CN109268077B - Flow loss control method for blade boundary layer fluid - Google Patents
Flow loss control method for blade boundary layer fluid Download PDFInfo
- Publication number
- CN109268077B CN109268077B CN201811006975.XA CN201811006975A CN109268077B CN 109268077 B CN109268077 B CN 109268077B CN 201811006975 A CN201811006975 A CN 201811006975A CN 109268077 B CN109268077 B CN 109268077B
- Authority
- CN
- China
- Prior art keywords
- boundary layer
- blade
- fluid
- flow loss
- layer fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/02—Surge control
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
The embodiment of the invention provides a flow loss control method of blade boundary layer fluid, which comprises the following steps: s1, classifying the motion of the boundary layer fluid of the blade; s2, obtaining the influence factors of the flow loss of the boundary layer fluid according to the motion type of the boundary layer fluid; and S3, taking corresponding measures to reduce the flow loss according to the influence factors of the flow loss of the boundary layer fluid. According to the invention, the motions of the boundary layer fluid are classified, different control methods are adopted for different types of boundary layer motions, and the method has the advantages of good universality, strong practicability and obvious control effect.
Description
Technical Field
The invention relates to the field of impeller machinery, in particular to a flow loss control method of blade boundary layer fluid.
Background
Impeller machines are widely used in industrial fields, such as aircraft engines, ground gas turbines, steam turbines, mine ventilation, pipeline transportation and the like, and reducing the flow loss inside the blades plays an important role in reducing energy loss and improving the work efficiency of the impeller. However, in the current process of reducing flow loss, different control methods are often required according to different flow field conditions, and a general guiding method for rapidly reducing flow loss is lacked.
Disclosure of Invention
In order to overcome at least one aspect of the above problems, embodiments of the present invention provide a method for controlling flow loss of a blade surface layer fluid, which has good versatility, strong practicability, and an obvious control effect.
According to an aspect of the present invention, there is provided a flow loss control method of a blade-facing fluid, including the steps of: s1, classifying the motion of the boundary layer fluid of the blade; s2, obtaining the influence factors of the flow loss of the boundary layer fluid according to the motion type of the boundary layer fluid; and S3, taking corresponding measures to reduce the flow loss according to the influence factors of the flow loss of the boundary layer fluid.
According to some embodiments, the motion of the boundary layer fluid of the blade is classified according to whether there is a separation line in the motion of the boundary layer fluid in step S1.
According to some embodiments, the presence or absence of a separation line is determined from a wall flow spectrum generated by the flow of the boundary layer fluid of the blade.
According to some embodiments, the movement of the boundary layer fluid of the blade is divided in step S1 into an attached vortex layer migration without a separation line and a free vortex layer migration from the separation line.
According to some embodiments, flow losses are reduced by creating a better pressure distribution in case the movement of the boundary layer fluid of the blade is a migration of the attached vortex layer.
According to some embodiments, creating a better pressure distribution includes subjecting the blades of the small-angle cascade to a positive bending process.
According to some embodiments, flow losses are reduced by reducing or altering the vortex distribution in the case where the motion of the boundary layer fluid of the blade is free vortex layer migration.
According to some embodiments, reducing or altering the swirl distribution includes a recurved treatment of a high angle cascade vane.
Compared with the prior art, the invention has at least the following advantages: the invention classifies the surface layer fluid motion, adopts different control methods for different flow field conditions, and has the advantages of good universality, strong practicability and obvious control effect.
Drawings
Other objects and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings, and may assist in a comprehensive understanding of the invention.
