CN116296231B - Air floatation balance for measuring wall friction of high-speed non-zero pressure gradient turbulence boundary layer - Google Patents
Air floatation balance for measuring wall friction of high-speed non-zero pressure gradient turbulence boundary layer Download PDFInfo
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- CN116296231B CN116296231B CN202310026186.7A CN202310026186A CN116296231B CN 116296231 B CN116296231 B CN 116296231B CN 202310026186 A CN202310026186 A CN 202310026186A CN 116296231 B CN116296231 B CN 116296231B
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- 238000005259 measurement Methods 0.000 claims abstract description 28
- 238000007667 floating Methods 0.000 claims description 56
- 230000007246 mechanism Effects 0.000 claims description 21
- 238000005188 flotation Methods 0.000 claims description 16
- 230000003321 amplification Effects 0.000 claims description 5
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 5
- 238000006073 displacement reaction Methods 0.000 claims description 2
- 230000009467 reduction Effects 0.000 description 12
- 238000007789 sealing Methods 0.000 description 8
- 238000007664 blowing Methods 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 239000012530 fluid Substances 0.000 description 5
- 238000000691 measurement method Methods 0.000 description 5
- 238000005452 bending Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000009966 trimming Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
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- 239000005431 greenhouse gas Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/06—Measuring arrangements specially adapted for aerodynamic testing
- G01M9/062—Wind tunnel balances; Holding devices combined with measuring arrangements
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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
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
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Abstract
The invention is suitable for the technical field of aerodynamic friction resistance measurement, and discloses an air floatation balance for measuring friction resistance of a wall surface of a high-speed non-zero pressure gradient turbulence boundary layer, which comprises a friction force amplifying and collecting module, a friction force capturing module, an air floatation assembly, an adjusting module and a base, wherein the friction force capturing module, the air floatation assembly, the adjusting module and the base are sequentially arranged from top to bottom; the air floatation assembly comprises a pump body, a pipeline, an air floatation flat plate, a fixed flat plate and a supporting air floatation block; the friction force amplifying and collecting module is used for amplifying the friction force collected by the friction force capturing module; the pump body is used for providing air pressure to suspend the air floatation plate and the friction force capturing module, and the air floatation plate and the supporting air floatation block are arranged in a non-contact mode at the moment. The friction force amplifying and collecting module enables the friction force captured by the friction force capturing module to be amplified or reduced through the lever principle, so that the purpose of measuring smaller friction force is achieved.
Description
Technical Field
The invention relates to the technical field of aerodynamic friction resistance measurement, in particular to an air floatation balance for measuring wall friction resistance of a high-speed non-zero pressure gradient turbulence boundary layer.
Background
In national defense industry engineering and national economic life, such as ships, high-speed rails, aircraft, etc., the existence of frictional resistance is visible everywhere. Taking various aircraft in the world as an example, drag is divided into frictional drag and differential pressure drag, where frictional drag accounts for about 50% of the total drag. The size of the friction is directly related to the fuel consumption, the reduction of the friction can bring great economic benefit, and the reduction of the fuel consumption can also effectively reduce the emission of greenhouse gases. However, the premise of reducing friction is how to accurately measure the friction, and various friction resistance measurement techniques have been reported in the literature, and the friction resistance measurement techniques can be basically classified into a direct measurement method and an indirect measurement method. Since indirect measurement techniques are based on basically various assumptions. In contrast to indirect measuring methods, force balances are therefore the most common direct measuring technique, without additional assumptions.
Friction resistance of friction resistance measurement experiment carried out in wind tunnel at present is generally less than 10 -3 N, in order to reduce measurement errors, a larger floating element is generally selected as the measurement surface or a turbulent boundary layer with a higher reynolds number is generally selected as the experimental condition. How to improve the resolution of the force balance becomes a problem to be solved in turbulent boundary layer drag reduction research. In order to solve the problem, the invention amplifies the measured force according to the experimental requirement according to the lever principle. On one hand, smaller friction resistance can be measured, and on the other hand, the resolution of the force measuring balance can be improved, so that the force measuring balance disclosed by the invention can be used for measuring the friction resistance more accurately. In addition, due to the characteristics of the lever principle, the measured friction resistance can be amplified or reduced according to the experiment requirement, so that the invention is applicable to various situations.
Disclosure of Invention
The invention aims to provide an air floatation balance for measuring friction of a wall surface of a high-speed non-zero pressure gradient turbulence boundary layer, which aims to solve the technical problems that small friction resistance cannot be measured and measurement accuracy is low.
