A space guide vane axial surface and plane hydraulic design method based on cascade theory

Abstract

The application relates to a space guide vane axial surface and plane hydraulic design method based on a cascade theory, the space guide vane comprising a rim, a hub, short radial blades and long axial blades, and comprising the following steps: determining the rim profile and the hub profile by a parameter-driven Guass equation, and mathematically controlling the axial surface flow area variation curve of the overall flow channel formed by the hub and the rim; determining the short radial blades and the long axial blades as airfoil structures; determining the distance between the short radial blade head and the space guide vane inlet edge, the distance between the short radial blade tail and the space guide vane transition position, the distance between the long axial blade head and the space guide vane transition position, and the distance between the long axial blade tail and the space guide vane outlet edge, and then arranging the short radial blades and the long axial blades in the space guide vane. The application has the effect of achieving high efficiency and stability.

Description

Technical Field

[0001] This application relates to the technical field of hydraulic machinery, and in particular to a spatial guide vane axial and planar hydraulic design method based on the blade cascade theory. Background Technology

[0002] In the field of turbomachinery, guide vanes are commonly found in multi-stage radial turbomachinery. Their function is to collect and guide the radially flowing fluid to the next stage flow channel. Simultaneously, by changing the flow area within the guide vane channel, the pump pressure is increased, achieving a fluid pressurization effect. This type of fluid equipment also has important applications in environmental protection, dredging, mining, new energy, and marine engineering. Therefore, measures to improve guide vane efficiency and operational stability are of great significance.

[0003] Unlike radial guide vanes, spatial guide vanes employ continuous, integrated blades to create a complete upstream and downstream flow channel. Their long axial length and good overall integrity theoretically result in superior hydraulic performance. However, the complex blade profiles with long blades and large wrap angles make practical optimization design very difficult, leading to suboptimal guide vane efficiency in real-world applications. Specifically, significant flow separation easily occurs at the flow channel transition points, including large vortices within the anti-reverse guide vane channel, resulting in low hydraulic efficiency and significant vibration and noise.

[0004] The configuration of long and short blades is common in the impeller blade design of centrifugal pumps. For example, Chinese patent application CN2018105302078 proposes a pump impeller structure with secondary flow-dividing blades, defining the placement angles and offset angles of the primary and secondary flow-dividing blades to suppress or reduce impeller flow separation or jet wake phenomena within the pump, thereby improving the pump's operating efficiency under low flow conditions. Another example is Chinese patent application CN2020112321920, which proposes a reversible pump-turbine with long and short blades, defining and mathematically describing the spatial curve configurations of the long and short blades, ultimately improving the overall efficiency and stability of the pump-turbine. Finally, Chinese patent application CN2023103760585 proposes a spatial guide vane design method for a molten salt pump with long and short blades, specifying the changes in the cross-sectional area, the blade inlet edge, and the relative position to eliminate vortices and improve efficiency.

[0005] Regarding the aforementioned technologies, the inventors believe that the combination of long and short blades or splitting blades is common in rotating impellers, but in fixed flow channels, especially in cases with a large axial bending radius, there is still no good, efficient and stable design method for long and short blades, thus there is room for improvement. Summary of the Invention

[0006] To achieve high efficiency and stability, this application provides a spatial guide vane axial and planar hydraulic design method based on cascade theory.

[0007] This application provides a spatial guide vane axial and planar hydraulic design method based on cascade theory, which adopts the following technical solution: A method for designing the axial and planar hydraulic surfaces of a spatial guide vane based on cascade theory, wherein the spatial guide vane includes a rim, a hub, short radial blades, and long axial blades, includes the following steps: The rim profile and hub profile are determined by the parameter-driven Gauss equation, and the axial flow area variation curve of the integral flow channel formed by the hub and rim is mathematically controlled. Both the short radial blades and the long axial blades are defined as airfoil structures; After determining the distances between the tip of the short radial blade and the inlet edge of the space guide vane, the distances between the tail of the short radial blade and the transition position of the space guide vane, the distances between the tip of the long axial blade and the transition position of the space guide vane, and the distances between the tail of the long axial blade and the outlet edge of the space guide vane, the short radial blades and long axial blades are arranged inside the space guide vane.