FIG. 1 is a flow chart of a method of flow loss control of a blade-facing fluid in accordance with an embodiment of the present invention;
FIG. 2 is a separated flow spectrum two-dimensional cross-sectional view of a vane boundary layer according to an embodiment of the invention;
FIG. 3 is a schematic perspective view of a blade according to an embodiment of the present invention, wherein (a) is a schematic view of a forward curved blade, (b) is a schematic view of a backward curved blade, and (c) is a schematic view of a straight blade;
FIG. 4 is a "C" shaped pressure profile of a low angle positive camber vane according to an embodiment of the present invention;
FIG. 5a is a schematic diagram of vortices formed by boundary layer free vortex layer migration using a large-turn straight blade before recurvation according to an embodiment of the present invention;
FIG. 5b is a schematic diagram of vortices formed by boundary layer free vortex layer migration using a large-turn blade after reverse bending according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the method and the embodiment proposed by the present invention, all other embodiments obtained by using the method proposed by the present invention will fall within the protection scope of the present invention without any creative work of the ordinary skilled person in the art.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
The invention provides a flow loss control method of a blade surface layer fluid, which has the advantages of good universality, strong practicability and obvious control effect.
The embodiments of the present invention will be further described with reference to the accompanying drawings.
Fig. 1 is an operational flowchart of a flow loss control method of a blade-facing fluid according to an embodiment of the present invention. As shown in fig. 1, the flow loss control method of the vane boundary layer fluid includes the steps of:
s1, classifying the motion of the boundary layer fluid of the blade.
When water, air or other viscous fluid flows along the surface of a solid or the solid moves in the fluid, a layer of low-speed fluid is formed on the surface of the solid, and the layer of fluid is a boundary layer. The movement of the boundary layer leaves a wall flow pattern in the wall where separation lines occur when flow separation occurs. FIG. 2 is a two-dimensional schematic illustration of a separation flow spectrum of a blade boundary layer according to an embodiment of the invention. As shown in fig. 2, the fluid flows in the direction indicated by the arrow, and when the fluid flows along the wall surface, the fluid kinetic energy of the boundary layer near the wall surface is greatly lost due to the influence of viscous friction, pressure gradient and the like, so that the fluid stops flowing at a certain point O near the wall surface, and the fluid inside the boundary layer after the point O has a phenomenon of backflow, and the point O is called a separation point.
According to a preferred embodiment, the movements of the boundary layer fluid of the blade are classified according to whether there is a separation line in the wall flow spectrum formed by the movements of the boundary layer fluid. The separation line can be directly observed, and the existence of the separation line indicates that the free vortex layer migrates; the absence of a separation line indicates attached vortex layer migration.
According to a preferred embodiment, the movement of the boundary layer fluid of the blade is divided in step S1 into an attached vortex layer migration without a separation line and a free vortex layer migration from the separation line. The attached vortex layer refers to an attached surface fluid developed along the wall surface; the free vortex layer refers to the vortex flow body entering the flow field. When there is no separation line, the motion of the boundary layer is the attached vortex layer; when there is a separation line, the movement of the boundary layer is converted from the attached vortex layer to the free vortex layer, starting from the separation line.
And S2, obtaining the influence factors of the flow loss of the boundary layer fluid according to the motion type of the boundary layer fluid.
The expression of the fluid momentum equation is:
wherein the left side of the equation is the momentum rate of change,
is the volume force to which the fluid is subjected,
in order to be a term of the pressure gradient,
is a sticky term. From the fluid momentum equation, the momentum change rate of the boundary layer fluid is determined by two key quantities: pressure gradient and viscosity.
When no separation line exists in the wall surface flow spectrum, the boundary layer always moves close to the wall surface, namely, the migration of the boundary layer occurs, and the flow loss is mainly influenced by the pressure gradient; when a separation line appears in the wall surface flow spectrum, the boundary layer leaves the wall surface through the separation line of the wall surface flow spectrum to form a free vortex layer, namely, the free vortex layer is migrated, and the flow loss is mainly influenced by viscosity, namely vortex.
And S3, taking corresponding measures to reduce the flow loss according to the influence factors of the flow loss of the boundary layer fluid.
