CN116717499B - Hydrofoil blade top leakage flow vortex eliminating device based on passive jet - Google Patents
Hydrofoil blade top leakage flow vortex eliminating device based on passive jet Download PDFInfo
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- CN116717499B CN116717499B CN202310663154.8A CN202310663154A CN116717499B CN 116717499 B CN116717499 B CN 116717499B CN 202310663154 A CN202310663154 A CN 202310663154A CN 116717499 B CN116717499 B CN 116717499B
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- hydrofoil
- tip
- flow
- blade
- vortex
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- 238000000034 method Methods 0.000 claims description 4
- 230000003746 surface roughness Effects 0.000 claims description 2
- 238000000926 separation method Methods 0.000 abstract description 9
- 230000002401 inhibitory effect Effects 0.000 abstract description 4
- 239000012530 fluid Substances 0.000 description 14
- 238000010586 diagram Methods 0.000 description 5
- 230000002441 reversible effect Effects 0.000 description 3
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 238000010146 3D printing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/18—Rotors
- F04D29/181—Axial flow rotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/669—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for liquid pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/68—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers
- F04D29/688—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers especially adapted for liquid pumps
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T70/00—Maritime or waterways transport
- Y02T70/10—Measures concerning design or construction of watercraft hulls
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Hydraulic Turbines (AREA)
Abstract
The invention discloses a hydrofoil tip leakage flow vortex eliminating device based on passive jet flow, which is characterized in that a drainage hole is designed between a hydrofoil working pressure surface and an end surface along the chord length direction of a hydrofoil, and the passive jet flow led into a tip clearance by the drainage hole can cause vortex and block leakage flow in a tip clearance area based on the working principle of a Tesla valve, so that huge flow loss is caused to the tip leakage flow, and the generation of a hydrofoil tip separation vortex and a tip leakage vortex is effectively inhibited. The invention can effectively inhibit the leakage flow of the hydrofoil top, thereby reducing energy loss, inhibiting cavitation damage of the hydrofoil top and improving the efficiency and performance of the hydrofoil device.
Description
Technical Field
The invention relates to the technical field of fluid machinery, in particular to a hydrofoil blade tip leakage flow vortex eliminating device based on passive jet.
Background
In axial flow fluid machines such as axial flow pumps, hydro propellers, etc., there is a small gap between the blade tips and the end walls to avoid friction. At the tip clearance, due to the pressure differential between the suction side and the pressure side of the blade, fluid therein flows under the action of static pressure, creating a clearance flow from the pressure side to the suction side. The gap flow is mainly divided into two parts, and fluid (the majority of the gap flow at the tip end face of the blade) smoothly passes through the gap and is accelerated under the action of pressure difference, and the fluid is mixed with the main flow after passing through the gap to form a tip leakage vortex. And the flow velocity of the fluid at the position close to the tip end face of the blade is reduced to zero under the action of a boundary layer to form flow separation and reverse flow, so that a tip separation vortex is generated. Gap flow cavitation occurs when the pressure at the scroll center is below the saturation vapor pressure. According to different cavitation positions and causes, separation vortex cavitation and leakage vortex cavitation are classified. The gap cavitation can cause the variation of hydraulic mechanical properties, the induction of vibration, noise and other phenomena, and the cavitation erosion and other phenomena of the top end part of the blade and the outer edge of the blade.
Disclosure of Invention
The invention aims to inhibit or eliminate the leakage vortex and the separation vortex of a blade top clearance caused by the leakage flow of the blade top of the hydrofoil by designing the vortex elimination of the blade top of the hydrofoil, inhibit cavitation damage of the blade top, prolong the service life of the hydrofoil and improve the operation efficiency and the stability of the hydrofoil.
In order to achieve the aim of the invention, the invention adopts the following technical scheme: a hydrofoil blade top design method based on a Tesla valve working principle comprises the steps of forming a plurality of drainage holes from a hydrofoil pressure surface to a blade top end surface at the hydrofoil blade top position. The distance between the center point of the drainage hole inlet and the tip end surface of the blade is 2 times of the distance between the tip end surface of the blade and the tip end surface of the blade, and the distance between the first drainage hole on the front edge and the front edge is 1% of the chord length. The center point of the outlet is positioned on the arc line in the end face of the hydrofoil. The axis of the drainage hole is positioned on a plane which is 30-60 degrees with the chord length direction. The drainage holes are distributed on the front half section of the hydrofoil along the chord length direction, and the number of the drainage holes is 3-5. The drainage hole spacing is gradually sparse from the hydrofoil leading edge to the downstream, and the spacing increases exponentially according to 1.05.
In the scheme, the surface roughness Ra of the flow channel inside the drainage hole is not more than 0.01.
In the scheme, the included angle between the axis of the inlet section of the drainage hole and the end face of the blade tip is within the range of 0-20 degrees; the included angle between the axis of the outlet section of the drainage hole and the top end face of the blade is 70-90 degrees.
