CN116614927A - Grid-shaped plasma exciter for turbulence resistance reduction - Google Patents
Grid-shaped plasma exciter for turbulence resistance reduction Download PDFInfo
- Publication number
- CN116614927A CN116614927A CN202310383337.4A CN202310383337A CN116614927A CN 116614927 A CN116614927 A CN 116614927A CN 202310383337 A CN202310383337 A CN 202310383337A CN 116614927 A CN116614927 A CN 116614927A
- Authority
- CN
- China
- Prior art keywords
- grid
- voltage electrode
- plasma
- turbulence
- plasma exciter
- 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.)
- Pending
Links
- 230000009467 reduction Effects 0.000 title claims abstract description 47
- 230000005284 excitation Effects 0.000 claims abstract description 18
- 239000000758 substrate Substances 0.000 claims abstract description 18
- 239000010410 layer Substances 0.000 claims description 54
- 230000000694 effects Effects 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 11
- 230000005684 electric field Effects 0.000 claims description 9
- 238000007664 blowing Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 6
- 239000004642 Polyimide Substances 0.000 claims description 4
- 238000003491 array Methods 0.000 claims description 4
- 229920001721 polyimide Polymers 0.000 claims description 4
- 230000001133 acceleration Effects 0.000 claims description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 3
- 230000009471 action Effects 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 3
- 239000012530 fluid Substances 0.000 claims description 3
- 239000003574 free electron Substances 0.000 claims description 3
- 239000003292 glue Substances 0.000 claims description 3
- 239000011229 interlayer Substances 0.000 claims description 3
- 150000002500 ions Chemical class 0.000 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 238000012545 processing Methods 0.000 abstract description 9
- 238000005516 engineering process Methods 0.000 abstract description 8
- 230000006872 improvement Effects 0.000 abstract description 3
- 206010063385 Intellectualisation Diseases 0.000 abstract description 2
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 230000002265 prevention Effects 0.000 abstract description 2
- 238000000926 separation method Methods 0.000 abstract description 2
- 230000007613 environmental effect Effects 0.000 abstract 1
- 230000001965 increasing effect Effects 0.000 description 6
- 230000004044 response Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000011889 copper foil Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 238000010146 3D printing Methods 0.000 description 1
- 244000137852 Petrea volubilis Species 0.000 description 1
- 229920005372 Plexiglas® Polymers 0.000 description 1
- 239000003522 acrylic cement Substances 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000005281 excited state Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000009832 plasma treatment Methods 0.000 description 1
- 229920003223 poly(pyromellitimide-1,4-diphenyl ether) Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000012418 validation experiment Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/2406—Generating plasma using dielectric barrier discharges, i.e. with a dielectric interposed between the electrodes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
Abstract
The grid-shaped plasma exciter for turbulence drag reduction comprises a high-voltage electrode (11), a dielectric layer (13), a low-voltage electrode (12) and an insulating substrate (14) from top to bottom, wherein the high-voltage electrode (11) is in a staggered grid shape, the high-voltage electrode (12) is in an array square shape, and the central position of each square corresponds to the central position of each grid hole of the high-voltage electrode (11). The grid-shaped net-shaped plasma exciter solves the problems of high processing difficulty, high cost, complex structure, limited effective drag reduction wind speed range of a common plasma exciter and the like in the traditional flow control technology. Because the excitation intensity and the working mode of the plasma exciter are controlled by the electric signals, the plasma exciter is beneficial to realizing the self-adaptive adjustment of different environmental parameters and realizing the intellectualization. The invention has friction drag reduction and flow separation control, and can greatly improve the performance of a military low-speed unmanned aerial vehicle, including stall prevention under a large attack angle, widening of a flight safety boundary, improvement of a flight range and the like.
Description
Technical Field
The invention relates to the technical field of plasma flow control, in particular to a novel-configuration plasma exciter for friction drag reduction of a turbulent boundary layer.