In the case where the movement of the boundary layer fluid of the blade is attached vortex layer migration, the flow loss is reduced by creating a better pressure distribution. According to a preferred embodiment, creating a better pressure distribution comprises subjecting the blades of the small-angle cascade to a positive bending treatment. Fig. 3 is a perspective view of the blade. As shown in fig. 3, (c) is a straight blade, (a) is a forward curved blade, and (b) is a backward curved blade. The positive bending blade can control the attached vortex layer flow on the surface of the blade and improve the pneumatic performance of the blade cascade. In the straight blade flow channel, low-speed boundary layer fluid is mainly and intensively distributed near two end walls and in an angle area of the end walls/suction surfaces, the flow loss of the near end walls and the angle area of the end walls/suction surfaces is large, fig. 4 is a C-shaped pressure distribution diagram formed by the small-corner positive bending blade according to the embodiment of the invention along the height direction of the blade, and as shown in fig. 4, C-shaped static pressure distribution with high pressure along two ends of a blade span and low intermediate pressure is formed, so that better pressure distribution is formed, and a boundary layer at the root of the driving blade is moved to the middle of the blade, so that the flow loss of the near the end walls and the angle area of the end walls/suction surfaces is remarkably reduced.
In the case where the movement of the shrouded fluid of the blade is free vortex layer migration, flow losses are reduced by reducing or altering the vortex distribution. According to a preferred embodiment, reducing or modifying the swirl distribution comprises a back-bending treatment of the large-turn cascade vanes. The flow spectrum of the blade suction surface of a cascade with large turning angles (such as 60 degrees of compressor blades and 120 degrees of turbine blades) has a large number of separation lines, and the fluid generates vortices at the separation lines, so that the flow is dominated by free vortex layer migration. The strength and range of the vortices are reduced by adopting the reversely bent vanes, or the distribution and the position relation among the vortices are changed, so that the viscous blending loss among the vortices is reduced. Figures 5a and 5b are swirl distribution diagrams before and after the use of large turn angle recurved vanes according to an embodiment of the present invention. As shown in fig. 5a and 5b, PV is the channel vortex, TV is the trailing edge vortex, SV is the secondary vortex, and CV is the wall angle vortex. From fig. 5a to 5b, it is apparent that by using the recurved vanes, the range of influence of the channel vortex and the trailing edge vortex becomes significantly smaller, the secondary vortex disappears, and thus the viscous blending loss is reduced.
The invention provides a flow loss control method of a blade boundary layer fluid, which determines the development of the boundary layer fluid by two key quantities of pressure gradient and viscosity in a momentum equation. On the basis, the invention classifies the surface layer fluid movement according to the existence of the separation line, adopts different control methods for different flow field conditions, and has the advantages of good universality, strong practicability and obvious control effect.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (4)
1. A flow loss control method for a blade boundary layer fluid includes the steps of:
s1, classifying the motion of the boundary layer fluid of the blade;
classifying the motion of the boundary layer fluid according to whether or not there is a separation line in the motion of the boundary layer fluid of the blade in step S1;
dividing the movement of the boundary layer fluid of the blade into an attached vortex layer migration where there is no separation line in the wall surface spectrum and a free vortex layer migration from the separation line in the wall surface spectrum in step S1;
s2, obtaining the influence factors of the flow loss of the boundary layer fluid according to the type of the motion of the boundary layer fluid;
s3, taking corresponding measures to reduce the flow loss according to the influence factors of the flow loss of the boundary layer fluid;
wherein the taking corresponding measures to reduce the flow loss according to the influence factors of the flow loss of the boundary layer fluid comprises:
in the case where the movement of the boundary layer fluid of the blade is attached vortex layer migration, flow loss is reduced by forming a better pressure distribution; or
In the case where the movement of the shrouded fluid of the blade is free vortex layer migration, flow losses are reduced by reducing or altering the vortex distribution.
2. The method of controlling flow loss of a fluid flowing on a blade surface according to claim 1, wherein whether or not the separation line exists is determined based on a wall surface flow spectrum generated by the flow of the fluid flowing on the blade surface.
3. The method for controlling flow loss of a vane surface layer fluid according to claim 1, wherein the forming of a better pressure distribution includes subjecting the vanes of a small-angle cascade to a positive camber treatment.