In order to achieve the above purpose, the invention provides the following scheme:
an air floatation balance for measuring friction of a wall surface of a high-speed non-zero pressure gradient turbulence boundary layer comprises a friction force amplifying and collecting module, a friction force capturing module, an air floatation assembly, an adjusting module and a base which are sequentially arranged from top to bottom;
the air floatation assembly comprises a pump body, a pipeline, an air floatation flat plate, a fixed flat plate and a supporting air floatation block; the pump body is connected with the supporting air-floating block through a pipeline, the supporting air-floating block is arranged between the air-floating flat plate and the fixed flat plate, and the air-floating flat plate is arranged on the supporting air-floating block;
the friction force capturing module is connected with the air flotation flat plate, the fixed flat plate is connected with the adjusting module, the adjusting module is connected with the base, the friction force amplifying and collecting module is connected with the air flotation flat plate and the fixed flat plate, and the friction force amplifying and collecting module is used for amplifying the friction force collected by the friction force capturing module;
the pump body is used for providing air pressure to enable the air floatation plate and the friction force capturing module to suspend, and at the moment, the air floatation plate and the supporting air floatation block are arranged in a non-contact mode.
Optionally, the air floatation assembly further comprises a limiting air floatation block, the fixed flat plate is provided with a mounting groove, the supporting air floatation block is arranged at the bottom of the mounting groove, and the limiting air floatation block is arranged on the side wall of the mounting groove and is positioned between the fixed flat plate and the air floatation flat plate;
the pipeline comprises a first branch and a second branch, wherein the first branch is connected with the supporting air-float block, and the second branch is connected with the limiting air-float block.
Optionally, the friction force amplifying and collecting module comprises a lever mechanism and a force transducer, wherein the lever mechanism is connected between the air floatation flat plate and the fixed flat plate, and the force transducer is connected with the lever mechanism and is positioned on one side of the fixed flat plate away from the air floatation flat plate.
Optionally, the friction force amplifying and collecting module further comprises a sensor base and a locking block, wherein the sensor base is connected between the fixed flat plate and the force transducer, and the lever mechanism is connected with the air floatation flat plate and/or the fixed flat plate through the locking block.
Optionally, the adjustment module includes a coarse adjustment assembly and a horizontal fine adjustment assembly, the horizontal fine adjustment assembly is disposed between the fixed plate and the coarse adjustment assembly, and the coarse adjustment assembly is mounted on the base.
Optionally, the coarse adjustment assembly includes a Z-axis moving platform and an XY two-dimensional moving platform, the XY two-dimensional moving platform is connected to the horizontal fine adjustment assembly and the Z-axis moving platform, and the Z-axis moving platform is mounted on the base;
the Z-axis moving platform is used for driving the XY two-dimensional moving platform and the horizontal fine adjustment assembly to move along a first direction, the XY two-dimensional moving platform is used for driving the horizontal fine adjustment assembly to move along a second direction and/or a third direction, and the first direction, the second direction and the third direction are mutually perpendicular.
Optionally, the coarse adjustment assembly further includes a rotary coarse adjustment sliding table, and the rotary coarse adjustment sliding table is connected between the horizontal fine adjustment assembly and the XY two-dimensional moving platform.
Optionally, the rotatory coarse and fine tuning slip table includes Z axle accurate slip table, rotary hinge and ball joint bearing, Z axle accurate slip table connect in rotary hinge with XY two-dimensional moving platform is between, ball joint bearing connect in rotary hinge with between the fixed platform.
Optionally, the friction force capturing module comprises a friction force sensing flat plate, an exciter and a mounting plate which are sequentially arranged from top to bottom, and the mounting plate is connected with the air floatation flat plate.
Optionally, the friction force capturing module further comprises a bushing connected between the exciter and the friction force sensing plate; and/or the number of the groups of groups,
the air floatation assembly further comprises a filter, and the filter is arranged on the pipeline.
Compared with the prior art, the invention has the beneficial effects that:
the air floatation balance for measuring the friction of the wall surface of the high-speed non-zero pressure gradient turbulence boundary layer comprises an air floatation component, an adjusting module, a friction force capturing module and a friction force amplifying and collecting module, wherein the friction force captured by the friction force capturing module is amplified or reduced by the friction force amplifying and collecting module through a lever principle, so that the purpose of measuring smaller friction force is achieved. In addition, due to the rough adjusting component and the horizontal fine adjusting component of the device, the friction force capturing module of the balance system can be provided with various turbulence boundary layer control exciters, such as a plasma exciter, a blowing exciter, a wall vibration exciter and the like, and the wall friction force can be accurately measured under the on or off state of the exciters.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an air-float balance for measuring wall friction of a high-speed non-zero pressure gradient turbulence boundary layer;
FIG. 2 is a schematic structural diagram of an air-float balance for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement according to the invention;
FIG. 3 is a schematic diagram of the elevation structure of an air bearing assembly of the air bearing balance for high-speed non-zero pressure gradient turbulent boundary layer wall friction measurement of the present invention;
FIG. 4 is a schematic diagram of a single-foot adjustment structure of a horizontal fine tuning assembly of an air balance for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement according to the present invention.