[0008] Preferably, the hub profile satisfies the Gauss equation, which is as follows: In the formula: y 11 =26.2, x c1 =312.9, ω=1484.6, A=1.61.

[0009] Preferably, the rim profile satisfies the Gaussian equation, which is as follows: In the formula: y 12 =-8526.1, x c2 =122.8, ω=1484.6, A=1.61.

[0010] Preferably, the axial flow area variation curve of the integral flow channel formed by the hub and rim is a piecewise ascending curve, and the equation of the axial flow area variation curve is as follows: .

[0011] The preferred equation for the short radial blade airfoil structure is as follows: Top edge: y 短径向叶片上沿 = -7e -7 x 4 + 0.0002x 3 - 0.018x 2 + 0.8931x + 0.9731; Bottom edge: y 短径向叶片上沿 = 3e-10 x 6 –1e -7 x 5 + 2e -5 x 4 - 0.0014x 3 + 0.0527x 2 - 0.7193x +0.597; The equations for the long-axis blade airfoil structure are as follows: Top edge: y 长轴向叶片上沿 = -3e -12 x 6 + 3e -9 x 5 –1e -6 x 4 + 0.0003x 3 - 0.0264x 2 + 1.5516x - 1.6557; Bottom edge: y 长轴向叶片上沿 = 3e -12 x 6 –3e -9 x 5 + 1e -6 x 4 - 0.0002x 3 + 0.0193x 2 - 0.5577x -0.2568.

[0012] Preferably, the number of blades in the short radial blade is 8 to 12, and the tail of the short radial blade is a twisted structure to adapt to the streamline direction of the transition position of the spatial guide vane. The number of blades in the long axial blade is 8 to 12, and the head of the long axial blade is a twisted structure to adapt to the streamline direction of the transition position of the spatial guide vane.

[0013] Preferably, the distance between the tip of the short radial blade and the edge of the inlet of the space guide vane is 3~5 mm; The distance between the tail of the short radial blade and the transition position of the spatial guide vane is (1~2)*πR; The distance between the tip of the long-axis blade and the transition position of the spatial guide vane is (0.3~1)0.5*πR; The distance between the tail of the long-axis blade and the edge of the space guide vane outlet is 0~10mm.

[0014] Preferably, the design method further includes the following steps: Calculate the flow area a1 at the tip of the short radial blade and the flow area a2 at the tail of the short radial blade, and determine that the area ratio of the flow area a1 at the tip of the short radial blade and the flow area a2 at the tail of the short radial blade is 1.4~1.7. Calculate the flow area b1 at the tip of the long axial blade and the flow area b2 at the tail of the long axial blade, and determine that the area ratio of the flow area b1 at the tip of the long axial blade and the flow area b2 at the tail of the long axial blade is 1.3~1.5.

[0015] Preferably, the design method further includes the following steps: The wetted perimeter formed by the short radial blades, long axial blades, hub, and rim, as well as the flow channel plane area, are monitored. The length-to-diameter ratio γ and offset angle θ of the short radial blades and long axial blades are adjusted so that the flow channel plane area satisfies the variation characteristic equation, which is as follows: .

[0016] Preferably, the relationship between the aspect ratio γ of the short radial blades and the long axial blades and the change in the flow channel planar area is as follows: In the formula, ; The relationship between the offset angle θ of the short radial blades and the long axial blades and the change in the flow channel planar area is as follows: In the formula, .

