Improvement method for centrifugal pump blade, centrifugal pump blade and centrifugal pump

Abstract

The invention discloses an improvement method for a centrifugal pump blade, the centrifugal pump blade and a centrifugal pump. The improvement method for the centrifugal pump blade comprises the steps that a plurality of annular flow channel sections are arranged in a fluid channel in the radial direction of a rotating shaft; determining a total entropy output value in each annular flow channel section; determining a target optimization region of the blade based on the total entropy output value; and setting bionic ribs in the target optimization area. A plurality of annular flow channel sections are arranged in a fluid channel formed by rotation of a plurality of blades, the total entropy output value in each annular flow channel section is calculated, the target optimization area of the blades is determined according to the total entropy output value, and then the bionic ribs are arranged in the target optimization area. In this way, the total entropy output value in the section of the annular flow channel can be reduced through the bionic ribs, the energy flow loss is reduced, the flow state of fluid in the fluid channel is improved, then flow separation in a target optimization area on the blade is reduced, and development of cavitation in the fluid channel is restrained.

Description

Technical Field

[0001] This application belongs to the field of centrifugal pump technology, specifically relating to an improved method for centrifugal pump blades, centrifugal pump blades, and a centrifugal pump. Background Technology

[0002] Centrifugal pumps have advantages such as high head, high efficiency, and small size, and are widely used in various fields such as military, industry, and agriculture. As the core component of a centrifugal pump, the blades convert mechanical energy into fluid pressure energy through rotation, thereby achieving the purpose of fluid pressurization. Therefore, the shape of the blades directly determines the performance of the centrifugal pump.

[0003] As the operating environment and working conditions change, the inlet pressure of the centrifugal pump will also change. When the drop is large, cavitation will form in a local area of ​​the suction surface of the blade, resulting in a deterioration of the flow field, a decrease in head and efficiency. This cavitation phenomenon will greatly affect the maintenance cost and service life of the centrifugal pump. Summary of the Invention

[0004] This application aims to provide an improved method for centrifugal pump blades, centrifugal pump blades, and a centrifugal pump, which can solve the problem of poor cavitation resistance of centrifugal pumps in related technologies, affecting the maintenance cost and service life of centrifugal pumps.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows: In a first aspect, embodiments of this application propose an improved method for centrifugal pump blades, applied to a centrifugal pump. The centrifugal pump includes a housing, a rotating shaft, and multiple blades. The housing has a receiving cavity, the rotating shaft passes through the receiving cavity and is rotatably connected to the housing, and the multiple blades are disposed in the receiving cavity and arranged circumferentially around the rotating shaft. The rotating shaft can drive the multiple blades to rotate relative to the housing, so that the multiple blades rotate to form a fluid channel. The method includes: Along the radial direction of the rotating shaft, a plurality of annular flow channel sections are provided within the fluid channel; Determine the total entropy production value within each of the said annular flow channel cross sections; The target optimization region for the blade is determined based on the total entropy output value; Bionic ribs are set in the target optimization area.

[0006] Optionally, determining the total entropy output within each of the annular flow channel cross sections includes: Obtain the performance parameters of each of the annular flow channel cross sections and the corresponding portion of the blades; Based on the performance parameters, the entropy production rate corresponding to the annular flow channel cross section is calculated; wherein, the entropy production rate includes direct dissipation entropy production rate, turbulent dissipation entropy production rate, and wall entropy production rate; The total entropy production value corresponding to the annular flow channel cross section is determined based on the entropy production rate.

[0007] Optionally, determining the target optimization region of the blade based on the total entropy output includes: The largest total entropy output value is determined based on the total entropy output value corresponding to the multiple annular flow channel cross sections; The annular flow channel cross section corresponding to the largest total entropy output value is taken as the target annular flow channel cross section; Based on the target annular flow channel cross section, the target optimization area of ​​the blade is determined.

[0008] Optionally, setting the biomimetic ribs in the target optimization region includes: Determine the suction surface and pressure surface of the blade; The biomimetic ribs are arranged at positions corresponding to the target optimization area on the suction surface and the pressure surface.

[0009] Optionally, the step of setting the biomimetic rib at a position corresponding to the target optimization region on the suction surface and the pressure surface includes: Along the extension direction of the blade, a plurality of biomimetic ribs are arranged at intervals at positions corresponding to the target optimization area on the suction surface and the pressure surface.

[0010] Secondly, this application also proposes a centrifugal pump blade, which is prepared using the improved method for centrifugal pump blades described in any of the above embodiments.

[0011] Optionally, the thickness of the blade is D1, and the thickness of the biomimetic rib is D2, satisfying: 4≤D1 / D2≤8.

[0012] Optionally, the biomimetic ribs extend from one end of the blade to the other end along the width direction of the blade.

