CN115266001A - A two-degree-of-freedom aeroelasticity experimental device - Google Patents

Abstract

The invention relates to the field of wind tunnel testing of large-scale wind turbine blades and aviation wings, in particular to a two-degree-of-freedom aeroelasticity experimental device, comprising a wind-tunnel experimental model, a two-degree-of-freedom support mechanism, and a signal acquisition system; the wind tunnel experimental model includes Wing segment model, pressure measuring tube, end plate, central torsion axis, locking mechanism and center of mass adjustment mechanism; two-degree-of-freedom support mechanism includes wind tunnel fixing plate, wind tunnel anti-turbulence cover, support plate, linear bracket, angular displacement Sensor fixing flange, torsion shaft fixing rod, torsion support rod, smooth linear straight rod, ups and downs elastic mechanism, pitching linear spring, pitching spring connecting column, linear sliding bearing, outer spherical bearing, ups and downs limit device and pitch limit device. The invention can be used to study the aeroelastic characteristics of the wind tunnel experimental model under the support conditions of pitch and ups and downs, that is, an experimental device for exploring the surface flow separation, dynamic stall, flutter and other phenomena of the wing section during the aeroelastic test.

Description

A two-degree-of-freedom aeroelasticity experimental device

technical field

The invention relates to the field of wind tunnel testing of large wind turbine blades and aviation wings, in particular to a two-degree-of-freedom aeroelasticity experimental device.

Background technique

At present, wind turbine blades are gradually developing in the direction of large size and flexibility, and blades with high aspect ratios are applied immediately. In addition, aircraft wings also have high aspect ratios. These high-aspect-ratio blades and wings face many problems caused by nonlinear aeroelasticity, such as flutter phenomena.

Taking the flutter test of wind turbine blades as an example, there are many factors that affect the flutter of the blades, mainly including the structural dynamic parameters of the rotor blades, the characteristics of incoming flow and the aerodynamic force on the rotor blades. In the test, the movement of two degrees of freedom of the airfoil is often involved. In addition, when the flutter occurs, the surface of the airfoil will also appear flow separation. From a structural fatigue point of view, predicting the vibration frequencies and amplitudes of pitching and heaving associated with flutter is a major engineering task. Therefore, it is very necessary to use a two-degree-of-freedom aeroelastic experimental device to explore the mechanical characteristics of the fluid-solid interaction of the blade in the wind tunnel test.

The aeroelastic models currently used in the test are all airfoil models with a fixed center of mass, and the measurement of the aerodynamic characteristics of the airfoil surface is realized by a number of miniature pressure sensors arranged on the airfoil surface. However, this model is limited to a single centroid position, and the arrangement of micro pressure sensors on the surface of the wing section is relatively complicated, and the protruding part of the pressure sensor on the surface of the wing section will also have a certain impact on the aerodynamic characteristics near the wing section.

In addition, the aeroelastic model currently designed in the test needs to place the device as a whole in the wind tunnel, which will not only increase the blocking effect of the wind tunnel, but more importantly, will cause damage to the airfoil due to the exposure of the support mechanism to the wind tunnel. affect the overall aerodynamic characteristics.

Contents of the invention

In order to solve the above problems, the present invention provides a two-degree-of-freedom aeroelastic experimental device, which can be used to study the aeroelastic characteristics of the wind tunnel experimental model under the two-degree-of-freedom support conditions of pitch and ups and downs, that is, to explore when performing aeroelasticity tests. Experimental device for flow separation on the surface of wing section and phenomena such as dynamic stall and flutter.

In order to achieve the above object, the technical scheme that the present invention takes is:

A two-degree-of-freedom aeroelasticity experimental device, including a wind tunnel experimental model, a two-degree-of-freedom support mechanism, and a signal acquisition system;

The wind tunnel experiment model includes a wing section model, 16-28 piezometric tubes, two end plates, a set of central torsion shafts, a set of locking mechanisms, and a set of center-of-mass adjustment mechanisms;

The wing section model is manufactured by 3D printing. There are through holes for placing bolts inside the wing section model, and 8 to 14 pressure measuring holes with a diameter of 1.6mm are designed on the upper and lower surfaces of the wing section model at the mid-span position. , 8 to 14 pressure measuring holes are all along the normal direction of the airfoil surface. The pressure measuring holes are connected to the pressure measuring tube through the air channel designed inside the airfoil model, and the pressure measuring tube extends outside the wind tunnel to connect with the pressure transmitter. device to connect;

The two end plates are manufactured by 3D printing, which have the same hollow design as the cross section of the wing section model, and are connected to both ends of the wing section model through a locking mechanism to prevent the end effect of the wing section and ensure the flow is a quasi-two-dimensional flow;

The set of central torsion shaft includes a high-strength torsion shaft bolt, a torsion shaft locknut and an anti-slip sheet, and the high-strength torsion shaft bolt passes through the anti-slip sheet, two end plates and the reserved space inside the wing model The through hole of the bolt is connected with the torsion shaft fixing rod on the two-degree-of-freedom support mechanism, and is fixed with the torsion shaft locknut, wherein a part of the anti-slip sheet is embedded in the end plate on the side away from the support mechanism, and is connected with the high-strength torsion The head of the shaft bolt is fixedly connected to prevent relative sliding between the central torsion shaft and the wing model;

The set of locking mechanisms is located near the trailing edge of the wing section model, and includes fixing bolts and locknuts. The fixing bolts connect the wing section model and the two bolts through the end plate and the through holes reserved inside the wing section model for placing bolts. The two end plates are connected together and fixed with locknuts;

The set of center-of-mass adjustment mechanism includes 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, with a hole in the center, and the two eccentric mass blocks are made of brass Material, eccentric drilling, the weight of the eccentric mass is the same as that of the conventional mass; the combination of two conventional masses is used to adjust the position of the center of mass of the wing section model, making it closer to the center of the torsion axis, so that the wing section model is from the leading edge to the rear The three-center relative position relationship between the aerodynamic center and the torsion axis center (center of gravity) is formed by the edge; two eccentric mass blocks are used in combination to adjust the position of the center of mass of the wing section model, making it closer to the leading edge of the wing section model, so that the wing section model From the leading edge to the trailing edge, a three-center relative position relationship of aerodynamic center-center of gravity-torsion axis center is formed; a conventional mass block and an eccentric mass block are used in combination to adjust the position of the center of mass of the wing section model to make it closer to the wing section model trailing edge, so that the airfoil model forms a three-center relative position relationship of aerodynamic center-torsion axis center-center of gravity from the leading edge to the trailing edge; a set of mass block fixing mechanism is composed of mass block fixing bolts and mass block locknuts. To meet the requirements of different centroid positions in the test, use the mass block fixing bolts and mass block locknuts to fix the two mass blocks on the end plates on both sides of the wing section model, so as to realize the change of the position of the wing section model's center of mass;

The two-degree-of-freedom support mechanism includes a wind tunnel fixing plate, a wind tunnel anti-turbulence cover, two supporting plates, two linear brackets, a fixing flange for an angular displacement sensor, a torsion shaft fixing rod, two torsion Support rods, four smooth linear straight rods, four sets of sinking and floating elastic mechanisms, four sets of pitching linear springs, eight pitching spring connecting columns, eight linear sliding bearings, two outer spherical bearings, four sets of sinking and floating limit devices and eight sets of Pitch limit device;

The signal acquisition system includes 16 to 28 pressure transmitters, an angular displacement sensor, a non-contact magnetic hysteresis displacement sensor and a set of multi-channel data acquisition and analysis system, the pressure measurement of 16 to 28 pressure transmitters One end is respectively connected with the pressure measuring tube drawn from the wind tunnel, and the other end is respectively connected to the signal acquisition channel of the multi-channel data acquisition instrument through the strain signal input line, and the angular displacement sensor is fixed on the fixed flange of the angular displacement sensor, and then connected with the The supporting shaft hole of the torsion shaft fixed rod is connected, and the signal output end of the angular displacement sensor is connected to the signal acquisition channel of the multi-channel data acquisition instrument through the strain signal input line, which is used to acquire the instantaneous pitch angle signal of the wind tunnel experimental model, which is not The contact type hysteresis stretching displacement sensor is connected to the fixed plate of the wind tunnel, and the distance between it and the floating magnet fixed on the linear bracket is 2mm; the up and down movement of the wind tunnel test model drives the linear movement of the linear bracket and then drives the floating magnet. Linear movement, through the sliding distance of the floating magnet on the measuring rod of the non-contact magneto-hysteretic displacement sensor, and then measure the instantaneous ups and downs displacement of the wind tunnel experimental model. The signal output end of the non-contact hysteresis stretching displacement sensor is connected to the signal acquisition channel of the multi-channel data acquisition instrument through the strain signal input line, and is used to acquire the instantaneous ups and downs displacement signals of the wind tunnel experimental model.

As a further design of this scheme, eight sets of pitch limit devices are used to limit the large displacement of the wind tunnel experimental model during the pitch movement, so as to prevent excessive pitch displacement from damage to the two-degree-of-freedom support mechanism and sensor system ;Each set of pitch limit device consists of a pitch limit device metal fixing plate, four pitch limit device metal fixing plate connecting bolts, a pitch limit device rubber brake block and two pitch limit device countersunk connecting bolts It is composed of two pitch limit device countersunk head connecting bolts and matching nuts, among which, the eight pitch limit device metal fixing pieces are respectively fixed on two linear brackets through thirty-two pitch limit device metal fixing piece connecting bolts , and then the sixteen countersunk head connecting bolts of the pitch limit device pass through the rubber brake blocks of the eight pitch limit devices respectively, and are fixed on the eight pitch limit device metal On the fixed piece

As a further design of this scheme, the inlet end of the air channel inside the wing model is smoothly connected to the pressure measuring hole, and the outlet end of the air channel is located at the end of the wing model on the side where the support mechanism is provided. Then, the pressure on the surface of the airfoil model is led out to the pressure transmitter outside the wind tunnel by piercing the pressure measuring tube at the outlet end of the air channel at the end of the wing model. The pressure measuring holes and air flow channels are all designed with high precision using modeling software. At the same time, 3D printing technology also ensures the processing accuracy of the solid wing model.

As a further design of this scheme, the pressure measuring tube is connected to the air channel inside the wing section model through one end, and is sealed with a sealant at the interface, and the other end is connected to the measuring tube of the pressure transmitter outside the wind tunnel. The pressure end is connected to realize the measurement of the surface pressure of the airfoil model.

As a further design of this solution, the contact position between the eccentric mass and the end plate is provided with anti-slip grooves to prevent the eccentric mass from sliding relative to the end plate during the movement of the wing model.

As a further design of this program, the wind tunnel fixing plate is used to fix two support plates, the wind tunnel anti-turbulence cover and the non-contact hysteresis telescopic displacement sensor, and the wind tunnel is fixed by the wind tunnel fixing plate fixing bolts. The fixed plate is fixed on the side wall of the closed section of the wind tunnel; the anti-turbulence cover of the wind tunnel is fixed on the fixed plate of the wind tunnel through the fixing bolts of the fixed plate of the wind tunnel, which covers the two-degree-of-freedom support mechanism outside the wind tunnel Inside the spoiler, it is used to prevent the wind tunnel side wall opening from affecting the air flow inside the wind tunnel; the two support plates include the upper support plate and the lower support plate, which are respectively fixed on the wind tunnel fixing plate by the support plate fixing bolts, and the upper support plate Both the plate and the lower support plate are provided with bolt holes for fixing the ups and downs limit device and grooves for fixing the ups and downs elastic mechanism, and the upper support plate is also provided with bolt holes for connecting smooth linear straight rods, and the two sides of the lower support plate Countersunk bolt holes and cylindrical grooves for connecting smooth linear straight rods are respectively arranged on one surface.

As a further design of this solution, the two linear brackets include an inner linear bracket and an outer linear bracket, and the two linear brackets are provided with through holes for passing through the smooth linear straight rod and the torsion shaft fixing rod and Grooves for fixing outer spherical bearings, linear sliding bearings, and ups and downs elastic mechanisms, as well as bolt holes for fixing pitch spring connecting columns and pitch limit devices, and the outer linear bracket is also provided with a fixed angular displacement sensor Bolt holes for fixing the flange; eight linear sliding bearings and eight sinking and floating linear spring fixing seats are fixed in the grooves set on the linear bracket through the fixing bolts of the sinking and floating elastic mechanism, and the two linear brackets are respectively passed through four sets of sinking and floating elastic mechanisms Suspended between the upper support plate and the lower support plate; the middle parts of the two linear brackets are respectively provided with an outer spherical bearing, and the torsion shaft fixing rod is connected with the linear bracket through the outer spherical bearing, and the two linear brackets are respectively Through four sets of pitch linear springs, the eight pitch spring connecting columns are connected with two torsion struts to provide the pitch restoring moment of the wind tunnel experimental model, and the side of the inner linear bracket is also installed with a non-contact magnetic The floating magnet used in conjunction with the hysteresis telescopic displacement sensor is used to collect the ups and downs motion data of the wind tunnel experimental model in real time.

As a further design of this scheme, the angular displacement sensor fixing flange is fixed on the outer linear bracket, and it is achieved by fixing the angular displacement sensor, the linear bracket and the torsion shaft fixing rod together to realize the The pitching motion of the wind tunnel experimental model can be measured while the model is doing ups and downs; one end of the torsion shaft fixing rod is provided with a torsion shaft fixing fixture, and the other end is provided with a connection port matched with an angular displacement sensor, which passes through two outer spherical bearings respectively. It is connected with two linear brackets; the torsion strut passes through the torsion shaft fixing rod vertically, and is fixed on the torsion shaft fixing rod by the torsion strut fixing bolt, and the two torsion struts are respectively connected by four sets of pitch linear springs. Connect with eight pitch spring connecting columns. It is used to convert the pitching motion of the wind tunnel experimental model into the linear motion of the pitching linear spring; one end of the four smooth linear straight rods is provided with a thread and the other end is provided with a bolt hole, and the four smooth linear straight rods pass through four sets of ups and downs elastic springs respectively. The mechanism, eight linear sliding bearings and two linear brackets inside and outside are connected to the upper and lower support plates; four sets of ups and downs elastic mechanisms include eight ups and downs linear springs, sixteen ups and downs linear spring fixing seats, and sixty-four U-shaped Bolts and sixty-four U-shaped bolts supporting nuts. Each ups and downs elastic mechanism fixes the two ends of one ups and downs linear spring respectively on two ups and downs linear spring fixing seats through eight U-shaped bolts and eight supporting nuts of U-shaped bolts. The eight ups and downs linear springs in the four sets of ups and downs elastic mechanisms all adopt preloaded tension springs. One end of the up and down elastic mechanism is connected to the support plate through the fixing bolt of the up and down elastic mechanism, and the other end is connected to the linear bracket through the fixing bolt of the up and down elastic mechanism. The elastic mechanism suspends a linear bracket, and then suspends the linear bracket and the wind tunnel test model connected with the linear bracket between the upper and lower support plates, so that the wind tunnel test model is subjected to the force of the airflow in the wind tunnel During the up-and-down movement, it provides the restoring force for the wind tunnel experimental model in the up-and-down movement. The four sets of pitch linear springs are preloaded tension springs, and the two pitch linear springs on one side of the linear bracket are located on both sides of the torsion strut as a group. One end is fixed on the pitch spring connecting column, and the other end is fixed on the through The torsional support of the torsion axis fixed rod is used to provide the torsional restoring moment for the wind tunnel experimental model during the pitching movement. The eight pitching spring connecting columns are connected by threads and fixed on two linear brackets to fix four sets of Pitching linear spring; eight linear sliding bearings are respectively connected with four sets of sinking and floating linear spring fixing seats at one end of the sinking and floating elastic mechanism, and the sinking and floating linear spring fixing seat connected with the linear sliding bearing at one end of the sinking and floating elastic mechanism is fixed by using the fixing bolt of the sinking and floating elastic mechanism In the grooves set on the inner and outer linear brackets, the fixed connection between the linear sliding bearing and the linear bracket is realized, and the eight linear sliding bearings are respectively fixed in the grooves at the connection between the smooth linear straight rod and the linear bracket , to reduce the friction of the wind tunnel test model during the ups and downs; two outer spherical bearings are respectively fixed at the connection between the torsion axis fixed rod and the linear bracket to reduce the friction of the wind tunnel test model during the pitching movement. Friction; four sets of sinking and floating limit devices are used to limit the large displacement of the wind tunnel experimental model during the sinking and floating movement, so as to prevent excessive sinking and floating displacement from damage to the two-degree-of-freedom support mechanism and sensor system. Each set of ups and downs limit device consists of two metal support columns for the ups and downs limit device, a metal gasket for the ups and downs limit device, a rubber brake block for the ups and downs limit device and two countersunk head connecting bolts for the ups and downs limit device; , One end of the metal support column of the sinking and floating limit device is provided with a thread, and the other end is provided with a bolt hole, and the eight metal support columns of the sinking and floating limit device are respectively connected to the upper and lower support plates, and then the eight sinking heads of the sinking and floating limit device are connected The bolts respectively pass through the rubber brake blocks of the four sinking and floating limiting devices and the four metal gaskets of the sinking and floating limiting devices and are connected in the bolt holes on one side of the metal support columns of the eight sinking and floating limiting devices.

As a further design of this program, the set of multi-channel data acquisition and analysis system includes: 18-30 strain signal input lines, a multi-channel data acquisition instrument, PC terminal signal analysis system, 18-30 strain signal input lines The wires respectively connect the output terminals of the sensors with the signal input terminals of the multi-channel data acquisition instrument, and are used to transmit the electrical signals collected by the sensors.

As a further design of this scheme, the multi-channel data acquisition instrument is used to collect the electrical signal output by the sensor during the test, which is connected with the PC signal analysis system to convert the electrical signal into an identifiable physical quantity to be measured. The terminal signal analysis system is used to analyze and process the electrical signals collected by the multi-channel data acquisition instrument, and then the user can process and analyze the collected physical quantities to be measured in real time.

Compared with the prior art, the present invention has the following advantages:

1) The present invention realizes the position change of the position of the center of mass of the wing section model relative to the center of the torsion axis through the design of the center of mass adjustment mechanism, so as to facilitate the exploration of the influence of the structural characteristics of the wing section on its aerodynamic characteristics and vibration characteristics, and can meet the requirements of wind tunnel experiments. The research requirements of the model under different centroid positions.

2) The present invention adopts the design of the air channel type airfoil model surface pressure measurement system, which realizes the pressure on the mid-span position of the wing model surface under the condition that there is no protrusion on the surface of the wing model and no influence on the flow field in the area to be measured. Measurement.

3) The design of the anti-slip sheet in a set of central torsion shafts designed by the present invention can effectively prevent relative sliding between the airfoil model and the central torsion shaft, thereby reducing systematic errors in the test.

4) A two-degree-of-freedom aeroelasticity experimental device designed by the present invention can place the support mechanism and the motion measurement mechanism of the wind tunnel experimental model outside the wind tunnel, so that the wind tunnel blocking ratio can be reduced while reducing the airfoil. The impact of the object on the test results.

5) The two-degree-of-freedom support mechanism designed by the present invention can reduce the mechanical friction when the wind tunnel experimental model vibrates to a minimum due to the addition of linear sliding bearings in the degree of freedom of ups and downs and the addition of outer spherical bearings in the degree of freedom of pitching , so as to reduce the systematic error in the experiment.

6) The torsion shaft fixing fixture at one end of the torsion shaft fixing rod designed by the present invention can arbitrarily adjust the angle of attack of the wind tunnel experimental model when the wind tunnel is not blowing, and can provide a variety of initial working conditions for experimental research.

7) The pitching and sinking limit device designed in the present invention can effectively prevent the damage to the two-degree-of-freedom support mechanism and the sensor system when the wind tunnel experimental model vibrates with a large amplitude.

8) The two-degree-of-freedom support mechanism designed in the present invention can effectively decouple the two degrees of freedom of pitching and sinking. At the same time, when the wind tunnel experimental model experiences large-amplitude ups and downs, the linear spring is limited to smooth On the linear straight rod, there will be no obvious lateral inclination of the sinking and floating linear spring, so the linear change of the geometric stiffness of the sinking and floating linear spring is guaranteed.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is the structural representation of wind tunnel experiment model of the present invention;

Fig. 3 is a structural schematic diagram of a two-degree-of-freedom support mechanism of the present invention;

Fig. 4 is that the wind tunnel experiment model of the present invention adjusts the position of the center of mass by the center of mass adjustment mechanism, so that the wing section model forms a schematic diagram of the relative position relationship of the three centers of the aerodynamic center-torsion axis center (center of gravity) from the leading edge to the trailing edge;

Fig. 5 is a schematic diagram of the relative position relationship of the three centers of the aerodynamic center-center of gravity-torsion axis center formed by the airfoil model from the leading edge to the trailing edge by adjusting the center of mass position of the wind tunnel experimental model of the present invention;

Fig. 6 is a schematic diagram of the relative position relationship of the three centers of the aerodynamic center-torsion axis center-center of gravity formed by the airfoil model from the leading edge to the trailing edge through the adjustment of the center of mass position of the wind tunnel experimental model of the present invention;

Fig. 7 is the schematic diagram of connecting the piezometric tube of the wing section model of the present invention;

Fig. 8 is a schematic diagram of the cross-sectional air channel of the wing section model of the present invention;

Fig. 9 is a schematic diagram of a conventional mass of the present invention;

Fig. 10 is a schematic diagram of the eccentric mass of the present invention;

Fig. 11 is a partial schematic diagram of a two-degree-of-freedom support mechanism of the present invention;

Fig. 12 is a schematic diagram of the connection between the ups and downs elastic mechanism of the present invention, the support plate and the linear bracket;

Fig. 13 is a schematic diagram of the connection between the wind tunnel experimental model of the present invention and the two-degree-of-freedom support mechanism;

Fig. 14 is a schematic diagram of the sinking and floating limiting device of the present invention;

Fig. 15 is a schematic diagram of the pitch limiting device of the present invention;

Fig. 16 is a schematic diagram of the ups and downs elastic mechanism of the present invention.

In the figure, 1-wind tunnel anti-turbulence cover, 2-multi-channel data acquisition instrument, 3-PC terminal signal analysis system, 4-pressure transmitter, 5-strain signal input line, 6-pressure measuring tube, 7- Special network cable for multi-channel data acquisition instrument, 8-wind tunnel, 9-wing model, 10-end plate, 11-pressure measuring hole, 12-through hole for placing bolts, 13-high-strength torsion shaft bolts, 14-anti-slip 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-floating limit device, 27-pitch limit device, 28-angular displacement sensor fixing flange, 29-angular displacement sensor, 30-non-contact hysteresis telescopic displacement sensor, 31-floating magnet, 32-floating elastic mechanism, 33-floating linear spring, 34-floating linear spring fixing seat, 35-U-bolt, 36-U-bolt matching nut, 37-pitch linear spring, 38-torsion strut, 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 strut Fixing bolts, 45-fixing bolts for sinking and floating elastic mechanisms, 46-fixing bolts for outer spherical bearings, 47-fixing bolts for floating magnets, 48-fixing bolts for torsion shaft clamps, 49-fixing bolts for supporting plates, 50-fixing bolts for wind tunnel fixing plates, 51-Metal support column of sinking and floating limiting device, 52-Metal gasket of sinking and floating limiting device, 53-Rubber brake block of sinking and floating limiting device, 54-Sunk head connecting bolt of sinking and floating limiting device, 55-Metal fixing of pitching limiting device Sheet, 56-pitch limiting device metal fixing piece connecting bolt, 57-pitch limiting device rubber brake block, 58-pitch limiting device countersunk head connecting bolt, 59-pitch limiting device countersunk head connecting bolt supporting nut.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

As shown in Figures 1-16, a two-degree-of-freedom aeroelasticity experimental device according to an embodiment of the present invention includes a wind tunnel experimental model, a two-degree-of-freedom support mechanism, and a signal acquisition system;

The wind tunnel test model includes a wing section model 9, 16-28 piezometric tubes 6, two end plates 10, a set of central torsion shafts, a set of locking mechanisms, and a set of center-of-mass adjustment mechanisms;

The wing section model 9 is manufactured by 3D printing. The wing section model 9 is designed with through holes 12 for placing bolts. The upper and lower surfaces of the wing section model 9 at the mid-span position are respectively designed with holes 8 to 14 with a diameter of 1.6 mm. pressure measuring holes 11, 8-14 pressure measuring holes 11 are all along the normal direction of the airfoil surface, the pressure measuring holes 11 are connected with the pressure measuring tube 6 through the air flow channel 22 designed inside the airfoil model 9, and the pressure measuring tube 6 extends to the outside of the wind tunnel 8, and is connected with the pressure transmitter 4;

The two end plates 10 are manufactured by 3D printing, which have the same hollow-out design as the section hollow-out shape of the wing section model 9, and are fixedly connected to both ends of the wing section model 9 by bolts to prevent the end effect of the wing section. Ensure that the flow is a quasi-two-dimensional flow;

The set of central torsion shafts includes a high-strength torsion shaft bolt 13, a torsion shaft locknut 15 and an anti-slip sheet 14, and the high-strength torsion shaft bolt 13 passes through the anti-slip sheet 14, two end plates 10 and the wings The bolt-placed through-hole 12 reserved inside the model 9 is connected to the torsion axis fixing rod 41 on the two-degree-of-freedom support mechanism, and fixed with the torsion axis locknut 15, wherein a part of the anti-slip sheet 14 is embedded in a position far away from the support mechanism. and fixedly connected with the head of the high-strength torsion shaft bolt 13 to prevent relative sliding between the high-strength torsion shaft bolt 13 and the wing model 9;

The set of locking mechanisms is located near the trailing edge of the wing model 9 and includes fixing bolts 16 and locknuts 17. The fixing bolts 16 pass through the end plate 10 and through holes reserved inside the wing model 9 for placing bolts. 12 Connect the wing section model 9 and the two end plates 10 together, and fix them with locknuts 17;

The set of center-of-mass adjustment mechanism includes two conventional mass blocks 20, two eccentric mass blocks 21 and a set of mass block fixing mechanisms; the two conventional mass blocks 20 are made of brass, with a hole in the center, and the two eccentric mass blocks 21 is made of brass, eccentrically drilled, and the eccentric mass 21 has the same weight as the conventional mass 20; two conventional mass 20 are used in combination to adjust the position of the center of mass of the wing model 9, making it closer to the center of the torsion axis , so that the wing section model 9 forms a three-center relative positional relationship of aerodynamic center-torsion axis center (center of gravity) from the leading edge to the trailing edge; two eccentric masses 21 are used in combination to adjust the position of the wing section model 9 center of mass, so that Closer to the leading edge of the wing section model 9, so that the wing section model 9 forms a three-center relative positional relationship of aerodynamic center-center of gravity-torsion axis center from the leading edge to the trailing edge, and a conventional mass 20 is used in combination with an eccentric mass 21 , for adjusting the position of the center of mass of the wing section model 9, making it closer to the trailing edge of the wing section model 9, so that the wing section model 9 forms a three-center relative positional relationship of aerodynamic center-torsion axis center-center of gravity from the leading edge to the trailing edge; A set of mass fixing mechanism is composed of mass fixing bolts 18 and mass locking nuts 19. According to the requirements for different centroid positions in the test, the mass fixing bolts 18 and mass locking nuts 19 are used to connect the two mass respectively fixed on the end plates 10 on both sides of the wing section model 9, so as to realize the change of the position of the center of mass of the wing section model 9;

The two-degree-of-freedom support mechanism includes a wind tunnel fixing plate 23, a wind tunnel anti-turbulence cover 1, two support plates 24, two linear brackets 25, an angular displacement sensor fixing flange 28, and a torsion shaft fixing Rod 41, two torsion struts 38, four smooth linear straight rods 43, four groups of ups and downs elastic mechanisms 32, four groups of pitch linear springs 37, eight pitch spring connecting columns 42, eight linear sliding bearings 39, two outer Spherical bearing 40, four sets of ups and downs limit devices 26 and eight sets of pitch limit devices 27;

The signal acquisition system includes 16 to 28 pressure transmitters 4, an angular displacement sensor 29, a non-contact magnetic hysteresis displacement sensor 30 and a set of multi-channel data acquisition and analysis system, 16 to 28 pressure transmitters The pressure measuring ends of 4 are respectively connected to the pressure measuring tubes 6 drawn from the wind tunnel 8, and the other ends are respectively connected to the signal acquisition channels of the multi-channel data acquisition instrument 2 through the strain signal input lines 5, and the angular displacement sensor 29 is fixed at the angle The displacement sensor is fixed on the flange 28, and then connected with the supporting shaft hole of the torsion shaft fixed rod 41, the signal output end of the angular displacement sensor 29 is connected to the signal acquisition channel of the multi-channel data acquisition instrument 2 through the strain signal input line 5, For collecting the instantaneous pitch angle signal of the wind tunnel experimental model, the non-contact hysteresis telescopic displacement sensor 30 is connected on the wind tunnel fixed plate 23, and the distance between it and the floating magnet 31 fixed on the linear bracket 25 is 2 mm; The up and down motion of the hole test model drives the linear motion of the linear bracket 25, which in turn drives the linear motion of the floating magnet 31. The distance that the floating magnet 31 slides on the measuring rod of the non-contact magneto-hysteretic displacement sensor 30 is used to measure the distance of the wind tunnel experiment. The instantaneous heave displacement of the model. The signal output end of the non-contact hysteresis stretching displacement sensor 30 is connected to the signal acquisition channel of the multi-channel data acquisition instrument 2 through the strain signal input line 5, and is used for collecting instantaneous ups and downs displacement signals of the wind tunnel experimental model.

During assembly, the following steps are included: assembling the two-degree-of-freedom support mechanism, specifically, first, fixing the eight ups and downs linear springs 33 with sixty-four U-bolts 35 and sixty-four U-bolt matching nuts 36 On the sixteen ups and downs linear spring holders 34, four groups of eight ups and downs elastic mechanisms 32 are then assembled. It should be noted that the four sets of ups and downs elastic mechanisms 32 are a group of two up and down symmetrical up and down elastic mechanisms 32 for each linear bracket 25 , wherein each linear bracket 25 is suspended by two sets of ups and downs elastic mechanisms 32 . Then four sets of sinking and floating limiting devices 26 are respectively installed on the upper and lower two support plates 24, and each set of sinking and floating limiting devices 26 is composed of two sinking and floating limiting device metal support columns 51, a sinking and floating limiting device metal gasket 52, A sinking and floating limiting device rubber brake block 53 and two sinking and floating limiting device countersunk head connecting bolts 54 are formed, wherein one end of the sinking and floating limiting device metal support column 51 is provided with threads, and the other end is provided with bolt holes, eight The metal support columns 51 of the sinking and floating limiting devices are respectively connected to the upper and lower support plates 24, and then the eight sinking head connecting bolts 54 of the sinking and floating limiting devices respectively pass through the four rubber brake blocks 53 of the sinking and floating limiting devices and the four rubber brake blocks 53 of the sinking and floating limiting devices. The position device metal gasket 52 is connected in the bolt holes on one side of the metal support columns 51 of the eight ups and downs limit devices. It should be noted that two sets of ups and downs limiting devices 26 are installed on each support plate 24 , and the ups and downs limit devices 26 on the upper and lower support plates 24 are symmetrically arranged. Then the threaded ends of four smooth linear straight rods 43 are connected in the reserved bolt holes on the upper support plate. Wherein one end of smooth linear straight rod 43 is provided with screw thread, and the other end is provided with bolt hole, and also is provided with the groove of fixed ups and downs elastic mechanism 32 on the upper support plate, then four ups and downs elastic mechanisms 32 pass through 4 respectively smooth linear straight bar 43, and the ups and downs linear spring holders 34 at one end of the four ups and downs elastic mechanisms 32 are fixed in the grooves on the upper support plate through the ups and downs elastic mechanism fixing bolts 45.

Secondly, four linear sliding bearings 39 are respectively passed through four smooth linear straight rods 43 and connected with the sinking and floating linear spring holders 34 at the other end of the four sinking and floating elastic mechanisms 32 on the upper supporting plate, and then the upper supporting The four smooth linear straight rods 43 of the board pass through the through holes provided on the inner and outer linear brackets 25, and the ups and downs linear spring fixing seat 34 connected with the linear sliding bearing 39 is fixed on the inner and outer two by using the ups and downs elastic mechanism fixing bolts 45. In the groove provided above the linear bracket 25. The inner linear bracket mentioned here refers to the linear bracket on the side close to the wind tunnel fixing plate 23 , and the outer linear bracket refers to the linear bracket on the side away from the wind tunnel fixing plate 23 .

Then other four linear sliding bearings 39 are connected with the sinking and floating linear spring holders 34 at one end of the other four sinking and floating elastic mechanisms 32, and then the connected sinking and floating elastic mechanisms 32 and linear sliding bearings 39 are passed through and connected to the upper support plate Four smooth linear straight rods 43, and utilize the ups and downs elastic mechanism fixing bolt 45 to be connected with the ups and downs of the linear sliding bearing 39.

Then the lower support plate that is fixed with the ups and downs limiter 26 is installed on one end of four smooth linear straight rods 43 with bolt holes, wherein two surfaces of the lower support plate are respectively provided with four connecting smooth linear straight rods 43 Countersunk bolt holes and four cylindrical grooves, wherein the four cylindrical grooves on the top of the lower support plate are used to connect one end of the bolt holes of four smooth linear straight rods 43, and the four countersunk bolt holes on the bottom of the lower support plate are used The bolt holes at the bottoms of four smooth linear straight rods 43 are fixedly connected by bolts. In addition, a groove for fixing the ups and downs elastic mechanism 32 is also provided on the lower support plate. Then the ups and downs linear spring holder 34 at the other end of the four ups and downs elastic mechanisms 32 that are connected below the two linear brackets 25 inside and outside is fixed in the groove on the lower support plate by the ups and downs elastic mechanism fixing bolt 45 .

Then two outer spherical bearings 40 are fixed in the grooves on the outside of the two linear brackets 25 inside and outside with the outer spherical bearing fixing bolts 46. The outside mentioned here refers to a part of the inner linear bracket close to the wind tunnel fixing plate 23. The side and the outer linear bracket are away from the side of the wind tunnel fixing plate 23 . Then the torsion shaft fixed rod 41 is passed through two outer spherical bearings 40 and the fastening fit of the shaft and the bearing is carried out; and fix it on the torsion shaft fixing rod 41 by twisting the rod fixing bolt 44. The through holes mentioned in the front and rear of the torsion shaft fixing rod 41 are all set at the same distance from the outer surfaces of the inner and outer linear brackets 25 . Then on the outside of the two linear brackets 25 inside and outside, four groups or eight pitch spring connecting columns 42 are respectively installed by threaded connection, wherein the left and right symmetrical two pitch spring connecting columns 42 on one side of each linear bracket 25 are One set, two sets of pitch spring connecting columns 42 are symmetrically installed on each linear bracket 25 with respect to the section center of the torsion axis fixing rod 41 . Then the four sets of pitching linear springs 37 connect the four sets of pitching spring connecting columns 42 and the two torsion struts 38 together, wherein the left and right symmetrical two pitching linear springs 37 on one side of each linear bracket 25 form a group, Two sets of pitch linear springs 37 are mounted on each linear bracket 25 . Then eight sets of pitch limiting devices 27 are installed on two linear brackets 25 inside and outside respectively, wherein four sets of pitch limiting devices 27 are installed on the outside of each linear bracket 25, with every two sets as a group of symmetrical Installed on both sides of the torsion strut 38 , two sets of pitch limiting devices 27 on each linear bracket 25 are respectively symmetrical with respect to the center of the section of the torsion axis fixing rod 41 . Every set of pitch limiter 27 is composed of a pitch limiter metal fixing piece 55, four pitch limiter metal fixing pieces connecting bolts 56, a pitch limiter rubber brake block 57 and two pitch limiter 24 Head connecting bolt 58 and two pitch limiter countersunk head connecting bolt supporting nuts 59 are formed. Wherein, the installation of a set of pitch limiter 27 is taken as an example for illustration: a pitch limiter metal fixing piece 55 is fixed on a linear bracket 25 through four pitch limiter metal fixing piece connecting bolts 56, and then two A pitch limit device countersunk connecting bolt 58 passes through a pitch limit device rubber brake block 57, and is fixed on a pitch limit device metal retainer 55 by two pitch limit device countersunk head connecting bolt supporting 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 fixed with the angular displacement sensor 29 is fixed on the outer linear bracket with bolts. Then the floating magnet 31 used in conjunction with the non-contact hysteresis telescopic displacement sensor 30 is fixed on the inner linear bracket with the floating magnet fixing bolt 47, and then the non-contact hysteresis telescopic displacement sensor 30 is fixed on the wind tunnel with bolts. plate 23, and then the assembled upper and lower support plates 24 are fixed on the wind tunnel fixed plate 23 with support plate fixing bolts 49, and then the wind tunnel anti-turbulence cover 1 is connected to the wind tunnel through the wind tunnel fixing plate fixing bolts 50. On the hole fixing plate 23, then the integral two-degree-of-freedom support mechanism is fixed on the outer wall surface of the wind tunnel 8 with the wind tunnel fixing plate fixing bolt 50.

Carry out the assembly of wind tunnel experiment model then, specifically, at first the pressure measuring tube 6 is connected with the air channel 22 inside the wing section model 9, and then at the interface of the air channel 22 of the wing section model 9 and the pressure measuring tube 6 Seal with sealant. Among them, 10 pressure measuring holes 11 with a diameter of 1.6mm are designed with high precision on the upper and lower surfaces at the mid-span position of the wing model 9, and the designed pressure measuring holes 11 are all along the normal direction of the surface of the wing model 9, The pressure measuring hole 11 is connected with the pressure measuring tube 6 through the air channel 22 designed inside the airfoil model 9 . The air channel 22 designed inside the wing section model 9 mentioned therein has its inlet end smoothly connected with the pressure measuring hole 11, and the outlet end of the air channel 22 is located on the wing section model 9 on the side of the two-degree-of-freedom support mechanism. the end of. Then use a set of central torsion shaft and a set of locking mechanism to fix the wing section model 9 and the two end plates 10 together. Two of the end plates 10 have the same hollow-out design as the cross-sectional hollow shape of the wing model 9, and are fixedly connected to both ends of the wing model 9 by bolts to prevent the end effect of the wing model 9 and ensure that the flow is a quasi-two-dimensional flow . The mentioned set of central torsion shafts includes a high-strength torsion shaft bolt 13, a torsion shaft locknut 15, and an anti-slip sheet 14, wherein a part of the anti-slip sheet 14 is embedded in the end plate on the side away from the support mechanism, and It is fixedly connected with the head of the high-strength torsion shaft bolt 13 to prevent relative sliding between the high-strength torsion shaft bolt 13 and the wing model 9 . The set of locking mechanisms mentioned is located near the trailing edge of the wing segment model 9 and includes fixing bolts 16 and locknuts 17 . Fixing bolts 16 connect the wing section model 9 and the two end plates 10 through the end plate 10 and through holes 12 for placing bolts reserved inside the wing section model 9 , and are fixed with locknuts 17 . Then the high-strength torsion shaft bolt 13 of the wind tunnel experiment model that is connected is fixed on the torsion shaft fixing fixture one end of the torsion shaft fixing rod 41 on the two-degree-of-freedom support mechanism with the torsion shaft clamp fixing bolt 48. Then the center of mass adjustment mechanism is installed on the wing section model 9, wherein a set of center of mass adjustment mechanism includes two conventional mass blocks 20, two eccentric mass blocks 21, and a set of mass block fixing mechanisms. Wherein the eccentric mass 21 has the same weight as the conventional mass 20 . The mentioned eccentric mass 21 is designed with an eccentric hole, and the mentioned conventional mass 20 is designed with a center hole. The masses are made of brass and are used to adjust the position of the center of mass of the wing model 9 . A set of mass block fixing mechanism is composed of mass block fixing bolts 18 and mass block locknuts 19, and the two mass blocks are respectively fixed on the two sides of the wing section model 9 by using the mass block fixing bolts 18 and the mass block locknuts 19. On the end plate 10, the position of the mass block can be adjusted according to different requirements of the center of mass during the test, thereby achieving the effect of changing the position of the center of mass.

Finally, connect the pressure measuring pipeline with the signal acquisition system, specifically, first lead the other end of the pressure measuring tube 6 connected to the air channel 22 of the airfoil model 9 out of the wind tunnel 8 and connect it with the pressure transmitter 4 Connect the pressure measuring end, and then use the pressure transmitter 4 and the multi-channel data acquisition and analysis system to check the air tightness of the connected pressure measuring channel. After ensuring that the airtightness of all the pressure measurement channels is intact, the angular displacement sensor 29 and the non-contact magnetostrictive displacement sensor 30 are connected to the multi-channel data acquisition and analysis system. The multi-channel data acquisition and analysis system includes: a strain signal input line 5 , a multi-channel data acquisition instrument 2 and a PC terminal signal analysis system 3 . The mentioned strain signal input line 5 respectively connects the output end of the sensor with the signal input end of the multi-channel data acquisition instrument 2, and then the multi-channel data acquisition instrument 2 is connected to the network cable interface end of the PC through the dedicated network cable 7 of the multi-channel data acquisition instrument connected. Among them, the strain signal input line 5 is used to transmit the signal collected by the sensor, the multi-channel data acquisition instrument 2 is used to collect the electrical signal output by the sensor during the test, and the PC terminal signal analysis system 3 is used for analysis and processing by the multi-channel data acquisition instrument 2 The collected electrical signal, and then the user can process and analyze the collected physical quantity to be measured in real time.

So far all the experimental devices designed by the present invention have been installed, and the connected experimental devices will be further described below through several embodiments:

Example 1

Taking the experimental study of the influence of the centroid position of the wind turbine wing section model on flutter as an example, the operation is explained.

When the wind tunnel 8 is not blowing, temporarily fix the high-precision digital inclinometer to the end plate 10 at one end of the wing model 9, and then adjust the high-strength torsion shaft bolt 13 relative to the torsion shaft fixing fixture at one end of the torsion shaft fixing rod 41 The angle of the wing section model 9 displayed by the digital inclinometer is used to fix the wing section model 9 under the three centroid positions at the same angle of attack, and the adjustment of the three centroid positions of the wing section model 9 is by adjusting The position of the mass block in the center of mass adjustment mechanism is realized. For a two-degree-of-freedom aeroelasticity experimental device disclosed in the present invention, three bolt through holes for fixing the mass blocks are provided inside the wing model 9, corresponding to the three centroid positions of the wing model 9, namely Aerodynamic center-torsion axis center (center of gravity) (as shown in Figure 4); pneumatic center-gravity center-torsion axis center (as shown in Figure 5); aerodynamic center-torsion axis center-gravity center (as shown in Figure 6). Under the three centroid positions, the ratios of the distance x between the centroid and the center of the torsion axis and the airfoil chord length c are 0, +0.0303, -0.0623 respectively. Then, at different centroid positions, by gradually increasing the wind speed in the wind tunnel, the angular displacement sensor 29, the non-contact magnetic hysteresis displacement sensor 30 and the pressure transmitter 4 are used to collect the test data at the same time, and then through the strain signal input line 5 The electrical signal collected by the sensor is transmitted to the multi-channel data acquisition instrument 2, and finally the electrical signal is analyzed and processed by the PC terminal signal analysis system 3 and the multi-channel data acquisition instrument 2, and then converted into the wing section model that needs to be measured in the test9 The instantaneous pitch angle, the instantaneous ups and downs displacement and the surface pressure signal of the wing section model 9. Then by observing the vibration of the wing section model 9 under the three centroid positions, the flutter critical wind speed of the wing section model 9 under the three centroid positions is determined, and then the pitching and heaving motion data of the wing section model 9 in the limit cycle oscillation state are determined. And the pressure signal on its surface is recorded. Finally, by exploring the influence of the position of the centroid of the wing model 9 on the critical flutter velocity, the optimal centroid position of the wing model 9 is found to realize the control of the flutter boundary of the wing model 9 .

Example 2

Taking the bifurcation behavior of airfoil stall flutter in a low-speed wind tunnel as an example to illustrate the operation.

After the mass center position of the wing section model 9 is fixed by installing mass blocks on the wing section model 9, when the wind tunnel 8 is not blowing, adjust the angle of attack of the wing section model 9 to a certain angle. Then the wind tunnel 8 is opened, and the air flow pressure at the mid-span position on the surface of the wing section model 9 is measured by utilizing the pressure transmitter 4, the pressure measuring tube 6, the air passage 22 inside the wing section model 9, and the pressure measuring hole 11, Then the pressure signal is measured, combined with the instantaneous pitch angle measured by the angular displacement sensor 29 , and then the lift coefficient and the pitch moment coefficient of the wing section model 9 are obtained. Simultaneously in conjunction with wing section model 9 instantaneous pitch, the change curve of ups and downs displacement with time judges the vibration state that wing section model 9 experiences, when wing section model 9 vibrations reach stall flutter state, record wing section model 9 pitch angles (heavy displacement, ups and downs displacement, The relationship between the limit cycle vibration amplitude experienced by the lift coefficient and the pitching moment coefficient and the wind speed in the wind tunnel. Then change the angle of attack of the wing section model 9 under the condition of no wind, repeat the above test steps, and finally obtain that the pitch angle (heavy displacement, lift coefficient, pitch moment coefficient) of multiple groups of wing section models 9 under different angles of attack The relationship between the amplitude of the experienced limit cycle vibration and the wind speed in the wind tunnel is used to explore the bifurcation behavior of the airfoil model 9 during stall flutter.

Example 3

The operation is explained by taking the flow separation phenomenon on the surface of the wing when it stalls and flutters as an example.

After the mass center position of the wing section model 9 is fixed by installing mass blocks on the wing section model 9, when the wind tunnel 8 is not blowing, adjust the angle of attack of the wing section model 9 to a certain angle. Then open the wind tunnel 8, when the vibration of the wing section model 9 reaches the stall flutter state, by using the pressure transmitter 4, the pressure measuring tube 6, the air flow channel 22 inside the wing section model 9 and the pressure measuring hole 11 to the wing section The airflow pressure at the mid-span position on the surface of the model 9 is measured, and then the variation of the pressure coefficient of the upper and lower surfaces of the wing model 9 with the airfoil chord length is studied when the wing model 9 experiences different pitch angles, and then the surface of the wing model 9 is analyzed. aerodynamic characteristics. In addition, the flow separation on the surface of the airfoil model 9 can be further studied in combination with the particle image velocimetry technology, so that it can be compared with the pressure change trend on the surface of the airfoil model 9 measured by the pressure transmitter 4, and then the airfoil section The mechanism of the induced stall flutter of model 9 is explored.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present 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.

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