[0017] In summary, this application includes at least one of the following beneficial technical effects: This application adopts a structure combining short radial blades and long axial blades in a space guide vane. Based on the space airfoil structure, a design method is proposed for the profiles of the short radial blades and long axial blades to determine their positions in the space guide vane, thereby improving hydraulic efficiency. Under low specific speed conditions, both stability and efficiency are greatly improved. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a multistage pump.

[0019] Figure 2 This is a schematic diagram of the space guide vane.

[0020] Figure 3 This is a schematic diagram of the first water body of the space guide vanes and impeller.

[0021] Figure 4 This is a schematic diagram of the second water body of the space guide vanes and impeller.

[0022] Figure 5This is a schematic diagram of the water body on the axial surface of the guide vanes and impeller.

[0023] Figure 6 This is a schematic diagram of the airfoil structure of a short radial blade.

[0024] Figure 7 This is a schematic diagram of the airfoil structure of a long-axis blade.

[0025] Figure 8 This is a schematic diagram of the wetted perimeter structure.

[0026] Figure 9a This is a schematic diagram illustrating the changing state of the length-to-diameter ratio adjustment.

[0027] Figure 9b This is a schematic diagram illustrating the changing states of the offset angle adjustment.

[0028] Figure 10 This is a comparison diagram of the lift performance of the space guide vane.

[0029] Figure 11 This is a comparison diagram of the efficiency and performance of the space guide vane.

[0030] Explanation of reference numerals in the attached drawings: 1. Inlet pump body; 2. Outlet pump body; 3. Spatial guide vane; 31. Rim; 32. Hub; 33. Short radial blade; 34. Long axial blade; 4. Impeller; 5. Main shaft; 6. Motor. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1-11 This application will be described in further detail.

[0032] In existing technologies, combinations of long and short blades or split-flow blades are common in rotating impellers. However, in fixed flow channels, especially in situations with large axial bending radii, there is still no good, efficient, and stable design method for long and short blades. The profile configuration of long and short blades is still unclear. In particular, according to traditional hydraulic design ideas, the flow channel is long and narrow, and the bending radius of the blades at the transition position of the spatial guide vane 3 is very large. The small inlet angle will lead to abrupt changes in the blade profile and a narrow inlet flow channel, which makes the integrated curved surface design difficult. At the same time, the processing and manufacturing difficulty is increased, making it difficult to guarantee efficient hydraulic performance.

[0033] Based on the above, the configuration of the short radial blades 33 and the long axial blades 34 in the spatial guide vane 3 proposed in this application is upstream and downstream, that is, the short radial blades 33 and the long axial blades 34 are not axially coincident in the spatial guide vane 3. The profiles of the short radial blades 33 and the long axial blades 34 are specifically designed, their starting positions and angles are defined, and the axial flow area change curve of the overall flow channel is mathematically constrained, ultimately achieving a highly efficient and stable effect. In particular, under low specific speed conditions, both stability and efficiency will be greatly improved.

[0034] Specifically, this application proposes a spatial guide vane three-axis and planar hydraulic design method based on cascade theory, applied to multistage pumps, the structure of which is as follows: Figure 1 As shown, the multistage pump includes an inlet pump body 1, an outlet pump body 2, spatial guide vanes 3, an impeller 4, a main shaft 5, and a motor 6. The inlet pump body 1 has an inlet, and the outlet pump body 2 has an outlet. Several spatial guide vanes 3 are stacked between the inlet pump body 1 and the outlet pump body 2. The impeller 4 is set in the spatial guide vanes 3. The main shaft 5 passes through the spatial guide vanes 3 to connect with the impeller 4. The motor 6 is set on the outlet pump body 2 to connect with the main shaft 5. The motor 6 drives the main shaft 5 to rotate, and the main shaft 5 drives the impeller 4 to rotate. The water passes through the inlet and is pressurized step by step through the impeller 4 and the spatial guide vanes 3 before being discharged from the outlet.