The beneficial effect of this patent: the invention provides a set of drainage holes at the top of the hydrofoil. When the hydrofoil tip leakage flow flows through the hydrofoil tip position, the flow channel of the tip clearance is narrow, the flow velocity is high, the pressure is low, and the high-pressure fluid at the position of the hydrofoil tip pressure surface flows to the tip clearance with low pressure through the drainage tube and impacts the leakage flow in the tip clearance at a certain angle. Based on the working principle of the Tesla valve, the jet fluid introduced into the clearance at the top of the blade by the drainage hole can cause huge flow loss to the leakage flow at the top of the blade, and can effectively inhibit the generation of the separation vortex at the top of the hydrofoil blade and the leakage vortex at the top of the blade. Thereby inhibiting or eliminating the leakage vortex and separation vortex of the clearance between the blade tops caused by the leakage flow of the blade tops of the hydrofoils, inhibiting cavitation damage of the blade tops, prolonging the service life of the hydrofoils and improving the running efficiency and stability of the hydrofoils.
Drawings
FIG. 1 is a schematic diagram of the vortex shedding design of the hydrofoil tip of the present invention.
FIG. 2 is a schematic partial cross-sectional view of a hydrofoil tip vortex shedding design of the present invention.
Fig. 3 is a schematic diagram of the working principle of the Tesla valve.
Fig. 4 is a schematic diagram of the principle of vortex shedding of the hydrofoil tip.
FIG. 5 is a flow architecture diagram of an original hydrofoil and a hydrofoil tip after deswirl design.
Reference numerals of the above drawings: 1. drainage holes; 2. a hydrofoil; 3. a pressure surface; 4. the tip end face of the leaf.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments, but the scope of the present invention should not be limited thereto, such as the number of drainage holes on the tip of the blade, the geometric shape and size of the section, the size and angle of the position of the openings, and the distribution of the drainage holes.
As shown in fig. 1, the hydrofoil tip vortex eliminating design mainly designs the tip region of the hydrofoil 2, and processes a drainage hole 1 from a pressure surface 3 to a tip end surface 4 of the hydrofoil 2. The plane of the axis of the drainage hole 1 is 30-60 degrees with the chord length direction. The distance between the center point of the drainage hole inlet and the tip end surface of the blade is 2 times of the distance between the tip end surface of the blade and the tip end surface of the blade, and the distance between the first drainage hole on the front edge and the front edge is 1% of the chord length. The center point of the outlet is positioned on the arc line in the end face of the hydrofoil. The axis of the drainage hole is positioned on a plane which is 30-60 degrees with the chord length direction. The drainage holes are distributed on the front half section of the hydrofoil along the chord length direction, and the number of the drainage holes is 3-5. The drainage hole spacing is gradually sparse from the hydrofoil leading edge to the downstream, and the spacing increases exponentially according to 1.05.
As shown in fig. 2, in the design of vortex elimination of the blade tip of the hydrofoil 2, the design and processing of the drainage hole 1 do not change the original appearance and size of the hydrofoil 2, and a 3D printing and accurate grinding mode is adopted during processing.
Fig. 3 shows a schematic diagram of the working principle of the Tesla valve. Tesla valve operates with both forward and reverse flow. In the forward direction, the fluid flow is stable and basically does not receive larger resistance. When the flow is reversed, part of the fluid in the main flow is separated from the main flow through the drainage flow channel, and is led back to the main flow at the downstream position of the main flow, and the flowing direction is obtuse to the flowing direction of the main flow. When the drainage fluid intersects with the main flow fluid, vortexes are generated in the flow channel and flow is blocked, so that the fluid resistance is increased during reverse flow. After passing through the plurality of drainage channels, the main flow is gradually inhibited under the action of layer-by-layer resistance dissipation.
Technical solution in this embodiment as shown in fig. 4, a series of drainage holes 1 are arranged at the top of the hydrofoil 2. When the leakage flow of the blade tip of the hydrofoil 2 flows through the position of the blade tip of the hydrofoil, the flow channel of the gap of the blade tip is narrow, the flow velocity is high, the pressure is low, and the high-pressure fluid at the position of the pressure surface of the blade tip of the hydrofoil flows to the gap of the blade tip with low pressure through the drainage tube and impacts the leakage flow in the gap of the blade tip at a certain angle. Based on the working principle of the Tesla valve, the passive jet flow introduced into the clearance of the blade top by the drainage hole 1 can cause vortex and block leakage flow in the clearance area of the blade top, so that huge flow loss is caused to the leakage flow of the blade top, and therefore the generation of the separation vortex of the blade top of the hydrofoil 2 and the leakage vortex of the blade top can be effectively inhibited. The invention can effectively inhibit or eliminate the leakage vortex and the separation vortex of the clearance between the blade tops caused by the leakage flow of the blade tops of the hydrofoils based on the passive jet, inhibit cavitation damage of the blade tops, prolong the service life of the hydrofoils and improve the operation efficiency and stability of the hydrofoils.