Background
High lift drag reduction has been the pursuit of aerodynamic design of aircraft. The friction resistance of the large-sized conveyor and the large-aspect ratio unmanned aerial vehicle is approximately 50% of the total resistance in the cruising flight stage. Therefore, the cruise lift-drag ratio of the aircraft can be improved by reducing the friction resistance, particularly the turbulent friction resistance, so that the oil consumption of an engine is reduced, the range and the endurance of the aircraft are improved, and the energy consumption is saved. The boundary layer flow drag reduction control technology is mainly divided into a passive control mode and an active control mode. Typical flow control means are small ribs, grooves, micro-blowing arrays, etc. The small ribs and the grooves are used as a passive control technology to obtain a certain drag reduction effect, but the working range is limited, the groove structure size needs to be developed to the micron level in the high-speed and high-Reynolds number flow, the processing mode is more complex, and the cost is increased. The prior researches show that the micro-blowing array realizes friction drag reduction in a turbulent boundary layer, but has the problems of complex air supply system, difficult maintenance of porous medium and the like. Compared with other modes, the novel active flow control technology has the advantages of simple structure, quick response, wide frequency band and the like.
The application of existing plasma exciters to turbulent drag reduction can be broadly divided into three categories: flow direction jet, spanwise jet (CN 111465162A, turbulent boundary layer plasma drag reduction system and method, huang Zhiwei Zhou Yucheng schottky Ouyang Teng) and spanwise oscillation (CN 115023017a, an oscillating discharge plasma exciter for turbulent boundary layer drag reduction control, wugao super Yan Rihua Zheng Haibo Wang Yuling); the basic idea is to interact with the near-wall flow structure of the boundary layer by inducing wall parallel jets. Although the three plasma exciters all achieve a certain drag reduction effect, the range of the active incoming wind speed is mostly below 15 m/s. In order to further improve the flow control drag reduction effect, the thinking paradigm of traditional flow direction/direction-spreading plasma jet drag reduction must be eliminated, and a novel plasma exciter is designed to solve the technical problems.
The plasma exciter configuration may be combined from different electrode patterns. The vast majority of configurations for turbulent drag reduction are described in patent CN113068294A, CN115023017a and CN109587920a, where the high voltage electrode is comb, strip or wire shaped and the high voltage electrode is a rectangular long surface. As described in other patents CN112399694A, CN107914865A, CN101511146A, CN111225486a and CN112607032a, the high-voltage electrode is circular, square, mesh, and rectangular. The effect of vertical jet disturbance on the wall surface cannot be achieved by adopting a conventional electrode configuration, and a square-grid-configuration plasma exciter can meet the requirements. Plasma actuators similar to the checkered configuration are mentioned in both patent CN111432543A, CN111298974A, CN111328955A, CN203554775U and CN108016622 a. However, the patents CN111432543A, CN111298974A, CN111328955A and CN108016622A mainly focus on biomedical plasma treatment, plasma sterilization and disinfection and aircraft deicing fields, and are not applicable to turbulent friction drag reduction. The upper surface electrode and the lower surface electrode are overlapped in the configuration designed in the patent CN203554775U, so that the parasitic capacitance of the exciter is large, a large part of the power supply is reactive power consumption in the working process, and the working efficiency is low. The application of the checkered shape in the patent CN108016622a is mainly to increase the plasma length per unit area, thereby improving the heat generation and anti-icing effect of the exciter, and is not suitable for turbulent friction drag reduction, and the expected function of the device is yet to be verified. Table 1 lists prior art features and applicable scenarios.