Reference numerals illustrate:
100. an air floatation balance for measuring wall friction of a high-speed non-zero pressure gradient turbulence boundary layer; 1. a friction force capturing module; 101. a bushing; 103. a friction force sensing plate; 104. an exciter; 105. a mounting plate; 2. a friction force amplifying and collecting module; 201. a load cell; 202. a lever mechanism; 203. a locking block; 204. a sensor base; 3. an air floatation assembly; 301. an air floatation plate; 302. fixing the flat plate; 303. supporting the air floatation block; 304. a limiting air floatation block; 305. an air pipe; 306. a filter; 307. a pump body; 4. a coarse adjustment assembly; 401. a Z-axis moving platform; 402. an XY two-dimensional moving platform; 403. rotating the coarse and fine adjustment sliding table; 5. a horizontal fine tuning assembly; 501. z-axis precise sliding table; 502. a rotary hinge; 503. ball joint bearings; 6. a sealing cover; 7. and (5) a plane to be measured.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indications (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship between the components, the movement condition, etc. in a specific posture, and if the specific posture is changed, the directional indication is changed accordingly.
It will also be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element through intervening elements.
Furthermore, the description of "first," "second," etc. in this disclosure is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The main disadvantage of existing fulcrum floating balances is the effect of non-uniform pressure on the floating element. These non-uniform pressures result from the shear stress of the fluid on the floating element, the pressure of the fluid on the peripheral edges of the floating element, the air flow at the bottom of the floating element, and the asymmetric cavity flow in the gaps around the floating element, thereby causing the fulcrum floating balance to produce disturbing bending moments other than wall friction induced bending moments, severely disturbing the accuracy of the measurements, particularly under high reynolds number conditions. The capture and collection of friction force is realized through the air floatation assembly of the balance system, so that the influence of nonuniform pressure on the surface of the floating element is solved. The existing floating force balance has small universality and low resolution.
Turbulent boundary layer drag reduction studies are largely divided into active drag reduction and passive drag reduction. Based on the passive drag reduction method, the invention can simply replace the friction sensing panel in the friction capturing module for experimental study according to the experimental requirement. Based on active drag reduction methods, such as methods of blowing drag reduction technology, plasma drag reduction technology, wall vibration drag reduction technology and the like, the active drag reduction technologies can lead to uneven pressure distribution above a friction sensing flat plate to a certain extent, thereby leading to measurement errors.
In order to solve the problems, the air floatation balance for measuring the friction of the wall surface of the high-speed non-zero pressure gradient turbulence boundary layer provided by the application fuses the advantages of the existing fulcrum floating balance and floating force measuring balance, so that the device can overcome the problem that the measurement error is caused by uneven pressure distribution above a friction sensing plate, and the measurement accuracy of a customer is small.
As shown in fig. 1-4, the specific scheme is as follows: an air floatation balance 100 for measuring friction of a wall surface of a high-speed non-zero pressure gradient turbulence boundary layer comprises a friction force amplifying and collecting module 2, a friction force capturing module 1, an air floatation assembly 3, an adjusting module and a base which are sequentially arranged from top to bottom; the air floatation assembly 3 comprises a pump body 307, a pipeline, an air floatation plate 301, a fixed plate 302 and a supporting air floatation block 303; the pump body 307 is connected with the supporting air-float block 303 through a pipeline, the supporting air-float block 303 is arranged between the air-float flat plate 301 and the fixed flat plate 302, and the air-float flat plate 301 is arranged on the supporting air-float block 303; the friction force capturing module 1 is connected with the air floating flat plate 301, the fixed flat plate 302 is connected with the adjusting module, the adjusting module is connected with the base, the friction force amplifying and collecting module 2 is connected with the air floating flat plate 301 and the fixed flat plate 302, and the friction force amplifying and collecting module 2 is used for amplifying the friction force collected by the friction force capturing module 1; the pump body 307 is used for providing air pressure to suspend the air floating plate 301 and the friction force capturing module 1, and the air floating plate 301 and the supporting air floating block 303 are arranged in a non-contact manner. Illustratively, in the present embodiment, two support air bearing blocks 303 are provided, and the two support air bearing blocks 303 are mounted and fixed on the fixed plate 302, and the air bearing plate 301 is placed on the support air bearing blocks 303, and the support air bearing blocks 303 are used for suspending the friction force capturing module 1. The friction force capturing module 1 is enabled to move in one direction along the flow direction, so that the influence of uneven pressure above the friction force capturing module 1 on experiments is solved. Of course, in a specific application, the number of the supporting air bearing blocks 303 is not limited thereto, and for example, as an alternative, one, three, or four supporting air bearing blocks 303 may be provided, and the specific number is not limited thereto. Meanwhile, due to the characteristic of air floatation, the displacement of the friction force capturing module 1 can be regarded as completely depending on the friction force suffered by the surface of the friction force capturing module 1 without being influenced by other mechanical mechanisms. Therefore, force is transmitted to the force sensor according to the lever principle, and friction resistance is accurately amplified and measured.
