Symmetrical rotor blade parameterization design method of impact turbine and related equipment

Abstract

The invention relates to the field of fluid machinery and turbine blade design, and discloses a symmetric rotor blade parameterization design method of an impact turbine and related equipment, and the method comprises the following steps: firstly, determining key parameters such as a deflection angle, a geometric angle, a chord length, a fillet radius, a divergence angle and a maximum half thickness of a blade based on blade shape parameters; and then, calculating control point coordinates of the rotor blade mean camber line according to the deflection angle, the geometric angle and the chord length, and drawing the turbine mean camber line. Then, according to the fillet radius and the divergence angle, the control points of the blade front and rear edge arcs and the overall thickness curve are determined, and the thickness curve is further refined by combining the maximum half thickness; and the thickness curve is lengthened in the normal direction of the mean camber line, the pressure surface and suction surface molded lines of the blade are obtained, and then the symmetrical two-dimensional blade shape is generated. And finally, a plurality of two-dimensional blade shapes are created in the blade height direction and stacked, a blade three-dimensional model is formed, and parameterization design is completed. According to the method, blade design is achieved through a small number of parameters, and it is ensured that molded lines are smooth and aerodynamic performance is excellent.

Description

Technical Field

[0001] The present invention relates to the field of fluid machinery and turbine blade design, and specifically to a parametric design method for symmetric rotor blades of an impulse turbine and related equipment. Background Art

[0002] In the field of wave energy power generation, as the core energy conversion device, the performance of an impulse turbine is directly related to the efficiency and reliability of the wave energy power generation system. Among them, the rotor blade, as the core component of the impulse turbine, its design rationality plays a decisive role in the energy conversion efficiency of the turbine. However, there are many deficiencies in the current design method of the impulse turbine rotor blade, which seriously restricts the further improvement of the overall performance of the turbine.

[0003] Currently, the blade profile design of impulse turbines generally follows the traditional design method proposed by Maeda et al. in 1999. This method constructs the blade profile by combining an elliptical arc suction surface and a circular arc pressure surface. Although it has the advantage of simple geometric construction, it has significant defects in parametric design. Specifically, the control accuracy of the key geometric parameters of the blade (such as chord length, installation angle, and throat area) by this design method is relatively low, and the adjustable parameter range is limited. This limitation results in insufficient freedom in the design optimization process, making it difficult to deeply explore the potential impact of the blade geometry on the turbine performance, and thus restricting the breakthrough improvement of the overall efficiency of the impulse turbine.

[0004] In view of this, the existing blade design methods can no longer meet the urgent needs of the wave energy power generation system for highly efficient and reliable energy conversion devices, and it is urgent to develop new blade design technologies to break through the current technical bottleneck. Summary of the Invention

[0005] In order to overcome the defects of the above-mentioned existing technologies, the purpose of the present invention is to provide a parametric design method for symmetric rotor blades of an impulse turbine and related equipment to solve the technical problem of how to improve the overall performance of the turbine in the existing technology.

[0006] The present invention is realized through the following technical solutions: In a first aspect, the present invention provides a parametric design method for symmetric rotor blades of an impulse turbine, including: Determining the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade expansion angle, and maximum half thickness of the blade based on the blade shape parameters; Determining the control point coordinates of the mean camber line of the rotor blade according to the determined blade deflection angle, blade geometric angle, and chord length; and drawing the mean camber line of the turbine using the control point coordinates of the mean camber line of the rotor blade; Determine the control points on the thickness curves at the leading and trailing edges of the blade and on the blade thickness curve based on the blade fillet radius and the blade expansion angle, and determine the control points on the blade thickness curve based on the maximum half-thickness of the blade; use the control points on the thickness curves at the leading and trailing edges of the blade, the control points on the blade thickness curve, and the control points on the blade thickness curve to draw the middle part of the blade thickness curve. Extend the middle part of the blade thickness curve along the turbine mean line in the normal direction to both sides to obtain the profiles of the pressure surface and the suction surface of the blade, and obtain the symmetric two-dimensional blade profile based on the profiles of the pressure surface and the suction surface of the blade; create a number of two-dimensional blade profiles along the blade height direction, and stack the number of two-dimensional blade profiles to obtain the three-dimensional blade model, thus completing the parametric design of the rotor blade of the impulse turbine.