TABLE 1 prior art characteristics and applicable scenarios
In view of this, there is a need for further improvements to square mesh actuators that make them more suitable for use in the field of turbulent drag reduction.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides a grid-shaped plasma exciter for turbulence drag reduction, which comprises a high-voltage electrode 11, a dielectric layer 13, a low-voltage electrode 12 and an insulating substrate 14 from top to bottom,
the dielectric layer 13 is a rectangular sheet;
the high-voltage electrodes 11 are in a staggered grid shape and are arranged on the upper surface of the medium layer 13, the warps and the wefts of the grid are long strips, the warps and the wefts of the grid are respectively parallel to the four sides of the medium layer 13, the warps and the wefts of the outermost layer are respectively kept at a certain distance from the four sides of the medium layer 13, a plurality of grid holes are formed between the warps and the wefts, and all the grid holes are square;
the low-voltage electrodes 12 are arranged on the lower surface of the dielectric layer 13 in the shape of square blocks of an array, are positioned in an interlayer of the dielectric layer 13 and the insulating substrate 14, are not contacted with air except for wiring positions of the low-voltage electrodes 12, and are completely corresponding to the central positions of grid holes of the high-voltage electrodes 11; four edges of each square in the low-voltage electrode 12 are aligned with edges of the strip-shaped warps and wefts of the high-voltage electrode, and the four edges are not overlapped, namely, the square is just filled with grid holes;
the insulating substrate 14 is arranged at the bottom of the dielectric layer 13, the projection of which on the horizontal plane coincides with the projection of the dielectric layer 13.
In one embodiment of the present invention, the length and width of the grid-like plasma exciter 1 ranges from 50 to 500mm; the width of the warp and the weft of the high-voltage electrode 11 ranges from 0.5 mm to 3mm; the side length of each square in the low voltage electrode 12 ranges from 5 to 20mm; the thickness of the high voltage electrode 11 and the low voltage electrode 12 ranges from 50 to 100 μm.
In one embodiment of the present invention, the width of the warp and weft of the high-voltage electrode 11 is 1mm; the side length of each square in the low-voltage electrode 12 was 10mm, and the thickness of the high-voltage electrode 11 and the low-voltage electrode 12 was 75 μm.
In another embodiment of the present invention, the material of the dielectric layer 13 is polyimide, and is glued with the high-voltage electrode 11 and the high-voltage electrode 12 through acrylic glue; the thickness of the dielectric layer 13 ranges from 100 μm to 250 μm; the thickness of the insulating base 14 is 50-200 μm.
In another embodiment of the invention, the dielectric layer 13 has a thickness of 200 μm; the thickness of the insulating base 14 is 100 μm.
The grid-shaped plasma exciter facing the turbulence drag reduction is manufactured through a flexible circuit board processing technology.
The grid-shaped plasma exciter device for the turbulent flow resistance reduction is provided, based on the grid-shaped plasma exciter for the turbulent flow resistance reduction, the positive electrode of the plasma power supply 2 is connected with the high-voltage electrode 11, and the negative electrode is grounded together with the low-voltage electrode 12.
In one embodiment of the present invention, the plasma power supply 2 can modulate the output sinusoidal voltage waveform in addition to outputting a steady sinusoidal wave, and change parameters such as discharge voltage, discharge frequency, pulse frequency, duty cycle, etc. to realize excitation with different intensities or vertical jet pulse excitation with different frequencies.
In addition, the working process of the grid-shaped mesh plasma exciter device for turbulence resistance reduction is provided, and the working process is based on the grid-shaped mesh plasma exciter device for turbulence resistance reduction, wherein when an alternating current sine wave plasma power supply is adopted, after the grid-shaped mesh plasma exciter 1 is connected with the plasma power supply 2, a strong electric field is formed near the longitude and latitude edges of the grid-shaped high-voltage electrodes 11; a small amount of free electrons in the air are accelerated in the electric field and collide with a neutral example at a high speed, so that gas molecules are ionized to generate more positive and negative ions, and an unbalanced discharge plasma area is generated between the two electrodes; the charged particles do directional acceleration movement under the action of an electric field, namely the pneumatic excitation of plasma; excitation induces a start vortex firstly and then is evolved into a near-wall jet, and high-voltage electrodes 11 are arranged on the periphery of a square-shaped electrode 12, so that airflow accelerated from the periphery to the center is induced inside each grid hole; from the perspective of cross section, the left air flow and the right air flow collide and merge at the middle part, so that the vertical jet flow along the normal direction is generated by arching; the wall surface normal jet flows in hundreds of grid holes are combined together to form a plasma jet flow array; the use of plasma wall surface normal jet arrays in turbulent boundary layers can produce an effect similar to micro-blowing: the jet flow array can cause disturbance to the boundary layer flow field, lifts fluid, damages the near-wall vortex structure, and further inhibits the generation of near-wall turbulence, so that the friction resistance is reduced.