As shown in fig. 1, fig. 2 and fig. 3, the air-float balance 100 for measuring friction of wall surface of high-speed non-zero pressure gradient turbulence boundary layer provided by the application comprises an air-float assembly 3, an adjusting module, a friction force capturing module 1 and a friction force amplifying and collecting module 2, wherein the friction force captured by the friction force capturing module 1 is amplified or reduced by the friction force amplifying and collecting module 2 through a lever principle, so that the purpose of measuring smaller friction force is achieved, in addition, the air-float assembly 3 is arranged to enable the friction force capturing module 1 to be in a suspension state, the influence of non-uniform pressure on a floating element is fundamentally eliminated, the measurement precision of the device is improved, and the device can be used for accurately measuring on the premise of not increasing the area of the friction force capturing module 1. In addition, thanks to the coarse adjustment assembly 4 and the horizontal fine adjustment assembly 5 of the device, the friction force capturing module 1 of the balance system can be provided with various turbulence boundary layer control exciters 104, such as a plasma exciters 104, a blowing exciters 104, a wall vibration exciters 104 and the like, and can accurately measure the wall friction force in the state that the exciters 104 are turned on or turned off.
As shown in fig. 1, 2 and 3, the air-float balance 100 for measuring friction resistance of wall surface of high-speed non-zero pressure gradient turbulence boundary layer of the invention is provided with a friction force amplifying and collecting module 2, has higher measuring precision and can reach 10 at the minimum -4 N. The invention uses the air floatation assembly 3 to fundamentally eliminate the influence of non-uniform pressure on the floating element and ensure the accuracy of the measurement result. Thanks to the coarse adjustment component 4 and the horizontal fine adjustment component 5 of the air balance 100 for measuring the wall friction of the high-speed non-zero pressure gradient turbulence boundary layer, the friction force capturing module 1 of the air balance 100 for measuring the wall friction of the high-speed non-zero pressure gradient turbulence boundary layer can be provided with various turbulence boundary layer control exciters 104, such as a plasma exciter 104, a blowing exciter 104, a wall vibration exciter 104 and the like, has higher universality, and can be used in different types of wind tunnels and even water holes.
As shown in fig. 1, 2 and 3, as an embodiment, the air floatation assembly 3 further includes a limiting air floatation block 304, the fixed plate 302 has a mounting groove, the supporting air floatation block 303 is disposed at the bottom of the mounting groove, and the limiting air floatation block 304 is disposed on a side wall of the mounting groove and between the fixed plate 302 and the air floatation plate 301; the pipeline includes first branch road and second branch road, and first branch road is connected with support air supporting piece 303, and the second branch road is connected with spacing air supporting piece 304. Illustratively, two limiting air floating blocks 304 are provided, and the limiting air floating blocks 304 are used for limiting the friction force capturing module 1, so that the friction force capturing module 1 moves in one direction along the flow direction, and the influence of uneven pressure above the friction force capturing module 1 on an experiment is solved. Of course, in a specific application, the number of the limiting air-bearing blocks 304 is not limited thereto, and for example, as an alternative, one, three, or four limiting air-bearing blocks 304 may be provided, and the specific number is not limited thereto.
As shown in fig. 1, 2 and 3, as an embodiment, the friction force amplifying and collecting module 2 includes a lever mechanism 202 and a force sensor 201, wherein the lever mechanism 202 is connected between the air floatation plate 301 and the fixed plate 302, and the force sensor 201 is connected with the lever mechanism 202 and is located at a side of the fixed plate 302 away from the air floatation plate 301. Illustratively, the principle of the air-float balance 100 for measuring wall friction of a high-speed non-zero pressure gradient turbulence boundary layer according to the application is based on the lever principle, and the amplification factor of the air-float balance is determined by the distance from the load cell 201 in the friction force amplification acquisition module 2 to the lever structure and the distance from the air-float flat plate 301 in the air-float assembly 3 to the lever structure. Because of the adjustability of the distance, the magnification of the balance (even the measured force is reduced) can be adjusted to meet different experimental requirements, so that the application has wide applicability.
As shown in fig. 1, 2 and 3, as an embodiment, the friction force amplifying and collecting module 2 further includes a sensor base 204 and a locking block 203, where the sensor base 204 is connected between a fixed plate 302 and a load cell 201, and the lever mechanism 202 is connected to the air floating plate 301 and/or the fixed plate 302 through the locking block 203. Illustratively, the sensor mount 204 in the friction force amplifying and collecting module 2 is used to fix the load cell 201, and the lock block 203 is used to fix the load cell 201 and the air bearing plate 301 in the air bearing assembly 3 to the lever structure in the friction force amplifying and collecting module 2 to form a force transmission structure. The sensor base 204 in the friction force amplifying and collecting module 2 and the lever mechanism 202 are connected to the lower surface of the fixed flat plate 302 of the air floatation assembly 3 through screws, and the force sensor 201 is connected to the sensor base 204. The lock blocks 203 are then connected to the air bearing plate 301 and the load cell 201 in the air bearing assembly 3 by studs, respectively.