[0007] Preferably, with the turbine axis as the reference, fix the leading edge endpoint of the blade mean line as the origin to obtain the blade profile parameters.

[0008] Preferably, the range of the blade geometric angle is 55° to 65°; the range of the blade fillet radius is 1% to 3% of the chord length; the range of the blade expansion angle is 6° to 15°; the range of the maximum half-thickness of the blade is 5% to 12.5% of the chord length.

[0009] Preferably, in the step of drawing the turbine mean line using the control point coordinates of the rotor blade mean line, the control points of the rotor blade mean line include control point a0, control point a1, and control point a2. Set control point a0 and control point a2 as the two endpoints of the chord length respectively. Draw auxiliary lines from the two endpoints towards the middle at an angle relative to the chord length, and the intersection point is control point a1.

[0010] Furthermore, draw a Bézier curve through control point a0, control point a1, and control point a2, and use the Bézier curve as the turbine mean line. Among them, the formula of the Bézier curve is as follows:

[0011] Among them, t represents the curve parameter. 。

[0012] Preferably, the control points on the blade thickness curve include control point b0 and control point b2; the control points on the blade thickness curve include control point b1. Draw a B-spline curve through the control points b0, b1, and b2, and obtain the middle part of the blade thickness curve through the B-spline curve. The B-spline curve is tangent to the thickness curves at the leading and trailing edges of the blade.

[0013] Furthermore, the formula of the B-spline curve is as follows:

[0014] Among them, t represents the curve parameter, .

[0015] In a second aspect, the present invention also provides a parametric design system for a symmetric rotor blade of an impulse turbine, including: A data determination module for determining the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade expansion angle, and maximum half thickness of the blade based on the blade profile parameters; A first drawing module for determining the control point coordinates of the mean camber line of the rotor blade according to the determined blade deflection angle, blade geometric angle, and chord length; and drawing the turbine mean camber line using the control point coordinates of the mean camber line of the rotor blade; A second drawing module for determining the control points of the thickness curve at the front and rear edges of the blade and the control points of the blade thickness curve according to the blade fillet radius and blade expansion angle, and determining the control points of the blade thickness curve according to the maximum half thickness of the blade; and drawing the middle part of the blade thickness curve using the control points of the thickness curve at the front and rear edges of the blade, the control points of the blade thickness curve, and the control points of the blade thickness curve; A blade model design module for extending the middle part of the blade thickness curve along the normal directions on both sides of the turbine mean camber line to obtain the profiles of the pressure surface and suction surface of the blade, and obtaining a symmetric two-dimensional blade profile according to the profiles of the pressure surface and suction surface of the blade; creating a plurality of two-dimensional blade profiles along the blade height direction, and stacking the plurality of two-dimensional blade profiles to obtain a three-dimensional blade model, thereby completing the parametric design of the rotor blade of the impulse turbine.

[0016] In a third aspect, the present invention also provides a mobile terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the parametric design method for the symmetric rotor blade of the impulse turbine as described above are implemented.

[0017] In a fourth aspect, the present invention also provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the parametric design method for the symmetric rotor blade of the impulse turbine as described above are implemented.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a parametric design method for symmetric rotor blades of an impulse turbine, which realizes the parametric design of the inner rotor blades of the impulse turbine by using a small number of parameter points. Within the proposed parameter range, the blade profile can be ensured to be smooth and have excellent aerodynamic performance. The present invention uses a parametric method to realize the design of symmetric rotor blades in an impulse turbine. While considering the smoothness of the blade profile and meeting the requirements of symmetric blades, the number of control points is greatly reduced, achieving efficient parametric design. This method has strong adaptability in the design of blades under different working conditions and flexibility in the blade modification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the parametric design process of the symmetric blade profile of the impulse turbine rotor blade in the present invention; Figure 2 It is a schematic diagram of the definition method of the mean camber line of the blade in the present invention; Figure 3 It is a schematic diagram of the definition method of the blade thickness distribution curve in the present invention; Figure 4 It is a schematic diagram of the two-dimensional blade profile in the present invention; Figure 5 It is a schematic diagram of the three-dimensional blade model in the present invention; Figure 6 It is an optimized effect diagram of the blade flow characteristics in the present invention; Figure 7 It is a blade load curve diagram in the present invention; Figure 8 It is a schematic diagram of the principle of the parametric design system of the symmetric rotor blade of the impulse turbine in the present invention; In the figure: 1. Blade thickness; 2. Blade suction surface profile; 3. Blade mean camber line; 4. Blade pressure surface profile; 5. Blade chord length; 6. Blade suction surface; 7. Blade pressure surface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] The purpose of the present invention is to provide a parametric design method and related equipment for symmetric rotor blades of an impulse turbine to solve the technical problem of how to improve the overall performance of the turbine in the prior art.