The invention provides a grid-shaped net-shaped plasma exciter, which solves the problems of high processing difficulty, high cost, complex structure, limited effective drag reduction wind speed range of a common plasma exciter and the like in the traditional flow control technology. Because the excitation intensity and the working mode of the plasma exciter are controlled by electric signals, the plasma exciter is beneficial to realizing the self-adaptive adjustment of different environment parameters (such as incoming flow speed and turbulence degree) and realizing the intellectualization. In addition, the friction drag reduction and flow separation control are combined, and the performance of the military low-speed unmanned aerial vehicle can be greatly improved, including stall prevention under a large attack angle, widening of a flight safety boundary, improvement of a flight range and the like.
Drawings
FIG. 1 is a schematic diagram of the overall structure of a grid-like plasma actuator;
FIG. 2 high voltage electrode and low voltage electrode plane geometry;
FIG. 3 is a partial cross-sectional view of a grid-like plasma actuator;
FIG. 4 is a schematic diagram of a grid-like plasma exciter jet array;
FIG. 5 is a grid plasma exciter airfoil experimental layout;
FIG. 6 is a graph of wind tunnel test results of a grid-like plasma exciter.
The drawings are marked with the following description:
1 square grid-shaped plasma exciter 11 high-voltage electrode 12 low-voltage electrode 13 dielectric layer 14 insulating substrate 2 plasma power supply 3 airfoil 4 flat plate model 5 pneumatic measuring device
Detailed Description
As shown in fig. 1 to 3, the invented grid-like plasma actuator 1 is composed of a high-voltage electrode 11, a low-voltage electrode 12, a dielectric layer 13 and an insulating substrate 14. The length and width of the grid-like plasma exciter 1 need to be adapted to the specific application, typically in the range of 50-500mm. In the embodiment of fig. 1, the total width of the exciter 1 is 100mm and the total length is 300mm. The length and width dimensions are determined by the airfoil model of the later validation experiment. The high-voltage electrodes 11 are in a staggered grid shape and are arranged on the upper surface of the dielectric layer 13, the warps and the wefts of the grid are long strips, and the widths of the warps and the wefts are in a range of 0.5-3mm (preferably 1 mm). The low-voltage electrodes 12 are arranged on the lower surface of the dielectric layer 13 in the shape of square blocks in an array, and are positioned in an interlayer of the dielectric layer 13 and the insulating substrate 14, and the center position of each square block completely corresponds to the center position of each grid hole of the high-voltage electrode 11. In order to facilitate observation of the correspondence between the high-voltage electrode 11 and the low-voltage electrode 12, the dielectric layer 13 in fig. 1 is drawn in a semitransparent shape. Fig. 2 is a plan geometry of each electrode. The high voltage electrode 11 and the low voltage electrode 12 may be made of thin copper foil or other conductive metal coating (e.g., silver, tungsten, etc.), and the thickness of the electrode layer is in the range of 50-100 μm, preferably 75 μm from the viewpoint of reducing disturbance to the incoming flow. The low voltage electrode 12 has a side length of each square in the range of 5-20mm (preferably 10 mm), and four edges of the square are aligned with the edges of the high voltage electrode strip-shaped warp and weft lines, and the two are non-overlapping, i.e. the square is just filled with grid holes, preferably the pitch error is less than 0.1mm (the square is located in the grid, the size of the square corresponds to the grid holes, and in an ideal case the square is aligned with the grid hole boundaries, i.e. the pitch is 0 mm). This non-overlapping arrangement is mainly intended to reduce parasitic capacitance of the exciter and to reduce reactive power consumption during the supply of the power source. In the embodiment of fig. 1, the high-voltage electrode 11 and the low-voltage electrode 12 are formed of 8 rows and 25 columns, and include 200 grid meshes. The material of the dielectric layer 13 is, for example, polyimide (Kapton), for example, glued to the high-voltage electrodes 11, 12 by means of an acrylic glue. The thickness of the dielectric layer 13 is in the range of 100-250 μm, preferably 200 μm. To prevent the contact of the electrode 12 with air, an insulating substrate 14, for example made of polyimide material, is provided at the bottom of the dielectric layer 13. The insulating substrate 14 and the dielectric layer 13 are bonded together, for example, by an acrylic adhesive, and then air bubbles possibly existing between the adhesive layers are further removed by a vacuum hot pressing process. The thickness of the insulating substrate 14 is typically 50-200 μm, with a thin insulating substrate layer of 100 μm thickness being preferred due to the need for flexible adhesion of the actuator.
