A blade design method and system with a blade tip winglet
The parametric design method is used to finely control the tip winglet structure of the turbine blade, which solves the problems of aerodynamic losses and heat transfer efficiency caused by leakage flow in the tip gap, and achieves more efficient turbine performance.
Patent Information
- Application Number
- CN202111447752.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-11-30
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2041-11-30
AI Technical Summary
In existing turbine blade designs, leakage flow in the tip gap results in aerodynamic losses and reduced heat transfer efficiency, and the winglet geometry cannot be refined.
The parametric design method is adopted to generate the shape of the tip winglet by adjusting some parameters, so as to achieve refined control of the winglet geometric structure, and generate reasonable and highly variable leaflet shapes.
It effectively reduces the leakage flow in the tip gap, improves the aerodynamic efficiency and heat transfer performance of the turbine, and avoids tip ablation.
Smart Images
Figure CN114036695B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of blade tip winglet design, and in particular relates to a blade design method and system with a blade tip winglet. Background Art
[0002] The turbine is one of the core components of the gas turbine engine power unit. It is a turbine machine that converts the energy of high-temperature, high-pressure gas into kinetic energy and mechanical energy. The high-temperature, high-pressure gas flows from the turbine inlet through the guide blade row and turns and expands, converting the gas pressure potential energy into gas kinetic energy. The high-speed gas passes through the working blade row to generate mechanical work and is provided to the compressor by the gas turbine shaft for air compression. The quality of the turbine design determines the overall design level of the engine, and its development level plays a vital role in the development of aircraft engines.
[0003] In the actual flow process of the turbine, the tip leakage flow has the characteristics of strong three-dimensionality, strong shear and unsteadiness. The flow of gas in the turbine tip gap will reduce the work done by the airflow on the turbine, especially at the tip of the moving blade. The airflow entering the tip gap is not turned by the action of the turbine working blades, and the rim work of the airflow flowing through the tip gap is almost zero. Due to the existence of the tip gap at the turbine tip, part of the high-temperature gas will flow from the pressure side of the turbine to the suction side of the turbine. This will cause the aerodynamic loss of the turbine and the heat transfer coefficient of the turbine tip to increase sharply. Studies have found that the tip leakage loss accounts for 1 / 3 of the total aerodynamic loss, and ablation of the turbine tip will also occur. Specifically, the airflow in the tip clearance will cause various flow losses, including separation losses caused by the formation of separation bubbles after the airflow bypasses the pressure surface of the blade; losses caused by the mixing of leakage flows from different areas on the tip pressure surface side in the gap; friction losses caused by the friction between the airflow in the tip clearance and the blade top surface and the inner wall of the outer casing; losses caused by the leakage vortex formed by the influence of the tangential reverse pressure gradient in the channel and the radial movement of the boundary layer on the suction surface side after the leakage flow flows from the suction side of the blade into the blade channel; losses caused by the mixing of the leakage vortex with the channel vortex when the leakage vortex flows downstream, etc. The airflow flowing in the turbine tip clearance will also reduce the effective flow area of the flow channel. The generation of leakage vortices hinders the flow of the mainstream in the flow channel, making the actual flow area of the flow channel smaller than the theoretical value; the leakage flow will also change the aerodynamic conditions at the downstream cascade inlet, especially near the tip of the blade. The tip leakage flow makes the distribution of aerodynamic parameters of the cascade inlet downstream of the blade more uneven.
[0004] The application of tip winglet technology to the blades of turbomachinery is inspired by the successful use of aircraft winglets to control wingtip vortices and reduce aircraft induced drag. After adding a control blade of a certain shape and thickness to the top of the rotor blade, the tip thickness is widened, which will help weaken the leakage flow, reduce leakage losses, and thus improve turbine efficiency. Although the gap vortex formed by the gap flow in the moving blades of the turbomachinery has a similar generation mechanism to the wingtip vortex formed by the wings of an aircraft, the flow field complexity of the flow in the gap between the moving blades of the engine is much greater. Research on turbine tip winglets began in the 1980s, and a large number of studies have shown that turbine tip winglets can reduce blade tip leakage losses, improve turbine aerodynamic efficiency, and effectively improve the heat exchange conditions at the blade tip.