[0035] It is worth noting that along the direction from the inlet pump body 1 to the outlet pump body 2, several spatial guide vanes 3 and impellers 4 are stacked together. The water is transported in stages in the spatial guide vanes 3. That is, the spatial guide vanes 3 have the concept of a first-stage spatial guide vane 3 and a next-stage spatial guide vane 3, and the impellers 4 have the concept of a first-stage impeller 4 and a next-stage impeller 4.

[0036] In this application, a spatial guide vane three-axis and planar hydraulic design method based on cascade theory is proposed, referring to... Figure 2 As shown, the spatial guide vane 3 includes a rim 31, a hub 32, short radial blades 33, and long axial blades 34. The rim 31 refers to the outer wall surface of the spatial guide vane 3 that forms the overall flow channel, and the hub 32 refers to the inner wall surface of the spatial guide vane 3 that forms the overall flow channel. The rim 31 and hub 32 together form the overall flow channel of the spatial guide vane 3. The overall flow channel refers to the space guide vane 3 without the short radial blades 33 and long axial blades 34.

[0037] Short radial blades 33 and long axial blades 34 are arranged in the space guide vane 3, that is, the short radial blades 33 and long axial blades 34 are arranged in the integral flow channel between the rim 31 and the hub 32. The integral flow channel is separated by the short radial blades 33 and long axial blades 34 to form a flow channel for water to flow.

[0038] This application proposes a three-axis and planar hydraulic design method for spatial guide vanes based on cascade theory, comprising the following steps: Step S100: Determine the profile of rim 31 and hub 32 using parameter-driven Gauss equations, and mathematically control the axial flow area variation curve of the integral flow channel formed by hub 32 and rim 31. In step S200, both the short radial blade 33 and the long axial blade 34 are determined to be airfoil structures; In step S300, after determining the distance between the head of the short radial blade 33 and the inlet edge of the space guide vane 3, the distance between the tail of the short radial blade 33 and the transition position of the space guide vane 3, the distance between the head of the long axial blade 34 and the transition position of the space guide vane 3, and the distance between the tail of the long axial blade 34 and the outlet edge of the space guide vane 3, the short radial blade 33 and the long axial blade 34 are arranged inside the space guide vane 3.

[0039] According to the technical solution defined in step S100, specifically, the 32-shaped profile of the wheel hub satisfies the Gaussian equation, and the equation of the 32-shaped profile of the wheel hub is as follows: In the formula: y 11 =26.2, x c1 =312.9, ω=1484.6, A=1.61.

[0040] The 31-type rim profile satisfies the Gaussian equation, which is as follows: In the formula: y 12 =-8526.1, x c2 =122.8, ω=1484.6, A=1.61.

[0041] Among them, reference Figure 5 As shown, the axial flow area variation curve of the integral flow channel formed by the hub 32 and the rim 31 is a segmented ascending curve. The axial flow area variation curve is the centerline of the integral flow channel. The equation of the axial flow area variation curve is as follows: .

[0042] In the formula, l represents the length of the overall flow channel. The overall flow channel is obtained by constructing the hub 32 and the rim 31, and its length l is measured. The axial flow area of ​​the overall flow channel is controlled by the axial surface flow area variation curve. Therefore, by mathematically controlling the profiles of the rim 31, the hub 32, and the axial surface flow area variation curve of the overall flow channel, the requirements for high hydraulic efficiency and stability are met.

[0043] According to the technical solution defined in step S200, specifically, the short radial blade 33 is determined to be an airfoil structure, and the airfoil structure of the short radial blade 33 is as follows: Figure 6 As shown. In this embodiment, the number of blades in the short radial blade 33 is 8 to 12. The tail of the short radial blade 33 is a twisted structure to adapt to the streamline direction of the transition position of the spatial guide vane 3, and to adapt to the angle of the long axial blade 34 accordingly.