[0022] The following further describes the present invention in detail with reference to the accompanying drawings: See Figure 1 , in an embodiment of the present invention, a parametric design method for a symmetric rotor blade of an impulse turbine is provided, including: Based on the blade profile parameters, determine the blade deflection angle Gc, blade geometric angle Bc, chord length lc, blade fillet radius R, blade divergence angle A, and maximum half-thickness t of the blade h ; Determine the control point coordinates of the median arc of the rotor blade according to the determined blade deflection angle Gc, blade geometric angle Bc, and chord length lc; draw the turbine median arc using the control point coordinates of the median arc of the rotor blade; Determine the control points on the thickness curves at the leading and trailing edge arcs of the blade and the control points on the blade thickness curve according to the blade fillet radius R and blade divergence angle A, and determine the control points on the blade thickness curve according to the maximum half-thickness t of the blade h ; draw the middle part of the blade thickness curve using the control points on the thickness curves at the leading and trailing edge arcs of the blade, the control points on the blade thickness curve, and the control points on the blade thickness curve; Extend the middle part of the blade thickness curve along the normal directions on both sides of the turbine median arc to obtain the profiles of the pressure surface and suction surface of the blade, and obtain the symmetric two-dimensional blade profile according to the profiles of the pressure surface and suction surface of the blade; create a number of two-dimensional blade profiles along the blade height direction, and stack the number of two-dimensional blade profiles to obtain the three-dimensional model of the blade, completing the parametric design of the rotor blade of the impulse turbine.

[0023] Specifically, with the turbine axis as the reference, fix the leading edge endpoint of the blade median arc as the origin to obtain the blade profile parameters.

[0024] Specifically, the range of the blade geometric angle Bc is from 55° to 65°; the range of the blade fillet radius R is from 1% to 3% of the chord length; the range of the blade divergence angle A is from 6° to 15°; the maximum half-thickness t of the blade h has a range of 5% to 12.5% of the chord length.

[0025] Specifically, in the step of drawing the turbine median arc using the control point coordinates of the rotor blade median arc, the control points of the rotor blade median arc include control point a0, control point a1, and control point a2; Set control point a0 and control point a2 as the two endpoints of the chord length respectively, draw auxiliary lines from the two endpoints towards the middle at an angle relative to the chord length, and the intersection point is control point a1.

[0026] Among them, a Bezier curve is drawn through control point a0, control point a1, and control point a2, and the Bezier curve is used as the turbine median arc; Among them, the formula of the Bezier curve is as follows:

[0027] Among them, \(t\) represents the curve parameter, .

[0028] Specifically, the control points in the blade thickness curve include control point \(b0\) and control point \(b2\); the control points in the blade thickness curve include control point \(b1\); The B-spline curve is drawn by the control point \(b0\), control point \(b1\) and control point \(b2\), and the middle part of the blade thickness curve is obtained through the B-spline curve; The B-spline curve is tangent to the thickness curves at the front and rear edges of the blade.

[0029] Furthermore, the formula of the B-spline curve is as follows:

[0030] Among them, \(t\) represents the curve parameter, .

[0031] In one embodiment, as Figure 2 shown, the mean camber line of the blade is determined by the blade deflection angle \(G\) c chord length \(l\) r and the blade geometric angle \(B\) c together, and it is a second-order Bezier curve, including three control points.

[0032] In one embodiment, as Figure 3 shown, the blade thickness distribution curve consists of two parts: the front and rear edge fillets and the main blade thickness. Among them, the main blade thickness curve part is a second-order B-spline curve, including three control points, and this curve is tangent to the front and rear edge fillet thickness curves.

[0033] In one embodiment, as Figure 4 shown, a two-dimensional blade shape established by this method includes blade thickness 1 perpendicular to the mean camber line, blade suction surface profile 2, blade mean camber line 3, blade pressure surface profile 4 and blade chord length 5. The pitch and throat between the blades are as shown in the figure and are determined by the blade profile and the number of blades together.