As shown in fig. 1, 2 and 3, as an embodiment, the adjustment module includes a coarse adjustment assembly 4 and a horizontal fine adjustment assembly 5, where the horizontal fine adjustment assembly 5 is disposed between the fixed plate 302 and the coarse adjustment assembly 4, and the coarse adjustment assembly 4 is mounted on a base.
As shown in fig. 1, 2 and 3, as an embodiment, the coarse adjustment assembly 4 includes a Z-axis moving platform 401 and an XY two-dimensional moving platform 402, the XY two-dimensional moving platform 402 is connected to the horizontal fine adjustment assembly 5 and the Z-axis moving platform 401, and the Z-axis moving platform 401 is mounted on a base; the Z-axis moving platform 401 is configured to drive the XY two-dimensional moving platform 402 and the horizontal fine adjustment assembly 5 to move along a first direction, and the XY two-dimensional moving platform 402 is configured to drive the horizontal fine adjustment assembly 5 to move along a second direction and/or a third direction, where the first direction, the second direction, and the third direction are mutually perpendicular. Illustratively, the Z-axis compact slipway, swivel hinge 502, and ball joint bearing 503 comprise the horizontal fine adjustment assembly 5. According to the principle of determining a plane at three points, the inclination angle of the air floatation plate 301 in the air floatation assembly 3 can be adjusted by adjusting the height adjusting knob of the Z-axis compact slipway. The air floatation plate 301 needs to be adjusted to be in a horizontal state, and the locking knob of the Z-axis compact sliding table is locked. To avoid the influence of gravity on the load cell 201 in the friction acquisition module by the air floatation plate 301, so that the electric signal indication of the pressure sensor is within an acceptable range.
As shown in fig. 1, 2 and 3, as an embodiment, the coarse adjustment assembly 4 further includes a rotary coarse adjustment sliding table 403, and the rotary coarse adjustment sliding table 403 is connected between the horizontal fine adjustment assembly 5 and the XY two-dimensional moving platform 402.
As shown in fig. 1, 2 and 4, as an embodiment, the rotating coarse and fine adjustment slide table 403 includes a Z-axis precise slide table 501, a rotating hinge 502 and a ball joint bearing 503, where the Z-axis precise slide table 501 is connected between the rotating hinge 502 and the XY two-dimensional moving platform 402, and the ball joint bearing 503 is connected between the rotating hinge 502 and the fixed platform. Illustratively, the Z-axis moving platform 401 in the coarse tuning assembly 4 is coupled to a bottom support base, and the two-dimensional moving platform in the coarse tuning assembly 4 is coupled to the Z-axis moving platform 401 via a bottom plate. The rotating coarse and fine adjustment sliding table 403 in the coarse adjustment assembly 4 is connected with the XY two-dimensional moving platform 402 through a bottom plate, and the Z-axis precise sliding table 501 in the 3 horizontal fine adjustment assemblies 5 is connected with the rotating coarse and fine adjustment sliding table 403. Then the connecting hinge in the horizontal fine tuning component 5 is connected with the Z-axis precise sliding table 501 through a connecting block, and the spherical joint bearing 503 in the horizontal fine tuning component 5 is connected with the connecting hinge through a connecting block.
As shown in fig. 1, 2 and 3, as an embodiment, the friction force capturing module 1 includes a friction force sensing plate 103, an actuator 104 and a mounting plate 105, which are disposed in this order from top to bottom, and the mounting plate 105 is connected to an air floating plate 301. Illustratively, the mounting plate 105 of the friction force capturing module 1 has a threaded structure thereon, and the inclination angle of the friction force sensing plate 103 can be adjusted by adjusting the fastening screw thereon. During experiments, the mounting plate 105, the coarse adjustment assembly 4 and the horizontal fine adjustment assembly 5 in the friction force capturing module 1 need to be adjusted together so that the friction force sensing flat plate 103 in the friction force capturing module 1 meets the experimental requirements.
As shown in fig. 1, 2 and 4, the spherical joint bearing 503 in the horizontal fine adjustment assembly 5 is connected with the fixed plate 302 in the air flotation assembly 3 through threads, the limiting air flotation block 304 in the air flotation assembly 3 is fixed on the fixed plate 302, and then the air flotation plate 301 in the air flotation assembly 3 is placed on the supporting air flotation block 303. After the mounting plate 105 in the friction force capturing module 1 is connected to the air floating flat plate 301 through threads, the actuator 104 in the friction force capturing module 1 is connected to the mounting plate 105 through a sealing ring and a screw, the bushing 101 is connected to the actuator 104 through the sealing ring and the screw, and finally the friction force sensing flat plate 103 is connected to the bushing 101 through the sealing ring and the screw.