[0044] The airfoil structure of the short radial blade 33 has an upper edge and a lower edge. The airfoil structure of the short radial blade 33 is formed by mathematically controlling the upper and lower edges of the blade. The equations for the airfoil structure of the short radial blade 33 are as follows: Top edge: y 短径向叶片上沿 = -7e -7 x 4 + 0.0002x 3 - 0.018x 2 + 0.8931x + 0.9731; Bottom edge: y 短径向叶片上沿 = 3e -10 x 6 –1e -7 x 5 + 2e -5 x 4 - 0.0014x 3 + 0.0527x 2 - 0.7193x +0.597.

[0045] The long-axis blade 34 is defined as an airfoil structure, and the airfoil structure of the long-axis blade 34 is as follows: Figure 7 As shown. In this embodiment, the number of long axial blades 34 is 8 to 12. The head of the long axial blades 34 has a twisted structure to adapt to the streamline direction of the transition position of the space guide vane 3, and correspondingly adapt to the angle of the impeller 4 in the next stage space guide vane 3. It is worth noting that the number of long axial blades 34 is the same as the number of short radial blades 33. For example, if there are 8 short radial blades 33 in the space guide vane 3, then there are also 8 long axial blades 34 in the space guide vane 3.

[0046] The airfoil structure of the long-axis blade 34 has an upper edge and a lower edge. The airfoil structure of the long-axis blade 34 is formed by mathematically controlling the upper and lower edges of the blade. The equations for the airfoil structure of the long-axis blade 34 are as follows: Top edge: y 长轴向叶片上沿 = -3e -12 x 6 + 3e -9 x 5 –1e -6 x 4 + 0.0003x 3 - 0.0264x 2 + 1.5516x - 1.6557; Bottom edge: y 长轴向叶片上沿 = 3e -12 x 6 –3e -9 x 5+ 1e -6 x 4 - 0.0002x 3 + 0.0193x 2 - 0.5577x -0.2568.

[0047] It is worth noting that, as mentioned above, the tail of the short radial blade 33 is a twisted structure to adapt to the streamline direction of the transition position of the spatial guide vane 3, and the head of the long axial blade 34 is a twisted structure to adapt to the streamline direction of the transition position of the spatial guide vane 3. The transition position of the spatial guide vane 3 is explained as follows.

[0048] Reference Figure 3 As shown, the overall flow channel in the spatial guide vane 3 consists of a rim 31 and a hub 32. Both the profile of the hub 32 and the profile of the rim 31 satisfy the Gauss equation. The transition position of the spatial guide vane 3 is located at the bend point of the profile of the hub 32 and the profile of the rim 31.

[0049] Therefore, this application adopts an airfoil structure for the short radial blade 33 and the long axial blade 34. The head of the short radial blade 33 is connected to the impeller 4 to play a role in diffusion and flow stabilization, and the tail of the long axial blade 34 is connected to the impeller 4 to play a role in flow guidance.

[0050] According to the technical solution defined in step S300, specifically, by constraining the positions of the short radial blade 33 and the long axial blade 34, a highly efficient and stable effect can be achieved.

[0051] Reference Figure 3 and Figure 4 As shown, the distance t1 between the head of the short radial blade 33 and the inlet edge of the space guide vane 3 is 3~5mm, preferably 4mm, which is the radial line connecting the head of the short radial blade 33 and the central axis of the space guide vane 3. The distance between the head of the short radial blade 33 and the inlet edge of the space guide vane 3 is controlled in this line direction.

[0052] The distance t2 between the tail of the short radial blade 33 and the transition position of the space guide vane 3 is (1~2)*πR, in mm. That is, the line connecting the tail of the short radial blade 33 and the transition position of the space guide vane 3 along the axial direction. In this line direction, the distance between the tail of the short radial blade 33 and the transition position of the space guide vane 3 is controlled. R refers to the radius of curvature of the transition position of the space guide vane 3.

