CN115266001A - Two-degree-of-freedom pneumatic elasticity experimental device - Google Patents

Two-degree-of-freedom pneumatic elasticity experimental device Download PDF

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Publication number
CN115266001A
CN115266001A CN202210807650.1A CN202210807650A CN115266001A CN 115266001 A CN115266001 A CN 115266001A CN 202210807650 A CN202210807650 A CN 202210807650A CN 115266001 A CN115266001 A CN 115266001A
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China
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linear
wind tunnel
sinking
floating
pitching
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Chinese (zh)
Inventor
高志鹰
赵保仲
汪建文
东雪青
马剑龙
温彩凤
白叶飞
张立茹
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Inner Mongolia University of Technology
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Inner Mongolia University of Technology
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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
    • G01M9/02—Wind tunnels
    • G01M9/04—Details
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
    • B64F5/00—Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
    • B64F5/60—Testing or inspecting aircraft components or systems
    • 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
    • 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
    • G01M9/08—Aerodynamic models
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Transportation (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)

Abstract

The invention relates to the field of wind tunnel tests of large wind turbine blades and aviation wings, in particular to a two-degree-of-freedom aeroelasticity experimental device which comprises a wind tunnel test model, a two-degree-of-freedom supporting mechanism and a signal acquisition system, wherein the two-degree-of-freedom supporting mechanism is connected with the wind tunnel test model; the wind tunnel experiment model comprises a wing section model, a piezometer tube, an end plate, a central torsion shaft, a locking mechanism and a mass center adjusting mechanism; the two-degree-of-freedom supporting mechanism comprises a wind tunnel fixing plate, a wind tunnel turbulence-resisting cover, a supporting plate, a linear bracket, an angular displacement sensor fixing flange, a torsion shaft fixing rod, a torsion supporting rod, a smooth linear straight rod, a sinking and floating elastic mechanism, a pitching linear spring, a pitching spring connecting column, a linear sliding bearing, an outer spherical bearing, a sinking and floating limiting device and a pitching limiting device. The invention can be used for researching the aeroelasticity characteristics of a wind tunnel experimental model under the supporting conditions of two degrees of freedom of pitching and sinking and floating, namely, the experimental device for researching the phenomena of flow separation, dynamic stall, flutter and the like on the surface of a wing section during aeroelasticity test.

Description

Two-degree-of-freedom pneumatic elasticity experimental device
Technical Field
The invention relates to the field of wind tunnel tests of large wind turbine blades and aviation wings, in particular to a two-degree-of-freedom aeroelasticity experimental device.
Background
At present, the wind turbine blades gradually develop towards large-scale and flexible directions, the blades with high aspect ratio are applied immediately, and in addition, the airplane wings also have high aspect ratio. These high aspect ratio blades and airfoils face problems caused by non-linear aeroelasticity, such as flutter.
Taking a flutter test of a wind turbine blade as an example, factors influencing the flutter of the blade are many, and the factors mainly comprise structural power parameters of the wind turbine blade, incoming flow characteristics and aerodynamic force borne by the wind turbine blade. In tests, movements of the wing are often involved in two degrees of freedom, and flow separation occurs on the surface of the wing in the event of flutter. From a structural fatigue perspective, predicting the vibration frequency and amplitude of pitch and heave associated with flutter is a major engineering task. Therefore, it is necessary to explore the fluid-solid coupling mechanical characteristics of the blade by using a two-degree-of-freedom aeroelasticity experimental device in a wind tunnel test.
Currently, aeroelastic models used in tests are wing section models with fixed mass centers, and measurement of aerodynamic characteristics of the surfaces of the wing sections is realized through a plurality of miniature pressure sensors arranged on the surfaces of wing sections. However, the model is limited to a single centroid position, the arrangement of the miniature pressure sensors on the surface of the wing panel is complex, and the protruding parts of the pressure sensors on the surface of the wing panel can influence the aerodynamic characteristics of the vicinity of the wing panel.
In addition, the aeroelastic model designed in the test at present needs to be integrally placed in the wind tunnel, so that the blocking effect of the wind tunnel is increased, and more importantly, the whole aerodynamic characteristics of the wing section are influenced because the supporting mechanism is exposed in the wind tunnel.
Disclosure of Invention
In order to solve the problems, the invention provides a two-degree-of-freedom aeroelasticity experimental device which can be used for researching aeroelasticity characteristics of a wind tunnel experimental model under the supporting conditions of two degrees of freedom of pitching and sinking, namely the experimental device for researching phenomena of flow separation, dynamic stall, flutter and the like on the surface of a wing section during aeroelasticity test.
In order to achieve the purpose, the invention adopts the technical scheme that:
a two-degree-of-freedom aeroelasticity experimental device comprises a wind tunnel experimental model, a two-degree-of-freedom supporting mechanism and a signal acquisition system;
the wind tunnel experimental model comprises a wing section model, 16-28 pressure measuring pipes, two end plates, a set of central torsion shaft, a set of locking mechanism and a set of mass center adjusting mechanism;
the wing section model is manufactured through 3D printing, a through hole for placing a bolt is designed in the wing section model, 8-14 pressure measuring holes with the diameter of 1.6mm are respectively designed on the upper surface and the lower surface of the midspan position of the wing section model, the 8-14 pressure measuring holes are all arranged along the normal direction of the surface of the wing section, the pressure measuring holes are connected with a pressure measuring pipe through an air flow channel designed in the wing section model, and the pressure measuring pipe extends out of the wind tunnel and is connected with a pressure transmitter;
the two end plates are manufactured through 3D printing, contain hollow designs with the same hollow shapes as the hollow shapes of the sections of the wing section models, and are connected to the two ends of the wing section models through locking mechanisms so as to prevent the end effect of the wing sections and ensure that the flow is quasi two-dimensional flow;
the set of central torsion shaft comprises a high-strength torsion shaft bolt, a torsion shaft locknut and an anti-slip sheet, wherein the high-strength torsion shaft bolt penetrates through the anti-slip sheet, the two end plates and a through hole reserved in the wing section model and used for placing a bolt, is connected with a torsion shaft fixing rod on the two-freedom-degree supporting mechanism and is fixed by the torsion shaft locknut, and one part of the anti-slip sheet is embedded into the end plate on one side far away from the supporting mechanism and is fixedly connected with the head of the high-strength torsion shaft bolt so as to prevent the central torsion shaft and the wing section model from sliding relatively;
the locking mechanism is positioned at the position, close to the rear edge, of the wing section model and comprises a fixing bolt and a locknut, the fixing bolt connects the wing section model and the two end plates together through the end plates and through holes, reserved in the wing section model, for placing bolts, and the fixing bolt is fixed by the locknuts;
the set of mass center adjusting mechanism comprises two conventional mass blocks, two eccentric mass blocks and a set of mass block fixing mechanism; the two conventional mass blocks are made of brass, holes are formed in the centers of the two conventional mass blocks, the two eccentric mass blocks are made of brass, holes are formed in the centers of the two eccentric mass blocks, and the weights of the eccentric mass blocks and the conventional mass blocks are the same; the two conventional mass blocks are used in combination and used for adjusting the mass center position of the wing section model to enable the mass center position to be closer to the center of the torsion shaft, so that the wing section model forms a three-center relative position relation of a pneumatic center and the center (gravity center) of the torsion shaft from the front edge to the rear edge; the two eccentric mass blocks are used in combination and used for adjusting the mass center position of the wing section model to enable the mass center position to be closer to the front edge of the wing section model, so that the wing section model forms a three-center relative position relation of a pneumatic power center-gravity center-torsion shaft center from the front edge to the rear edge; the conventional mass block is combined with an eccentric mass block for use, and is used for adjusting the mass center position of the wing section model to enable the mass center position to be closer to the rear edge of the wing section model, so that the wing section model forms a three-center relative position relation of a pneumatic power center-torsion shaft center-gravity center from the front edge to the rear edge; the set of mass block fixing mechanisms are composed of mass block fixing bolts and mass block locknuts, and two mass blocks are respectively fixed on end plates on two sides of the wing section model by the mass block fixing bolts and the mass block locknuts according to the requirements on different mass center positions in the test, so that the change of the mass center position of the wing section model is realized;
the two-degree-of-freedom supporting mechanism comprises a wind tunnel fixing plate, a wind tunnel turbulence-resisting cover, two supporting plates, two linear brackets, an angular displacement sensor fixing flange, a torsion shaft fixing rod, two torsion supporting rods, four smooth linear straight rods, four groups of sinking and floating elastic mechanisms, four groups of pitching linear springs, eight pitching spring connecting columns, eight linear sliding bearings, two spherical outside bearings, four groups of sinking and floating limiting devices and eight groups of pitching limiting devices;
the signal acquisition system comprises 16-28 pressure transmitters, an angular displacement sensor, a non-contact hysteresis telescopic displacement sensor and a set of multichannel data acquisition and analysis system, wherein the pressure measurement ends of the 16-28 pressure transmitters are respectively connected with pressure measurement pipes led out from a wind tunnel, the other ends of the pressure transmitters are respectively connected with a signal acquisition channel of the multichannel data acquisition instrument through strain signal input lines, the angular displacement sensor is fixed on an angular displacement sensor fixing flange and further connected with a matched shaft hole of a torsion shaft fixing rod, the signal output end of the angular displacement sensor is connected with the signal acquisition channel of the multichannel data acquisition instrument through the strain signal input lines and used for acquiring an instantaneous pitch angle signal of a wind tunnel experimental model, the non-contact hysteresis telescopic displacement sensor is connected with a wind tunnel fixing plate, and the distance between the non-contact hysteresis telescopic displacement sensor and a floating magnet fixed on a linear bracket is 2mm; the up-and-down motion of the wind tunnel experiment model drives the linear motion of the linear bracket to further drive the linear motion of the floating magnet, and the instantaneous sinking and floating displacement of the wind tunnel experiment model is measured by the sliding distance of the floating magnet on the measuring rod of the non-contact hysteresis telescopic displacement sensor. The signal output end of the non-contact hysteresis telescopic displacement sensor is connected to a signal acquisition channel of the multi-channel data acquisition instrument through a strain signal input line and is used for acquiring instantaneous sinking and floating displacement signals of the wind tunnel experimental model.
As a further design of the scheme, eight sets of pitching limiting devices are used for limiting the phenomenon of large displacement of the wind tunnel experiment model in the pitching motion process so as to prevent the damage of the two-degree-of-freedom supporting mechanism and the sensor system caused by excessive pitching displacement; each set of pitching limiting device is composed of a pitching limiting device metal fixing sheet, four pitching limiting device metal fixing sheet connecting bolts, a pitching limiting device rubber brake block, two pitching limiting device countersunk head connecting bolts and two pitching limiting device countersunk head connecting bolts matched nuts, wherein the eight pitching limiting device metal fixing sheets are fixed on the two linear brackets through the thirty-two pitching limiting device metal fixing sheet connecting bolts respectively, then the sixteen pitching limiting device countersunk head connecting bolts penetrate the eight pitching limiting device rubber brake blocks respectively, and the eight pitching limiting device metal fixing sheets are fixed on the eight pitching limiting device metal fixing sheets through the sixteen pitching limiting device countersunk head connecting bolts matched nuts
According to the further design of the scheme, the inlet end of an air flow channel inside the wing section model is in smooth connection with the pressure measuring hole, the outlet end of the air flow channel is located at the end part of the wing section model on one side provided with the supporting mechanism, then the pressure measuring pipe penetrates through the outlet end of the air flow channel at the end part of the wing section model, and then the pressure on the surface of the wing section model is led out to a pressure transmitter outside the wind tunnel. The pressure measuring holes and the air flow channels are designed with high precision by utilizing modeling software, and meanwhile, the machining precision of the solid wing section model is also ensured by the 3D printing technology.
As a further design of the scheme, the pressure measuring pipe is connected with an air flow channel in the wing section model through one end and sealed by sealant at a joint, and the other end is connected with a pressure measuring end of a pressure transmitter outside the wind tunnel, so that the surface pressure of the wing section model is measured.
As a further design of the scheme, anti-skidding grooves are arranged at the contact positions of the eccentric mass blocks and the end plates so as to prevent the eccentric mass blocks from sliding relative to the end plates in the motion process of the wing section model.
As a further design of the scheme, the wind tunnel fixing plate is used for fixing the two supporting plates, the wind tunnel turbulence resisting cover and the non-contact hysteresis telescopic displacement sensor, and is fixed on the side wall of the wind tunnel closed section through a wind tunnel fixing plate fixing bolt; the wind tunnel turbulence resisting cover is fixed on the wind tunnel fixing plate through a wind tunnel fixing plate fixing bolt, and a two-degree-of-freedom supporting mechanism outside the wind tunnel is covered inside the wind tunnel turbulence resisting cover and used for preventing the influence of an opening on the side wall of the wind tunnel on the airflow inside the wind tunnel; two backup pads include backup pad and bottom suspension fagging, fix on the wind-tunnel fixed plate through backup pad fixing bolt respectively, all be provided with the bolt hole of fixed ups and downs stop device and be used for the fixed recess of ups and downs elastic mechanism on last backup pad and the bottom suspension fagging, and go up and still be provided with the bolt hole of connecting smooth linear straight-bar on the backup pad, be provided with countersunk head bolt hole and the cylinder recess of connecting smooth linear straight-bar on two faces of bottom suspension fagging respectively.
As a further design of the scheme, the two linear brackets comprise an inner linear bracket and an outer linear bracket, the two linear brackets are both provided with through holes for penetrating through the smooth linear straight rod and the torsion shaft fixing rod and grooves for fixing an outer spherical surface bearing, a linear sliding bearing and a sinking-floating elastic mechanism, and are also provided with bolt holes for fixing a pitching spring connecting column and a pitching limiting device, and the outer linear bracket is also provided with bolt holes for fixing a fixing flange of the angular displacement sensor; the eight linear sliding bearings and the eight sinking and floating linear spring fixing seats are fixed in grooves formed in the linear brackets through sinking and floating elastic mechanism fixing bolts, and the two linear brackets are respectively suspended between the upper supporting plate and the lower supporting plate through four groups of sinking and floating elastic mechanisms; the middle parts of the two linear brackets are respectively provided with an outer spherical bearing, the torsion shaft fixing rod is connected with the linear brackets through the outer spherical bearings, the two linear brackets are respectively connected with eight pitching spring connecting columns and two torsion supporting rods through four groups of pitching linear springs, so that pitching restoring moment of the wind tunnel experiment model is provided, and floating magnets matched with the non-contact hysteresis telescopic displacement sensor for use are further installed on the side edges of the inner side linear brackets, so that sinking and floating motion data of the wind tunnel experiment model can be collected in real time.
According to the further design of the scheme, the angular displacement sensor fixing flange is fixed on the outer linear bracket, and the angular displacement sensor, the linear bracket and the torsion shaft fixing rod are fixed together, so that pitching motion of the wind tunnel experiment model can be measured while the wind tunnel experiment model makes ups and downs motion; one end of the torsion shaft fixing rod is provided with a torsion shaft fixing clamp, and the other end of the torsion shaft fixing rod is provided with a connector matched with the angular displacement sensor and respectively connected with the two linear brackets through the two spherical outside bearings; the torsion support rod vertically penetrates through the torsion shaft fixing rod and is fixed on the torsion shaft fixing rod through a torsion support rod fixing bolt, and the two torsion support rods and the eight pitching spring connecting columns are connected through four groups of pitching linear springs respectively. The pitching linear spring is used for converting pitching motion of the wind tunnel experiment model into linear motion of the pitching linear spring; one end of each of the four smooth linear straight rods is provided with a thread, and the other end of each of the four smooth linear straight rods is provided with a bolt hole; the four groups of sinking and floating elastic mechanisms comprise eight sinking and floating linear springs, sixteen sinking and floating linear spring fixing seats, sixty-four U-shaped bolts and sixty-four matched nuts of the U-shaped bolts. Each sinking-floating elastic mechanism fixes two ends of one sinking-floating linear spring on two sinking-floating linear spring fixing seats respectively through eight U-shaped bolts and eight nuts matched with the U-shaped bolts. And 8 sinking and floating linear springs in the four groups of sinking and floating elastic mechanisms are all preloaded extension springs. The one end of ups and downs elastic mechanism is connected in the backup pad through ups and downs elastic mechanism fixing bolt, the other end is connected on linear bracket through ups and downs elastic mechanism fixing bolt, and two ups and downs elastic mechanism are a set of mode, hang a linear bracket through two sets of ups and downs elastic mechanism, and then hang linear bracket and the wind tunnel experiment model of being connected with linear bracket between two backup pads from top to bottom, thereby receive the effort of air current and when carrying out the ups and downs motion of direction from top to bottom in the wind tunnel experiment model, provide the restoring force for the wind tunnel experiment model in the ups and downs motion. The four groups of pitching linear springs are pre-loaded extension springs, two pitching linear springs which are positioned on two sides of the torsion support rod on one side of the linear bracket are taken as a group, a torsion recovery moment is provided for the wind tunnel experiment model in pitching motion in a mode that one end of each pitching linear spring is fixed on a pitching spring connecting column, and the other end of each pitching linear spring is fixed on the torsion support rod penetrating through the torsion shaft fixing rod, and the eight pitching spring connecting columns are connected through threads and fixed on the two linear brackets and used for fixing the four groups of pitching linear springs; the eight linear sliding bearings are respectively connected with the sinking and floating linear spring fixing seats at one ends of the four groups of sinking and floating elastic mechanisms, the sinking and floating linear spring fixing seats with one ends of the sinking and floating elastic mechanisms connected with the linear sliding bearings are fixed in grooves formed in the inner linear bracket and the outer linear bracket by utilizing the sinking and floating elastic mechanism fixing bolts, so that the linear sliding bearings are fixedly connected with the linear brackets, and the eight linear sliding bearings are respectively fixed in the grooves at the connecting positions of the smooth linear straight rods and the linear brackets so as to reduce the friction force of the wind tunnel experimental model in the sinking and floating movement process; the two outer spherical bearings are respectively fixed at the connecting part of the torsion shaft fixing rod and the linear bracket so as to reduce the friction force of the wind tunnel experiment model in the pitching motion process; the four sets of sinking and floating limiting devices are used for limiting the large displacement phenomenon of the wind tunnel experimental model in the sinking and floating motion process so as to prevent the damage of the two-degree-of-freedom supporting mechanism and the sensor system caused by the overlarge sinking and floating displacement. Each set of sinking and floating limiting device consists of two sinking and floating limiting device metal supporting columns, a sinking and floating limiting device metal gasket, a sinking and floating limiting device rubber brake block and two sinking and floating limiting device countersunk head connecting bolts; wherein, the one end of the stop device metal support post that floats that sinks is provided with the screw thread, and the other end is provided with the bolt hole, and eight stop device metal support posts that float that sink are connected respectively in two upper and lower backup pads, then eight stop device countersunk head connecting bolt that float that sink pass four stop device rubber brake pads that float and four stop device metal gaskets that float that sink are connected in the bolt hole of eight stop device metal support post one side that float that sink respectively.
As a further design of the present solution, the set of multi-channel data acquisition and analysis system includes: 18-30 strain signal input lines, a multichannel data acquisition instrument and a PC end signal analysis system, wherein the 18-30 strain signal input lines are respectively used for connecting the output end of the sensor with the signal input end of the multichannel data acquisition instrument and transmitting the electric signals acquired by the sensor.
As a further design of the scheme, the multichannel data acquisition instrument is used for acquiring electric signals output by the sensor in the test process, the multichannel data acquisition instrument is connected with the PC end signal analysis system, the electric signals are converted into identifiable physical quantity to be detected, the PC end signal analysis system is used for analyzing and processing the electric signals acquired by the multichannel data acquisition instrument, and then a user can process and analyze the acquired physical quantity to be detected in real time.
Compared with the prior art, the invention has the following advantages:
1) The invention realizes the position change of the wing section model mass center position relative to the torsion shaft center through the design of the mass center adjusting mechanism, thereby conveniently exploring the influence of the structural characteristics of the wing section on the aerodynamic characteristics and the vibration characteristics of the wing section, and meeting the research requirements of wind tunnel experimental models at different mass center positions.
2) The invention adopts the design of the air flow channel type wing section model surface pressure measurement system, and realizes the pressure measurement of the span position of the wing section model surface under the condition that the wing section model surface has no protrusion and has no influence on the flow field of the area to be measured.
3) The design of the anti-slip sheet in the set of central torsion shaft can effectively prevent the wing panel model and the central torsion shaft from sliding relatively, thereby reducing the system error in the test.
4) The two-degree-of-freedom aeroelasticity experimental device can place the supporting mechanism and the motion measuring mechanism of the wind tunnel experimental model outside the wind tunnel, so that the blocking ratio of the wind tunnel is reduced, and the influence of objects except wing sections on the experimental result is reduced.
5) The two-freedom-degree supporting mechanism designed by the invention can reduce the mechanical friction of the wind tunnel experiment model during vibration to the minimum and further reduce the system error in the experiment because the linear sliding bearing is added in the sinking and floating freedom degree and the spherical outside bearing is added in the pitching freedom degree.
6) The torsion shaft fixing clamp at one end of the torsion shaft fixing rod can be used for randomly adjusting the attack angle of a wind tunnel experiment model when wind is not blown in a wind tunnel, and can provide various initial working conditions for experimental research.
7) The pitching and sinking-floating limiting device designed by the invention can effectively prevent the wind tunnel experimental model from damaging the two-freedom-degree supporting mechanism and the sensor system during large-amplitude vibration.
8) The two-degree-of-freedom supporting mechanism designed by the invention can effectively decouple the pitching-sinking and floating degrees of freedom, and meanwhile, under the condition that a wind tunnel experimental model experiences sinking and floating vibration with large amplitude, the sinking and floating linear spring is limited on the smooth linear straight rod, so that the obvious lateral inclination of the sinking and floating linear spring cannot occur, and the linear change of the geometric stiffness of the sinking and floating linear spring is also ensured.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic structural diagram of a wind tunnel experimental model of the present invention;
FIG. 3 is a schematic structural diagram of a two-degree-of-freedom support mechanism of the present invention;
FIG. 4 is a schematic diagram of a three-center relative position relationship of a wind tunnel experimental model of the present invention, in which the center of mass is adjusted by a center of mass adjusting mechanism, so that the wing section model forms a center of aerodynamic force-center of torsion axis center (center of gravity) from the leading edge to the trailing edge;
FIG. 5 is a schematic diagram of a wind tunnel experimental model of the present invention, in which the position of the center of mass is adjusted by a center of mass adjusting mechanism, so that the wing section model forms a three-center relative position relationship of aerodynamic center-of-gravity-center of torsion axis from the leading edge to the trailing edge;
FIG. 6 is a schematic diagram of a wind tunnel experimental model of the present invention, in which the position of the center of mass is adjusted by a center of mass adjusting mechanism, so that the wing section model forms a three-center relative position relationship of the aerodynamic center-the center of torsion axis-the center of gravity from the leading edge to the trailing edge;
FIG. 7 is a schematic view of a wing panel model connecting piezometer tube of the present invention;
FIG. 8 is a schematic view of a section air flow path of a panel model of the present invention;
FIG. 9 is a schematic view of a conventional proof mass of the present invention;
FIG. 10 is a schematic view of an eccentric mass of the present invention;
FIG. 11 is a partial schematic view of a two degree of freedom support mechanism of the present invention;
FIG. 12 is a schematic view of the connection of the floating-sinking elastic mechanism of the present invention with the support plate and the linear carriage;
FIG. 13 is a schematic view of a wind tunnel experimental model of the present invention connected to a two-degree-of-freedom support mechanism;
FIG. 14 is a schematic view of the sinking-floating limiting device of the present invention;
FIG. 15 is a schematic view of a pitch limiting device of the present invention;
fig. 16 is a schematic view of the sinking-floating elastic mechanism of the invention.
In the figure, 1-wind tunnel turbulence-resisting cover, 2-multichannel data acquisition instrument, 3-PC terminal signal analysis system, 4-pressure transmitter, 5-strain signal input line, 6-piezometer tube, 7-multichannel data acquisition instrument special network cable, 8-wind tunnel, 9-wing segment model, 10-end plate, 11-piezometer hole, 12-through hole for placing bolt, 13-high strength torsion shaft bolt, 14-antiskid sheet, 15-torsion shaft locknut, 16-fixing bolt, 17-locknut, 18-mass block fixing bolt, 19-mass block locknut, 20-conventional mass block, 21-eccentric mass block, 22-air flow channel, 23-wind tunnel fixing plate, 24-supporting plate, 25-linear bracket, 26-sinking and floating limiting device, 27-pitch limiting device, 28-angular displacement sensor fixing flange, 29-angular displacement sensor, 30-non-contact hysteresis telescopic displacement sensor, 31-floating magnet, 32-ups and downs elastic mechanism, 33-ups and downs linear spring, 34-ups and downs linear spring fixing seat, 35-U type bolt, 36-U type bolt matching nut, 37-pitch linear spring, 38-torsion support rod, 39-linear sliding bearing, 40-outer spherical bearing, 41-torsion shaft fixing rod, 42-pitch spring connecting column, 43-smooth linear straight rod, 44-torsion support rod fixing bolt, 45-ups and downs elastic mechanism fixing bolt, 46-outer spherical bearing fixing bolt, 47-floating magnet fixing bolt, 48-torsion shaft clamp fixing bolt, 49-support plate fixing bolt, 50-wind tunnel fixing plate fixing bolt, 51-ups and downs limiting device metal support column, 52-ups and downs limiting device metal gasket, 53-ups and downs limiting device rubber brake block, 54-ups and downs limiting device countersunk head connecting bolt, 55-pitches limiting device metal fixing plate, 56-pitches limiting device metal fixing plate connecting bolt, 57-pitches limiting device rubber brake block, 58-pitches limiting device countersunk head connecting bolt, 59-pitches limiting device countersunk head connecting bolt matching nut.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
As shown in fig. 1 to 16, a two-degree-of-freedom aeroelasticity experimental apparatus according to an embodiment of the present invention includes a wind tunnel experimental model, a two-degree-of-freedom supporting mechanism, and a signal acquisition system;
the wind tunnel experimental model comprises a wing section model 9, 16-28 piezometer tubes 6, two end plates 10, a set of central torsion shaft, a set of locking mechanism and a set of mass center adjusting mechanism;
the wing section model 9 is manufactured through 3D printing, a through hole 12 for placing a bolt is designed in the wing section model 9, 8-14 pressure measuring holes 11 with the diameter of 1.6mm are respectively designed on the upper surface and the lower surface of the midspan position of the wing section model 9, the 8-14 pressure measuring holes 11 are all along the normal direction of the surface of the wing section, the pressure measuring holes 11 are connected with a pressure measuring pipe 6 through an air flow passage 22 designed in the wing section model 9, and the pressure measuring pipe 6 extends out of the air tunnel 8 and is connected with a pressure transmitter 4;
the two end plates 10 are manufactured through 3D printing, comprise hollow designs with the same hollow shapes as the hollow shapes of the sections of the wing section models 9, and are fixedly connected to the two ends of the wing section models 9 through bolts so as to prevent the end effect of the wing sections and ensure that the flow is quasi two-dimensional flow;
the set of central torsion shaft comprises a high-strength torsion shaft bolt 13, a torsion shaft locknut 15 and an antiskid sheet 14, wherein the high-strength torsion shaft bolt 13 penetrates through the antiskid sheet 14, the two end plates 10 and a through hole 12 reserved in the wing section model 9 and used for placing a bolt, is connected with a torsion shaft fixing rod 41 on the two-degree-of-freedom supporting mechanism and is fixed by the torsion shaft locknut 15, wherein one part of the antiskid sheet 14 is embedded into the end plate far away from one side of the supporting mechanism and is fixedly connected with the head part of the high-strength torsion shaft bolt 13 so as to prevent the high-strength torsion shaft bolt 13 and the wing section model 9 from sliding relatively;
the set of locking mechanism is positioned at the position, close to the rear edge, of the wing section model 9 and comprises a fixing bolt 16 and a locknut 17, the fixing bolt 16 connects the wing section model 9 and the two end plates 10 together through the end plates 10 and through holes 12, reserved in the wing section model 9, for placing bolts, and the locknuts 17 are used for fixing;
the set of mass center adjusting mechanism comprises two conventional mass blocks 20, two eccentric mass blocks 21 and a set of mass block fixing mechanism; the two conventional mass blocks 20 are made of brass, holes are punched in the centers, the two eccentric mass blocks 21 are made of brass, holes are punched in the centers, and the weights of the eccentric mass blocks 21 and the conventional mass blocks 20 are the same; the two conventional mass blocks 20 are used in combination, and are used for adjusting the position of the mass center of the wing section model 9 to be closer to the center of the torsion shaft, so that the wing section model 9 forms a three-center relative position relation of an aerodynamic center and the center (gravity center) of the torsion shaft from the front edge to the rear edge; the two eccentric mass blocks 21 are used in combination for adjusting the position of the mass center of the wing section model 9 to be closer to the front edge of the wing section model 9 and enabling the wing section model 9 to form a three-center relative position relation of a pneumatic power center-a gravity center-a torsion shaft center from the front edge to the rear edge, and the conventional mass block 20 is used in combination with one eccentric mass block 21 for adjusting the position of the mass center of the wing section model 9 to be closer to the rear edge of the wing section model 9 and enabling the wing section model 9 to form a three-center relative position relation of a pneumatic power center-a torsion shaft center-a gravity center from the front edge to the rear edge; a set of mass block fixing mechanisms consists of mass block fixing bolts 18 and mass block locknuts 19, and two mass blocks are respectively fixed on the end plates 10 at two sides of the wing section model 9 by using the mass block fixing bolts 18 and the mass block locknuts 19 according to the requirements of different mass center positions in the test, so that the change of the mass center position of the wing section model 9 is realized;
the two-degree-of-freedom supporting mechanism comprises a wind tunnel fixing plate 23, a wind tunnel turbulence preventing cover 1, two supporting plates 24, two linear brackets 25, an angular displacement sensor fixing flange 28, a torsion shaft fixing rod 41, two torsion supporting rods 38, four smooth linear straight rods 43, four groups of ups and downs elastic mechanisms 32, four groups of pitching linear springs 37, eight pitching spring connecting columns 42, eight linear sliding bearings 39, two spherical outer bearings 40, four sets of ups and downs limiting devices 26 and eight sets of pitching limiting devices 27;
the signal acquisition system comprises 16-28 pressure transmitters 4, an angular displacement sensor 29, a non-contact hysteresis telescopic displacement sensor 30 and a set of multi-channel data acquisition and analysis system, wherein the pressure measurement ends of the 16-28 pressure transmitters 4 are respectively connected with a pressure measuring pipe 6 led out from a wind tunnel 8, the other ends of the pressure measuring pipes are respectively connected with a signal acquisition channel of the multi-channel data acquisition instrument 2 through a strain signal input line 5, the angular displacement sensor 29 is fixed on an angular displacement sensor fixing flange 28 and further connected with a matched shaft hole of a torsion shaft fixing rod 41, the signal output end of the non-contact hysteresis telescopic displacement sensor 30 is connected with the signal acquisition channel of the multi-channel angular displacement instrument 2 through a strain signal input line 5 and is used for acquiring an instantaneous pitch angle signal of a wind tunnel experimental model, the non-contact hysteresis telescopic displacement sensor 30 is connected on a wind tunnel fixing plate 23, and the distance between the non-contact hysteresis telescopic displacement sensor 30 and a floating magnet 31 fixed on a linear bracket 25 is 2mm; the linear bracket 25 is driven to move linearly by the up-and-down movement of the wind tunnel experimental model, so as to drive the floating magnet 31 to move linearly, and the instantaneous sinking and floating displacement of the wind tunnel experimental model is measured by the sliding distance of the floating magnet 31 on the measuring rod of the non-contact hysteresis telescopic displacement sensor 30. The signal output end of the non-contact hysteresis telescopic displacement sensor 30 is connected to a signal acquisition channel of the multichannel data acquisition instrument 2 through a strain signal input line 5, and is used for acquiring instantaneous sinking and floating displacement signals of the wind tunnel experiment model.
When being assembled, the method comprises the following steps: the assembly of the two-degree-of-freedom support mechanism is performed, specifically, first, the eight floating linear springs 33 are fixed on the sixteen floating linear spring fixing seats 34 by using sixty-four U-shaped bolts 35 and sixty-four U-shaped bolt mating nuts 36, respectively, and then four groups, that is, eight floating elastic mechanisms 32 are assembled. It should be noted that: the four groups of floating elastic mechanisms 32 are two floating elastic mechanisms 32 which are symmetrical up and down on each linear bracket 25, wherein each linear bracket 25 is suspended by the two groups of floating elastic mechanisms 32. Then four sets of ups and downs limiting device 26 are respectively installed on the upper supporting plate 24 and the lower supporting plate 24, each set of ups and downs limiting device 26 is composed of two ups and downs limiting device metal supporting columns 51, one ups and downs limiting device metal gasket 52, one ups and downs limiting device rubber brake block 53 and two ups and downs limiting device countersunk head connecting bolts 54, wherein one end of each ups and downs limiting device metal supporting column 51 is provided with a thread, the other end of each ups and downs limiting device metal supporting column 51 is provided with a bolt hole, the eight ups and downs limiting device metal supporting columns 51 are respectively connected to the upper supporting plate 24 and the lower supporting plate 24, and then the eight ups and downs limiting device countersunk head connecting bolts 54 respectively pass through the four ups and downs limiting device rubber brake blocks 53 and the four ups and downs limiting device metal gasket 52 and are connected to the bolt holes in one side of the eight ups and downs limiting device metal supporting columns 51. It should be noted that: two sets of sinking and floating limiting devices 26 are mounted on each supporting plate 24, and the sinking and floating limiting devices 26 on the upper supporting plate 24 and the lower supporting plate 24 are symmetrically arranged. The threaded ends of the four smooth linear straight rods 43 are then connected into the bolt holes reserved in the upper support plate. One end of each smooth linear straight rod 43 is provided with threads, the other end of each smooth linear straight rod 43 is provided with a bolt hole, a groove for fixing the sinking and floating elastic mechanism 32 is further formed in the upper supporting plate, then the four sinking and floating elastic mechanisms 32 respectively penetrate through 4 smooth linear straight rods 43, and the sinking and floating linear spring fixing seats 34 at one ends of the four sinking and floating elastic mechanisms 32 are fixed in the grooves in the upper supporting plate through sinking and floating elastic mechanism fixing bolts 45.
And secondly, the four linear sliding bearings 39 are respectively connected with the sinking and floating linear spring fixing seats 34 at the other ends of the four sinking and floating elastic mechanisms 32 connected to the upper supporting plate by penetrating the four smooth linear straight rods 43 connected with the upper supporting plate through holes arranged on the inner linear bracket 25 and the outer linear bracket 25, and the sinking and floating linear spring fixing seats 34 connected with the linear sliding bearings 39 are fixed in grooves arranged above the inner linear bracket 25 and the outer linear bracket 25 by utilizing sinking and floating elastic mechanism fixing bolts 45. The inner linear bracket referred to herein means a linear bracket on the side close to the wind tunnel fixing plate 23, and the outer linear bracket means a linear bracket on the side far from the wind tunnel fixing plate 23.
Then, the other four linear sliding bearings 39 are connected with the sinking and floating linear spring fixing seats 34 at one ends of the other four sinking and floating elastic mechanisms 32, then the connected sinking and floating elastic mechanisms 32 and the linear sliding bearings 39 penetrate through the four smooth linear straight rods 43 connected to the upper supporting plate, and the sinking and floating linear spring fixing seats 34 connected with the linear sliding bearings 39 are fixed in the grooves arranged below the inner linear bracket 25 and the outer linear bracket 25 by using the sinking and floating elastic mechanism fixing bolts 45.
And then installing the lower supporting plate fixed with the sinking-floating limiting device 26 at one end of the four smooth linear straight rods 43 with bolt holes, wherein four countersunk bolt holes and four cylindrical grooves for connecting the smooth linear straight rods 43 are respectively arranged on two surfaces of the lower supporting plate, wherein the four cylindrical grooves at the top of the lower supporting plate are used for connecting one ends of the bolt holes of the four smooth linear straight rods 43, and the four countersunk bolt holes at the bottom of the lower supporting plate are used for fixedly connecting the bolt holes at the bottom ends of the four smooth linear straight rods 43 through bolts. In addition, a groove for fixing the sinking-floating elastic mechanism 32 is also arranged on the lower supporting plate. And then the sinking and floating linear spring fixing seats 34 connected with the other ends of the four sinking and floating elastic mechanisms 32 below the inner and outer linear brackets 25 are fixed in the grooves on the lower supporting plate through the sinking and floating elastic mechanism fixing bolts 45.
The two spherical bearings 40 are then secured in the recesses on the outside of the inner and outer linear brackets 25, where the outside is the side of the inner linear bracket closer to the wind tunnel fixing plate 23 and the side of the outer linear bracket further from the wind tunnel fixing plate 23, by spherical bearing fixing bolts 46. Then, the torsion shaft fixing rod 41 passes through the two spherical outside bearings 40 and is tightly fitted with the bearings, and then the two torsion struts 38 vertically pass through two pre-arranged through holes in the front and rear of the torsion shaft fixing rod 41 and are fixed on the torsion shaft fixing rod 41 by the torsion strut fixing bolts 44. The through holes reserved in the front and back of the torsion shaft fixing rod 41 are all arranged at the same distance from the outer side surfaces of the inner linear bracket 25 and the outer linear bracket 25. Then, four groups of eight pitch spring connection columns 42 are respectively installed on the outer sides of the inner and outer linear brackets 25 through threaded connection, wherein two pitch spring connection columns 42 which are bilaterally symmetrical on one side of each linear bracket 25 are used as one group, and two groups of pitch spring connection columns 42 are symmetrically installed on each linear bracket 25 about the center of the section of the torsion shaft fixing rod 41. Then, the four groups of pitch linear springs 37 connect the four groups of pitch spring connection posts 42 with the two torsion struts 38, in which two groups of pitch linear springs 37 are mounted on each linear carriage 25 in a left-right symmetrical arrangement with respect to one side of each linear carriage 25. Then, eight sets of pitch limit devices 27 are respectively installed on the inner linear bracket 25 and the outer linear bracket 25, wherein four sets of pitch limit devices 27 are installed on the outer side of each linear bracket 25, every two sets of pitch limit devices are symmetrically installed on two sides of the torsion support rod 38, and the two sets of pitch limit devices 27 on each linear bracket 25 are respectively symmetrical about the cross-sectional center of the torsion shaft fixing rod 41. Each set of pitch limiting device 27 is composed of a pitch limiting device metal fixing piece 55, four pitch limiting device metal fixing piece connecting bolts 56, a pitch limiting device rubber brake block 57, two pitch limiting device countersunk head connecting bolts 58 and two pitch limiting device countersunk head connecting bolt matching nuts 59. The installation of a set of pitch limiting devices 27 is taken as an example for explanation: a pitch limiting device metal fixing plate 55 is fixed on a linear bracket 25 through four pitch limiting device metal fixing plate connecting bolts 56, then two pitch limiting device countersunk head connecting bolts 58 pass through a pitch limiting device rubber brake block 57, and are fixed on a pitch limiting device metal fixing plate 55 through two pitch limiting device countersunk head connecting bolt matching nuts 59. Then, the angular displacement sensor fixing flange 28 and the angular displacement sensor 29 are fixed by bolts, and then the angular displacement sensor fixing flange 28 to which the angular displacement sensor 29 is fixed by bolts to the outer linear bracket. Then, the floating magnet 31 used in cooperation with the non-contact hysteresis telescopic displacement sensor 30 is fixed on the inner side linear bracket by the floating magnet fixing bolt 47, then the non-contact hysteresis telescopic displacement sensor 30 is fixed on the wind tunnel fixing plate 23 by the bolt, then the assembled upper and lower two support plates 24 are fixed on the wind tunnel fixing plate 23 by the support plate fixing bolt 49, then the wind tunnel turbulence preventing cover 1 is connected on the wind tunnel fixing plate 23 by the wind tunnel fixing plate fixing bolt 50, and then the integral two-degree-of-freedom support mechanism is fixed on the outer side wall surface of the wind tunnel 8 by the wind tunnel fixing plate fixing bolt 50.
And then assembling the wind tunnel experiment model, specifically, firstly connecting the pressure measuring pipe 6 with an air flow passage 22 in the wing section model 9, and then sealing the interface between the air flow passage 22 of the wing section model 9 and the pressure measuring pipe 6 by using a sealant. 10 pressure measuring holes 11 with the diameter of 1.6mm are designed on the upper surface and the lower surface of the midspan position of the wing section model 9 respectively in a high-precision mode, the designed pressure measuring holes 11 are all along the normal direction of the surface of the wing section model 9, and the pressure measuring holes 11 are connected with the pressure measuring pipe 6 through an air flow channel 22 designed in the wing section model 9. The inlet end of the air flow channel 22 designed in the wing section model 9 is smoothly connected with the pressure measuring hole 11, and the outlet end of the air flow channel 22 is positioned at the end part of the wing section model 9 at one side provided with the two-degree-of-freedom supporting mechanism. The panel mould 9 is then secured to the end plates 10 by a set of central torsion shafts and a set of locking mechanisms. The two end plates 10 have hollow designs with the same hollow shapes as the hollow shapes of the sections of the wing section model 9 and are fixedly connected to the two ends of the wing section model 9 through bolts so as to prevent the end effect of the wing section model 9 and ensure that the flow is quasi-two-dimensional flow. The mentioned set of central torsion shaft includes a high strength torsion shaft bolt 13 and a torsion shaft locknut 15 and a slip-preventing plate 14, wherein a part of the slip-preventing plate 14 is embedded in the end plate on the side away from the support mechanism and is fixedly connected with the head of the high strength torsion shaft bolt 13 to prevent the relative sliding between the high strength torsion shaft bolt 13 and the wing section model 9. The mentioned set of locking mechanisms is located in the panel model 9 near the trailing edge and comprises a fixing bolt 16 and a locknut 17. The fixing bolt 16 connects the wing section model 9 and the two end plates 10 together through the end plates 10 and through holes 12 reserved inside the wing section model 9 for placing bolts, and is fixed by a locknut 17. And then fixing the high-strength torsion shaft bolt 13 of the connected wind tunnel experimental model at one end of the torsion shaft fixing clamp of the torsion shaft fixing rod 41 on the two-degree-of-freedom supporting mechanism by using a torsion shaft clamp fixing bolt 48. And then installing a mass center adjusting mechanism on the wing panel model 9, wherein one set of the mass center adjusting mechanism comprises two conventional mass blocks 20, two eccentric mass blocks 21 and one set of mass block fixing mechanism. Wherein the eccentric mass 21 has the same weight as the conventional mass 20. The mentioned eccentric mass 21 is of eccentric perforated design and the mentioned conventional mass 20 is of central perforated design, the masses being of brass material and being used for adjusting the position of the centre of mass of the panel mould 9. One set of mass block fixing mechanism comprises mass block fixing bolts 18 and mass block locknuts 19, and two mass blocks are respectively fixed on the end plates 10 on two sides of the wing section model 9 by utilizing the mass block fixing bolts 18 and the mass block locknuts 19, so that the positions of the mass blocks can be adjusted according to different mass center requirements in an experiment, and the effect of changing the mass center position is further achieved.
And finally, connecting the pressure measuring pipeline with a signal acquisition system, specifically, leading the other end of the pressure measuring pipe 6 connected with the air flow channel 22 of the wing section model 9 out of the wind tunnel 8 and connecting the other end with the pressure measuring end of the pressure transmitter 4, and then carrying out air tightness inspection on the connected pressure measuring channel by using the pressure transmitter 4 and a multi-channel data acquisition and analysis system. After ensuring that all pressure measuring channels are complete in air tightness, the angular displacement sensor 29 and the non-contact hysteresis telescopic displacement sensor 30 are connected with a multi-channel data acquisition and analysis system. Wherein multichannel data acquisition analytic system includes: strain signal input line 5, multichannel data acquisition instrument 2 and PC end signal analysis system 3. The mentioned strain signal input line 5 connects the sensor output end with the signal input end of the multichannel data acquisition instrument 2, and then the multichannel data acquisition instrument 2 is connected with the network cable interface end of the PC end through the network cable 7 special for the multichannel data acquisition instrument. Wherein strain signal input line 5 is used for transmitting the signal that the sensor was gathered, and multichannel data acquisition instrument 2 is arranged in gathering the signal of telecommunication of experimental in-process sensor output, and PC end signal analysis system 3 is used for the signal of telecommunication of analysis processing by multichannel data acquisition instrument 2 collection, and then the user can be in real time to the physical quantity that awaits measuring of gathering and handle the analysis.
To this end, the experimental apparatus designed by the present invention is installed, and the following will further describe the connected experimental apparatus by several embodiments:
example 1
The experimental study of the influence of the center of mass position of the wind turbine wing section model on flutter is taken as an example for operation explanation.
When the wind tunnel 8 does not blow, the high-precision digital inclinometer is fixed on the end plate 10 at one end of the wing section model 9 for a short time, then the angle of the high-strength torsion shaft bolt 13 relative to the torsion shaft fixing clamp at one end of the torsion shaft fixing rod 41 is adjusted, and then the wing section model 9 at three mass center positions is fixed at the same attack angle through the real-time inclination angle of the wing section model 9 displayed by the digital inclinometer, wherein the adjustment of the three mass center positions of the wing section model 9 is realized by adjusting the positions of the mass blocks in the mass center adjusting mechanism. For the two-degree-of-freedom aeroelasticity experimental device disclosed by the invention, three bolt through holes for fixing the mass block are arranged in the wing section model 9 and respectively correspond to three mass center positions of the wing section model 9, namely an aerodynamic center-torsion axis center (gravity center) (as shown in fig. 4); aerodynamic center-center of gravity-center of torsion axis center (as shown in fig. 5); aerodynamic center-torsion axis center-center of gravity (as shown in fig. 6). Under the three centroid positions, the ratio of the distance x between the centroid and the torsion shaft center to the airfoil chord length c is respectively 0, +0.0303 and-0.0623. Then, under different mass center positions, by gradually increasing the wind speed of the wind tunnel, the angular displacement sensor 29, the non-contact hysteresis telescopic displacement sensor 30 and the pressure transmitter 4 are used for collecting test data, then the electric signals collected by the sensors are transmitted to the multichannel data collector 2 through the strain signal input line 5, and finally the electric signals are analyzed and processed through the PC end signal analysis system 3 and the multichannel data collector 2, so that the signals are converted into instantaneous pitch angle, instantaneous sinking and floating displacement of the wing section model 9 and surface pressure signals of the wing section model 9 which need to be measured in the test. And then determining the flutter critical wind speed of the wing section model 9 at the three mass center positions by observing the vibration conditions of the wing section model 9 at the three mass center positions, and then recording pitching and sinking movement data and pressure signals of the surface of the wing section model 9 in a limit ring oscillation state. And finally, the influence of the mass center position of the wing section model 9 on the critical flutter speed is researched, so that the optimal mass center position of the wing section model 9 is found, and the control on the flutter boundary of the wing section model 9 is realized.
Example 2
The operation is described by taking the example of exploring the bifurcation behavior of airfoil stall flutter in a low-speed wind tunnel.
After the mass center position of the wing section model 9 is fixed by mounting the mass block on the wing section model 9, the attack angle of the wing section model 9 is adjusted to a certain angle when the wind tunnel 8 does not blow wind. And then, starting the wind tunnel 8, measuring the airflow pressure at the surface midspan position of the wing section model 9 by using the pressure transmitter 4, the pressure measuring pipe 6, the air flow passage 22 in the wing section model 9 and the pressure measuring hole 11, further measuring a pressure signal, and simultaneously combining the instantaneous pitch angle measured by the angular displacement sensor 29, further obtaining a change curve of the lift coefficient and the pitch moment coefficient of the wing section model 9 along with time. Meanwhile, the variation curve of the instantaneous pitching and heaving displacement of the wing section model 9 along with the time is combined to judge the vibration state experienced by the wing section model 9, and when the wing section model 9 vibrates to reach the stall flutter state, the variation relation of the limit ring vibration amplitude value experienced by the pitching angle (heaving displacement, lift coefficient and pitching moment coefficient) of the wing section model 9 along with the wind speed of the wind tunnel is recorded. And then changing the attack angle of the wing section model 9 under the windless condition, repeating the test steps, and finally obtaining the change relation of the limit ring vibration amplitude value experienced by the pitching angle (ups and downs displacement, lift coefficient and pitching moment coefficient) of a plurality of groups of wing section models 9 under different attack angles along with the wind speed of the wind tunnel, thereby further exploring the bifurcation behavior experienced by the wing section models 9 when the wing section models are in stall flutter.
Example 3
The operation is described by taking the phenomenon of flow separation on the surface of the wing when the wing stalls and flutters as an example.
After the mass center position of the wing section model 9 is fixed by mounting the mass block on the wing section model 9, the attack angle of the wing section model 9 is adjusted to a certain angle when the wind tunnel 8 does not blow wind. And then, starting the wind tunnel 8, and when the wing section model 9 vibrates to reach a stall flutter state, measuring the airflow pressure at the mid-span position of the surface of the wing section model 9 by using the pressure transmitter 4, the pressure measuring pipe 6, the air flow channel 22 inside the wing section model 9 and the pressure measuring hole 11, further researching the change condition of the upper and lower surface pressure coefficients of the wing section model 9 along with the wing section chord length when the wing section model 9 undergoes different pitch angles, and further analyzing the aerodynamic characteristics of the surface of the wing section model 9. In addition, the flow separation condition of the surface of the wing section model 9 can be further researched by combining a particle image velocimetry technology, so that the comparison and comparison are carried out on the pressure change trend of the surface of the wing section model 9 measured by the pressure transmitter 4, and the mechanism of inducing the stall flutter of the wing section model 9 is further researched.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims (10)

1. The two-degree-of-freedom aeroelasticity experimental device is characterized in that: the device comprises a wind tunnel experiment model, a two-degree-of-freedom supporting mechanism and a signal acquisition system;
the wind tunnel experimental model comprises a wing section model, 16-28 pressure measuring pipes, two end plates, a set of central torsion shaft, a set of locking mechanism and a set of mass center adjusting mechanism;
the wing section model is manufactured through 3D printing, a through hole for placing a bolt is designed in the wing section model, 8-14 pressure measuring holes with the diameter of 1.6mm are respectively designed on the upper surface and the lower surface of the middle position of the wing section model span, the 8-14 pressure measuring holes are all arranged along the normal direction of the wing section surface, the pressure measuring holes are connected with a pressure measuring pipe through an air flow channel designed in the wing section model, and the pressure measuring pipe extends out of the wind tunnel and is connected with a pressure transmitter;
the two end plates are manufactured through 3D printing, contain hollow designs with the same hollow shapes as the section of the wing section model, and are connected to the two ends of the wing section model through locking mechanisms so as to prevent the end effect of the wing section and ensure that the flow is quasi two-dimensional flow;
the set of central torsion shaft comprises a high-strength torsion shaft bolt, a torsion shaft locknut and an anti-slip sheet, wherein the high-strength torsion shaft bolt penetrates through the anti-slip sheet, the two end plates and a through hole reserved in the wing section model and used for placing a bolt, is connected with a torsion shaft fixing rod on the two-freedom-degree supporting mechanism and is fixed by the torsion shaft locknut, and one part of the anti-slip sheet is embedded into the end plate on one side far away from the supporting mechanism and is fixedly connected with the head of the high-strength torsion shaft bolt so as to prevent the central torsion shaft and the wing section model from sliding relatively;
the locking mechanism is positioned at the position, close to the rear edge, of the wing section model and comprises a fixing bolt and a locknut, the fixing bolt connects the wing section model and the two end plates together through the end plates and through holes, reserved in the wing section model, for placing bolts, and the fixing bolt is fixed by the locknuts;
the set of mass center adjusting mechanism comprises two conventional mass blocks, two eccentric mass blocks and a set of mass block fixing mechanism; the two conventional mass blocks are made of brass, holes are formed in the centers of the two conventional mass blocks, the two eccentric mass blocks are made of brass, holes are formed in the centers of the two eccentric mass blocks, and the weights of the eccentric mass blocks and the conventional mass blocks are the same; the two conventional mass blocks are used in combination and used for adjusting the mass center position of the wing section model to enable the mass center position to be closer to the center of the torsion shaft, so that the wing section model forms a three-center relative position relation of a pneumatic center and the center of the torsion shaft from the front edge to the rear edge; the two eccentric mass blocks are used in combination and used for adjusting the mass center position of the wing section model to enable the mass center position to be closer to the front edge of the wing section model, so that the wing section model forms a three-center relative position relation of a pneumatic power center-gravity center-torsion shaft center from the front edge to the rear edge; the conventional mass block is combined with an eccentric mass block for use, and is used for adjusting the mass center position of the wing section model to enable the mass center position to be closer to the rear edge of the wing section model, so that the wing section model forms a three-center relative position relation of a pneumatic power center-torsion shaft center-gravity center from the front edge to the rear edge; the set of mass block fixing mechanisms are composed of mass block fixing bolts and mass block locknuts, and two mass blocks are respectively fixed on end plates on two sides of the wing section model by the mass block fixing bolts and the mass block locknuts according to the requirements on different mass center positions in the test, so that the change of the mass center position of the wing section model is realized;
the two-degree-of-freedom supporting mechanism comprises a wind tunnel fixing plate, a wind tunnel turbulence-resisting cover, two supporting plates, two linear brackets, an angular displacement sensor fixing flange, a torsion shaft fixing rod, two torsion supporting rods, four smooth linear straight rods, four groups of ups and downs elastic mechanisms, four groups of pitching linear springs, eight pitching spring connecting columns, eight linear sliding bearings, two spherical outside surface bearings, four sets of ups and downs limiting devices and eight sets of pitching limiting devices;
the signal acquisition system comprises 16-28 pressure transmitters, an angular displacement sensor, a non-contact hysteresis telescopic displacement sensor and a set of multichannel data acquisition and analysis system, wherein the pressure measurement ends of the 16-28 pressure transmitters are respectively connected with pressure measurement pipes led out from a wind tunnel, the other ends of the pressure transmitters are respectively connected with a signal acquisition channel of the multichannel data acquisition instrument through strain signal input lines, the angular displacement sensor is fixed on an angular displacement sensor fixing flange and further connected with a matched shaft hole of a torsion shaft fixing rod, the signal output end of the angular displacement sensor is connected with the signal acquisition channel of the multichannel data acquisition instrument through the strain signal input lines and used for acquiring an instantaneous pitch angle signal of a wind tunnel experimental model, the non-contact hysteresis telescopic displacement sensor is connected with a wind tunnel fixing plate, and the distance between the non-contact hysteresis telescopic displacement sensor and a floating magnet fixed on a linear bracket is 2mm; the up-and-down motion through the wind tunnel experiment model drives the linear motion of linear bracket and then drives the linear motion of floating magnet, and then measure the instantaneous ups and downs displacement of wind tunnel experiment model through the gliding distance of floating magnet on non-contact hysteresis extension displacement sensor's measuring staff, non-contact hysteresis extension displacement sensor's signal output part is connected on the signal acquisition passageway of multichannel data acquisition instrument through the signal input line that meets an emergency for gather the instantaneous ups and downs displacement signal of wind tunnel experiment model.
2. The two-degree-of-freedom aeroelasticity experimental device as claimed in claim 1, wherein: the inlet end of an air flow channel in the wing section model is in smooth connection with a pressure measuring hole, the outlet end of the air flow channel is located at the end part of the wing section model on one side provided with the supporting mechanism, and then the pressure of the surface of the wing section model is led out to a pressure transmitter located outside the wind tunnel by penetrating a pressure measuring pipe into the outlet end of the air flow channel at the end part of the wing section model.
3. The two-degree-of-freedom aeroelasticity experimental device as claimed in claim 1, wherein: the pressure measuring pipe is connected with an air flow channel inside the wing section model through one end and sealed by sealant at a joint, and the other end of the pressure measuring pipe is connected with a pressure measuring end of a pressure transmitter outside the wind tunnel, so that the surface pressure of the wing section model is measured.
4. The two-degree-of-freedom aeroelasticity experimental device as claimed in claim 1, wherein: the contact positions of the eccentric mass block and the end plate are provided with anti-skidding grooves so as to prevent the eccentric mass block from sliding relative to the end plate in the motion process of the wing section model.
5. The two-degree-of-freedom aeroelasticity experimental apparatus as claimed in claim 1, wherein: the wind tunnel fixing plate is used for fixing the two supporting plates, the wind tunnel anti-turbulence cover and the non-contact hysteresis telescopic displacement sensor, and is fixed on the side wall of the wind tunnel closed section through a wind tunnel fixing plate fixing bolt; the wind tunnel turbulence resisting cover is fixed on the wind tunnel fixing plate through a wind tunnel fixing plate fixing bolt, and a two-degree-of-freedom supporting mechanism outside the wind tunnel is covered inside the wind tunnel turbulence resisting cover and used for preventing the influence of an opening on the side wall of the wind tunnel on the airflow inside the wind tunnel; two backup pads include backup pad and bottom suspension fagging, fix on the wind-tunnel fixed plate through backup pad fixing bolt respectively, all be provided with the bolt hole of fixed ups and downs stop device and be used for the fixed recess of ups and downs elastic mechanism on last backup pad and the bottom suspension fagging, and go up and still be provided with the bolt hole of connecting smooth linear straight-bar on the backup pad, be provided with countersunk head bolt hole and the cylinder recess of connecting smooth linear straight-bar on two faces of bottom suspension fagging respectively.
6. The two-degree-of-freedom aeroelasticity experimental device as claimed in claim 1, wherein: the two linear brackets comprise an inner linear bracket and an outer linear bracket, the two linear brackets are respectively provided with a through hole for penetrating through the smooth linear straight rod and the torsion shaft fixing rod and a groove for fixing an outer spherical surface bearing, a linear sliding bearing and a sinking-floating elastic mechanism, in addition, a bolt hole for fixing a pitching spring connecting column and a pitching limiting device is also arranged, and the outer linear bracket is also provided with a bolt hole for fixing a fixing flange of the angular displacement sensor; the eight linear sliding bearings and the eight sinking and floating linear spring fixing seats are fixed in grooves formed in the linear brackets through sinking and floating elastic mechanism fixing bolts, and the two linear brackets are respectively suspended between the upper supporting plate and the lower supporting plate through four groups of sinking and floating elastic mechanisms; the middle parts of the two linear brackets are respectively provided with an outer spherical bearing, the torsion shaft fixing rod is connected with the linear brackets through the outer spherical bearings, the two linear brackets are respectively connected with eight pitching spring connecting columns and two torsion supporting rods through four groups of pitching linear springs, so that pitching restoring moment of the wind tunnel experiment model is provided, and floating magnets matched with the non-contact hysteresis telescopic displacement sensor for use are further installed on the side edges of the inner side linear brackets, so that sinking and floating motion data of the wind tunnel experiment model can be collected in real time.
7. The two-degree-of-freedom aeroelasticity experimental apparatus as claimed in claim 1, wherein: the eight pitching limiting devices are used for limiting the large displacement phenomenon of the wind tunnel experiment model in the pitching motion process so as to prevent the damage of the two-degree-of-freedom supporting mechanism and the sensor system caused by the overlarge pitching displacement; each set of pitching limiting device is composed of a pitching limiting device metal fixing piece, four pitching limiting device metal fixing piece connecting bolts, a pitching limiting device rubber brake block, two pitching limiting device countersunk head connecting bolts and two pitching limiting device countersunk head connecting bolt matching nuts, wherein the eight pitching limiting device metal fixing pieces are fixed on the two linear brackets through thirty-two pitching limiting device metal fixing piece connecting bolts respectively, then the sixteen pitching limiting device countersunk head connecting bolts penetrate through the eight pitching limiting device rubber brake blocks respectively, and are fixed on the eight pitching limiting device metal fixing pieces through the sixteen pitching limiting device countersunk head connecting bolt matching nuts.
8. The two-degree-of-freedom aeroelasticity experimental apparatus as claimed in claim 1, wherein: the angular displacement sensor fixing flange is fixed on the outer linear bracket, and the angular displacement sensor, the linear bracket and the torsion shaft fixing rod are fixed together, so that pitching motion of the wind tunnel experiment model can be measured while the wind tunnel experiment model performs sinking and floating motion; one end of the torsion shaft fixing rod is provided with a torsion shaft fixing clamp, and the other end of the torsion shaft fixing rod is provided with a connecting port matched with the angular displacement sensor and respectively connected with the two linear brackets through two spherical outside bearings; the torsion strut vertically penetrates through the torsion shaft fixing rod, is fixed on the torsion shaft fixing rod through a torsion strut fixing bolt, and is respectively connected with two torsion struts and eight pitching spring connecting columns through four groups of pitching linear springs for converting the pitching motion of the wind tunnel experiment model into the linear motion of the pitching linear springs; one end of each of the four smooth linear straight rods is provided with a thread, and the other end of each of the four smooth linear straight rods is provided with a bolt hole; the four groups of sinking and floating elastic mechanisms comprise eight sinking and floating linear springs, sixteen sinking and floating linear spring fixing seats, sixty-four U-shaped bolts and sixty-four matched nuts of the U-shaped bolts, wherein each sinking and floating elastic mechanism respectively fixes two ends of one sinking and floating linear spring on the two sinking and floating linear spring fixing seats through the eight U-shaped bolts and the eight matched nuts of the U-shaped bolts, 8 sinking and floating linear springs in the four groups of sinking and floating elastic mechanisms adopt pre-loaded extension springs, one end of each sinking and floating elastic mechanism is connected on a supporting plate through a sinking and floating elastic mechanism fixing bolt, the other end of each sinking and floating elastic mechanism is connected on a linear bracket through a sinking and floating elastic mechanism fixing bolt, and the two groups of sinking and floating elastic mechanisms form a group, and one linear bracket is suspended through the two groups of sinking and floating elastic mechanisms, the linear bracket and the wind tunnel experiment model connected with the linear bracket are suspended between an upper supporting plate and a lower supporting plate, so that when the wind tunnel experiment model is subjected to the action force of air flow in a wind tunnel to perform up-and-down sinking and floating movement, restoring force is provided for the wind tunnel experiment model in the sinking and floating movement, four groups of pitching linear springs adopt preloaded extension springs, two pitching linear springs positioned at two sides of a torsion support rod on one side of the linear bracket are taken as one group, torsion restoring moment is provided for the wind tunnel experiment model in the pitching movement in a mode that one end of each pitching linear spring is fixed on a pitching spring connecting column, and the other end of each pitching linear spring connecting column is fixed on the torsion support rod penetrating through a torsion shaft fixing rod, and eight pitching spring connecting columns are connected through threads and fixed on the two linear brackets and are used for fixing the four groups of pitching linear springs; the eight linear sliding bearings are respectively connected with the sinking-floating linear spring fixing seats at one ends of the four groups of sinking-floating elastic mechanisms, the sinking-floating linear spring fixing seats with one ends of the sinking-floating elastic mechanisms connected with the linear sliding bearings are fixed in grooves formed in the inner linear bracket and the outer linear bracket by utilizing the sinking-floating elastic mechanism fixing bolts, so that the linear sliding bearings are fixedly connected with the linear brackets, and the eight linear sliding bearings are respectively fixed in the grooves at the connecting positions of the smooth linear straight rods and the linear brackets so as to reduce the friction force of the wind tunnel test model in the sinking-floating motion process; the two outer spherical bearings are respectively fixed at the connecting part of the torsion shaft fixing rod and the linear bracket so as to reduce the friction force of the wind tunnel experiment model in the pitching motion process; the four sets of sinking and floating limiting devices are used for limiting the large displacement phenomenon of the wind tunnel experimental model in the sinking and floating movement process so as to prevent the damage of the two-degree-of-freedom supporting mechanism and the sensor system caused by the excessive sinking and floating displacement; each set of sinking and floating limiting device consists of two sinking and floating limiting device metal supporting columns, a sinking and floating limiting device metal gasket, a sinking and floating limiting device rubber brake block and two sinking and floating limiting device countersunk head connecting bolts; wherein, the one end of the stop device metal support post that floats that sinks is provided with the screw thread, and the other end is provided with the bolt hole, and eight stop device metal support posts that float that sink are connected respectively in two upper and lower backup pads, then eight stop device countersunk head connecting bolt that float that sink pass four stop device rubber brake pads that float and four stop device metal gaskets that float that sink are connected in the bolt hole of eight stop device metal support post one side that float that sink respectively.
9. The two-degree-of-freedom aeroelasticity experimental device as claimed in claim 1, wherein: the set of multi-channel data acquisition and analysis system comprises: 18-30 strain signal input lines, a multichannel data acquisition instrument, PC end signal analysis system, 18-30 strain signal input lines are connected the signal input end of sensor output end and multichannel data acquisition instrument respectively for the signal of telecommunication that the transmission sensor was gathered.
10. The two-degree-of-freedom aeroelasticity experimental device as claimed in claim 1, wherein: the multichannel data acquisition instrument is used for acquiring electric signals output by the sensor in the test process, and the multichannel data acquisition instrument is connected with the PC end signal analysis system to convert the electric signals into identifiable physical quantity to be detected, the PC end signal analysis system is used for analyzing and processing the electric signals acquired by the multichannel data acquisition instrument, and then a user can process and analyze the acquired physical quantity to be detected in real time.
CN202210807650.1A 2022-07-12 2022-07-12 Two-degree-of-freedom pneumatic elasticity experimental device Pending CN115266001A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
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CN115585978A (en) * 2022-12-09 2023-01-10 中国航空工业集团公司沈阳空气动力研究所 Test device for two-degree-of-freedom motion of transonic wind tunnel
CN116499689A (en) * 2023-06-20 2023-07-28 中国空气动力研究与发展中心高速空气动力研究所 Large-scale wind tunnel beam supporting device convenient to disassemble and assemble for scale effect test
CN116754172A (en) * 2023-08-17 2023-09-15 中国航空工业集团公司沈阳空气动力研究所 High Mach number free inflow wind tunnel flutter test system and test method
CN117686176A (en) * 2024-02-04 2024-03-12 中国空气动力研究与发展中心高速空气动力研究所 Temporary flushing supersonic wind tunnel flutter test device and method

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115585978A (en) * 2022-12-09 2023-01-10 中国航空工业集团公司沈阳空气动力研究所 Test device for two-degree-of-freedom motion of transonic wind tunnel
CN115585978B (en) * 2022-12-09 2023-03-14 中国航空工业集团公司沈阳空气动力研究所 Test device for two-degree-of-freedom motion of transonic wind tunnel
CN116499689A (en) * 2023-06-20 2023-07-28 中国空气动力研究与发展中心高速空气动力研究所 Large-scale wind tunnel beam supporting device convenient to disassemble and assemble for scale effect test
CN116499689B (en) * 2023-06-20 2023-09-01 中国空气动力研究与发展中心高速空气动力研究所 Large-scale wind tunnel beam supporting device convenient to disassemble and assemble for scale effect test
CN116754172A (en) * 2023-08-17 2023-09-15 中国航空工业集团公司沈阳空气动力研究所 High Mach number free inflow wind tunnel flutter test system and test method
CN116754172B (en) * 2023-08-17 2023-11-03 中国航空工业集团公司沈阳空气动力研究所 High Mach number free inflow wind tunnel flutter test system and test method
CN117686176A (en) * 2024-02-04 2024-03-12 中国空气动力研究与发展中心高速空气动力研究所 Temporary flushing supersonic wind tunnel flutter test device and method

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