[0013] Optionally, the side of the biomimetic rib facing away from the blade is provided as an arc surface; And / or, the biomimetic ribs and the blades are an integral structure.

[0014] Thirdly, embodiments of this application also propose a centrifugal pump, including the centrifugal pump blades described in any of the above embodiments.

[0015] In the embodiments of this application, multiple annular flow channel sections are set within the fluid channel formed by the rotation of multiple blades. The total entropy production value within each annular flow channel section is calculated, and the target optimization region of the blade is determined based on the total entropy production value. Then, biomimetic ribs are set within the target optimization region. This utilizes biomimetic ribs to reduce the total entropy production value within the annular flow channel section and reduce energy flow loss, thereby improving the flow state of the fluid within the fluid channel. This, in turn, reduces flow separation within the target optimization region on the blade, suppresses the development of cavitation within the fluid channel, and effectively improves the anti-cavitation performance of the centrifugal pump.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a partial structural schematic diagram of a centrifugal pump according to an embodiment of this application; Figure 2 This is a flowchart of an improved method for centrifugal pump blades according to an embodiment of this application; Figure 3 This is a schematic diagram of the blade structure according to an embodiment of this application; Figure 4 This is a flowchart illustrating the determination of the total entropy output within each annular flow channel cross-section according to embodiments of this application; Figure 5 This is a flowchart illustrating the determination of the target optimization region of a blade based on total entropy output value according to an embodiment of this application. Figure 6 This is a flowchart illustrating the setting of biomimetic ribs in the target optimization region according to an embodiment of this application; Figure 7 This is a distribution diagram of the total entropy output value within the nine annular flow channel cross sections of this application embodiment; Figure 8 This is an axial projection view of the blade according to an embodiment of this application; Figure 9 This is a comparison chart of the turbulent dissipation entropy output values ​​in the comparative examples and embodiments of this application; Figure 10 This is a diagram showing the relationship between net positive suction head (NPSH) and centrifugal pump head in the embodiments of this application. Figure 11 This is based on the relationship diagram between net positive suction head (NPSH) and centrifugal pump efficiency in the embodiments of this application; Figure 12 This is one of the comparison charts of local average entropy yield based on the comparative examples and embodiments of this application; Figure 13 This is the second comparison chart of the local average entropy yield in the comparative examples and embodiments of this application; Figure 14 This is one of the schematic diagrams of the monitoring points of the centrifugal pump according to the embodiments of this application; Figure 15 This is a second schematic diagram of the monitoring points of the centrifugal pump according to the embodiments of this application; Figure 16 This is a graph showing the test results of five monitoring points in the centrifugal pump of Comparative Example 1 of this application; Figure 17 This is a graph showing the test results of five monitoring points in a centrifugal pump according to Embodiment 1 of this application.

[0018] Figure label: 10: Shell; 20: Shaft; 30: Blade; 31: First end; 32: Second end; 33: Third end; 34: Fourth end; 301: First section profile; 302: Second section profile; 40: Bionic rib. Detailed Implementation

[0019] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a link; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] The following description, in conjunction with the accompanying drawings, details an improved method for centrifugal pump blades, centrifugal pump blades, and centrifugal pump provided in this application, through specific embodiments and application scenarios.

[0024] A centrifugal pump is a mechanical device that uses the centrifugal force generated by the rotation of an impeller to transport fluids; it belongs to the category of dynamic pumps. The core working principle of a centrifugal pump is to convert mechanical energy into the kinetic and pressure energy of the fluid through a high-speed rotating impeller, thereby achieving fluid transport, pressurization, or circulation. However, due to insufficient fluid pressure at the pump inlet or the influence of liquid saturated vapor pressure, cavitation, also known as vapor cavitation, can occur during centrifugal pump operation. This can easily lead to pitting corrosion of the impeller or pump casing, thus affecting the service life of the centrifugal pump and reducing its head and efficiency.

[0025] Cavitation is a phenomenon where, during fluid flow, vapor bubbles begin to appear and grow when the local pressure is lower than the saturated vapor pressure at that temperature. When these vapor bubbles pass through a region and the pressure increases to exceed their saturated vapor pressure at that temperature, they rapidly rupture and condense. This cavitation process creates voids, and the surrounding high-pressure fluid flows towards these voids at extremely high speeds, resulting in intense collisions. When the cavitation ruptures and condenses on the surface of a centrifugal pump casing or blades, the surrounding high-pressure fluid directly collides with these components, causing vibration and damage—a phenomenon known as cavitation. Since the pressure generated during these collisions can reach hundreds of megapascals, and the collision frequency can reach tens of thousands of times per second, this can easily lead to fatigue of the centrifugal pump casing or blades, pitting corrosion on their surface, and even breakage.