As shown in FIG. 5, the numerical simulation calculation results of the hydrofoil tip leakage flow vortex eliminating device based on passive jet and the original hydrofoil of the same model under the same working condition are shown. The graph results (1) are the vortex isosurface of q=7×10 6s-2, and (2) are the pressure isosurface of p=3574 Pa (saturated vapor pressure) (representing cavitation profile). Compared with the original hydrofoil, the device has a very obvious effect of inhibiting The Leakage Vortex (TLV) of the gap of the hydrofoil top.
Claims (2)
1. A hydrofoil blade tip vortex eliminating design method comprises hydrofoils and drainage holes, wherein a group of drainage holes from the pressure side surface of the hydrofoils to the end surface of the blade tip are formed in the position of the hydrofoils; the drainage holes are distributed on the front half section of the hydrofoil along the chord length direction, and the number of the drainage holes is 3-5; the pitch of drainage holes is gradually sparse from the front edge of the hydrofoil to the downstream, and the pitch is exponentially increased according to 1.05; the distance between the center point of the drainage hole inlet and the top end face of the blade is 2 times of the distance between the front edge and the first drainage hole is 1% chord length; the center point of the outlet is positioned on the middle arc line of the end surface of the hydrofoil; the included angle between the plane of the axis of the drainage hole and the chord length direction is 30-60 degrees; the included angle between the axis of the inlet section of the drainage hole and the end face of the blade tip is within the range of 0-20 degrees; the included angle between the axis of the outlet section and the top end face of the blade is in the range of 70-90 degrees.
2. The method of claim 1, wherein the surface roughness Ra of the flow channels inside all drainage holes is not greater than 0.01.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310663154.8A CN116717499B (en) | 2023-06-06 | 2023-06-06 | Hydrofoil blade top leakage flow vortex eliminating device based on passive jet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310663154.8A CN116717499B (en) | 2023-06-06 | 2023-06-06 | Hydrofoil blade top leakage flow vortex eliminating device based on passive jet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116717499A CN116717499A (en) | 2023-09-08 |
| CN116717499B true CN116717499B (en) | 2024-05-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310663154.8A Active CN116717499B (en) | 2023-06-06 | 2023-06-06 | Hydrofoil blade top leakage flow vortex eliminating device based on passive jet |
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| Country | Link |
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| CN (1) | CN116717499B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114934914B (en) * | 2022-05-11 | 2024-04-09 | 江苏大学 | Symmetrical blade and end surface bionic structure thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05306697A (en) * | 1992-04-30 | 1993-11-19 | Kubota Corp | Leakage loss reduction system of chip clearance in pump |
| CN101571142A (en) * | 2009-05-26 | 2009-11-04 | 上海大学 | Groove suction vane for pump |
| CN201635775U (en) * | 2009-10-21 | 2010-11-17 | 南京航空航天大学 | Reverse vortex generator capable of suppressing airflow leakage of impeller tip |
| CN104775854A (en) * | 2015-04-23 | 2015-07-15 | 华能国际电力股份有限公司 | Movable vane top structure capable of restraining tip leakage and reducing tip temperature |
| CN107246285A (en) * | 2017-05-19 | 2017-10-13 | 燕山大学 | A kind of turbomachine clearance leakage of blade tip is combined passive control methods |
| CN112628192A (en) * | 2021-01-12 | 2021-04-09 | 江苏大学 | Blade structure for inhibiting axial flow pump blade tip leakage vortex |
| CN116717500A (en) * | 2023-06-06 | 2023-09-08 | 江苏大学镇江流体工程装备技术研究院 | Vortex eliminating device |
-
2023
- 2023-06-06 CN CN202310663154.8A patent/CN116717499B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05306697A (en) * | 1992-04-30 | 1993-11-19 | Kubota Corp | Leakage loss reduction system of chip clearance in pump |
| CN101571142A (en) * | 2009-05-26 | 2009-11-04 | 上海大学 | Groove suction vane for pump |
| CN201635775U (en) * | 2009-10-21 | 2010-11-17 | 南京航空航天大学 | Reverse vortex generator capable of suppressing airflow leakage of impeller tip |
| CN104775854A (en) * | 2015-04-23 | 2015-07-15 | 华能国际电力股份有限公司 | Movable vane top structure capable of restraining tip leakage and reducing tip temperature |
| CN107246285A (en) * | 2017-05-19 | 2017-10-13 | 燕山大学 | A kind of turbomachine clearance leakage of blade tip is combined passive control methods |
| CN112628192A (en) * | 2021-01-12 | 2021-04-09 | 江苏大学 | Blade structure for inhibiting axial flow pump blade tip leakage vortex |
| CN116717500A (en) * | 2023-06-06 | 2023-09-08 | 江苏大学镇江流体工程装备技术研究院 | Vortex eliminating device |
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| CN116717499A (en) | 2023-09-08 |
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