As shown in fig. 1, 2 and 3, as an embodiment, the friction force capturing module 1 further includes a bushing 101, and the bushing 101 is connected between the actuator 104 and the friction force sensing plate 103. The bushing 101 in the friction force capturing module 1 is illustratively connected to the actuator 104, and the actuator 104 is connected to the mounting plate 105, and if air blowing is required during the experiment, sealing rings are required to be respectively added between the bushing 101 and the actuator 104 and between the actuator 104 and the mounting plate 105 so that the whole system is in a sealed state.
As shown in fig. 1, 2 and 3, the air floatation assembly 3 further includes a filter 306, and the filter 306 is disposed on the pipeline. The pump body 307 in the air floating assembly 3 is connected with the filter 306 through the air pipe 305, and the filter 306 is respectively connected with the supporting air floating block 303 and the limiting air floating block 304 through the air pipe 305.
As shown in fig. 1, 2 and 3, the air-float balance 100 for measuring the wall friction of the high-speed non-zero pressure gradient turbulence boundary layer further comprises a sealing cover 6, the sealing cover 6 is used for protecting a main body part of the air-float balance 100 for measuring the wall friction of the high-speed non-zero pressure gradient turbulence boundary layer, and a plane 7 to be measured is further arranged at the top of the sealing cover 6. An opening is formed in the plane 7 to be tested, the top of the friction force capturing module 1 is exposed through the opening, and a gap of 0.2mm is reserved between the friction force capturing module 1 and the opening.
The use method of the air-float balance 100 for measuring the wall friction of the high-speed non-zero pressure gradient turbulence boundary layer comprises the following steps:
(1) Adjustment of air-bearing balance 100 for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement
First, the horizontal trimming assembly 5 is adjusted, the horizontal trimming portion determining a planar principle based on three points. Due to the spherical joint bearing 503 and the rotary hinge 502, the rotation range of the spherical joint bearing 503 can be enlarged, and then the three Z-axis precise sliding tables 501 are adjusted until the air floatation plate 301 is horizontal, and the three Z-axis precise sliding tables 501 are locked by locking knobs on the Z-axis precise sliding tables 501 after leveling.
Next, the pump body 307 is opened to suspend the air floating plate 301, and simultaneously, the fastening screw on the fixing plate 302 is adjusted to adjust the position of the limiting air floating block 304, so that the air floating plate 301 can move smoothly. The coarse adjustment assembly 4 is then adjusted to adjust the Z-axis moving stage 401, the xy two-dimensional moving stage 402, and the rotating coarse adjustment slide 403, respectively, so that the floating original enters the area of the outer bushing 101. And then, adjusting the fastening screw on the mounting plate 105 to finely adjust the position of the floating element, so that the floating element is flush with the outer bushing 101, and locking and rotating the locking knob on the coarse fine adjustment sliding table 403 after leveling is finished.
Finally, the lever mechanism 202 in the acquisition module 2 is adjusted to be vertical by adjusting the friction force, and then the fastening screw on the locking block 203 connected with the air floatation plate 301 is adjusted until the lever mechanism 202 and the air floatation plate 301 are locked.
The locking block 203 of the lever mechanism 202 connected with the pressure sensor is then adjusted, and the fastening screw on the locking block 203 is adjusted until the voltage indicator connected with the pressure sensor is near 0.
(2) Calibration mode of air-float balance 100 for measuring wall friction of high-speed non-zero pressure gradient turbulence boundary layer
First, the filament is connected to the air bearing plate 301 by means of the filament, then the filament is passed around the pulley and vertically down (the position of the pulley needs to be adjusted so that the filament is in a horizontal plane with the air bearing plate 301), and then the filament is connected to a weight box. Weights with different masses are respectively placed in the weight boxes, electric signals of the force transducers 201 displayed in the computer are recorded, and the electric signals and the force related relation function can be obtained through fitting according to the obtained data and the placed weights because the force transducers 201 are linear sensors, so that the invention is calibrated.
(3) Acquisition mode of air-float balance 100 for measuring wall friction of high-speed non-zero pressure gradient turbulence boundary layer
First, when fluid flows over the surface of the floating element, the floating element moves in the flow direction by friction, thereby driving the lower air bearing plate 301 to move in the flow direction. The frictional resistance of the floating element under the action of the lever mechanism 202202 is amplified or reduced and transmitted to the pressure sensor. The electric signal of the pressure sensor is amplified by the amplifier and then transmitted to the acquisition card, and then the acquisition card transmits the electric signal to the computer, so that the electric signal of the pressure sensor is acquired.
