A gravity-based drag measurement device for wind tunnel models

Abstract

This application belongs to the technical field of drag measurement, and relates to a drag measurement device for a wind tunnel model based on gravity, including: a balance component and an angle adjustment component provided in the wind tunnel model; the balance component includes: a platform provided on the angle adjustment component, a guide rail provided on the platform, and sensors provided at both ends of the guide rail; the angle adjustment component is used to adjust the horizontal inclination angle of the platform so that the object to be measured provided on the guide rail can slide along the guide rail under the action of gravity; the angle adjustment component is adjusted bidirectionally until neither of the two sensors outputs a signal, and according to the horizontal inclination angle of the platform, the drag of the object to be measured in the wind tunnel model is obtained. Using this application can achieve accurate measurement of the wind resistance of the model.

Description

Technical Field

[0001] The present application relates to the technical field of drag measurement, and particularly to a wind tunnel model drag measurement device based on gravity. Background Art

[0002] As an important device for studying the aerodynamic performance of object motion, the application of a wind tunnel model drag measurement device can not only verify the reliability of numerical simulation results, but also help engineers test the effects of different part design schemes.

[0003] In the prior art, in order to measure the drag of a trolley or other objects, traditional drag measurement devices directly measure the total drag received by the model by using a force sensor (such as a force balance scale). In addition, there is also a method of fixing the trolley and then installing a differential pressure sensor outside the trolley body to measure the static pressure difference on the surface of the trolley, thereby calculating the drag received by the trolley.

[0004] Through the cooperation of sensors in the wind tunnel, the above-mentioned drag measurement device can basically measure the drag received by the trolley more accurately. However, there are still the following problems:

[0005] 1. The accurate measurement of traditional pressure requires high precision of the instrument, and the complete set of pressure measurement devices belong to high-cost equipment, which brings great economic pressure to some non-industrial institutional research projects;

[0006] 2. Traditional solutions more or less need to install force sensors on the object, which belong to contact measurement solutions and affect the flow field structure, resulting in an unknown difference between the finally measured drag and the actual one;

[0007] 3. Traditional devices do not have universality for the drag measurement of different objects in the wind tunnel. When measuring different objects, it is necessary to reinstall sensors and adjust parameters, and the experimental steps are relatively cumbersome during multiple measurements. Summary of the Invention

[0008] Based on this, in view of the above technical problems, it is necessary to provide a wind tunnel model drag measurement device based on gravity, which can accurately measure the wind drag of the model.

[0009] A wind tunnel model drag measurement device based on gravity includes: a balance component and an angle adjustment component arranged in the wind tunnel model;

[0010] The balance component includes: a platform arranged on the angle adjustment component, a guide rail arranged on the platform, and sensors arranged at both ends of the guide rail; there are two sensors, which are respectively arranged at both ends of the guide rail and are used to detect the position of the object to be measured and judge whether the object to be measured reaches force balance;

[0011] The angle adjustment component is used to adjust the horizontal inclination angle of the platform, so that the object to be measured arranged on the guide rail can slide along the guide rail under the action of gravity;

[0012] Adjust the angle adjustment component bidirectionally until no output signal is generated by both sensors, and then obtain the resistance of the object to be measured in the wind tunnel model according to the horizontal inclination angle of the platform.

[0013] In one embodiment, the guide rail is a maglev guide rail.

[0014] In one embodiment, the length direction of the guide rail is consistent with the length direction of the wind tunnel model.

[0015] In one embodiment, both the balance component and the angle adjustment component are arranged in the test section of the wind tunnel model.

[0016] In one embodiment, both the balance component and the angle adjustment component are connected to the wind tunnel model through an airtight and stretchable rubber layer to form a transition structure.

[0017] In one embodiment, obtaining the resistance of the object to be measured in the wind tunnel model according to the horizontal inclination angle of the platform includes:

[0018] ;

[0019] wherein, is the resistance of the object to be measured in the wind tunnel model, is the mass of the object to be measured, is the acceleration of gravity, is the horizontal inclination angle of the platform.

[0020] In one embodiment, the angle adjustment component includes: a top plate, a bottom plate and a telescopic mechanism;

[0021] Both corresponding ends of the top plate and the bottom plate are connected by a telescopic mechanism, so that one corresponding end of the top plate and the bottom plate is hinged, and the other corresponding end of the top plate and the bottom plate is arranged at an interval, so that the platform has a non-zero horizontal inclination angle.

[0022] In one embodiment, the telescopic mechanism includes: a telescopic member, a top seat, a bottom seat and a motor;

[0023] Both ends of the telescopic member are respectively hinged to the top seat and the bottom seat, and the telescopic member is also connected to the motor and has different states of extension and contraction under the driving action of the motor to adjust the horizontal inclination angle of the platform.

[0024] In one embodiment, the telescopic member includes: a worm gear and a worm;

[0025] The output end of the motor is rotationally connected to the worm gear, and the edge of the worm gear meshes with the worm.

[0026] In one embodiment, the telescopic member includes: a sleeve and a lead screw;

[0027] The output end of the motor is rotationally connected to the sleeve, the sleeve is sleeved outside the lead screw, and the sleeve is threadedly connected to the lead screw.

[0028] The above-mentioned wind tunnel model resistance measurement device based on gravity designs a balance component and an angle adjustment component, realizes the precise balance of the object to be measured in the air flow, converts the actual air flow resistance received by the object into the component force of the object gravity along the platform by means of force balance, thereby obtains the gravity component force through the force analysis of the object, and further obtains the resistance received by the object under the wind tunnel working conditions, can realize the rapid measurement of the model wind resistance, and ensures the high precision of the resistance measurement. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the balance component of the wind tunnel model resistance measurement device based on gravity in one embodiment;

[0030] Figure 2 It is a schematic diagram of the angle adjustment component of the wind tunnel model resistance measurement device based on gravity in one embodiment;

[0031] Figure 3 It is a three-dimensional schematic diagram of the balance component of the wind tunnel model resistance measurement device based on gravity in another embodiment;

[0032] Figure 4 It is a front view of the balance component of the wind tunnel model resistance measurement device based on gravity in another embodiment, wherein the circle is the connection schematic of the pulley and the guide rail body;

[0033] Figure 5 For Figure 3 The detailed schematic diagram of the structure at the circle in

[0034] Figure 6 It is a schematic diagram of the wind tunnel model in one embodiment.

[0035] Reference Signs:

[0036] Air inlet A, expansion section B, test section C, air outlet D;

[0037] Platform 1, guide rail 2, body 21, magnetic member 22, support portion 23, sensor 3, connecting member 4, support table 41, pulley 42, inner core 421, bearing 422, outer ring 423, ball 424;

[0038] Top plate 5, bottom plate 6, telescopic mechanism 7. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0040] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0041] In addition, the descriptions such as "first" and "second" in the present application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "multiple groups" is at least two groups, such as two groups, three groups, etc., unless otherwise specifically defined.

[0042] In the present application, unless otherwise clearly defined and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, a physical connection or a wireless communication connection; it may be directly connected or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0043] In addition, the technical solutions between various embodiments of the present application can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0044] The present application provides a wind tunnel model drag measurement device based on gravity, as Figure 1 and Figure 2 shown. In one embodiment, it includes: a balance component and an angle adjustment component.

[0045] The balance component is used to achieve force balance for the object to be measured provided on the balance component. The balance component includes: a platform, a guide rail, and sensors; the platform is rigidly connected to the angle adjustment component (the specific connection method is prior art), and is used to provide support for the guide rail and the sensors; the guide rail (the specific structure can adopt prior art) is provided on the platform and is used to support the object to be measured; there are two sensors, which are respectively provided at both ends of the guide rail and are used to detect the position of the object to be measured and judge whether the object to be measured reaches force balance. For example: the sensor is a pyroelectric position sensor, which uses a thermocrystal with polarization phenomenon (such as a ferroelectric body). When irradiated by infrared radiation, it causes a temperature change, a decrease in polarization intensity, a reduction in surface charge, and has high sensitivity and fast response characteristics; in actual use, infrared rays are always irradiated on the sensor, and the sensor has no output signal. When the platform tilts to one side, it will block the infrared rays, causing the sensor to have an output signal, so that it tilts to the other side. When there is no output signal on both sides, it is judged that the object to be measured reaches force balance.

[0046] The angle adjustment component is used to adjust the horizontal inclination angle of the platform so that the object to be measured provided on the guide rail can slide along the guide rail under the action of gravity, ensuring that the balance between the object resistance and the component of the gravity along the guide rail direction can be achieved under general working conditions.

[0047] In this embodiment, both the balance component and the angle adjustment component are provided in the wind tunnel model; the angle adjustment component is adjusted bidirectionally until both sensors have no output signal, and it is judged that the object to be measured reaches force balance (that is: the wind resistance and the component of the gravity along the guide rail surface are balanced). Through force analysis, according to the horizontal inclination angle of the platform, the resistance of the object to be measured under specific working conditions in the wind tunnel model can be obtained:

[0048] ;

[0049] In the formula, is the resistance of the object to be measured in the wind tunnel model, is the mass of the object to be measured, is the acceleration due to gravity, is the horizontal inclination angle of the platform.

[0050] Preferably, the guide rail is a maglev guide rail to reduce friction through magnetic levitation, maintain an ultra-low resistance state, and further reduce measurement errors and improve measurement accuracy.

[0051] Further preferably, the length direction of the guide rail is consistent with the length direction of the wind tunnel model to ensure the consistency of the air flow direction and the axial direction of the stable section, avoid the influence of the air flow direction deviation on the experimental results, and will not affect the direction angle between the air flow and the object.

[0052] Even more preferably, as Figures 3 to 5As shown in the figure, the balance assembly further includes: a connecting member, so that the object to be measured is arranged on the guide rail through the connecting member. Specifically: the guide rail includes a main body and a magnetic member; there are two main bodies, which are arranged in parallel at intervals on both sides of the platform. The main body includes a first part, a second part and a third part connected in sequence. The cross-sectional width of the second part is smaller than that of the first part and the third part at the same time, so that the cross-section of the main body forms a "work" - shaped structure. A curved groove is provided at the corner end of the first part away from the second part, so that the top surface of the main body of the guide rail has a concave circular arc top angle. The side surface of the second part is recessed towards the axis direction of the guide rail, so that the main body of the guide rail forms a concave arc side surface. Taking the circular arc top angle of the first part as the top surface and the arc side surface of the second part as the bottom surface, a protruding support part is formed on the side surface of the guide rail main body; the magnetic member is arranged between the two main bodies and is divided into an upper magnet and a lower magnet. The upper magnet is connected to the connecting member, and the lower magnet is connected to the platform. The polarities of the upper magnet and the lower magnet are the same, so as to generate a repulsive magnetic force, so that a uniform gap is formed between the upper magnet and the lower magnet, realizing the functions of suspension and guidance; the connecting member includes a support table and a pulley; the support table is a flat plate structure, made of high-strength materials such as aluminum alloy, and is fixedly connected to the upper magnet in the middle. The two sides are connected to the side surface of the main body of the guide rail through pulleys; the pulley is a rotating body structure, including an inner core, a bearing and an outer ring sleeved in sequence from the inside to the outside. The inner core is a cylindrical structure and is fixedly connected to the support table. The bearing abuts against the inner core and the outer ring. A chute is provided on the side surface of the outer ring to be connected to the top surface and the bottom surface of the support part, so that the chute cooperates with the support part, and spherical balls are nested at the positions where the chute is connected to the top surface and the bottom surface of the support part. The rotation of the outer ring of the pulley is driven by the rolling of the balls between the side surface of the outer ring of the pulley and the side surface of the main body of the guide rail, so that the pulley slides on the main body of the guide rail, that is, a sliding connection is formed through rolling connection.

[0053] The above settings can improve the stability of the balance assembly in the wind tunnel, reduce the influence of vibration, and increase the friction area to further reduce friction, thereby improving the measurement accuracy; at the same time, the connecting member is arranged at the middle position of the main body of the guide rail to avoid the situation that the experimental results are inaccurate due to too small angle adjustment.

[0054] Further preferably, both the balance component and the angle adjustment component are provided in the test section of the wind tunnel model. The wind tunnel model adopts a flow intelligent control system to provide a stable airflow environment for the wind tunnel model and support the entire measuring device. Specifically, the flow intelligent control system includes: a flow sensor, a control module, and an actuator, which are connected in sequence; the flow sensor is used to monitor the airflow flow inside the wind tunnel model in real time and output a signal to the control module. The control module (including an anemometer installed behind the fan of the wind tunnel, which controls the wind speed by intelligently controlling the flow) calculates the airflow flow that needs to be adjusted through a preset intelligent control algorithm (which belongs to the prior art, such as PID control, Fuzzy control, or AI algorithm) and sends it to the actuator. The actuator adjusts components such as the airflow valve in the wind tunnel model accordingly, thereby achieving precise control of the airflow flow; the flow intelligent control system further includes an airflow stability module provided on the anemometer, which adopts a closed-loop feedback control technology (prior art) to ensure the stability of the airflow environment and avoid airflow fluctuations caused by external interference. Compared with the prior art, the above-mentioned flow intelligent control system has the innovative features of intelligent control and multi-dimensional monitoring, can dynamically adjust the airflow flow according to real-time data, and perform comprehensive control in combination with other parameters (such as temperature, pressure, etc.), thereby significantly improving the stability of the airflow environment; the system realizes fine-tuning control of the airflow flow through precise sensors and high-performance actuators to ensure high stability of the airflow environment; the application of the system can significantly improve the airflow environment stability of the wind tunnel model, reduce the influence of external interference on the airflow environment, and quickly respond to changes in the airflow flow through intelligent control to maintain the stability of the airflow environment, thereby significantly improving the measurement accuracy of the wind tunnel model and ensuring the reliability of the entire measuring device. It should be noted that the specific structures of the flow sensor, the control module, the actuator, and the airflow stability module all belong to the prior art.

[0055] Further preferably, the angle adjustment component is connected to the wind tunnel model through an airtight stretchable rubber layer (for example: silicone rubber, which has good plasticity and sealing performance) to form a transition structure for the sealed connection of the wind tunnel device. The airtight stretchable rubber layer can effectively prevent the cross-flow or air leakage of the airflow between the wind tunnel model and the external environment through its good sealing performance and stretchability, ensuring the airtightness of the wind tunnel device; at the same time, the airtight stretchable rubber layer can achieve a more flexible sealed connection according to the shape and structural changes of the wind tunnel model, reducing the sealing failure problem caused by dimensional errors or structural deformations; in addition, the airtight characteristic of the airtight stretchable rubber layer can effectively prevent the interference of external air, facilitate angle adjustment, and further improve the airflow stability of the wind tunnel device.

[0056] The working process of this application is as follows:

[0057] 1. The wind tunnel model includes: an air inlet, a diffuser section, a test section, and an air outlet D (such asFigure 6 As shown, place the object to be measured on the balance assembly in the test section, specifically on the support platform of the balance assembly.

[0058] 2. Horizontally move the support platform so that it touches the sensor at one end.

[0059] 3. Adjust the working state of the fan in the wind tunnel model until the fan supplies air stably.

[0060] 4. Turn on the detection sensor and slowly adjust the angle of the balance device so that the object to be measured drives the support platform to tilt due to gravity until the sensor at the other end is also blocked and emits a signal.

[0061] 5. Reverse-adjust the angle of the balance device to half of the previous angle on the balance device until the sensors in both directions are not blocked and do not emit signals. At this time, the object is in force balance.

[0062] 6. Record the angle between the stable section and the ground, that is, the angle between the plane where the object is located and the horizontal plane , and obtain the resistance of the object.

[0063] The above-mentioned wind tunnel model resistance measurement device based on gravity designs a balance assembly and an angle adjustment assembly, realizes the precise balance of the object to be measured in the air flow, converts the actual air flow resistance received by the object into the component force of the object's gravity along the platform through the method of force balance, thereby obtains the gravity component force through the force analysis of the object, and further obtains the resistance received by the object under the wind tunnel working conditions. It can realize the rapid measurement of the model wind resistance, ensure the high precision of the resistance measurement, and achieve the effect of accurately measuring the air flow resistance.

[0064] In addition, this application also has the following technical effects:

[0065] 1. Only need to ensure that the object does not slide on the guide rail, with low requirements for the measurement accuracy of the instrument, reducing the equipment cost and the economic pressure of the project;

[0066] 2. Do not need to install a force sensor on the object, which belongs to a non-contact measurement scheme for the actual resistance of the object, avoiding the additional interference of contact measurement, having less influence on the air flow structure of the original flow field, being able to restore the flow field within the whole body range of the object during movement to a large extent, making the finally measured resistance more in line with the actual situation and having high accuracy;

[0067] 3. It has universality for the resistance measurement of different objects in the wind tunnel, can measure the resistance of various shaped objects in the wind tunnel, and when measuring different objects, there is no need to reinstall the sensor and readjust the parameters. The steps are simple, the operation is fast, the experimental operation difficulty is low, and it is convenient for multiple measurements.

[0068] In one embodiment, the angle adjustment assembly includes: a top plate, a bottom plate, and a telescopic mechanism.

[0069] Wherein, both corresponding ends of the top plate and the bottom plate are connected by a telescopic mechanism, so that one corresponding end of the top plate and the bottom plate is hinged, and the other corresponding ends of the top plate and the bottom plate are spaced apart, so that the platform has a non-zero horizontal inclination angle.

[0070] Preferably, the telescopic mechanism includes: a telescopic member, a top seat, a bottom seat, and a motor. The two ends of the telescopic member are respectively hinged to the top seat and the bottom seat. The telescopic member is also connected to the motor and, under the driving action of the motor, has different states of extension and contraction to accurately adjust the horizontal inclination angle of the platform according to actual needs, with high flexibility and adjustability, thereby providing a stable test environment for the wind tunnel device.

[0071] For example, the telescopic member includes: a worm gear and a worm; the output end of the motor is rotationally connected to the worm gear, and the edge of the worm gear meshes with the worm, enabling smooth rotation and precise angle adjustment.

[0072] Another example is that the telescopic member includes: a sleeve and a lead screw; the output end of the motor is rotationally connected to the sleeve, the sleeve is sleeved outside the lead screw, and the sleeve is threadedly connected to the lead screw, which can ensure the stability and durability of the telescopic mechanism.

[0073] The telescopic mechanism of the above angle adjustment assembly has high flexibility and adjustability, can accurately adjust the horizontal inclination angle of the platform according to actual needs, thereby providing a stable test environment for the wind tunnel model; through the drive and precise meshing of the telescopic mechanism, precise control of the horizontal inclination angle of the platform is achieved, which not only improves the adjustment accuracy of the wind tunnel model, but also provides a more stable test environment for it, reducing measurement errors caused by inaccurate inclination angles; the telescopic member driven by the motor can achieve fast and smooth angle adjustment, further improving the stability of the test environment of the wind tunnel model; it can be dynamically adjusted according to the specific needs of the wind tunnel model, reducing the problem of inclination angle misalignment caused by dimensional errors or structural deformations; the telescopic mechanism has scalability and maintainability, and through modular design, each component can be independently replaced and repaired, extending the service life of the device.

[0074] In addition, by adjusting the angle of the stabilization section as a whole (the specific adjustment method belongs to the prior art), it can be ensured that the air flow direction is consistent with the axis of the stabilization section, avoiding resistance changes caused by inconsistency.

[0075] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0076] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0077] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A wind tunnel model resistance measurement device based on gravity, characterized in that: include: A balancing component and an angle adjustment component provided in a wind tunnel model; The balancing component comprises: a platform arranged on the angle adjustment component, a guide rail arranged on the platform, and sensors arranged at both ends of the guide rail; there are two sensors, which are used to detect the position of the object to be measured and determine whether the object to be measured has reached force balance; The angle adjustment assembly is used to adjust the horizontal inclination angle of the platform so that the object to be measured disposed on the guide rail can slide along the guide rail under the action of gravity; The angle adjustment assembly is bidirectionally adjusted until both sensors do not output signals, and the resistance of the object to be measured in the wind tunnel model is obtained according to the horizontal inclination angle of the platform.

2. The wind tunnel model resistance measurement device based on gravity according to claim 1, characterized in that: The guide rail is a magnetic levitation guide rail.

3. The wind tunnel model resistance measurement device based on gravity according to claim 2, characterized in that: The length direction of the guide rail is consistent with the length direction of the wind tunnel model.

4. The wind tunnel model resistance measurement device based on gravity according to claim 3, characterized in that: The balancing component and the angle adjustment component are both arranged in a test section of the wind tunnel model.

5. A wind tunnel model resistance measurement device based on gravity according to any one of claims 1 to 4, characterized in that: The balancing component and the angle adjustment component are both connected to the wind tunnel model through an airtight and stretchable rubber layer to form a transition structure.

6. A wind tunnel model resistance measurement device based on gravity according to claim 3 or 4, characterized in that: According to the horizontal inclination angle of the platform, the resistance of the object to be tested in the wind tunnel model is obtained, including: In the formula, is the resistance of the object to be tested in the wind tunnel model, is the mass of the object to be measured, is the acceleration due to gravity, is the horizontal inclination angle of the platform.

7. A wind tunnel model resistance measurement device based on gravity according to any one of claims 1 to 4, characterized in that: The angle adjustment assembly includes: a top plate, a bottom plate and a telescopic mechanism; The two corresponding ends of the top plate and the bottom plate are connected by a telescopic mechanism, so that the top plate is hinged to one corresponding end of the bottom plate, and the other corresponding end of the top plate and the bottom plate are spaced apart so that the platform has a non-zero horizontal inclination angle.

8. The wind tunnel model resistance measurement device based on gravity according to claim 7, characterized in that: The telescopic mechanism comprises: a telescopic member, a top seat, a base and a motor; The two ends of the telescopic member are respectively hinged to the top seat and the base. The telescopic member is also connected to the motor and has different states of extension and contraction under the driving action of the motor to adjust the horizontal inclination angle of the platform.

9. The wind tunnel model resistance measurement device based on gravity according to claim 8, characterized in that: The telescopic member comprises: a worm wheel and a worm; The output end of the motor is rotationally connected to the worm wheel, and the edge of the worm wheel is meshed with the worm.

10. The wind tunnel model resistance measurement device based on gravity according to claim 8, characterized in that: The telescopic member comprises: a sleeve and a screw rod; The output end of the motor is rotatably connected to the sleeve, the sleeve is sleeved on the outside of the screw rod, and the sleeve is threadedly connected to the screw rod.

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