymmetric concave-convex structure.

[0016] Optionally, the first non-axisymmetric concave-convex structure is based on a deformed first sine function, and / or, the second non-axisymmetric concave-convex structure is based on a deformed second sine function.

[0017] The technical solution provided by the present disclosure may include the following beneficial effects:

[0018] According to the control function, a first non-axisymmetric concave-convex endwall model and a second non-axisymmetric concave-convex endwall model are established. By coupling the first non-axisymmetric concave-convex endwall model with the blade tip model and coupling the second non-axisymmetric concave-convex endwall model with the casing model, a blade tip and a casing with non-axisymmetric concave-convex structures are prepared. Thus, the blade tip and the casing can utilize the non-axisymmetric concave-convex structures to reduce the fluid pressure difference in the clearance, thereby affecting the secondary flow velocity distribution, delaying the formation and development of the passage vortex, and thus achieving a reduction in the intensity of the passage vortex and a reduction in the secondary flow loss, and further effectively improving the efficiency of the turbine.

[0019] Additional aspects and advantages of the present disclosure will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present disclosure will become apparent and be readily understood from the following description of embodiments in conjunction with the drawings, wherein:

[0021] Figure 1 is a schematic flow chart of a method for preparing a blade tip and casing structure according to an embodiment of the present disclosure;

[0022] Figure 2 is a schematic structural diagram of a first model in the method for preparing a blade tip and casing structure according to an embodiment of the present disclosure;

[0023] Figure 3 is a schematic structural diagram of a second model in the method for preparing a blade tip and casing structure according to an embodiment of the present disclosure;

[0024] Figure 4 is a schematic structural diagram when the first model is established in the method for preparing a blade tip and casing structure according to an embodiment of the present disclosure;

[0025] Figure 5 is a schematic structural diagram when the second model is established in the method for preparing a blade tip and casing structure according to an embodiment of the present disclosure;

[0026] As shown in the figure: 1. Blade tip, 11. First non-axisymmetric concave-convex structure, 12. First axial control line, 13. Radial control line, 14. First cross control point;

[0027] 2. Casing, 21. Second non-axisymmetric concave-convex structure, 22. Second axial control line, 23. Circumferential control line, 24. Second cross control point. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Embodiments of the present disclosure will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present disclosure and should not be construed as limiting the present disclosure. On the contrary, the embodiments of the present disclosure include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0029] As Figure 1 , Figure 2 and Figure 3 shown, an embodiment of the present disclosure provides a method for manufacturing a structure of a blade tip 1 and a casing 2, including:

[0030] S1: Establish a first non-axisymmetric concave-convex end wall model and a second non-axisymmetric concave-convex end wall model according to a control function;

[0031] S2: Establish a model of the blade tip 1 and a model of the casing 2;

[0032] S3: Couple the first non-axisymmetric concave-convex end wall model and the model of the blade tip 1 to obtain a first model, and couple the second non-axisymmetric concave-convex end wall model and the model of the casing 2 to obtain a second model;

[0033] S4: Manufacture the blade tip 1 and the casing 2 according to the first model and the second model.

[0034] It can be understood that a first non-axisymmetric concave-convex end wall model and a second non-axisymmetric concave-convex end wall model are established according to a control function, and the blade tip 1 and the casing 2 having a non-axisymmetric concave-convex structure are manufactured by using the coupling of the first non-axisymmetric concave-convex end wall model and the blade tip 1 model and the coupling of the second non-axisymmetric concave-convex end wall model and the casing 2 model, so that the blade tip 1 and the casing 2 can use the non-axisymmetric concave-convex structure to reduce the fluid pressure difference in the gap, thereby affecting the secondary flow velocity distribution, delaying the formation and development of the passage vortex, and thus realizing the reduction of the passage vortex intensity and the reduction of the secondary flow loss, and further effectively improving the efficiency of the turbine.