[0034] In one embodiment, as Figure 5 shown, a three-dimensional blade established by this method includes blade suction surface 6 and blade pressure surface 7. The specific parameters of the blade are as follows: the blade geometric angle is 0°, the chord length is 200 mm, the fillet radius is 3 mm, the divergence angle is 12°, and the blade height is 120 mm.

[0035] In one embodiment, as Figure 6 shown, the comparison of the flow characteristics between the blade shape (right) created by this method and the traditional blade shape (left) shows that the flow separation phenomenon at the trailing edge of the blade is significantly weakened, effectively reducing the loss of the blade profile.

[0036] In one embodiment, as Figure 7 shown, it is the blade load curve of the leaf shape created by this method. There is no obvious fluctuation in the pressure on the pressure surface and the suction surface, the pressure difference between the two sides is large, and the cross - range of the pressure on both sides at the trailing edge of the blade is small, and the wake loss is small.

[0037] In summary, this embodiment provides a parametric design method for the symmetrical rotor blades of an impulse turbine. Using a small number of parameter points, it realizes the parametric design of the inner rotor blades of the impulse turbine, and within the proposed parameter range, it can ensure that the blade profile is smooth and has excellent aerodynamic performance. The present invention uses a parametric method to realize the design of the symmetrical rotor blades in the impulse turbine. While considering the smoothness of the blade profile and meeting the requirements of symmetrical blades, it greatly reduces the number of control points and realizes efficient parametric design. This method has strong adaptability in the blade design under different working conditions and flexibility in the blade modification process. Embodiment 2 According to Figure 8 shown, the present invention also provides a parametric design system for the symmetrical rotor blades of an impulse turbine, including: A data determination module, used to determine the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade expansion angle, and maximum half - thickness of the blade based on the leaf shape parameters; A first drawing module, used to determine the control point coordinates of the mean camber line of the rotor blade according to the determined blade deflection angle, blade geometric angle, and chord length; and draw the turbine mean camber line using the control point coordinates of the mean camber line of the rotor blade; A second drawing module, used to determine the control points on the thickness curves at the front and rear edges of the blade and the control points on the blade thickness curve according to the blade fillet radius and the blade expansion angle, and determine the control points on the blade thickness curve according to the maximum half - thickness of the blade; draw the middle part of the blade thickness curve using the control points on the thickness curves at the front and rear edges of the blade, the control points on the blade thickness curve, and the control points on the blade thickness curve; A blade model design module, used to extend the middle part of the blade thickness curve along the normal directions on both sides of the turbine mean camber line to obtain the blade pressure surface and suction surface profiles, and obtain a symmetrical two - dimensional leaf shape according to the blade pressure surface and suction surface profiles; create a number of two - dimensional leaf shapes along the blade height direction for the symmetrical two - dimensional leaf shape, and stack the number of two - dimensional leaf shapes to obtain the blade three - dimensional model, thus completing the parametric design of the rotor blades of the impulse turbine.

[0038] Embodiment 3 The present invention also provides a mobile terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, such as a parametric design program for the symmetrical rotor blades of an impulse turbine.

[0039] When the processor executes the computer program, it implements the steps of the above-mentioned parametric design method for the symmetric rotor blades of the impulse turbine, such as: Based on the blade profile parameters, determine the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade divergence angle, and maximum half-thickness of the blade; Determine the control point coordinates of the median arc of the rotor blade according to the determined blade deflection angle, blade geometric angle, and chord length; draw the turbine median arc using the control point coordinates of the median arc of the rotor blade; Determine the control points of the thickness curves at the front and rear edges of the blade and the control points in the blade thickness curve according to the blade fillet radius and blade divergence angle; determine the control points in the blade thickness curve according to the maximum half-thickness of the blade; draw the middle part of the blade thickness curve using the control points of the thickness curves at the front and rear edges of the blade, the control points in the blade thickness curve, and the control points in the blade thickness curve; Extend the middle part of the blade thickness curve along the turbine median arc in the normal direction on both sides to obtain the blade pressure surface and suction surface profiles; obtain the symmetric two-dimensional blade profile according to the blade pressure surface and suction surface profiles; create several two-dimensional blade profiles along the blade height direction, and stack the several two-dimensional blade profiles to obtain the three-dimensional blade model, completing the parametric design of the rotor blade of the impulse turbine.