[0053] The distance t3 between the head of the long axial blade 34 and the transition position of the space guide vane 3 is (0.3~1)0.5*πR, in mm. That is, the line connecting the head of the long axial blade 34 and the transition position of the space guide vane 3 along the axial direction. The distance between the head of the long axial blade 34 and the transition position of the space guide vane 3 is controlled in this line direction. R refers to the radius of curvature of the transition position of the space guide vane 3.

[0054] The distance t4 between the tail of the long axial blade 34 and the exit edge of the space guide vane 3 is 0~10mm, preferably 5mm, which is the radial line connecting the tail of the long axial blade 34 and the central axis of the space guide vane 3. The distance between the tail of the long axial blade 34 and the exit edge of the space guide vane 3 is controlled in this line direction.

[0055] This application proposes a spatial guide vane three-axis and planar hydraulic design method based on cascade theory, which further includes the following steps: Step S400: Calculate the flow area a1 at the head of the short radial blade 33 and the flow area a2 at the tail of the short radial blade 33, and determine that the area ratio of the flow area a1 at the head of the short radial blade 33 and the flow area a2 at the tail of the short radial blade 33 is 1.4~1.7. Step S500: Calculate the flow area b1 at the head of the long axial blade 34 and the flow area b2 at the tail of the long axial blade 34, and determine that the area ratio of the flow area b1 at the head of the long axial blade 34 and the flow area b2 at the tail of the long axial blade 34 is 1.3~1.5.

[0056] According to the technical solutions defined in steps S400 and S500, specifically, the overall flow channel is divided by short radial blades 33 and long axial blades 34 to form a flow channel for water flow. The flow area a1 refers to the planar area of ​​the flow channel where the head of the short radial blade 33 is located, and the flow area a2 at the tail of the short radial blade 33 refers to the planar area of ​​the flow channel where the tail of the short radial blade 33 is located. By calculating the planar area of ​​the flow channel where the head of the short radial blade 33 is located, and the planar area of ​​the flow channel where the tail of the short radial blade 33 is located, the area ratio of the flow area a1 at the head of the short radial blade 33 to the flow area a2 at the tail of the short radial blade 33 is controlled to be 1.4 to 1.7. In this embodiment, the preferred area ratio is 1.5.

[0057] The flow area b1 refers to the planar area of ​​the flow channel where the head of the long axial blade 34 is located, and the flow area b2 refers to the planar area of ​​the flow channel where the tail of the long axial blade 34 is located. By calculating the planar area of ​​the flow channel where the head of the long axial blade 34 is located, and the planar area of ​​the flow channel where the tail of the long axial blade 34 is located, the area ratio of the flow area b1 at the head of the long axial blade 34 and the flow area b2 at the tail of the long axial blade 34 is controlled to be 1.3 to 1.5. In this embodiment, the preferred area ratio is 1.4.

[0058] The flow area is calculated as follows: The flow area is the planar area of ​​the flow channel, which is calculated from the wetted perimeter formed by the short radial blades 33, the long axial blades 34, the hub 32, and the rim 31, with reference to... Figure 8 As shown, the flow channel is cut off by a plane perpendicular to the middle streamline, and the perimeter of the obtained cross-section is the wetted perimeter l = l. aa’ + l a’b’ + l b’b + l ab The area of ​​this cross section is the flow channel plane area of ​​the AA' surface, which is also the aforementioned flow area.

[0059] This application proposes a spatial guide vane three-axis and planar hydraulic design method based on cascade theory, which further includes the following steps: Step S600: Monitor the wetted perimeter formed by the short radial blade 33, the long axial blade 34, the hub 32, and the rim 31, as well as the flow channel planar area. Adjust the length-to-diameter ratio γ and the offset angle θ of the short radial blade 33 and the long axial blade 34 so that the flow channel planar area satisfies the variation characteristic equation, which is as follows: .

[0060] According to the technical solution defined in step S600, specifically, the relationship between the length-to-diameter ratio γ of the short radial blade 33 and the long axial blade 34, the offset angle θ of the short radial blade 33 and the long axial blade 34 and the characteristic equation of the change in the flow channel plane area is explained as follows.