[0026] Furthermore, centrifugal pumps inevitably experience energy losses during operation. Entropy production theory can be used to calculate these losses, thereby identifying unstable fluid flow regions within the pump and quantifying the magnitude of energy loss. When fluid temperature changes are minimal, entropy production due to heat transfer can be neglected. Therefore, for fluid entropy production, direct dissipation entropy production and turbulent dissipation entropy production can be primarily considered.

[0027] After obtaining the unstable region of the fluid inside the centrifugal pump using the above entropy production theory, this application also draws on the side shape of fish such as sturgeon in nature to set biomimetic ribs on the blades of the centrifugal pump to reduce cavitation phenomena generated during the operation of the centrifugal pump and improve the anti-cavitation performance of the centrifugal pump.

[0028] Figure 1 A partial structural schematic diagram of a centrifugal pump in an embodiment of this application is shown. The centrifugal pump includes a housing 10, a rotating shaft 20, and multiple blades 30. The housing 10 has a receiving cavity. The rotating shaft 20 passes through the receiving cavity and is rotatably connected to the housing 10. Multiple blades 30 are disposed in the receiving cavity and are arranged circumferentially around the rotating shaft 20. The rotating shaft 20 can drive the multiple blades 30 to rotate relative to the housing 10, so that the multiple blades 30 rotate to form a fluid channel. Figure 2 A flowchart illustrating an embodiment of this application provides a method for improving centrifugal pump blades. The method, applied to a centrifugal pump, includes the following steps: Step 101: Along the radial direction of the rotating shaft 20, a plurality of annular flow channel sections are provided in the fluid channel.

[0029] Specifically, the rotating shaft 20 is cylindrical, and multiple blades 30 are evenly spaced around the circumference of the rotating shaft 20. The rotating shaft 20 can rotate relative to the housing around its axial direction, thereby driving the multiple blades 30 to rotate relative to the housing 10. The rotation of the multiple blades 30 can drive the fluid in the receiving cavity to undergo centrifugal motion, thereby creating a fluid channel. Starting from the rotating shaft 20 and ending at the outer wall of the housing 10, multiple annular flow channel sections are arranged radially along the rotating shaft 20 within the fluid channel. The multiple annular flow channel sections are concentric rings.

[0030] For example, 6, 7, 8, 9, or 10 annular flow channel sections can be set in the fluid channel. Of course, the specific number and method of setting the annular flow channel sections can be flexibly adjusted according to actual needs, and the embodiments of this application do not limit them.

[0031] Step 102: Determine the total entropy production value within each of the said annular flow channel sections.

[0032] Specifically, the total entropy production value within each annular flow channel cross section is determined to obtain the energy loss within each annular flow channel cross section, thereby obtaining the unstable region of the fluid inside the centrifugal pump. The total entropy production value includes direct dissipation entropy production, turbulent dissipation entropy production, and wall entropy production.

[0033] The total entropy output value within each annular flow channel section is calculated based on Formula 1, which is:

[0034] in, For total entropy output, To directly dissipate entropy output, For the entropy output of turbulent dissipation, The entropy output of the wall For direct dissipation, For turbulent dissipation, W represents the surface area of ​​the blade.

[0035] The direct dissipation entropy output is calculated based on Formula 2, the turbulent dissipation entropy output is calculated based on Formula 3, and the wall entropy output is calculated based on Formula 4.

[0036] Formula 2 is: Formula 3 is: Formula 4 is: .

[0037] in, For direct dissipation of entropy production rate, For turbulent dissipation entropy production rate, Let V be the wall entropy yield, V be the volume of the fluid channel, and A be the surface area of ​​the blade and the inner surface of the casing.

[0038] Step 103: Determine the target optimization region of the blade based on the total entropy output value.

[0039] Specifically, the total entropy production value within multiple annular flow channel sections calculated according to Formula 1 above can reflect the energy loss in the fluid channel at different cavitation stages. The target optimization area of ​​the blade can be determined based on the total entropy production value within the annular flow channel section, which can more accurately locate the area that needs to be improved to reduce energy loss and cavitation phenomena.

[0040] Step 104: Set biomimetic ribs 40 in the target optimization area.

[0041] Specifically, such as Figure 3 As shown, raised ribs are provided in the target optimization area of ​​blade 30. These raised ribs are biomimetic ribs 40. Biomimetic ribs 40 refer to the setting of raised ribs on the surface of the target optimization area of ​​blade 30, which imitates the characteristics of living organisms. For example, they imitate the side shape of fish such as sturgeon in nature. The biomimetic ribs 40 are set on the surface of the target optimization area of ​​blade 30 to reduce fluid flow separation in the target optimization area of ​​blade 30, reduce energy loss, and thus reduce the total entropy production value in the annular flow channel cross section. This suppresses the development of cavitation in the fluid channel, thereby improving the anti-cavitation performance of the centrifugal pump and increasing the working efficiency and service life of the centrifugal pump.