The positive electrode of the plasma power supply 2 is connected with the high-voltage electrode 11, and the negative electrode is grounded together with the high-voltage electrode 12 to form a complete discharge loop. The plasma power supply 2 can be classified into sinusoidal alternating current, microsecond pulse and nanosecond pulse dielectric barrier discharge plasma excitation according to different driving voltage waveforms. The invention does not limit the frequency and voltage range of the driving waveform, as long as the invention can break down air to generate plasma discharge.
Taking a plasma power supply adopting alternating current sine waves as an example, after the grid-shaped plasma exciter 1 is connected with the plasma power supply 2, a strong electric field is formed near the edges of the warps and the wefts of the grid-shaped high-voltage electrodes 11; a small amount of free electrons in the air are accelerated in the electric field and collide with the neutral example at a high speed, ionizing the gas molecules, generating more positive and negative ions, thereby creating an unbalanced discharge plasma region between the two electrodes. The charged particles do directional acceleration motion under the action of an electric field, namely the pneumatic excitation of the plasma. The excitation induces a start vortex first and then becomes a near wall jet, and since the high voltage electrodes 11 are arranged around the square-shaped electrode 12, the airflow accelerated from the periphery to the center is induced inside each grid hole. Taking the cross-sectional view of fig. 3 as an example, the left and right air flows collide and merge in the middle, and arch to generate vertical jet flow along the normal direction. The highest instantaneous velocity of the jet can be up to 3m/s. The wall normal jets within hundreds of mesh holes combine together to form the plasma jet array of fig. 4. The use of plasma wall surface normal jet arrays in turbulent boundary layers can produce an effect similar to micro-blowing: the jet flow array can cause disturbance to the boundary layer flow field, lifts fluid, damages the near-wall vortex structure, and further inhibits the generation of near-wall turbulence, so that the friction resistance is reduced. Besides, the plasma power supply 2 can output a steady sine wave, and can modulate the output sine voltage waveform and change parameters such as discharge voltage, discharge frequency, pulse frequency, duty ratio and the like to realize excitation with different intensities or vertical jet pulse excitation with different frequencies.
In addition, compared with the traditional wall micro-blowing or small rib drag reduction method, the exciter can be conveniently manufactured by a flexible circuit board processing technology, and the processing cost of a single chip is in the order of tens of yuan to hundred yuan, which is far lower than the processing cost of micro-pore jet flow or wall small ribs. Compared with a mechanical shock resistance reduction method, the resistance reduction method has no mechanical device, has quick response, and is easier to realize the installation of complex wall surfaces because the exciter is made of flexible materials.