[0061] Reference Figure 9a As shown, the aspect ratio γ of the short radial blade 33 and the long axial blade 34 is explained using the short radial blade 33 as an example. The length of the short radial blade 33 is L, and its width is W. The aspect ratio γ is L / W. Adjusting the aspect ratio γ of the short radial blade 33 involves stretching or changing it along its length or width. In this embodiment, the aspect ratio γ of the short radial blade 33 and the aspect ratio γ of the long axial blade 34 are 0.6~1.5. Changing the aspect ratio γ of either the short radial blade 33 or the long axial blade 34 will result in... ,in Similarly, in order to satisfy the characteristic equation for the change of the flow channel plane area: The length-to-diameter ratio γ of the short radial blade 33 and the long axial blade 34 that need to be adjusted can be derived by using the above formula.

[0062] Reference Figure 9b As shown, the offset angle θ of the short radial blade 33 and the long axial blade 34 is explained using the short radial blade 33 as an example. Adjusting the offset angle θ of the short radial blade 33 involves rotating the head of the short radial blade 33 clockwise by a certain angle, which is the offset angle θ. In this embodiment, the offset angle θ of the short radial blade 33 and the long axial blade 34 is adjusted so that the flow channel plane area satisfies the changing characteristic equation. After changing the offset angle θ, it will make... ,in, Similarly, in order to satisfy the characteristic equation for the change of the flow channel plane area: The offset angle θ of the short radial blade 33 and the long axial blade 34 that need to be adjusted can be derived by using the above formula.

[0063] Therefore, by controlling the initial position and angle of the short radial blade 33 and the long axial blade 34 as described above, the hydraulic adaptability to different speed ratios can be effectively improved, especially the hydraulic stability under low specific speed conditions. Furthermore, as mentioned above, the short radial blade 33 and the long axial blade 34 can be respectively adapted to match the same impeller 4, thereby achieving the optimal configuration for industrial applications.

[0064] This application optimizes the design of the spatial guide vane 3 of a multi-stage pump and compares the hydraulic models designed using traditional methods and the method of this application. Numerical calculations are used to compare the methods and advantages / disadvantages of the two hydraulic models. The hydraulic model of the traditional method is model 0, and the hydraulic model of the method of this application is model 1. (Refer to...) Figure 10 and Figure 11 As shown, the spatial guide vane 3 designed by the method of this application significantly improves the performance of the multistage pump, and the efficiency of the multistage pump at high flow rate operating point is increased by nearly 10% year-on-year.

[0065] The x-axis involved in this application can be established with the central axis of the spatial guide vane, and the values ​​of the x and y points can be determined to complete the design of the rim profile, hub profile, short radial blades, and long axial blades. It is worth noting that this embodiment is not limited to using the central axis of the spatial guide vane as the x-axis; it is only necessary that the x and y coordinate systems of the rim profile, hub profile, short radial blades, and long axial blades are the same when establishing the x and y coordinate system.

[0066] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for axial and planar hydraulic design of a spatial guide vane based on blade cascade theory, wherein the spatial guide vane (3) comprises a rim (31), a hub (32), short radial blades (33), and long axial blades (34), characterized in that, Includes the following steps: The rim (31) profile and hub (32) profile are determined by parameter-driven Gauss equations, and the axial flow area variation curve of the integral flow channel formed by hub (32) and rim (31) is mathematically controlled. Both the short radial blade (33) and the long axial blade (34) are defined as airfoil structures; After determining the distance between the head of the short radial blade (33) and the inlet edge of the space guide vane (3), the distance between the tail of the short radial blade (33) and the transition position of the space guide vane (3), the distance between the head of the long axial blade (34) and the transition position of the space guide vane (3), and the distance between the tail of the long axial blade (34) and the outlet edge of the space guide vane (3), the short radial blade (33) and the long axial blade (34) are arranged inside the space guide vane (3). The design methodology also includes the following steps: Calculate the flow area a1 at the head of the short radial blade (33) and the flow area a2 at the tail of the short radial blade (33), and determine that the area ratio of the flow area a1 at the head of the short radial blade (33) and the flow area a2 at the tail of the short radial blade (33) is 1.4~1.