[0042] Figure 4 A flowchart illustrating the determination of the total entropy output within each annular channel cross-section in this embodiment is shown. Step 102 specifically includes: Step 1021: Obtain the performance parameters of each of the annular flow channel sections and the corresponding portion of the blade 30.

[0043] Specifically, the turbulent kinetic energy, temperature, dynamic viscosity, density, shear force of the fluid on the wall, velocity of the fluid near the blade wall, turbulent eddy viscosity frequency, volume of the fluid channel, and surface area of ​​the inner surfaces of the blade 30 and the shell 10 are obtained within each annular flow channel section.

[0044] Step 1022: Based on the performance parameters, calculate the entropy production rate corresponding to the annular flow channel cross section; wherein the entropy production rate includes the direct dissipation entropy production rate, the turbulent dissipation entropy production rate, and the wall entropy production rate.

[0045] Specifically, the performance parameters include fluid dynamic viscosity, average fluid velocity, fluid pulsation velocity, fluid temperature, fluid density, turbulent kinetic energy, turbulent eddy viscosity frequency, wall shear force, and near-wall velocity.

[0046] The direct dissipative entropy production rate is calculated based on Equation 5, where Equation 5 is:

[0047] In Formula 5 above, μ is the fluid dynamic viscosity, and u, v, and w are the average velocities of the fluid in the coordinate system. The four components are T, where T is the temperature of the fluid.

[0048] In this embodiment, the Reynolds-Averaged Navier-Stokes (RANS) equation is used to calculate the entropy production rate of turbulent dissipation. When using the RANS method, since the fluctuating velocity of the fluid cannot be directly represented, the entropy production rate caused by the component of the fluctuating velocity cannot be obtained. Instead, it is represented by the following formula 6. The following formulas 6 and 7 are imported into (Shear Stress Transport)... k−ω SST k-ω The model is transformed to obtain the following formula 8, and the turbulent dissipation entropy production rate is calculated based on formula 8. Formula 6 is as follows:

[0049] In Formula 6 above, ε is the turbulent dissipation rate. Let T be the fluid density and T be the temperature of the fluid.

[0050] Formula 7 is:

[0051] In Formula 7 above, μ is the fluid dynamic viscosity, and u, v, and w are the fluid pulsation velocities in the coordinate system, respectively. The four components are T, where T is the temperature of the fluid.

[0052] Formula 8 is:

[0053] In formula 8 above, The value is 0.09. Let be the fluid density, and k be the turbulent kinetic energy. Where is the turbulent eddy viscosity frequency, and T is the fluid temperature.

[0054] The wall entropy yield is calculated based on Equation 9, where Equation 9 is:

[0055] In formula 9 above, This refers to the wall shear force, which is the shear force exerted by the fluid near the blade surface. is the near-wall velocity, that is, the velocity of the fluid approaching the blade surface; T is the fluid temperature.

[0056] It should be noted that RANS is a method in computational fluid dynamics used to simulate turbulence. Its core idea is to characterize the effects of turbulent fluctuations through a statistical model (turbulence model) by averaging flow variables (such as velocity and pressure) over time, thereby significantly reducing computational costs. SST k−ω The model is the most commonly used turbulence model in computational fluid dynamics and has high analytical accuracy.

[0057] Step 1023: Determine the total entropy production value corresponding to the annular flow channel cross section based on the entropy production rate.

[0058] Specifically, according to Formula 2: The direct dissipative entropy output is calculated according to Formula 3: The turbulent dissipation entropy output was calculated according to Formula 4: The wall entropy output was calculated according to Formula 1: The total entropy output value corresponding to the cross section of the annular flow channel is obtained.

[0059] Figure 5 A flowchart is shown to determine the target optimization region of the blade based on the total entropy output value. Step 103 specifically includes: Step 1031: Determine the largest total entropy output value based on the total entropy output values ​​corresponding to the multiple annular flow channel cross sections.

[0060] Specifically, the total entropy production value within multiple annular flow channel sections is calculated through the above steps. The numerical relationship between the multiple total entropy production values ​​is compared, and the total entropy production value with the largest value is determined. The fluid flow in the region corresponding to the annular flow channel section with a higher total entropy production value is unstable and the energy loss is large. By optimizing the blades corresponding to the annular flow channel section with a higher total entropy production value, the cavitation resistance performance of the blade 30 can be further improved.

[0061] Step 1032: Take the annular flow channel cross section corresponding to the largest total entropy output value as the target annular flow channel cross section.

[0062] Step 1033: Based on the target annular flow channel cross section, determine the target optimization area of ​​the blade 30.

[0063] Specifically, such as Figure 8 The position indicated by the dashed line L is the projection of the target annular flow channel section onto the blade 30. The area near the dashed line L is the target optimization area of ​​the blade 30. This allows for targeted optimization and improvement of this area to reduce energy loss and cavitation within the centrifugal pump.

[0064] Figure 6 The flowchart illustrating the setting of the biomimetic rib 40 in the target optimization region is shown. Step 104 specifically includes: Step 1041: Determine the suction surface and pressure surface of the blade 30.

[0065] Specifically, such as Figure 3 As shown, the blade 30 has a concave surface and a convex surface along the thickness direction. The concave surface is the suction surface, and the convex surface is the pressure surface.

[0066] Step 1042: Set the biomimetic ribs at positions corresponding to the target optimization area on the suction surface and the pressure surface.

[0067] The blade 30 has biomimetic ribs 40 set at the target optimization area positions corresponding to the suction surface and the pressure surface, respectively. The biomimetic ribs 40 set on the suction surface are the first biomimetic ribs, and the biomimetic ribs 40 set on the pressure surface are the second biomimetic ribs. The first biomimetic ribs and the second biomimetic ribs correspond to each other along the thickness direction of the blade 30.

[0068] In some embodiments, the step of setting the biomimetic rib 40 at a position corresponding to the target optimization region on the suction surface and the pressure surface includes: Along the extension direction of the blade 30, a plurality of biomimetic ribs 40 are arranged at intervals at positions corresponding to the target optimization area on the suction surface and the pressure surface.

[0069] In one embodiment, multiple biomimetic ribs 40 can be spaced apart at positions corresponding to the target optimization region on the suction and pressure surfaces. For example, two biomimetic ribs 40 can be spaced apart on each of the suction and pressure surfaces, with each biomimetic rib 40 extending along the width direction of the blade 30. By spaced apart multiple biomimetic ribs 40, the guiding effect of the biomimetic ribs 40 on fluid flow can be further improved, reducing flow separation within the target optimization region, thereby more effectively suppressing cavitation within the fluid channel. Of course, the number of biomimetic ribs 40 can be flexibly selected according to actual needs, and this embodiment does not limit it.

[0070] This application also proposes a centrifugal pump blade, which is prepared using the improved method for centrifugal pump blades described in any of the above embodiments.

[0071] In the embodiments of this application, multiple annular flow channel sections are set within the fluid channel formed by the rotation of multiple blades 30. The total entropy production value within each annular flow channel section is calculated, and the target optimization region of the blades 30 is determined based on the total entropy production value. Then, biomimetic ribs 40 are set within the target optimization region. This utilizes biomimetic ribs to reduce the total entropy production value within the annular flow channel section and reduce energy flow loss, thereby improving the flow state of the fluid within the fluid channel. This, in turn, reduces flow separation within the target optimization region on the blades 30, thereby suppressing the development of cavitation within the fluid channel and effectively improving the anti-cavitation performance of the centrifugal pump.

[0072] In some embodiments, the thickness of the blade 30 is D1, and the thickness of the biomimetic rib 40 is D2, satisfying: 4≤D1 / D2≤8.

[0073] In this embodiment, by setting the ratio of the thickness D1 of the blade 30 to the thickness D2 of the bionic rib 40 to be greater than or equal to 4 and less than or equal to 8, it is possible to ensure that the bionic rib 40 has a certain structural strength while avoiding excessive thickness of the bionic rib 40, which would cause excessive flow resistance to the fluid near the bionic rib 40, hindering the flow of the fluid and thus affecting the working efficiency of the centrifugal pump.

[0074] For example, the ratio of the thickness D1 of the blade 30 to the thickness D2 of the biomimetic rib 40 can be set to any value such as 4, 5, 6, 7, 8 or any range between two values.

[0075] In some embodiments, the biomimetic ribs 40 extend from one end of the blade 30 to the other end along the width direction of the blade 30.

[0076] In this embodiment, by configuring the biomimetic ribs 40 to extend from one end of the blade 30 to the other along its width, the biomimetic ribs 40 can guide the flow of fluid throughout the entire width of the blade 30, further reducing flow separation and improving the centrifugal pump's anti-cavitation performance. Furthermore, the extension of the biomimetic ribs 40 along the width of the blade 30 also enhances the structural strength of the blade 30 and improves its durability.

[0077] It should be noted that, along the width direction of the blade 30, the blade 30 has a third end 33 and a fourth end 34. The third end 33 is the top of the blade 30, that is, the leaf tip, and the fourth end 34 is the root of the blade 30, that is, the leaf root. In other words, the biomimetic rib 40 extends from the leaf tip to the leaf root along the width direction of the blade 30.

[0078] In some embodiments, the side of the biomimetic rib 40 facing away from the blade 30 is provided as an arc surface.