[0035] It should be noted that due to the tiny gap between the turbine engine blade and the casing 2, the mixing loss is caused by the change in the flow direction of the mainstream within the gap. When the thermal load of the turbine blade increases, due to the influence of the secondary flow, the leakage air flow has an axial component velocity. Then the leakage air flow encounters the oncoming flow on the suction surface side and then separates, simultaneously forming a vortex. As the air flow flows out of the gap, the vortex will gradually expand, causing an increase in the secondary flow rate within the cascade passage, resulting in relatively large aerodynamic losses. In this embodiment, by modifying the blade tip 1 and the casing 2, specifically by respectively arranging non-axisymmetric concave-convex structures on the inner surfaces of the blade tip 1 and the casing 2, the flow area of the flow passage changes, reducing the fluid pressure difference at the blade tip 1 gap, thereby affecting the secondary flow velocity distribution, delaying the formation and development of the passage vortex, reducing the intensity of the passage vortex, and ultimately achieving a reduction in secondary flow losses.

[0036] Moreover, the blade tip 1 and the casing 2 with non-axisymmetric concave-convex structures prepared in this embodiment have a simple structure, low cost, and good control effect. They can effectively reduce the gap leakage flow, improve the aerodynamic efficiency and work capacity of the radial turbine, and increase the energy utilization efficiency of the gas turbine.

[0037] Meanwhile, the non-axisymmetric characteristics of the non-axisymmetric concave-convex end wall profile reduce the wear of the blade tip 1 to a certain extent and further inhibit concentrated wear.

[0038] In addition, the blade tip 1 and the casing 2 with non-axisymmetric concave-convex structures prepared in this embodiment can meet the requirements of the efficient operation of the gas turbine, promoting the application of the gas turbine in an efficient operation system. This technology enables the gas turbine to operate more efficiently and has processing feasibility and broad application prospects.

[0039] All in all, in this embodiment, the non-axisymmetric end wall is introduced into the concave-convex design, increasing the design freedom of the end wall profile. By locally concave-convex design to change the flow field near the end wall, the purpose of controlling the secondary flow and improving the turbine efficiency is achieved.

[0040] The first non-axisymmetric concave-convex end wall model and the model of the blade tip 1 are coupled to obtain the first model. That is to say, the first model takes the blade tip 1 as the main structure and the first non-axisymmetric concave-convex end wall as the auxiliary structure. Thus, by using the first model for processing and preparation, a blade tip 1 with a non-axisymmetric concave-convex structure can be obtained.

[0041] The second non-axisymmetric concave-convex end wall model and the model of the casing 2 are coupled to obtain the second model. That is to say, the second model takes the casing 2 as the main structure and the second non-axisymmetric concave-convex end wall as the auxiliary structure. Thus, by using the second model for processing and preparation, a casing 2 with a non-axisymmetric concave-convex structure on its inner surface can be obtained.

[0042] The non-axisymmetric concave-convex structure includes: a non-axisymmetric concave structure and a non-axisymmetric convex structure. The non-axisymmetric concave structure can reduce the flow rate and increase the pressure, while the non-axisymmetric convex structure can increase the flow rate and reduce the pressure.

[0043] Among them, the first non-axisymmetric concave-convex endwall model, the second non-axisymmetric concave-convex endwall model, the blade tip 1 model, the casing 2 model, etc. all refer to three-dimensional models.

[0044] In some embodiments, the method further includes:

[0045] Apply a first sine function in the radial and axial directions along the profile of the blade tip 1, and establish a first non-axisymmetric concave-convex endwall model according to the deformation of the first sine function.

[0046] It can be understood that the basic concave-convex structure of the first non-axisymmetric concave-convex endwall model is formed by using the first sine function, and the non-axisymmetry of the concave-convex structure is realized by using the deformation of the first sine function. Thus, the high-efficiency and high-quality acquisition of the first non-axisymmetric concave-convex endwall model is ensured.

[0047] It should be noted that applying a first sine function in the radial and axial directions along the profile of the blade tip 1 can form a concave-convex structure that is axisymmetric and regularly distributed, and the shape, size, etc. of the concave-convex structure are changed by using the deformation of the first sine function, so as to realize the non-axisymmetry of the concave-convex structure.

[0048] As Figure 4 shown, in some embodiments, the method further includes:

[0049] Arrange a first number of first axial control lines 12 along the profile of the blade tip 1;

[0050] Arrange a second number of radial control lines 13 along the profile of the blade tip 1, and make the first number of first axial control lines 12 and the second number of radial control lines 13 cross-distributed to form a third number of first cross control points 14;

[0051] Apply a first sine function in the radial and axial directions along the profile of the blade tip 1, and deform the first sine function at the first cross control points 14 to establish a first non-axisymmetric concave-convex endwall model.

[0052] It can be understood that by using the first number of first axial control lines 12 and the second number of radial control lines 13, a third number of first cross control points 14 can be formed along the profile of the blade tip 1, so as to quickly and accurately establish a first non-axisymmetric concave-convex endwall model by using the deformation at the first cross control points 14.

[0053] It should be noted that the first axial control line 12 is a reference line arranged within the blade tip 1 profile. Specifically, the first axial control line 12 extends radially along the axis of the gas turbine engine, and a first number of first axial control lines 12 are distributed at intervals along the axis of the gas turbine engine.

[0054] Among them, the first number can be set according to actual needs, and there is no limitation in this regard. By way of example, the first number can be 3.

[0055] The radial control line 13 is a reference line arranged within the blade tip 1 profile. Specifically, the radial control line 13 extends axially along the axis of the gas turbine engine, and a second number of radial control lines 13 are distributed at intervals along the radial direction of the gas turbine engine axis.

[0056] Among them, the second number can be set according to actual needs, and there is no limitation in this regard. By way of example, the second number can be 7.

[0057] The first cross control point 14 is a reference point arranged within the blade tip 1 profile. Specifically, a third number of first cross control points 14 are distributed in a matrix within the blade tip 1 profile.

[0058] Among them, the third number can be set according to actual needs, and there is no limitation in this regard. By way of example, the third number can be 27.

[0059] In some embodiments, the first non-axisymmetric concave-convex endwall model has a smooth deformed surface at the first cross control point 14.

[0060] It can be understood that since the first non-axisymmetric concave-convex endwall model has a smooth deformed surface at the first cross control point 14, the blade tip 1 profile has geometric continuity at the first cross control point 14, enabling a smooth transition, thereby reducing losses and improving turbine efficiency.

[0061] In some embodiments, the peak of the first sine function is close to the pressure surface of the blade, and the trough of the first sine function is close to the suction surface of the blade.

[0062] It can be understood that since the peak of the first sine function is close to the pressure surface of the blade and the trough of the first sine function is close to the suction surface of the blade, the non-axisymmetric concave-convex structure of the blade tip 1 can further reduce the fluid pressure difference in the gap, thereby reducing the secondary flow loss and improving the turbine efficiency.

[0063] It should be noted that the pressure surface of the blade is the side of the blade that moves relative to the airflow. When the airflow passes through this surface, the static pressure increases due to the decrease in flow velocity; the suction surface of the blade is the other side of the blade that moves relative to the airflow. When the airflow passes through this surface, the static pressure decreases due to the increase in flow velocity.

[0064] In some embodiments, the method further includes:

[0065] Apply a second sine function in the circumferential and axial directions along the profile of the casing 2, and establish a second non-axisymmetric concave-convex end wall model based on the deformation of the second sine function.

[0066] It can be understood that the basic concave-convex structure of the second non-axisymmetric concave-convex end wall model is formed by using the second sine function, and the non-axisymmetry of the concave-convex structure is achieved by using the deformation of the second sine function. Thus, the high-efficiency and high-quality acquisition of the second non-axisymmetric concave-convex end wall model is ensured.

[0067] It should be noted that applying a second sine function in the circumferential and axial directions along the profile of the casing 2 can form a concave-convex structure that is axisymmetric and regularly distributed, and by using the deformation of the second sine function to change the shape, size, etc. of the concave-convex structure, the non-axisymmetry of the concave-convex structure can be achieved.

[0068] As Figure 5 shown, in some embodiments, the method further includes:

[0069] Arrange a fourth number of second axial control lines 22 along the profile of the casing 2;

[0070] Arrange a fifth number of circumferential control lines 23 along the profile of the casing 2, and make the fourth number of second axial control lines 22 and the fifth number of circumferential control lines 23 cross-distributed to form a sixth number of second cross control points 24;

[0071] Apply a second sine function in the circumferential and axial directions along the profile of the casing 2, and deform the second sine function at the second cross control points 24 to establish a second non-axisymmetric concave-convex end wall model.

[0072] It can be understood that by using the fourth number of second axial control lines 22 and the fifth number of circumferential control lines 23, a sixth number of second cross control points 24 can be formed along the profile of the casing 2, so as to quickly and accurately establish a second non-axisymmetric concave-convex end wall model by using the deformation at the second cross control points 24.

[0073] It should be noted that the second axial control lines 22 are reference lines arranged within the profile of the casing 2. Specifically, the second axial control lines 22 extend circumferentially along the axis of the gas turbine engine, and the fourth number of second axial control lines 22 are axially spaced along the axis of the gas turbine engine.

[0074] Among them, the fourth number can be set according to actual needs, and there is no limitation on this. By way of example, for the area between adjacent blades on the inner wall of the casing 2, the fourth number can be 5.

[0075] The circumferential control line 23 is a reference line arranged within the profile of the casing 2. Specifically, the circumferential control line 23 extends axially along the axis of the gas turbine engine shaft, and a fifth number of circumferential control lines 23 are distributed at circumferential intervals along the gas turbine engine shaft.

[0076] Among them, the fifth number can be set according to actual needs, and there is no limitation in this regard. By way of example, for the area of the inner wall of the casing 2 between adjacent blades, the fifth number can be 8.

[0077] The second intersection control point 24 is a reference point arranged within the profile of the casing 2. Specifically, a sixth number of second intersection control points 24 are distributed in a matrix within the profile of the casing 2.

[0078] Among them, the sixth number can be set according to actual needs, and there is no limitation in this regard. By way of example, for the area of the inner wall of the casing 2 between adjacent blades, the sixth number can be 40.

[0079] In some embodiments, the second non-axisymmetric concave-convex end wall model has a smooth deformed surface at the second intersection control point 24.

[0080] It can be understood that since the second non-axisymmetric concave-convex end wall model has a smooth deformed surface at the second intersection control point 24, the profile of the casing 2 has geometric continuity at the second intersection control point 24, enabling a smooth transition, thereby reducing losses and improving turbine efficiency.

[0081] As Figure 2 and Figure 3 shown, the embodiments of the present disclosure also propose a structure of the blade tip 1 and the casing 2, including: the blade tip 1 and the casing 2. The inner walls of the blade tip 1 and the casing 2 are arranged opposite to each other and provided with a gap, and the blade tip 1 is provided with a first non-axisymmetric concave-convex structure 11, and the inner wall of the casing 2 is provided with a second non-axisymmetric concave-convex structure 21.

[0082] It can be understood that by using the first non-axisymmetric concave-convex structure 11 of the blade tip 1 and the second non-axisymmetric concave-convex structure 21 of the inner wall of the casing 2, the blade tip 1 and the casing 2 can use the non-axisymmetric concave-convex structure to reduce the fluid pressure difference in the gap, thereby affecting the secondary flow velocity distribution, delaying the formation and development of the passage vortex, and thus reducing the intensity of the passage vortex and the secondary flow loss, and effectively improving the efficiency of the turbine.

[0083] In some embodiments, the first non-axisymmetric concave-convex structure 11 is based on a deformed first sine function.

