Stable expansion type guide vane blade with local flexible structure

Abstract

The stability expansion type guide vane blade with the local flexible structure comprises a guide vane blade base body, a suction surface groove is formed in a suction surface of the guide vane blade base body, the groove is through in the blade height direction, a flexible part is embedded in the suction surface groove, and a sealing connection structure is arranged between the flexible part and the edge of the groove. According to the stability expansion type guide vane blade with the local flexible structure, the problems that in the prior art, the passive control adjusting capacity is insufficient, and separation of the suction surface of the guide vane and accumulation of local backflow vortexes are difficult to effectively restrain under the small-flow working condition are solved.

Description

Technical Field

[0001] This invention belongs to the field of flow control technology for turbomachinery, and specifically relates to a stabilized guide vane blade with a locally flexible structure. Background Technology

[0002] Guide vane centrifugal pumps are a type of critical fluid machinery widely used in industrial water supply and drainage, cooling circulation, and energy system transportation. Their operational stability directly affects system efficiency and reliability. Under low flow conditions, the strong coupling effect between the impeller and guide vanes easily induces boundary layer separation on the guide vane suction surface, forming a persistent local backflow vortex structure. This type of unstable flow is long-lasting and intense, easily causing local blockage and energy loss, as well as pressure pulsation and structural vibration, severely affecting the pump's operational stability. How to effectively weaken or suppress such unstable flows has become one of the main factors restricting the improvement of the stability performance of guide vane centrifugal pumps.

[0003] Existing flow control methods are mainly divided into two categories: active control and passive control. Active control relies on external energy input to intervene in the flow, resulting in complex structures and high energy consumption. Passive control improves the flow field through geometric adjustments, which can optimize local flow characteristics to some extent, but its applicability is usually limited to specific operating conditions, especially in complex and unstable flows with low flow rates, where its adjustment capability is limited. In addition, most existing guide vanes are made of rigid materials, whose inherent characteristics limit the flexibility of flow adjustment, making it difficult to achieve adaptive adjustment under complex operating conditions and effectively cope with flow instability. In contrast, locally flexible structures have greater adaptability and can adjust the flow through adaptive deformation under different operating conditions, compensating for the shortcomings of rigid guide vanes, thereby significantly improving system stability and performance and possessing great optimization potential. Summary of the Invention

[0004] The purpose of this invention is to provide a stabilized guide vane blade with a locally flexible structure, which solves the problems of insufficient passive control and regulation capability in the prior art, and difficulty in effectively suppressing guide vane suction surface separation and local backflow vortex accumulation under low flow conditions.

[0005] The technical solution adopted in this invention is: a stabilized guide vane blade with a locally flexible structure, including a guide vane blade base, a suction surface groove is formed on the suction surface of the guide vane blade base, the groove extends along the blade height direction, a flexible component is embedded in the suction surface groove, and a sealing connection structure is provided between the flexible component and the edge of the groove.

[0006] The invention is further characterized by: The flexible components are made of elastic materials, such as rubber, polyurethane, or composite elastomers.

[0007] The outer surface of the flexible component coincides with the outer boundary of the groove, and there is a gap between the inner surface of the flexible component and the inner surface of the groove. The upper surface of the flexible component is in contact with the suction surface profile of the guide vane blade substrate, and the thickness of the flexible component is less than the normal depth of the groove.

[0008] The thickness of the flexible component is 1 / 3 to 1 / 2 of the normal depth of the groove.

[0009] The planar boundary of the groove on the guide vane blade substrate is defined by the suction surface profile and two normal extension boundaries. The intersection points of the suction surfaces corresponding to the relative lengths a and b of the bone line are denoted as A and B, respectively. They are extended by a distance S along the normal direction pointing from the suction surface to the inside of the blade. The value of S is half of the average thickness of the blade in this section. The two extension endpoints are connected and enclosed with the suction surface profile to form a closed area, forming the planar projection range of the groove.

[0010] The range of the groove area can be optimized and determined according to the target working conditions, so that the flexible area corresponds to the position of the typical separation area.

[0011] The sealing connection structure includes an upper guide vane ring plate and a lower guide vane ring plate. The upper end of the flexible component is sealed to the upper guide vane ring plate, and the lower end of the flexible component is sealed to the lower guide vane ring plate. The upper guide vane ring plate and the lower guide vane ring plate respectively seal the upper and lower ends of the groove. The inner wall of the groove and the back of the flexible component opposite to it together form a sealed cavity set behind the flexible component.

[0012] The sealed cavity is kept at normal pressure and does not generate additional loads; it serves only as a space to release deformation constraints.

[0013] The sealing connection between the flexible component and the upper and lower ring plates of the guide vane can be achieved by embedding, bolt clamping, or sealant.

[0014] The beneficial effects of this invention are: (1) The guide vane blade of the present invention has a locally flexible structure. A groove is opened in a specific area of ​​the suction surface of the guide vane, and a flexible component is embedded in the groove. This allows the blade to undergo adaptive deformation under the action of fluid, thereby improving the hydraulic performance under low flow conditions while maintaining the design performance. Furthermore, the adaptive deformation changes the near-wall flow field distribution of the suction surface, thereby improving the flow stability under low flow conditions. (2) The guide vane blade of the present invention changes the near-wall flow characteristics of the suction surface through a local flexible structure, effectively suppressing the continuous accumulation of local backflow vortices and reducing local energy loss in the guide vane area; the present invention can achieve adaptive passive adjustment without complex active control means, and has simple structure, high reliability and good potential for promotion and application. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a traditional rigid guide vane; Figure 2 This is a schematic diagram of the overall structure of the locally flexible guide vane blade prepared according to the present invention; Figure 3 This is a schematic diagram of the partially flexible guide vane sealing structure of the present invention. Figure 4 The present invention relates to a partially flexible guide vane blade. Figure 2 Sectional view of section AA; Figure 5 The present invention relates to a partially flexible guide vane blade. Figure 2 Schematic diagram and enlarged view of the central groove structure; Figure 6 This is a comparison diagram of the hydraulic characteristics of the rigid guide vane and the partially flexible guide vane models in Embodiment 7 of the present invention; Figure 7 This is a comparison diagram of the streamlines of the rigid guide vane and the partially flexible guide vane models in Embodiment 7 of the present invention; Figure 8 This is a diagram showing the vortex structure evolution of the rigid guide vane and the locally flexible guide vane model in Embodiment 7 of the present invention.

[0016] In the figure: 1. Rigid guide vane, 2. Flexible guide vane, 3. Guide vane base, 4. Suction surface groove, 5. Flexible component, 6. Air cavity, 7. Upper guide vane ring plate, 8. Lower guide vane ring plate. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0018] The present invention relates to an extended-stability guide vane blade with a locally flexible structure, such as... Figure 2 As shown, the device includes a guide vane base 3, a suction surface groove 4 is provided on the suction surface of the guide vane base 3, the groove 4 extends along the blade height direction, a flexible component 5 is embedded in the suction surface groove 4, and a sealing connection structure is provided between the flexible component 5 and the edge of the groove 4.

[0019] Furthermore, the flexible component 5 is made of an elastic material, such as rubber, polyurethane, or a composite elastomer.

[0020] Furthermore, the outer surface of the flexible component 5 coincides with the outer boundary of the groove 4, a gap is left between the inner surface of the flexible component 5 and the inner surface of the groove 4, the upper surface of the flexible component 5 is in contact with the suction surface profile of the guide vane blade substrate, and the thickness of the flexible component 5 is 1 / 3 to 1 / 2 of the normal depth of the groove 4.

[0021] Among them, the planar boundary of the groove 4 on the guide vane blade base 3 is defined by the suction surface profile and two normal extension boundaries. The intersection points of the suction surfaces corresponding to the relative lengths a and b of the bone line are denoted as A and B, respectively. They are extended by a distance S along the normal direction pointing from the suction surface to the inside of the blade. The value of S is half of the average thickness of the blade in this section. The two extension endpoints are connected and enclosed with the suction surface profile to form a closed area, forming the planar projection range of the groove.

[0022] The range of the groove area can be optimized and determined according to the target working conditions, so that the flexible area corresponds to the position of the typical separation area.

[0023] Furthermore, such as Figure 3 As shown, the sealing connection structure includes an upper guide vane ring plate 7 and a lower guide vane ring plate 8. The upper end of the flexible component 5 is sealed to the upper guide vane ring plate 7, and the lower end of the flexible component 5 is sealed to the lower guide vane ring plate 8. The upper guide vane ring plate 7 and the lower guide vane ring plate 8 respectively seal the upper and lower ends of the groove 4. The inner wall of the groove 4 and the back of the flexible component 5 together form a sealed cavity 6 located behind the flexible component 5. Figure 4 As shown. The volume and shape of the back-sealed cavity 6 can be designed to match the expected deformation characteristics of the flexible component.

[0024] The sealed cavity is kept at normal pressure and does not generate additional loads; it serves only as a space to release deformation constraints.

[0025] Furthermore, the sealing connection between the flexible component and the upper and lower ring plates of the guide vane can be achieved by embedding, bolt clamping, or sealant, etc., and the present invention does not limit this.

[0026] like Figure 1 As shown in the figure, 1 is a traditional rigid guide vane blade 1. Figure 2 The flexible guide vane blade 2 of the present invention is different from the traditional guide vane blade 1, which does not have a flexible structure on its suction surface and is based on a reference model.

[0027] The present invention discloses a method for preparing a stabilized guide vane blade with a locally flexible structure, the specific method of which is as follows: Step 1: Provide the guide vane blade substrate, parameterize the blade ribs according to their length, and determine the arrangement area of ​​the flexible structure at the suction surface position corresponding to the section with a relative length of ribs from a to b. Step 2: Create grooves on the suction surface of the guide vane blade substrate; like Figure 5 As shown, the blade extends internally along the outer normal direction of points A and B by a distance S, which is half the average thickness of the blade in the AB section. The extension endpoints A′ and B′ are obtained. Connecting A′ and B′ and forming a closed area with the suction surface A–B section profile is the planar boundary of groove 4. Groove 4 extends through the blade height direction.

[0028] Step 3: Embed the flexible component within the groove; the specific method is as follows: Using the shape of the groove 4 as a mold cavity, a flexible component 5 matching its shape is prepared. The flexible component 5 is embedded in the groove 4, with the outer surface of the flexible component 5 coinciding with the outer boundary of the groove 4. A gap is left between the inner surface of the flexible component 5 and the inner surface of the groove 4 to ensure deformable space under fluid load. The upper surface of the flexible component is in contact with the suction surface profile of the guide vane blade substrate. The thickness of the flexible component is 1 / 3 to 1 / 2 of the normal depth of the groove. Stable fixation is achieved through embedding.

[0029] Step 4: Set sealing connection structures on both sides of the flexible component to fix it to the edge of the groove. This secures the flexible component and prevents fluid infiltration, resulting in a stabilized guide vane blade with a locally flexible structure. The specific method is as follows: The upper and lower ends of the flexible component are respectively sealed to the upper and lower ring plates of the guide vane, forming a closed cavity on the back. This cavity provides space for the deformation of the flexible component, reduces the constraint on the back, and prevents external water from seeping in, thus isolating external fluids.

[0030] The modified guide vane blade of this invention maintains the same outer contour as the original blade, without affecting the overall geometry of the guide vane channel. This allows for adaptive adjustment of the flow in the guide vane region and reduction of energy loss while ensuring the compatibility of the prototype structure.

[0031] Example 1 This embodiment features a stabilized guide vane blade with a locally flexible structure, such as... Figure 2 As shown, the device includes a guide vane base 3, a suction surface groove 4 is provided on the suction surface of the guide vane base 3, the groove 4 extends along the blade height direction, a flexible component 5 is embedded in the suction surface groove 4, and a sealing connection structure is provided between the flexible component 5 and the edge of the groove 4.

[0032] Among them, the flexible component 5 is made of elastic material, which is rubber, polyurethane or composite elastomer.

[0033] Example 2 This embodiment features a stabilized guide vane with a locally flexible structure. Based on embodiment 1, the outer surface of the flexible component 5 coincides with the outer boundary of the groove 4, a gap is left between the inner surface of the flexible component 5 and the inner surface of the groove 4, the upper surface of the flexible component 5 is in contact with the suction surface profile of the guide vane substrate, and the thickness of the flexible component 5 is 1 / 3 to 1 / 2 of the normal depth of the groove 4.

[0034] Example 3 This embodiment features a stabilized guide vane with a locally flexible structure. Based on Embodiment 2, further improvements are made, such as... Figure 3As shown, the sealing connection structure includes an upper guide vane ring plate 7 and a lower guide vane ring plate 8. The upper end of the flexible component 5 is sealed to the upper guide vane ring plate 7, and the lower end of the flexible component 5 is sealed to the lower guide vane ring plate 8. The upper guide vane ring plate 7 and the lower guide vane ring plate 8 respectively seal the upper and lower ends of the groove 4. The inner wall of the groove 4 and the back of the flexible component 5 together form a sealed cavity 6 located behind the flexible component 5. Figure 4 As shown.

[0035] The volume and shape of the back-sealed cavity 6 can be designed to match the expected deformation characteristics of the flexible component.

[0036] Example 4 The present invention discloses a method for preparing a stabilized guide vane blade with a locally flexible structure, the specific method of which is as follows: Step 1: Provide a guide vane blade substrate with a rib length of c. Take points a and b at relative lengths of 0.4c and 0.67c respectively. Determine the area from relative rib length a to b on its suction surface as the flexible structure arrangement area. Step 2: Create grooves on the suction surface of the guide vane blade substrate; Step 3: Embed the flexible component within the groove; Step 4: Set a sealing connection structure on both sides of the flexible component to fix it to the edge of the groove. This is used to fix the flexible component and prevent fluid from seeping in, thus obtaining a stabilized guide vane blade with a local flexible structure.

[0037] Example 5 The method for preparing the stabilized guide vane blade with a locally flexible structure according to the present invention, based on Example 4, further includes the following specific method for step 2: The planar boundary of the groove is defined by the suction surface profile and two normal extension boundaries. The intersection points of the suction surfaces corresponding to the relative lengths a and b of the bone line are denoted as A and B, respectively. The groove is extended by a distance S along the normal direction pointing from the suction surface to the inside of the blade. S is half of the average thickness of the blade in this section. The two extension endpoints are connected and enclosed with the suction surface profile to form a closed area, forming the planar projection range of the groove.

[0038] like Figure 5 As shown, the blade extends inwards along the outer normal direction from points A and B by a distance S, which is half the average blade thickness of the AB section. This results in extension endpoints A′ and B′. Connecting A′ and B′ and forming a closed region with the suction surface A–B section profile constitutes the planar boundary of groove 4. Groove 4 extends along the blade height direction, forming an asymmetric trapezoidal cross-section. The range of the groove region can be optimized and determined according to the target operating conditions, ensuring that the flexible zone corresponds to the typical separation zone.

[0039] Example 6 The method for preparing the stabilized guide vane blade with a locally flexible structure according to the present invention, based on Example 5, further includes the following specific method for step 3: Using the shape of the groove 4 as a mold cavity, a flexible component 5 matching its shape is prepared. The flexible component 5 is embedded in the groove 4, with the outer surface of the flexible component 5 coinciding with the outer boundary of the groove 4. A gap is left between the inner surface of the flexible component 5 and the inner surface of the groove 4 to ensure deformable space under fluid load. The upper surface of the flexible component is in contact with the suction surface profile of the guide vane blade substrate. The thickness of the flexible component is 1 / 3 to 1 / 2 of the normal depth of the groove. Stable fixation is achieved through embedding.

[0040] Example 7 The method for preparing the stabilized guide vane blade with a locally flexible structure according to the present invention, based on Example 6, further includes the following specific method for step 4: The upper and lower ends of the flexible component are respectively sealed to the upper and lower ring plates of the guide vane, forming a closed cavity on the back. This cavity provides space for the deformation of the flexible component, reduces the constraint on the back, and prevents external water from seeping in, thus isolating external fluids.

[0041] Furthermore, the sealing connection between the flexible component and the upper and lower ring plates of the guide vane can be achieved by embedding, bolt clamping, or sealant, etc., and the present invention does not limit this.

[0042] To verify the flow control effect of the flexible guide vane blade in this embodiment, a two-way fluid-structure interaction numerical simulation was performed using the CFX solver based on the finite volume method and the transient structure module. The flexible component was defined in the numerical model as a custom elastic material with the following parameters: density 800 kg·m³. -3 The parameters are: Poisson's ratio 0.4, Young's modulus 2.1 GPa. This combination of parameters is used to characterize typical finite deflection response and is not limited to any specific material.

[0043] By comparing the hydraulic performance and flow field characteristics of rigid and flexible guide vanes under different operating conditions, the influence of flexible structures on flow stability under low flow conditions is analyzed.

[0044] Figure 6 The hydraulic performance of the two guide vane models is compared, including head, efficiency, and energy loss distribution in the guide vane area. Under near-design conditions, the performance of the two models is basically the same, indicating that the flexible structure does not introduce additional losses. However, under low flow conditions, the flexible structure effectively reduces energy dissipation in the guide vane area, reduces local losses, improves overall hydraulic efficiency, and expands the stable operating range of the centrifugal pump by adaptively deforming and adjusting the near-wall flow adhesion state of the suction surface.

[0045] Figure 7The diagram shows a comparison of streamline distribution for the two guide vane models under low flow conditions. It can be seen that the rigid guide vane exhibits significant large-scale backflow and premature boundary layer separation in the suction surface region, while the flexible structure delays the appearance of the separation point, making the streamlines more closely adhere to the suction surface, significantly reducing the separation zone, and markedly improving the flow uniformity within the guide vane channel.

[0046] Figure 8 This is a comparison diagram of the vortex structure evolution of rigid and flexible guide vanes. The suction surface region of the rigid guide vane exhibits strong stagnant vortices and vortex accumulation, while the flexible structure undergoes adaptive deformation under fluid excitation, weakening the vortex intensity and promoting vortex structure shedding and dissipation, thereby improving the flow state of the guide vane channel.

[0047] As can be seen from the above results, the local flexible structure proposed in this invention can significantly improve the flow state inside the guide vane under low flow conditions while maintaining the performance of the design conditions, weaken the accumulation of backflow vortices near the suction surface, delay flow separation and reduce energy loss in the guide vane area, thereby improving the stability and efficiency of centrifugal pump operation.

Claims

1. A stabilized guide vane blade with a locally flexible structure, characterized in that, The system includes a guide vane base (3), on which a suction surface groove (4) is provided. The groove (4) extends along the blade height direction. A flexible component (5) is embedded in the suction surface groove (4), and a sealing connection structure is provided between the flexible component (5) and the edge of the groove (4).

2. The stabilized guide vane blade with a locally flexible structure according to claim 1, characterized in that, The flexible component (5) is made of an elastic material, which is rubber, polyurethane or a composite elastomer.

3. The stabilized guide vane blade with a locally flexible structure according to claim 1, characterized in that, The outer surface of the flexible component (5) coincides with the outer boundary of the groove (4), and there is a gap between the inner surface of the flexible component (5) and the inner surface of the groove (4). The upper surface of the flexible component (5) is in contact with the suction surface profile of the guide vane blade substrate, and the thickness of the flexible component (5) is less than the normal depth of the groove (4).

4. The stabilized guide vane blade with a locally flexible structure according to claim 3, characterized in that, The thickness of the flexible component is 1 / 3 to 1 / 2 of the normal depth of the groove.

5. The stabilized guide vane blade with a locally flexible structure according to claim 3, characterized in that, The planar boundary of the groove (4) on the guide vane blade base (3) is defined by the suction surface profile and two normal extension boundaries. The intersection points of the suction surfaces corresponding to the relative lengths a and b of the bone line are recorded as A and B, respectively. The groove is extended by a distance S along the normal direction pointing from the suction surface to the inside of the blade. The value of S is half of the average thickness of the blade in this section. The two extension endpoints are connected and enclosed with the suction surface profile to form a closed area, forming the planar projection range of the groove.

6. The stabilized guide vane blade with a locally flexible structure according to claim 5, characterized in that, The range of the groove area can be optimized and determined according to the target working conditions, so that the flexible area corresponds to the position of the typical separation area.

7. The stabilized guide vane blade with a locally flexible structure according to claim 1, characterized in that, The sealing connection structure includes an upper guide vane ring plate (7) and a lower guide vane ring plate (8). The upper end of the flexible component (5) is sealed to the upper guide vane ring plate (7), and the lower end of the flexible component (5) is sealed to the lower guide vane ring plate (8). The upper guide vane ring plate (7) and the lower guide vane ring plate (8) respectively seal the upper and lower ends of the groove (4). The inner wall of the groove (4) and the back of the flexible component (5) opposite to it together form a sealed cavity (6) disposed behind the flexible component (5).

8. The stabilized guide vane blade with a locally flexible structure according to claim 7, characterized in that, The sealing connection between the flexible component (5) and the upper ring plate (7) and lower ring plate (8) of the guide vane can be achieved by embedding, bolt clamping or sealant.

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