[0079] In this embodiment, by setting the side of the bionic rib 40 away from the blade 30 as an arc surface, the interference of the bionic rib 40 on the fluid flow can be further reduced, the turbulence intensity of the fluid near the bionic rib 40 can be reduced, thereby further reducing energy loss and improving the cavitation resistance of the blade 30; at the same time, the arc surface design can also enable the bionic rib 40 to better imitate the side shape of fish in nature, improving the bionic effect.

[0080] In some embodiments, the biomimetic rib 40 and the blade 30 are an integral structure.

[0081] In this embodiment, by setting the bionic ribs and blades 30 as an integral structure, the manufacturing process of blades 30 can be simplified and manufacturing efficiency improved. At the same time, the connection strength between the bionic ribs 40 and blades 30 can be improved, preventing the bionic ribs 40 from falling off or being damaged during the use of the centrifugal pump, thereby ensuring the stable operation of the centrifugal pump. In addition, the integrated structure design can also reduce the gap between the bionic ribs 40 and blades 30, preventing the fluid from generating eddies in the gap, further reducing energy loss and improving the working efficiency of the centrifugal pump.

[0082] This application also proposes a centrifugal pump, including the centrifugal pump blade 30 described in any of the above embodiments.

[0083] In the embodiments of this application, multiple annular flow channel sections are set within the fluid channel formed by the rotation of multiple blades 30. The total entropy production value within each annular flow channel section is calculated, and the target optimization region of the blades 30 is determined based on the total entropy production value. Then, biomimetic ribs 40 are set within the target optimization region. This allows the biomimetic ribs 40 to reduce the total entropy production value within the annular flow channel section and reduce energy flow loss, thereby improving the flow state of the fluid within the fluid channel. This, in turn, reduces flow separation within the target optimization region on the blades 30, suppresses the development of cavitation within the fluid channel, and effectively improves the anti-cavitation performance of the centrifugal pump.

[0084] The improved method for centrifugal pump blades provided by the present invention will be described in detail below through embodiments.

[0085] Example 1: Step 201: Along the radial direction of the rotating shaft 20, nine annular flow channel sections are set in the fluid channel; Step 202: Obtain the performance parameters of each annular flow channel section and the corresponding portion of the blades. These performance parameters include: the average fluid velocity, the fluctuating fluid velocity, the turbulent kinetic energy of the fluid, the fluid temperature, the fluid dynamic viscosity, the fluid density, the shear force τ at the wall, the fluid velocity near the wall, the turbulent eddy viscosity frequency, the volume V of the fluid channel, and the surface area A of the blades and the inner surface of the casing.

[0086] Step 203: Based on the above performance parameters, calculate the direct dissipation entropy production rate in each annular flow channel section according to Formula 5, calculate the turbulent dissipation entropy production rate in each annular flow channel section according to Formulas 6-8, and calculate the wall entropy production rate in each annular flow channel section according to Formula 9.

[0087] Step 204: Based on the direct dissipation entropy production rate calculated above, obtain the direct dissipation entropy production value based on Formula 2; based on the turbulent dissipation entropy production rate calculated above, obtain the turbulent dissipation entropy production value based on Formula 3; based on the wall entropy production rate calculated above, obtain the wall entropy production value based on Formula 4; finally, based on the direct dissipation entropy production value, turbulent dissipation entropy production value, and wall entropy production value, obtain the total entropy production value corresponding to each annular flow channel section based on Formula 1.

[0088] Step 205: Based on the entropy production values ​​of the nine annular flow channel sections obtained in Step 204, compare the numerical relationship of the above nine total entropy production values, determine the total entropy production value with the largest value, and select the annular flow channel section with the higher total entropy production value as the target annular flow channel section. Figure 7 The distribution of total entropy production values ​​within the nine annular flow channel sections calculated according to Formula 1 is shown. The value 1 at the leftmost end of the horizontal axis represents the leading edge of blade 30, i.e. Figure 3The first end 31 of the blade 30 shown in the diagram, with the rightmost value 9 on the horizontal axis, represents the trailing edge of the blade 30. Figure 3 The second end 32 of the blade 30 shown is in the direction of fluid flow from the first end 31 to the second end 32, and the vertical axis represents different cavitation stages within the centrifugal pump. Figure 7 It can be seen that the total entropy output is larger in the third annular flow channel section. Therefore, the third annular flow channel section is the target annular flow channel section.

[0089] Step 206: Take the third annular flow channel section as the target annular section, such as... Figure 8 As shown, the projection of the third annular flow channel section onto the blade 30 is the location of the dashed line L, and the area near the dashed line L is the target optimization area of ​​the blade 30.