[0084] It can be understood that the first sine function is used to form the basic concave-convex structure of the first non-axisymmetric concave-convex end wall model, and the deformation of the first sine function is used to achieve the non-axisymmetry of the concave-convex structure. Thus, the high-efficiency and high-quality acquisition of the first non-axisymmetric concave-convex end wall model is ensured.

[0085] In some embodiments, the second non-axisymmetric concave-convex structure 21 is based on a deformed second sine function.

[0086] It can be understood that the second sine function is used to form the basic concave-convex structure of the second non-axisymmetric concave-convex end wall model, and the deformation of the second sine function is used to achieve the non-axisymmetry of the concave-convex structure. Thus, the high-efficiency and high-quality acquisition of the second non-axisymmetric concave-convex end wall model is ensured.

[0087] It should be noted that in the description of the present disclosure, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "a plurality" is two or more.

[0088] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present disclosure includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed. This should be understood by those skilled in the technical field to which the embodiments of the present disclosure belong.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0090] Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A preparation method of a blade tip casing structure, characterized in that Including: Establishing a first non-axisymmetric concave-convex endwall model and a second non-axisymmetric concave-convex endwall model according to a control function; Establishing a model of the blade tip and a model of the casing; Coupling the first non-axisymmetric concave-convex endwall model and the model of the blade tip to obtain a first model, and coupling the second non-axisymmetric concave-convex endwall model and the model of the casing to obtain a second model; Manufacturing the blade tip and the casing according to the first model and the second model.

2. The preparation method of the blade tip casing structure according to claim 1, characterized in that The method further includes: Applying a first sine function in the radial and axial directions along the profile of the blade tip, and establishing the first non-axisymmetric concave-convex endwall model according to the deformation of the first sine function.

3. The preparation method of the blade tip casing structure according to claim 2, characterized in that, The method further includes: Arranging a first number of first axial control lines along the profile of the blade tip; Arranging a second number of radial control lines along the profile of the blade tip, and making the first number of first axial control lines and the second number of radial control lines cross-distributed to form a third number of first cross control points; Applying a first sine function in the radial and axial directions along the profile of the blade tip, and deforming the first sine function at the first cross control points to establish the first non-axisymmetric concave-convex endwall model.

4. The preparation method of the blade tip casing structure according to claim 3, characterized in that, The first non-axisymmetric concave-convex endwall model has a smooth deformed surface at the first cross control points.

5. The preparation method of the blade tip casing structure according to claim 2, characterized in that, The peak of the first sine function is close to the pressure surface of the blade, and the trough of the first sine function is close to the suction surface of the blade.

6. The preparation method of the blade tip casing structure according to claim 1, characterized in that, The method further includes: Applying a second sine function in the circumferential and axial directions along the profile of the casing, and establishing the second non-axisymmetric concave-convex endwall model according to the deformation of the second sine function.

7. The preparation method of the blade tip casing structure according to claim 6, characterized in that The method further includes: Arranging a fourth number of second axial control lines along the profile of the casing; Arranging a fifth number of circumferential control lines along the profile of the casing, and making the fourth number of second axial control lines and the fifth number of circumferential control lines cross-distributed to form a sixth number of second cross control points; Applying a second sine function in the circumferential and axial directions along the profile of the casing, and deforming the second sine function at the second cross control points to establish the second non-axisymmetric concave-convex endwall model.

8. The preparation method of the blade tip casing structure according to claim 7, characterized in that, The second non-axisymmetric concave-convex endwall model has a smooth deformed surface at the second cross control points.

9. A tip casing structure, characterized in that, Including: A blade tip and a casing; The inner walls of the blade tip and the casing are arranged opposite to each other and provided with a gap, and the blade tip is provided with a first non-axisymmetric concave-convex structure, and the inner wall of the casing is provided with a second non-axisymmetric concave-convex structure.

10. The tip casing structure according to claim 9, wherein, The first non-axisymmetric concave-convex structure is based on a deformed first sine function, and / or, the second non-axisymmetric concave-convex structure is based on a deformed second sine function.

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