7. Calculate the flow area b1 at the head of the long axial blade (34) and the flow area b2 at the tail of the long axial blade (34), and determine that the area ratio of the flow area b1 at the head of the long axial blade (34) and the flow area b2 at the tail of the long axial blade (34) is 1.3~1.

5.

2. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The hub (32) profile satisfies the Gauss equation, and the equation of the hub (32) profile is as follows: In the formula: y 11 =26.2, x c1 =312.9, ω=1484.6, A=1.

61.

3. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The flange (31) profile satisfies the Gauss equation, and the equation of the flange (31) profile is as follows: In the formula: y 12 =-8526.1, x c2 =122.8, ω=1484.6, A=1.

61.

4. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The axial flow area change curve of the integral flow channel formed by the hub (32) and the rim (31) is a segmented rising curve, and the equation of the axial flow area change curve is as follows: Where l is the length of the overall flow channel.

5. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The equations for the short radial blade (33) airfoil structure are as follows: Top edge: y 短径向叶片上沿 = -7e -7 x 4 + 0.0002x 3 - 0.018x 2 + 0.8931x + 0.9731; Bottom edge: y 短径向叶片上沿 = 3e -10 x 6 –1e -7 x 5 + 2e -5 x 4 - 0.0014x 3 + 0.0527x 2 - 0.7193x +0.597; The equations for the long-axis blade (34) airfoil structure are as follows: Top edge: y 长轴向叶片上沿 = -3e -12 x 6 + 3e -9 x 5 –1e -6 x 4 + 0.0003x 3 - 0.0264x 2 + 1.5516x -1.6557; Bottom edge: y 长轴向叶片上沿 = 3e -12 x 6 –3e -9 x 5 + 1e -6 x 4 - 0.0002x 3 + 0.0193x 2 - 0.5577x -0.2568.

6. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The number of blades in the short radial blade (33) is 8 to 12. The tail of the short radial blade (33) is a twisted structure to adapt to the streamline direction of the transition position of the space guide vane (3). The number of blades in the long axial blade (34) is 8 to 12. The head of the long axial blade (34) is a twisted structure to adapt to the streamline direction of the transition position of the space guide vane (3).

7. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The distance between the head of the short radial blade (33) and the inlet edge of the space guide vane (3) is 3~5 mm; The distance between the tail of the short radial blade (33) and the transition position of the space guide vane (3) is (1~2)*πR; The distance between the head of the long-axis blade (34) and the transition position of the space guide vane (3) is (0.3~1)0.5*πR; The distance between the tail of the long axial blade (34) and the exit edge of the space guide vane (3) is 0~10mm; Where R refers to the radius of curvature at the transition position of the spatial guide vane (3).

8. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 1, characterized in that, The design methodology also includes the following steps: The wetted perimeter formed by the short radial blade (33), the long axial blade (34), the hub (32), and the rim (31), as well as the flow channel plane area, are monitored. The length-to-diameter ratio γ and the offset angle θ of the short radial blade (33) and the long axial blade (34) are adjusted so that the flow channel plane area satisfies the variation characteristic equation, which is as follows: 。 9. The spatial guide vane axial and planar hydraulic design method based on cascade theory according to claim 8, characterized in that, The relationship between the aspect ratio γ of the short radial blade (33) and the long axial blade (34) and the change in the flow channel planar area is as follows: In the formula, ; The relationship between the offset angle θ of the short radial blade (33) and the long axial blade (34) and the change in the flow channel planar area is as follows: In the formula, .

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