[0040] Alternatively, when the processor executes the computer program, it implements the functions of each module in the above system, such as: A data determination module for determining the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade divergence angle, and maximum half-thickness of the blade based on the blade profile parameters; A first drawing module for determining the control point coordinates of the median arc of the rotor blade according to the determined blade deflection angle, blade geometric angle, and chord length; drawing the turbine median arc using the control point coordinates of the median arc of the rotor blade; A second drawing module for determining the control points of the thickness curves at the front and rear edges of the blade and the control points in the blade thickness curve according to the blade fillet radius and blade divergence angle; determining the control points in the blade thickness curve according to the maximum half-thickness of the blade; drawing the middle part of the blade thickness curve using the control points of the thickness curves at the front and rear edges of the blade, the control points in the blade thickness curve, and the control points in the blade thickness curve; A blade model design module for extending the middle part of the blade thickness curve along the turbine median arc in the normal direction on both sides to obtain the blade pressure surface and suction surface profiles; obtaining the symmetric two-dimensional blade profile according to the blade pressure surface and suction surface profiles; creating several two-dimensional blade profiles along the blade height direction, and stacking the several two-dimensional blade profiles to obtain the three-dimensional blade model, completing the parametric design of the rotor blade of the impulse turbine.

[0041] Exemplarily, the computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program in the mobile terminal.

[0042] For example, the computer program may be divided into a data determination module, a first drawing module, a second drawing module, and a blade model design module; The specific functions of each module are as follows: The data determination module is configured to determine the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade expansion angle, and maximum half-thickness of the blade based on the blade shape parameters; The first drawing module is configured to determine the control point coordinates of the mid-arc line of the rotor blade according to the determined blade deflection angle, blade geometric angle, and chord length; and draw the turbine mid-arc line by using the control point coordinates of the mid-arc line of the rotor blade; The second drawing module is configured to determine the control points on the thickness curves at the front and rear edges of the blade and the control points on the blade thickness curve according to the blade fillet radius and the blade expansion angle, and determine the control points on the blade thickness curve according to the maximum half-thickness of the blade; and draw the middle part of the blade thickness curve by using the control points on the thickness curves at the front and rear edges of the blade, the control points on the blade thickness curve, and the control points on the blade thickness curve; The blade model design module is configured to extend the middle part of the blade thickness curve along the normal directions on both sides of the turbine mid-arc line respectively to obtain the profiles of the pressure surface and the suction surface of the blade, and obtain the symmetric two-dimensional blade shape according to the profiles of the pressure surface and the suction surface of the blade; create a plurality of two-dimensional blade shapes along the blade height direction for the symmetric two-dimensional blade shape, and stack the plurality of two-dimensional blade shapes to obtain the three-dimensional blade model, thereby completing the parametric design of the rotor blade of the impulse turbine.

[0043] The mobile terminal may be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The mobile terminal may include, but is not limited to, a processor and a memory.

[0044] The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the mobile terminal, connecting various parts of the entire mobile terminal through various interfaces and circuits.

[0045] The memory can be used to store the computer programs and / or modules. The processor realizes various functions of the mobile terminal by running or executing the computer programs and / or modules stored in the memory, and by calling the data stored in the memory.

[0046] The memory may mainly include a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the mobile phone (such as audio data, phone book, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0047] Embodiment 4 The present invention also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the parameterization design method for the symmetric rotor blades of an impulse turbine are realized.

[0048] If the modules / units integrated in the mobile terminal are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0049] Based on such understanding, all or part of the processes in the above method of the present invention can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above aggregation reinforcement learning resource scheduling method can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc.