The air floatation balance 100 for measuring the wall friction of the high-speed non-zero pressure gradient turbulence boundary layer has the advantages that:
the capture and collection of friction is achieved by the air floatation assembly 3 of the air floatation balance 100 for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement, which fundamentally eliminates the effect of non-uniform pressure on the floating element compared to previously developed fulcrum floatation balances. These non-uniform pressures result from the shear stress of the fluid on the floating element, the pressure of the fluid on the peripheral edges of the floating element, the air flow at the bottom of the floating element, and the asymmetric cavity flow in the gaps around the floating element, thereby causing the fulcrum floating balance to produce disturbing bending moments other than wall friction induced bending moments, severely disturbing the accuracy of the measurements, particularly under high reynolds number conditions.
Thanks to the coarse adjustment assembly 4 and the horizontal fine adjustment assembly 5 of the air balance 100 for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement, the friction force capturing module 1 of the air balance 100 for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement can be provided with various turbulence boundary layer control exciters 104, such as a plasma exciters 104, a blowing exciters 104, wall vibration exciters 104 and the like, and can accurately measure wall friction force in the on or off state of the exciters 104, which cannot be achieved by air balance developed by the university of melbourne. In addition, the air-floating balance developed by the university of melbourne is used as a fixed balance, the requirement on the wind tunnel is high, and the air-floating balance 100 for measuring the wall friction of the high-speed non-zero-pressure gradient turbulence boundary layer can realize six-degree-of-freedom adjustment of a floating element, has high universality and can be used in different types of wind tunnels and even water tunnels.
The air-float balance 100 for measuring the friction of the wall surface of the high-speed non-zero pressure gradient turbulence boundary layer has the friction force amplifying and collecting module 2, integrates the advantages of amplifying friction force of the fulcrum floating balance and eliminating the influence of uneven pressure of the air-float balance, realizes the function of amplifying the friction force of the wall surface by utilizing the lever mechanism 202 in the friction force amplifying and collecting module 2, and has the measuring precision of 10 -4 N, which is critical for wall friction measurements under low reynolds number conditions. Because the wall friction force under the low Reynolds number working condition is very small, the air-float balance 100 for measuring the wall friction resistance of the high-speed non-zero pressure gradient turbulence boundary layer can still accurately measure on the premise of not increasing the area of the friction force capturing module 1.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (9)
1. The air floatation balance for measuring the friction of the wall surface of the high-speed non-zero pressure gradient turbulence boundary layer is characterized by comprising a friction force amplifying and collecting module, a friction force capturing module, an air floatation assembly, an adjusting module and a base which are sequentially arranged from top to bottom;
the air floatation assembly comprises a pump body, a pipeline, an air floatation flat plate, a fixed flat plate and a supporting air floatation block; the pump body is connected with the supporting air-floating block through a pipeline, the supporting air-floating block is arranged between the air-floating flat plate and the fixed flat plate, and the air-floating flat plate is arranged on the supporting air-floating block;
the friction force capturing module is connected with the air floatation flat plate, the fixed flat plate is connected with the adjusting module, the adjusting module is connected with the base, and the friction force amplifying and collecting module is connected with the air floatation flat plate and the fixed flat plate;
the friction force amplifying and collecting module is used for amplifying the friction force collected by the friction force capturing module; the pump body is used for providing air pressure to suspend the air floatation plate and the friction force capturing module, and the air floatation plate and the supporting air floatation block are arranged in a non-contact mode at the moment;
the friction force amplifying and collecting module comprises a lever mechanism and a force transducer, wherein the lever mechanism is connected between the air floatation plate and the fixed plate, and the force transducer is connected with the lever mechanism and is positioned at one side of the fixed plate far away from the air floatation plate;
according to the characteristics of air floatation, the displacement of the friction force capturing module completely depends on the friction force suffered by the surface of the friction force capturing module, and the friction force influence of other mechanical mechanisms is not added; force is conducted to the force sensor according to the lever principle, and friction resistance is accurately amplified and measured;
the amplification factor is determined by the distance from the force transducer in the friction force amplification acquisition module to the lever structure and the distance from the air floatation flat plate in the air floatation assembly to the lever structure, and due to the adjustability of the distance, the amplification factor of the balance can be adjusted, and even the measured force is reduced, so that different experimental requirements are met.
2. The air flotation balance for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement according to claim 1, wherein the air flotation assembly further comprises a limiting air flotation block, the fixed plate is provided with a mounting groove, the supporting air flotation block is arranged at the bottom of the mounting groove, and the limiting air flotation block is arranged on the side wall of the mounting groove and is positioned between the fixed plate and the air flotation plate;
the pipeline comprises a first branch and a second branch, wherein the first branch is connected with the supporting air-float block, and the second branch is connected with the limiting air-float block.