Experimental verification of practicality:
as shown in fig. 5, the grid-shaped mesh plasma exciter 1 provided by the invention is attached to an airfoil 3, and is integrally fixed on a flat model 4 in a low-speed wind tunnel of the air force engineering university for testing. The wind tunnel experimental section is 3m long, 1.2m wide and 1m high. The flat mold 4 is made of plexiglas, and has the following dimensions: 1.7m long by 1.2m wide by 0.02m thick. The wing section 3 is formed by adopting 3D printing processing, the material is ABS photosensitive resin 9400, NACA0012 wing sections are selected, the chord length c=0.4 m, the span length 1=0.44 m, a straight strip transition belt which is 1cm wide and is made of 30-mesh sand paper is arranged at the position 2cm away from the front edge, and transition is forced, so that the downstream boundary layer of the wing section 3 is ensured to be in a turbulent state. M6 threaded holes are reserved on chord lines of the upper end and the lower end of the airfoil 3, which are 10cm away from the front edge, and serve as positioning holes, so that the airfoil 3 can be conveniently fixed on the flat model 4. The grid-shaped plasma exciter 1 is attached to the middle of the wing section 3, and the edge is aligned with the tail edge. The airfoil 3 is vertically installed at the middle of the upper surface of the flat model 4, and the distance between the locating hole and the front edge of the flat plate is 1.235m. The high voltage electrode 11 and the low voltage electrode 12 of the exciter are connected to the plasma power source 2 by copper foil tape. In order to obtain the drag reduction effect of the grid-shaped plasma exciter 1 on the wing section 3, a pneumatic measuring device 5 is arranged at a position 320mm away from the tail edge of the wing section 3, data of a flow field are collected, a resistance measurement result is calculated by matching with a computer, and the drag reduction rate is defined as follows:
DR＝(C d，baseline -C d，plasma )/C d，baseline (1) Wherein C is d，baseline And C d，plasma The drag coefficients in the reference and excited states are represented respectively, DR is the drag reduction rate, and when the value is positive, it is indicated that the airfoil frictional resistance is reduced, and when the value is negative, it is indicated that the airfoil frictional resistance is increased.
When the working state parameters of the grid-shaped net-shaped plasma exciter are that the discharge voltage is 8kV, the pulse power is 100Hz and the duty ratio is 50%, the drag reduction effect under different incoming flow speeds is tested. FIG. 6 shows the trend of drag reduction rate with increasing flow rate, and shows the trend of drag reduction rate approaching zero after increasing with increasing flow rate. When the incoming flow speed is less than 10m/s, the excitation generates the resistance increasing effect; and when the incoming flow speed is more than 12m/s, the excitation realizes the drag reduction effect, and the maximum drag reduction result is 2.8% at 15 m/s.
From the above description of the working method and structure, it is clear that the advantages and effects of the present invention mainly include the following aspects:
1. simple structure and low cost. According to fig. 1-3, the invented grid-shaped plasma exciter mainly comprises high and low voltage electrodes, a dielectric layer and an insulating substrate, has a simple structure, very light and thin quality and thickness, has little influence on structural aerodynamic characteristics after installation, and is convenient to replace. Compared with other flow control technologies, the device has the advantages of simple structure, low cost, small processing difficulty, no moving parts and the like.
2. The response is rapid. The excitation intensity and the working mode of the invention are controlled by electric signals, and compared with other active control devices such as micro-blowing, the invention can be excited to generate induced jet flow in millisecond order, thus realizing quick response to the flow field.
3. The jet disturbance capability is good. Most of plasma exciters are applied to a flat boundary layer at a lower speed, and according to the experimental test, the grid-mesh plasma exciters can achieve a certain drag reduction effect on an airfoil at a higher wind speed, and have good engineering application prospects.