[0050] The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0051] It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice within the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0052] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still modifications or equivalent replacements can be made to the specific implementation manners of the present invention, and any modifications or equivalent replacements without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A parametric design method for the symmetrical rotor blades of an impulse turbine, characterized in that, Comprising: Determining the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade expansion angle and maximum half-thickness of the blade based on the leaf shape parameters; Determining the control point coordinates of the median arc of the rotor blade according to the determined blade deflection angle, blade geometric angle and chord length; drawing the turbine median arc using the control point coordinates of the median arc of the rotor blade; Determining the control points in the thickness curves at the front and rear edges of the blade and in the blade thickness curve according to the blade fillet radius and the blade expansion angle, and determining the control points in the blade thickness curve according to the maximum half-thickness of the blade; Drawing the middle part of the blade thickness curve using the control points in the thickness curves at the front and rear edges of the blade, the control points in the blade thickness curve, and the control points in the blade thickness curve; Extending the middle part of the blade thickness curve along the turbine median arc in the normal directions on both sides respectively to obtain the profiles of the blade pressure surface and the suction surface, and obtaining the symmetric two-dimensional blade shape according to the profiles of the blade pressure surface and the suction surface; creating a number of two-dimensional blade shapes along the blade height direction for the symmetric two-dimensional blade shape, and stacking the number of two-dimensional blade shapes to obtain the three-dimensional blade model, thus completing the parametric design of the rotor blade of the impulse turbine.

2. A parametric design method for a symmetric rotor blade of an impulse turbine according to claim 1, characterized in that Taking the turbine axis as the reference, fixing the leading edge endpoint of the blade median arc as the origin to obtain the leaf shape parameters.

3. A parametric design method for a symmetrical rotor blade of an impulse turbine according to claim 1, characterized in that, The range of the blade geometric angle is from 55° to 65°; the range of the blade fillet radius is from 1% to 3% of the chord length; the range of the blade expansion angle is from 6° to 15°; the range of the maximum half-thickness of the blade is from 5% to 12.5% of the chord length.

4. A parametric design method for a symmetric rotor blade of an impulse turbine according to claim 1, characterized in that, In the step of drawing the turbine median arc using the control point coordinates of the median arc of the rotor blade, the control points of the median arc of the rotor blade include control point a0, control point a1 and control point a2; Setting control point a0 and control point a2 as the two endpoints of the chord length respectively, and drawing auxiliary lines from the two endpoints towards the middle at an angle relative to the chord length, and the intersection point is control point a1.

5. A parametric design method for a symmetric rotor blade of an impulse turbine according to claim 3, characterized in that, Drawing a Bezier curve through control point a0, control point a1 and control point a2, and taking the Bezier curve as the turbine median arc; Wherein, the formula of the Bezier curve is as follows: where t represents the curve parameter, .

6. A parametric design method for a symmetric rotor blade of an impulse turbine according to claim 1, characterized in that, The control points in the blade thickness curve include control point b0 and control point b2; the blade The control points in the thickness curve include control point b1; Drawing a B-spline curve through control point b0, control point b1 and control point b2, and obtaining the middle part of the blade thickness curve through the B-spline curve; The B-spline curve is tangent to the thickness curves at the front and rear edges of the blade.

7. A parametric design method for the symmetrical rotor blades of an impulse turbine according to claim 6, characterized in that, The formula of the B-spline curve is as follows: where t represents the curve parameter, .

8. A parametric design system for the symmetrical rotor blades of an impulse turbine, characterized in that, Comprising: A data determination module for determining the blade deflection angle, blade geometric angle, chord length, blade fillet radius, blade expansion angle and maximum half-thickness of the blade based on the leaf shape parameters; A first drawing module for determining the control point coordinates of the median arc of the rotor blade according to the determined blade deflection angle, blade geometric angle and chord length; drawing the turbine median arc using the control point coordinates of the median arc of the rotor blade; A second drawing module for determining the control points in the thickness curves at the front and rear edges of the blade and in the blade thickness curve according to the blade fillet radius and the blade expansion angle, and determining the control points in the blade thickness curve according to the maximum half-thickness of the blade; The middle part of the blade thickness curve is obtained by drawing using the thickness curves at the leading and trailing edges of the blade, the control points in the blade thickness curve, and the control points in the blade thickness curve. The blade model design module is used to extend the middle part of the blade thickness curve along the turbine mean arc line in the normal directions on both sides to obtain the profiles of the blade pressure surface and the suction surface, and obtain the symmetric two-dimensional blade shape according to the profiles of the blade pressure surface and the suction surface; create a number of two-dimensional blade shapes along the blade height direction for the symmetric two-dimensional blade shape, and stack the number of two-dimensional blade shapes to obtain the three-dimensional blade model, thus completing the parametric design of the rotor blade of the impulse turbine.

9. A mobile terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the parametric design method of the symmetric rotor blade of the impulse turbine according to any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the parametric design method of the symmetric rotor blade of the impulse turbine according to any one of claims 1-7.

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