[0090] Step 207: As Figure 8 As shown, the target optimization area of ​​the blade 30 includes the first cross-sectional profile 301, which is located to the left of the dashed line L, that is, on the side of the dashed line L close to the first end 31 of the blade 30. Bionic ribs 40 are provided at the positions of the first cross-sectional profile 301 on the suction surface and pressure surface of the blade 30. The thickness of the bionic ribs 40 is set to 1 mm, and the thickness of the blade 30 is set to 8 mm.

[0091] Example 2: The difference between Example 2 and Example 1 is that, in step 107, the thickness of the biomimetic rib 40 at the position of the first cross-sectional profile 301 is set to 2mm.

[0092] Example 3: The difference between Example 3 and Example 1 is that, in step 107, the target optimization area of ​​the blade 30 includes the second cross-sectional profile 302, which is located to the right of the dashed line L, that is, on the side of the dashed line L away from the first end 31 of the blade 30. No biomimetic ribs are provided at the positions of the first cross-sectional profile 301 on the suction surface and pressure surface of the blade 30, and biomimetic ribs 40 are provided at the positions of the second cross-sectional profile 302 on the suction surface and pressure surface of the blade 30.

[0093] Example 4: The difference between Example 4 and Example 1 is that, in step 107, the target optimization area of ​​the blade 30 includes the second cross-sectional profile 302. No biomimetic ribs 40 are provided at the positions of the first cross-sectional profile 301 corresponding to the suction surface and pressure surface of the blade 30, but biomimetic ribs 40 are provided at the positions of the second cross-sectional profile 302 corresponding to the suction surface and pressure surface of the blade. The thickness of the biomimetic ribs 40 is set to 2mm.

[0094] Example 5: The difference between Example 5 and Example 1 is that, in step 107, the target optimization area of ​​the blade 30 includes the second cross-sectional profile 302, and biomimetic ribs 40 are provided at the positions of the first cross-sectional profile 301 and the second cross-sectional profile 302 corresponding to the suction surface and pressure surface of the blade 30.

[0095] Example 6: The difference between Example 6 and Example 1 is that, in step 107, the target optimization area of ​​the blade 30 includes the second cross-sectional profile 302, and biomimetic ribs 40 are provided at the positions of the first cross-sectional profile 301 and the second cross-sectional profile 302 corresponding to the suction surface and pressure surface of the blade 30, and the thickness of the biomimetic ribs 40 is set to 2mm.

[0096] Comparative Example 1: In the existing technology, the blades do not have biomimetic ribs 40.

[0097] The blades from each embodiment and comparative example were applied to centrifugal pumps, and the net positive suction head (NPSH) was tested. The specific method for NPSH testing can be performed according to GB / T 5657-2013 "Technical Conditions for Centrifugal Pumps (Class III)" to compare the cavitation resistance performance of centrifugal pumps in different embodiments and comparative examples. The test data are as follows: Figure 9-13 As shown.

[0098] Figure 9 This is a comparison chart showing the turbulent dissipation entropy production value within the target annular flow channel cross-section in Examples 1, 3, and 6, and the turbulent dissipation entropy production value at the corresponding location in Comparative Example 1. Figure 9 It can be seen that, compared with the turbulent dissipation entropy output in Comparative Example 1, the turbulent dissipation entropy output in Examples 1, 3 and 6 is significantly reduced. This indicates that the setting of the biomimetic rib 40 improves the flow state of the fluid in the target annular flow channel section and effectively reduces the energy flow loss of the fluid in the centrifugal pump.

[0099] Figure 10 This is a graph showing the relationship between net positive suction head (NPSH) and centrifugal pump head. Figure 11 The graph shows the relationship between net positive suction head (NPSH) and centrifugal pump efficiency. Figure 10 and 11 It can be seen that, compared with Comparative Example 1, the centrifugal pumps of Examples 1-6 all have better anti-cavitation performance, among which the centrifugal pump in Example 1 has the best anti-cavitation performance.

[0100] Figure 12 This is a comparison chart showing the local average entropy yield within the target annular flow channel cross-section in Examples 1, 3, and 6, and the local average entropy yield at the corresponding location in Comparative Example 1, during the initial cavitation stage of a centrifugal pump. Figure 12 It can be seen that, compared with Comparative Example 1, the local average entropy yield in Examples 1, 3 and 6 is significantly reduced, which indicates that the setting of the biomimetic rib 40 reduces the energy loss of the fluid in the target annular flow channel cross section.

[0101] Figure 13 This is a comparison chart of the local average entropy yield within the target annular flow channel cross-section in Examples 1, 3, and 6 and the local average entropy yield at the corresponding location in Comparative Example 1 during the critical cavitation stage of a centrifugal pump. Figure 13 It can be seen that, compared with Comparative Example 1, the local average entropy yield in Examples 1, 3 and 6 is significantly reduced, which also indicates that the setting of the biomimetic rib 40 reduces the energy loss of the fluid in the target annular flow channel cross section.