Claims (9)
1. The grid-shaped plasma exciter for reducing drag of turbulence comprises a high-voltage electrode (11), a dielectric layer (13), a low-voltage electrode (12) and an insulating substrate (14) from top to bottom,
the dielectric layer (13) is a rectangular sheet;
the high-voltage electrodes (11) are in a staggered grid shape and are arranged on the upper surface of the medium layer (13), warps and wefts of the grid are long strips, the warps and wefts are respectively parallel to four sides of the medium layer (13), the warps and wefts of the outermost layer are respectively kept at a certain distance from the four sides of the medium layer (13), a plurality of grid holes are formed between the warps and the wefts, and all the grid holes are square;
the low-voltage electrodes (12) are arranged on the lower surface of the medium layer (13) in the shape of square blocks of the array, are positioned in an interlayer of the medium layer (13) and the insulating substrate (14), are not contacted with air except for wiring positions of the low-voltage electrodes (12), and are completely corresponding to the central positions of grid holes of the high-voltage electrodes (11); four edges of each square in the high-voltage electrode (12) are aligned with edges of the high-voltage electrode strip warps and wefts, and the four edges are not overlapped, namely the square is just filled with grid holes;
the insulating substrate (14) is arranged at the bottom of the dielectric layer (13), and the projection of the insulating substrate on the horizontal plane is coincident with the projection of the dielectric layer (13).
2. The turbulence-drag-reducing oriented square grid plasma exciter of claim 1, characterized in that the square grid plasma exciter (1) has a length and width in the range of 50-500mm; the width range of the warp and the weft of the high-voltage electrode (11) is 0.5-3mm; the side length of each square in the low-voltage electrode (12) ranges from 5 mm to 20mm; the thickness of the high-voltage electrode (11) and the high-voltage electrode (12) is in the range of 50-100 mu m.
3. The grid-like plasma exciter for turbulence drag reduction according to claim 2, characterized in that the width of the warp and weft of the high-voltage electrode (11) of the plasma exciter (1) is 1mm; the side length of each square in the high-voltage electrode (12) is 10mm, and the thickness of the high-voltage electrode (11) and the thickness of the low-voltage electrode (12) are 75 mu m.
4. The grid-shaped plasma exciter for turbulence drag reduction as claimed in claim 1, wherein the material of the dielectric layer (13) is polyimide, and the dielectric layer is glued with the high-voltage electrode (11) and the high-voltage electrode (12) through acrylic glue; the thickness of the dielectric layer (13) ranges from 100 to 250 mu m; the thickness of the insulating substrate (14) is 50-200 μm.
5. The turbulence-drag-reducing oriented square grid plasma exciter of claim 1, characterized in that the thickness of the dielectric layer (13) is 200 μm; the thickness of the insulating substrate (14) is 100 μm.
6. The turbulence-oriented, drag-reducing, grid-like plasma actuator of claim 1, made by a flexible circuit board process.
7. A turbulence drag reduction oriented grid mesh plasma exciter device based on the turbulence drag reduction oriented grid mesh plasma exciter of any of claims 1 to 5, characterized in that the positive pole of the plasma power source (2) is connected to the high voltage electrode (11) and the negative pole is commonly grounded to the high voltage electrode (12).
8. The grid-shaped plasma exciter device for turbulence drag reduction according to claim 7, wherein the plasma power supply (2) can modulate the output sine voltage waveform besides outputting a steady sine wave, and change parameters such as discharge voltage, discharge frequency, pulse frequency, duty ratio and the like so as to realize excitation with different intensities or vertical jet pulse excitation with different frequencies.