[0005] The turbine blades with blade tip winglet structures generated by existing design methods have the disadvantages of simple structure and small geometric shape variation, and it is impossible to achieve fine control of the winglet geometry by adjusting parameters. Summary of the invention
[0006] In view of the above problems, the present invention provides a blade design method and system with a blade tip winglet, which adopts a parametric modeling design concept. The tip winglet structure can be modeled by adjusting only some parameters, thereby achieving refined control of the winglet geometric structure.
[0007] In order to achieve the above object, the present invention adopts the following technical solutions:
[0008] A method for designing a blade with a blade tip winglet comprises the following steps:
[0009] Determine the revolving surface along the radial direction of the blade, and take the contour curve of the revolving surface as the starting blade profile of the blade tip winglet;
[0010] Selecting the circumferential parameters of the starting blade profile, determining the circumferential control curve of the blade tip winglet, circumferentially shifting the starting blade profile, and obtaining the initial plane curve of the blade tip winglet;
[0011] Determine the radial control curve of the blade tip winglet, and generate the side surface of the blade tip winglet according to the initial plane curve and the circumferential control curve and the radial control curve;
[0012] Fill in the top curved surface of the leaf to obtain a leaf with a tip winglet.
[0013] Preferably, the selecting of the circumferential parameters of the starting blade profile comprises: dividing the starting blade profile into a suction surface and a pressure surface based on the mid-camber line, and selecting the circumferential parameters of the suction surface and the pressure surface respectively.
[0014] Preferably, the circumferential control curve is a numerical variation law of the tip winglet width along the initial blade profile.
[0015] Preferably, the radial control curve is a numerical variation law of the tip winglet width along the radial direction of the blade.
[0016] Preferably, the circumferential parameters include the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet ending point, and the winglet width; and the radial parameters include the winglet starting height.
[0017] Preferably, the circumferential parameters of the selected starting blade profile include:
[0018] The length of the curve between the leading edge and the trailing edge of the starting blade profile is taken as 1 for conversion, and points are taken along the starting blade profile to obtain the positions corresponding to the circumferential parameters.
[0019] Preferably, the winglet width is the width of the tip winglet along the circumference of the blade.
[0020] A blade design system with a blade tip winglet, comprising:
[0021] The initial blade profile generation module is used to determine the rotation surface along the radial direction of the blade, and take the contour curve of the rotation surface as the initial blade profile of the blade tip winglet;
[0022] A circumferential offset module is used to select the circumferential parameters of the starting blade profile, determine the circumferential control curve of the blade tip winglet, perform circumferential offset on the starting blade profile, and obtain the initial plane curve of the blade tip winglet;
[0023] A side surface generating module is used to determine the radial control curve of the blade tip winglet, and to generate the side surface of the blade tip winglet from the initial plane curve according to the circumferential control curve and the radial control curve;
[0024] The filling module is used to fill the blade top surface to obtain a blade with a blade tip winglet.
[0025] Preferably, the circumferential offset module is used to select the circumferential parameters of the starting blade profile, including: dividing the starting blade profile into a suction surface and a pressure surface based on the mid-camber line, and selecting the circumferential parameters of the suction surface and the pressure surface respectively.
[0026] Preferably, in the side surface generation module, the circumferential control curve is the numerical variation law of the tip winglet width along the starting blade profile; and the radial control curve is the numerical variation law of the tip winglet width along the radial direction of the blade.
[0027] Preferably, the circumferential parameters include the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet ending point, and the winglet width; and the radial parameters include the winglet starting height.
[0028] Preferably, the circumferential parameters of the selected starting blade profile include: taking the curve length between the leading edge and the trailing edge of the starting blade profile as 1 for conversion, taking points along the starting blade profile, and obtaining the positions corresponding to the circumferential parameters; the winglet width is the width of the blade tip winglet along the circumference of the blade; the winglet starting height is the starting height of the blade tip winglet changing in the radial direction of the blade.
[0029] The technical solution of the present invention has the following beneficial effects: the blade design method or system of the present invention adopts the design concept of parametric modeling, and only some parameters need to be adjusted to shape the tip winglet structure, and a tip winglet blade shape with a reasonable geometric structure and large variability can be generated with as few design parameters as possible. By adjusting the modeling parameters, the winglet structure model can be automatically constructed to achieve fine control of the winglet geometric structure, and at the same time, the continuous smoothness of the connection between the tip winglet and the blade body can be ensured; applied to the manufacture of gas turbine working blades, it can effectively avoid the problems of excessive tip leakage loss and easy occurrence of turbine blade tip ablation in gas turbine working blades.
[0030] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0032] Figure 1 A schematic diagram of various modeling parameters of the pressure surface blade tip winglet is shown;
[0033] Figure 2 The starting blade profile of the blade tip winglet of an embodiment of the present invention is shown;
[0034] Figure 3 A schematic diagram of the suction surface and pressure surface of the starting blade profile of the blade tip winglet according to an embodiment of the present invention is shown;
[0035] Figure 4 The circumferential control curve of the blade tip winglet according to an embodiment of the present invention is shown;
[0036] Figure 5 The initial plane curve of the tip winglet of an embodiment of the present invention is shown;
[0037] Figure 6The radial control curve of the blade tip winglet according to an embodiment of the present invention is shown;
[0038] Figure 7 The side surface of the blade tip winglet according to the embodiment of the present invention is shown. DETAILED DESCRIPTION
[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0040] A method for designing a blade with a blade tip winglet, exemplarily used for designing a turbine blade, comprises the following steps:
[0041] like Figure 2 As shown in FIG. 1 , the revolving surface is determined along the radial direction of the blade, and the contour curve of the revolving surface is taken as the starting blade profile of the blade tip winglet. The starting blade profile is divided into the suction surface and the pressure surface based on the mid-camber line of the starting blade profile. The circumferential parameters of the suction surface and the pressure surface are selected respectively, so as to control the suction surface and the pressure surface blade tip winglet separately, as shown in FIG. Figure 3 As shown, the concave surface in the figure is the pressure surface, and the convex surface is the suction surface;
[0042] The circumferential parameters of the starting blade profile are selected to determine the circumferential control curve of the blade tip winglet. The circumferential control curve is the numerical variation law of the blade tip winglet width along the starting blade profile, that is, a curve chart with the relative position from the leading edge to the trailing edge of one side of the blade profile as the horizontal coordinate and the winglet width as the vertical coordinate, such as Figure 4 As shown in the figure, points A and D are the starting and ending points of the winglet, and for example, points B and C are the starting and ending points of the effective width of the winglet, and the height of the straight line where points B and C are located is the absolute width of the winglet; in the starting blade, the circumferential parameter value of the blade tip winglet is controlled to achieve the law of controlling the blade curve of the starting blade along the circumferential direction of the blade, and the pressure surface and suction surface curves of the starting blade are circumferentially offset respectively (the circumferential and axial settings are as shown in Figure 1 As shown in Figure 2), the initial plane curve of the blade tip winglet is obtained, as Figure 5 As shown;
[0043] The radial control curve of the blade tip winglet is determined, and the side surface of the blade tip winglet is generated from the initial plane curve according to the circumferential control curve and the radial control curve; wherein the radial control curve is the numerical variation law of the blade tip winglet width along the radial direction of the blade, that is, a curve chart with the radial relative height of the blade as the abscissa and the winglet width as the ordinate, which is used to control the development law of various circumferential parameters of the blade tip winglet along the radial blade height direction, such as Figure 6 As shown, for example, the starting height of the pressure surface winglet is used as the relative height of the tip winglet from the initial blade shape along the radial direction to the blade tip, and the value range is 0 to 1. After determining the starting height, the radial control curve is used to control the width distribution of the winglet to ensure that the width distribution of the entire tip winglet in the blade height direction is continuous and smooth, where point A is the starting height of the pressure surface winglet. The blade radial direction is perpendicular to the starting blade shape, and together with the blade circumference and the blade circumference, it forms a three-dimensional space coordinate system;
[0044] Fill in the blade top surface to obtain a turbine blade with a blade tip winglet.
[0045] Furthermore, if Figure 1As shown in FIG. 1 , the radial parameters include the winglet starting height, which is the starting height of the tip winglet in the radial direction of the blade; the circumferential parameters include the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet ending point, the winglet width (the winglet width is the distance the tip winglet extends along the circumference of the blade), the winglet effective width starting and ending points (the winglet effective width starting and ending points) and the winglet length, wherein the parameters that need to be set are the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet ending point, the winglet width, the winglet effective width starting and ending points and the winglet length are auxiliary parameters, which do not need to be set manually, but can assist in determining other parameters of the winglet during the modeling process. Table 1 shows the circumferential parameters of the tip winglet on the pressure surface and the suction surface. Specifically, the length of the tip winglet distributed on the blade is determined by determining the starting and ending points of the tip winglet; the tip winglet width is divided into two parts: the effective width part and the ineffective width part. The effective width part is the part where the tip winglet width is the same as the set width, and the remaining part is the part where the original blade profile curve (i.e., the starting blade profile) transitions to the maximum width of the tip winglet (i.e., the transition curve), and the actual width of this part is less than the set winglet width; then, the development of the transition curve is controlled by using the front control coefficient and the rear control coefficient of the winglet. This parameter can determine the proportion of the ineffective width of the front and rear parts of the tip winglet, and then obtain the position of the starting point of the tip winglet width and the ending point of the winglet width. After determining the starting point of the tip winglet width, the ending point of the winglet width, and the starting and ending points of the effective width of the winglet, respectively connect the starting point of the winglet width with the starting point of the effective width of the winglet, and the ending point of the winglet width with the ending point of the effective width of the winglet, so as to obtain the complete curve of the maximum width of the winglet and the original plane blade profile. By adjusting the size of the front and rear control coefficients of the winglet, the effect of controlling the transition shape of the curve can be achieved.
[0046] Furthermore, in the process of selecting the circumferential parameters of the starting blade profile, since the methods used for parameterized modeling of the pressure surface and the suction surface of the starting blade profile of the blade tip winglet (i.e., selecting the circumferential parameters of the pressure surface and the suction surface) are consistent, the parameterized modeling process of the blade tip winglet on the pressure surface is exemplarily described in detail, as follows: Figure 1 As shown: the conversion is performed with the length of the curve between the leading edge and the trailing edge of the starting blade being 1, that is, the relative position of the point on the starting blade from the leading edge to the trailing edge of the blade changes from 0 to 1, and points are taken along the blade curve on the starting blade to obtain the position corresponding to the circumferential parameter. The purpose of this is to simplify the parameters and to more intuitively understand the relative position of the selected point in the blade. The starting and ending points of the tip winglets on both sides are selected by this method; when defining the tip winglet width, the actual width of the tip winglet is selected as the control parameter of its width, that is, the tip winglet width in the parametric modeling is consistent with the geometric width of the tip winglet.
[0047] The process of selecting the initial blade profile parameters of the tip winglet (parametric modeling process) is mainly divided into two parts: circumferential modeling of the tip winglet and radial modeling of the tip winglet. The present invention uses a modeling method that combines the relative position of the blade profile curve and the absolute circumferential width of the blade to simplify the parameters and provide a more intuitive understanding of the relative position of the selected point on the blade.
[0048] Table 1 Parameters of blade tip winglet on pressure and suction sides
[0049]
[0050]
[0051] A blade design system with a blade tip winglet, based on the above-mentioned blade design method with a blade tip winglet, comprises:
[0052] The initial blade profile generation module is used to determine the rotation surface along the radial direction of the blade, and take the contour curve of the rotation surface as the initial blade profile of the blade tip winglet;
[0053] A circumferential offset module is used to divide the starting blade profile into a suction surface and a pressure surface based on the mid-camber line, select the circumferential parameters of the suction surface and the pressure surface respectively, determine the circumferential control curve of the blade tip winglet, circumferentially offset the starting blade profile, and obtain the initial plane curve of the blade tip winglet. The circumferential control curve is the numerical variation law of the blade tip winglet width along the starting blade profile; the circumferential parameters include the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet end point, and the winglet width;
[0054] A side surface generation module is used to determine the radial control curve of the blade tip winglet, wherein the radial parameters include the starting height of the winglet, and the side surface of the blade tip winglet is generated from the initial plane curve according to the circumferential control curve and the radial control curve; the radial control curve is the numerical variation law of the width of the blade tip winglet along the radial direction of the blade;
[0055] The filling module is used to fill the blade top surface to obtain a blade with a blade tip winglet.
[0056] Furthermore, the circumferential parameters of the selected starting blade profile include: taking the curve length between the leading edge and the trailing edge of the starting blade profile as 1 for conversion, taking points along the starting blade profile, and obtaining the positions corresponding to the circumferential parameters; the winglet width is the width of the tip winglet along the circumference of the blade.
[0057] In summary, the blade design method or system of the present invention adopts a design concept of parametric modeling. It only needs to adjust some parameters to shape the tip winglet structure, and generate a tip winglet blade shape with a reasonable geometric structure and large variability with as few design parameters as possible. By adjusting the modeling parameters, the winglet structure model can be automatically constructed to achieve fine control of the winglet geometric structure, and at the same time, the continuous smoothness of the connection between the tip winglet and the blade body can be ensured; applied to the manufacture of gas turbine working blades, it can effectively avoid the problems of excessive tip leakage loss and easy turbine tip ablation of the gas turbine working blades. The gas turbine working blade with a tip winglet structure designed by the method of the present invention can effectively reduce the leakage flow in the tip gap, thereby improving the turbine efficiency.
[0058] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions 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 invention.
Claims
1. A method for designing a blade with a blade tip winglet, characterized in that: The following steps are involved: Determine the revolving surface along the radial direction of the blade, and take the contour curve of the revolving surface as the starting blade shape of the blade tip winglet; Selecting the circumferential parameters of the starting blade profile, determining the circumferential control curve of the blade tip winglet, circumferentially shifting the starting blade profile, and obtaining the initial plane curve of the blade tip winglet; Determine the radial control curve of the blade tip winglet, and generate the side surface of the blade tip winglet according to the initial plane curve and the circumferential control curve and the radial control curve; Fill in the top curved surface of the leaf to obtain a leaf with a tip winglet; The circumferential control curve is the numerical variation law of the tip winglet width along the initial blade profile; The radial control curve is the numerical variation law of the tip winglet width along the radial direction of the blade; The winglet width is the width of the tip winglet along the circumferential direction of the blade.
2. The method for designing a blade with a blade tip winglet according to claim 1, characterized in that: The selecting of the circumferential parameters of the initial blade profile includes: dividing the initial blade profile into a suction surface and a pressure surface based on the mid-camber line, and selecting the circumferential parameters of the suction surface and the pressure surface respectively.
3. The method for designing a blade with a blade tip winglet according to claim 1 or 2, characterized in that: The circumferential parameters include the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet ending point, and the winglet width; the radial parameters include the winglet starting height.
4. The method for designing a blade with a blade tip winglet according to claim 3, characterized in that: The circumferential parameters of the selected starting blade profile include: The length of the curve between the leading edge and the trailing edge of the starting blade profile is taken as 1 for conversion, and points are taken along the starting blade profile to obtain the positions corresponding to the circumferential parameters.
5. A blade design system with a blade tip winglet, characterized in that: include The initial blade profile generation module is used to determine the rotation surface along the blade radial direction and take the contour curve of the rotation surface as the initial blade profile of the blade tip winglet; A circumferential offset module is used to select the circumferential parameters of the starting blade profile, determine the circumferential control curve of the blade tip winglet, perform circumferential offset on the starting blade profile, and obtain the initial plane curve of the blade tip winglet; A side surface generating module is used to determine the radial control curve of the blade tip winglet, and to generate the side surface of the blade tip winglet from the initial plane curve according to the circumferential control curve and the radial control curve; A filling module is used to fill the top curved surface of the blade to obtain a blade with a blade tip winglet; The circumferential control curve is the numerical variation law of the tip winglet width along the starting blade profile; the radial control curve is the numerical variation law of the tip winglet width along the radial direction of the blade; The winglet width is the width of the tip winglet along the circumferential direction of the blade.
6. The blade design system with blade tip winglets according to claim 5, characterized in that: The circumferential offset module is used to select the circumferential parameters of the starting blade profile, including: dividing the starting blade profile into a suction surface and a pressure surface based on the mid-camber line, and selecting the circumferential parameters of the suction surface and the pressure surface respectively.
7. The blade design system with blade tip winglets according to claim 5 or 6, characterized in that: The circumferential parameters include the winglet starting point, the winglet front control coefficient, the winglet rear control coefficient, the winglet ending point, and the winglet width; the radial parameters include the winglet starting height.
8. The blade design system with blade tip winglets according to claim 7, characterized in that: The circumferential parameters of the selected starting blade profile include: taking the curve length between the leading edge and the trailing edge of the starting blade profile as 1 for conversion, taking points along the starting blade profile, and obtaining the positions corresponding to the circumferential parameters; the winglet starting height is the starting height of the blade tip winglet in the radial direction of the blade.