[0102] Five monitoring points were selected in the centrifugal pumps of Example 1 and Comparative Example 1, respectively corresponding to... Figure 14 C1, C2, C3 and Figure 15 In sections V1 and V2, the pressure pulsation frequency domain of the above five monitoring points is tested. By analyzing the pressure pulsation frequency domain of the fluid in the centrifugal pump, the cavitation state within the centrifugal pump can be evaluated. The test method for the pressure pulsation frequency domain can be performed with reference to SAE J1477 (hydraulic system pulsation standard), and the embodiments of this application do not limit it. Figure 16 This is a graph showing the test results at five monitoring points in the centrifugal pump of Comparative Example 1. Figure 17 The graph shows the test results at five monitoring points in the centrifugal pump of Example 1. Table 1 shows the test values ​​of the dominant frequency amplitude Cp of pressure pulsation at different monitoring points in Example 1 and Comparative Example 1. Figure 16 , Figure 17 As can be seen from Table 1, compared with Comparative Example 1, the amplitude of the main frequency of pressure pulsation Cp at the five monitoring points in Example 1 is reduced, which indicates that the setting of the biomimetic rib 40 in Example 1 effectively suppresses the development of cavitation.

[0103] Table 1

[0104] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0105] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An improved method for centrifugal pump blades, applied to a centrifugal pump, the centrifugal pump comprising a housing (10), a rotating shaft (20), and a plurality of blades (30), wherein the housing (10) has a receiving cavity, the rotating shaft (20) passes through the receiving cavity and is rotatably connected to the housing (10), the plurality of blades (30) are disposed in the receiving cavity and arranged circumferentially around the rotating shaft (20), the rotating shaft (20) can drive the plurality of blades (30) to rotate relative to the housing (10), so that the plurality of blades (30) rotate to form a fluid channel; characterized in that, The method includes: Along the radial direction of the rotating shaft (20), a plurality of annular flow channel sections are provided in the fluid channel; Determine the total entropy production value within each of the said annular flow channel cross sections; The target optimization region of the blade (30) is determined based on the total entropy output value; Bionic ribs (40) are provided in the target optimization area.

2. The improved method for centrifugal pump blades according to claim 1, characterized in that, Determining the total entropy output within each of the annular flow channel cross sections includes: Obtain the performance parameters of each of the annular flow channel sections and the corresponding portion of the blades (30); Based on the performance parameters, the entropy production rate corresponding to the annular flow channel cross section is calculated; wherein, the entropy production rate includes direct dissipation entropy production rate, turbulent dissipation entropy production rate, and wall entropy production rate; The total entropy production value corresponding to the annular flow channel cross section is determined based on the entropy production rate.

3. The improved method for centrifugal pump blades according to claim 1, characterized in that, The determination of the target optimization region for the blade (30) based on the total entropy output includes: The largest total entropy output value is determined based on the total entropy output value corresponding to the multiple annular flow channel cross sections; The annular flow channel cross section corresponding to the largest total entropy output value is taken as the target annular flow channel cross section; Based on the target annular flow channel cross section, the target optimization area of ​​the blade (30) is determined.

4. The improved method for centrifugal pump blades according to claim 1, characterized in that, The provision of biomimetic ribs (40) in the target optimization region includes: Determine the suction surface and pressure surface of the blade (30); The biomimetic ribs (40) are provided at positions corresponding to the target optimization area on the suction surface and the pressure surface.

5. The improved method for centrifugal pump blades according to claim 4, characterized in that, The provisioning of the biomimetic ribs (40) at positions corresponding to the target optimization area on the suction surface and the pressure surface includes: Along the extension direction of the blade (30), a plurality of biomimetic ribs (40) are provided at intervals at positions corresponding to the target optimization area on the suction surface and the pressure surface.

6. A centrifugal pump blade, characterized in that, It is prepared by the improved method for centrifugal pump blades as described in any one of claims 1-5.

7. The centrifugal pump blade according to claim 6, characterized in that, The thickness of the blade (30) is D1, and the thickness of the bionic rib (40) is D2, satisfying: 4≤D1 / D2≤8.

8. The centrifugal pump blade according to claim 6, characterized in that, Along the width direction of the blade (30), the biomimetic rib (40) extends from one end of the blade (30) to the other end.

9. The centrifugal pump blade according to any one of claims 6-8, characterized in that, The side of the biomimetic rib (40) facing away from the blade (30) is set as an arc surface; And / or, the biomimetic rib (40) and the blade (30) are an integral structure.

10. A centrifugal pump, characterized in that, Includes centrifugal pump blades as described in any one of claims 7 to 9.

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