3. The air-float balance for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement according to claim 2, wherein the friction force amplifying and collecting module further comprises a sensor base and a locking block, the sensor base is connected between the fixed flat plate and the force sensor, and the lever mechanism is connected with the air-float flat plate and/or the fixed flat plate through the locking block.
4. An air flotation balance for high speed non-zero pressure gradient turbulent boundary layer wall friction measurement as claimed in claim 3, wherein the adjustment module comprises a coarse adjustment assembly and a horizontal fine adjustment assembly, the horizontal fine adjustment assembly being disposed between the fixed plate and the coarse adjustment assembly, the coarse adjustment assembly being mounted on the base.
5. The air-float balance for high-speed non-zero pressure gradient turbulent boundary layer wall friction measurement according to claim 4, wherein the coarse adjustment assembly comprises a Z-axis moving platform and an XY two-dimensional moving platform, the XY two-dimensional moving platform being connected to the horizontal fine adjustment assembly and the Z-axis moving platform, the Z-axis moving platform being mounted on the base;
the Z-axis moving platform is used for driving the XY two-dimensional moving platform and the horizontal fine adjustment assembly to move along a first direction, the XY two-dimensional moving platform is used for driving the horizontal fine adjustment assembly to move along a second direction and/or a third direction, and the first direction, the second direction and the third direction are mutually perpendicular.
6. The air balance for high-speed non-zero pressure gradient turbulent boundary layer wall friction measurement of claim 5, wherein the coarse adjustment assembly further comprises a rotating coarse adjustment slip coupled between the horizontal fine adjustment assembly and the XY two-dimensional moving platform.
7. The air-float balance for high-speed non-zero pressure gradient turbulence boundary layer wall friction measurement according to claim 6, wherein the rotating coarse-fine tuning slipway comprises a Z-axis precise slipway, a rotating hinge and a ball joint bearing, wherein the Z-axis precise slipway is connected between the rotating hinge and the XY two-dimensional moving platform, and the ball joint bearing is connected between the rotating hinge and the fixed platform.
8. The air floatation balance for measuring wall friction of high-speed non-zero pressure gradient turbulence boundary layer according to claim 7, wherein the friction force capturing module comprises a friction force sensing flat plate, an exciter and a mounting plate which are sequentially arranged from top to bottom, and the mounting plate is connected with the air floatation flat plate.
9. The air flotation balance for high-speed non-zero pressure gradient turbulent boundary layer wall friction measurement as set forth in claim 8, wherein said friction capturing module further comprises a bushing connected between said actuator and said friction sensing plate; the air floatation assembly further comprises a filter, and the filter is arranged on the pipeline.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1641079A1 (en) * | 1989-03-28 | 1994-04-30 | Г.В. Енютин | Method measuring surface friction |
| JPH0989693A (en) * | 1995-09-25 | 1997-04-04 | Denso Corp | Method and apparatus for measuring extremely small frictional force |
| CN113188652A (en) * | 2021-04-21 | 2021-07-30 | 西北工业大学 | Method and device for measuring acoustic radiation force in suspension sound field |
| CN215492356U (en) * | 2021-08-23 | 2022-01-11 | 哈尔滨工业大学（深圳） | Force measuring balance for measuring air friction resistance of curved surface boundary layer wall surface |
| CN114216648A (en) * | 2022-02-21 | 2022-03-22 | 中国空气动力研究与发展中心超高速空气动力研究所 | High-frequency-response wide-range MEMS friction resistance sensor |
| CN114397050A (en) * | 2021-12-10 | 2022-04-26 | 西安理工大学 | Magnetic suspension type friction resistance measuring device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9983111B2 (en) * | 2015-11-20 | 2018-05-29 | The Regents Of The University Of California | Low profile shear-sensing unit |
-
2023
- 2023-01-09 CN CN202310026186.7A patent/CN116296231B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1641079A1 (en) * | 1989-03-28 | 1994-04-30 | Г.В. Енютин | Method measuring surface friction |
| JPH0989693A (en) * | 1995-09-25 | 1997-04-04 | Denso Corp | Method and apparatus for measuring extremely small frictional force |
| CN113188652A (en) * | 2021-04-21 | 2021-07-30 | 西北工业大学 | Method and device for measuring acoustic radiation force in suspension sound field |
| CN215492356U (en) * | 2021-08-23 | 2022-01-11 | 哈尔滨工业大学（深圳） | Force measuring balance for measuring air friction resistance of curved surface boundary layer wall surface |
| CN114397050A (en) * | 2021-12-10 | 2022-04-26 | 西安理工大学 | Magnetic suspension type friction resistance measuring device |
| CN114216648A (en) * | 2022-02-21 | 2022-03-22 | 中国空气动力研究与发展中心超高速空气动力研究所 | High-frequency-response wide-range MEMS friction resistance sensor |
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