9. The working process of the grid-shaped plasma exciter device for turbulence drag reduction is based on the grid-shaped plasma exciter device for turbulence drag reduction as claimed in claim 7, and is characterized in that when an alternating current sine wave plasma power supply is adopted, a strong electric field is formed near the longitude and latitude edges of a grid-shaped high-voltage electrode (11) after the grid-shaped plasma exciter (1) is connected with a plasma power supply (2); a small amount of free electrons in the air are accelerated in the electric field and collide with a neutral example at a high speed, so that gas molecules are ionized to generate more positive and negative ions, and an unbalanced discharge plasma area is generated between the two electrodes; the charged particles do directional acceleration movement under the action of an electric field, namely the pneumatic excitation of plasma; the excitation induces a start vortex firstly and then is evolved into a near-wall jet, and as the high-voltage electrodes (11) are arranged around the square-shaped electrode (12), the inside of each grid hole induces airflow accelerated from the periphery to the center; from the perspective of cross section, the left air flow and the right air flow collide and merge at the middle part, so that the vertical jet flow along the normal direction is generated by arching; the wall surface normal jet flows in hundreds of grid holes are combined together to form a plasma jet flow array; the use of plasma wall surface normal jet arrays in turbulent boundary layers can produce an effect similar to micro-blowing: the jet flow array can cause disturbance to the boundary layer flow field, lifts fluid, damages the near-wall vortex structure, and further inhibits the generation of near-wall turbulence, so that the friction resistance is reduced.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310383337.4A CN116614927A (en) | 2023-04-11 | 2023-04-11 | Grid-shaped plasma exciter for turbulence resistance reduction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310383337.4A CN116614927A (en) | 2023-04-11 | 2023-04-11 | Grid-shaped plasma exciter for turbulence resistance reduction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116614927A true CN116614927A (en) | 2023-08-18 |
Family
ID=87680757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310383337.4A Pending CN116614927A (en) | 2023-04-11 | 2023-04-11 | Grid-shaped plasma exciter for turbulence resistance reduction |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116614927A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117682060A (en) * | 2024-02-01 | 2024-03-12 | 中国空气动力研究与发展中心计算空气动力研究所 | Resistance reducing device for controlling shock wave boundary layer interference by plasma excitation |
-
2023
- 2023-04-11 CN CN202310383337.4A patent/CN116614927A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117682060A (en) * | 2024-02-01 | 2024-03-12 | 中国空气动力研究与发展中心计算空气动力研究所 | Resistance reducing device for controlling shock wave boundary layer interference by plasma excitation |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6566503B2 (en) | Fluid machinery | |
| CN109665093B (en) | Wing profile capable of delaying flow separation and exciter arranged on wing profile | |
| US8235072B2 (en) | Method and apparatus for multibarrier plasma actuated high performance flow control | |
| JP5255903B2 (en) | A method for controlling the flight of an airborne platform and a plasma actuator for influencing boundary layer flow over the surface of an object | |
| US7017863B2 (en) | Turbulent flow drag reduction | |
| CN101296842B (en) | Plasma actuators for drag reduction on wings, nacelles and/or fuselage of vertical take-off and landing aircraft | |
| JP5793343B2 (en) | Airflow control device and airflow control method | |
| US7066431B2 (en) | Turbulent flow drag reduction | |
| EP2347637B1 (en) | Disbanded cascaded array for generating and moving plasma clusters for active airflow control and method thereof | |
| EP2321084B1 (en) | System and method for aerodynamic flow control | |
| Touchard | Plasma actuators for aeronautics applications-State of art review | |
| CN116614927A (en) | Grid-shaped plasma exciter for turbulence resistance reduction | |
| EP3147207B1 (en) | Embedded dielectric structures for active flow control plasma sources | |
| CN101508338A (en) | Plasma gurney flap | |
| CN107914865A (en) | The virtual dynamic bionic apparatus and method of plasma for the leading edge of a wing | |
| WO2021102171A1 (en) | Vortex control on engine nacelle strake and other vortex generators | |
| CN203222109U (en) | Plasma vortex generator | |
| CN109665092B (en) | Cylinder capable of delaying flow separation and exciter arranged on cylinder | |
| Hua et al. | Experimental investigation of airfoil suction side flow separation control by spanwise nanosecond actuation | |
| EP4332386A1 (en) | Device and method for flow forcing of a fluid | |
| CN113068294B (en) | Microsecond oscillation plasma discharge system and method for turbulence drag reduction control | |
| JP2014049428A (en) | Plasma actuator | |
| CN211930949U (en) | Turbulent boundary layer plasma drag reduction system | |
| JP5955996B2 (en) | Airflow control device and airflow control method | |
| CN115023017A (en) | Oscillating discharge plasma exciter for drag reduction control of turbulent boundary layer |
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 |