4. The method of claim 1, wherein the reducing or modifying the swirl distribution comprises reverse-bending the high-angle cascade vanes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811006975.XA CN109268077B (en) | 2018-08-30 | 2018-08-30 | Flow loss control method for blade boundary layer fluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811006975.XA CN109268077B (en) | 2018-08-30 | 2018-08-30 | Flow loss control method for blade boundary layer fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109268077A CN109268077A (en) | 2019-01-25 |
| CN109268077B true CN109268077B (en) | 2021-07-09 |
Family
ID=65155069
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811006975.XA Active CN109268077B (en) | 2018-08-30 | 2018-08-30 | Flow loss control method for blade boundary layer fluid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109268077B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101666343A (en) * | 2008-09-03 | 2010-03-10 | 中国科学院工程热物理研究所 | Control system and control method for plasma excitation for cascade internal flow |
| KR20160047715A (en) * | 2014-10-23 | 2016-05-03 | 한국에너지기술연구원 | Mixed flow impeller having hollow airfoil blades |
| CN107366634A (en) * | 2017-08-17 | 2017-11-21 | 西北工业大学 | A kind of compressor blade row loss calculation method |
-
2018
- 2018-08-30 CN CN201811006975.XA patent/CN109268077B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101666343A (en) * | 2008-09-03 | 2010-03-10 | 中国科学院工程热物理研究所 | Control system and control method for plasma excitation for cascade internal flow |
| KR20160047715A (en) * | 2014-10-23 | 2016-05-03 | 한국에너지기술연구원 | Mixed flow impeller having hollow airfoil blades |
| CN107366634A (en) * | 2017-08-17 | 2017-11-21 | 西北工业大学 | A kind of compressor blade row loss calculation method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109268077A (en) | 2019-01-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN202176548U (en) | Intermediate blade of air compressor used for high power gas turbine | |
| US11333167B2 (en) | Method of designing blade of axial flow fluid machine and blade | |
| CN107742011B (en) | Design method of impeller blade drag reduction micro-texture | |
| CN109779972B (en) | Two-dimensional blade profile optimization method for gas compressor considering low Reynolds number working condition performance | |
| US10036392B2 (en) | Axial fan for industrial use | |
| CN105840551A (en) | Pneumatic implementation method for multi-operating-point high-load compressor blades | |
| CN107050542B (en) | Miniature centrifugal blood pump capable of preventing blood cells from being damaged and circulating blood supply method thereof | |
| CN111734577B (en) | Slit type wind turbine blade device and slit method | |
| CN111717381B (en) | Asymmetric double-blunt-tip airfoil profile for rotor root of high-speed helicopter and design method | |
| CN101149061A (en) | Centrifugal impeller suitable for high rotation speed operation | |
| CN111255744B (en) | Micro-air injection method for controlling flow separation of suction surface of compressor/fan stator blade | |
| CN111120401A (en) | Multi-wing centrifugal ventilator blade design method based on NACA wing profile | |
| CN106762824B (en) | Axial flow fan ternary impeller with vein structure and gull-shaped splitter blades | |
| CN105179322B (en) | Blade root opens up the Profile For Compressor Stator leaf grating of wide straight-line groove | |
| CN201159202Y (en) | Moving blade tip winglet of compressor | |
| CN109815590B (en) | Three-dimensional blade modeling method and blade of multistage axial-flow compressor based on end region boundary layer | |
| CN109989876B (en) | Blade and wind generating set comprising same | |
| CN109268077B (en) | Flow loss control method for blade boundary layer fluid | |
| CN104763477B (en) | A kind of turbomachine movable vane tip segment shroud structure | |
| CN109779971B (en) | High-load compressor blade profile radial stacking modeling optimization method based on curvature control | |
| CN210422698U (en) | Low pressure turbine blade with wavy suction surface | |
| CN105298912B (en) | Bulge leading edge inlet guiding blade | |
| CN214499309U (en) | Airfoil profile applicable to wind driven generator blade under low Reynolds number working condition | |
| CN114021265A (en) | Airplane wing section based on logarithmic spiral | |
| CN113653672A (en) | Axial flow impeller with splitter blades |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |