Parallel air bridge balance force measuring system and design method thereof

Abstract

The invention discloses a parallel air bridge balance force measuring system and a design method thereof, and belongs to the technical field of aviation wind tunnel tests. The parallel air bridge balance force measuring system is installed in a ventilation machine body, the fixed end of an integrated parallel balance is connected with a belly supporting rod, the measuring end of the integrated parallel balance is connected with the ventilation machine body, and a middle air inlet channel is connected with the measuring end of the integrated parallel balance. The air bridge fixing end support is connected with the integrated parallel balance fixing end, meanwhile, the air inlet end of the air bridge pipeline is connected with the air bridge fixing end support, and the air outlet end of the air bridge pipeline is connected with the ventilation machine body. And a gap is reserved between the air bridge fixed end support and the ventilation machine body. A reinforcing rib is installed on the ventilation fuselage, the wind tunnel model balance structure design problem caused by insufficient model space and difficult arrangement of an air bridge balance system under special air inlet channel conditions such as an air inlet channel in the middle of an airplane is solved, and the applicability and the flexibility of the air bridge system are improved.

Description

Technical Field

[0001] This invention relates to a parallel air bridge balance force measurement system and its design method, belonging to the field of aerospace wind tunnel testing technology. Background Technology

[0002] Wind tunnel testing is an important aerodynamic experimental method used to study the interaction between gas flow and aircraft models to understand the aerodynamic characteristics of aircraft. In dynamic simulation wind tunnel force measurement tests, such as those involving TPS nacelles or air-motor driven propellers, engine simulation devices, unlike real engines, are often driven by high-pressure air. To drive the engine simulation device, dedicated pipelines are needed to deliver high-pressure air. According to the test technical requirements, such wind tunnel tests require a corresponding internal air bridge balance to reduce the measurement inaccuracies caused by high-pressure air supply and low-pressure return. A key challenge in dynamic simulation testing is ensuring that the pipeline can deliver high-pressure air while minimizing and stabilizing its impact on the balance's force measurement, and simultaneously overcoming the internal forces, temperature effects, and flow influences of the high-pressure air. The internal air bridge balance is a key technology for solving this problem and is widely used in dynamic simulation testing, including TPS nacelle dynamic simulation and air-motor driven propeller simulation.

[0003] An internal air bridge balance can greatly eliminate the influence of high-pressure air flow on the balance's accuracy, allowing the wind tunnel balance to function normally in force measurement. The function of an internal air bridge balance is to transmit high-pressure air without affecting the balance's force measurement accuracy. Specifically, the aerodynamic load of the model is transmitted to the support system simultaneously through the balance and the air bridge piping. The air bridge piping must not only deliver high-pressure air but also be properly decoupled to minimize and stabilize the impact of the entire air supply system on the balance's force measurement.

[0004] The internal airbridge balance system mainly consists of two parts: the balance itself and the airbridge piping. Each airbridge piping consists of three noise reduction units and several irregularly shaped metal tubes. The three noise reduction units are placed in two mutually perpendicular directions to ensure that each airbridge piping has six degrees of freedom of noise reduction capability, while reducing the influence of the airbridge on the force measurement of the balance. Under normal circumstances, the internal airbridge balance system is an independent system. The balance and airbridge piping are used together for balance calibration and wind tunnel testing, and are generally not disassembled for use. When designing the wind tunnel test model, corresponding support components, air supply piping, and other parts need to be designed to be compatible with the airbridge balance. The model needs to arrange the airbridge, balance, etc., within the limited space of the fuselage. However, some aircraft configurations have air intakes in the middle of the fuselage. In wind tunnel tests of aircraft models with this central air intake layout, the middle of the fuselage is occupied by the air intake, making it impossible to properly place the internal airbridge balance system, thus hindering the smooth conduct of the wind tunnel test.

[0005] Therefore, it is urgent to propose a parallel air bridge balance force measurement system and its design method to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to solve the structural design problem of wind tunnel model balances caused by insufficient model space and difficulty in arranging the air bridge balance system under the condition of the aircraft's mid-air intake. A brief overview of the invention is provided below to offer a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0007] The technical solution of the present invention:

[0008] Option 1: Parallel air bridge balance force measurement system, including a ventilation body, a central air intake, an integrated parallel balance, air bridge piping, an air bridge fixed end support, and a belly support rod; the central air intake is located in the middle of the ventilation body, the integrated parallel balance is located inside the ventilation body, the fixed end of the integrated parallel balance is connected to the belly support rod, the measuring end of the integrated parallel balance is connected to the ventilation body, the air bridge fixed end support is connected to the fixed end of the integrated parallel balance, the air inlet end of the air bridge piping is connected to the air bridge fixed end support, the air outlet end of the air bridge piping is connected to the ventilation body, and a gap is left between the air bridge piping and the ventilation body.

[0009] Preferably, the ventilator body is provided with an upper reinforcing rib and a lower reinforcing rib, which are only connected to the ventilator body.

[0010] Preferably, the integrated parallel balance adopts two sets of six-component lever balances arranged symmetrically. The measuring ends of the two sets of six-component lever balances are integrally machined into a single measuring structure, and the fixed ends of the two sets of six-component lever balances are integrally machined into a single fixing structure.

[0011] Preferably, the strain elements of each group of six-component bar balances include a first rectangular beam, a first T-beam, a second T-beam, and a second rectangular beam, and strain gauges and temperature sensitivity compensation plates are attached to the first rectangular beam, the first T-beam, the second T-beam, and the second rectangular beam.

[0012] Option 2: Design method of parallel air bridge balance force measurement system, wherein the parallel air bridge balance force measurement system is the parallel air bridge balance force measurement system, including the following steps:

[0013] Step 1: The integrated parallel balance adopts two sets of six-component bar balances arranged symmetrically. The fixed end interface of the integrated parallel balance is matched with the belly support rod, and the measuring end interface of the integrated parallel balance is matched with the ventilation body.

[0014] Step 2: Calculate the air bridge piping parameters.

[0015] (1)

[0016] In the formula Where is the air density, P is the maximum design pressure of the pipeline, m is the molar mass of air, R is the universal gas constant, and T is the Kelvin temperature;

[0017] (2)

[0018] In the formula S For the air bridge pipe (5) flow area, M This refers to the mass flow rate of a single air bridge tube. The velocity of air flowing within the air bridge duct;

[0019] The air bridge piping is a circular pipe, therefore:

[0020] (3)

[0021] In the formula, D is the inner diameter of the air bridge pipe, and π is pi.

[0022] Based on the performance of the air bridge piping material, welding requirements, piping weight, and the thickness and sealing requirements of other component connections, a piping wall thickness t1 is selected. Subsequently, a pressure resistance check of the piping wall thickness is performed, requiring that the actual selected wall thickness t1 be greater than the minimum pressure-resistant wall thickness t.

[0023] (4)

[0024] In the formula, t is the minimum pressure-resistant wall thickness, and D1 is the outer diameter of the pipe, where D1 = D + 2 * t1. Where Ej is the allowable stress of the pipeline material, Ej is the welding coefficient (taken as 1 for seamless steel pipes), and Y is the influence coefficient.

[0025] Preferably, the method for assembling a parallel air bridge balance includes:

[0026] Strain gauges and temperature sensitivity compensation gauges are attached to the first rectangular beam, first T-beam, second T-beam, and second rectangular beam of each group of six-component lever balances to form a Wheatstone bridge.

[0027] In the first group of six-component bar balances, the strain gauges on the first rectangular beam are grouped into groups of four, forming bridges M1 and M3; in the first group of six-component bar balances, the strain gauges on the second rectangular beam are grouped into groups of four, forming bridges M2 and M4; and the strain gauges on the first T-beam and the second T-beam are grouped into groups of four, forming bridge M5.

[0028] In the second group of six-component lever balances, the strain gauges on the first rectangular beam are grouped into four groups to form bridges M6 and M7; in the first group of six-component lever balances, the strain gauges on the second rectangular beam are grouped into four groups to form bridges M8 and M9; and the strain gauges on the first T-beam and the second T-beam are grouped into four groups to form bridge M10. By performing combined calculations on bridges M1 to M10, the six-component output results of the integrated parallel balance are obtained.

[0029] Preferably, the calculation formula for the six-component output result is as follows:

[0030] The formula for calculating lift ΔUY is:

[0031] △UY=△U1+△U6-△U2-△U7 (5)

[0032] The formula for calculating the pitch moment ΔUMz is:

[0033] △UMz=△U1+△U2+△U6+△U7 (6)

[0034] The formula for calculating lateral force is:

[0035] △UZ=△U4+△U9-△U3-△U8 (7)

[0036] The formula for calculating rolling torque is:

[0037] △UMx=△U1+△U2-△U6-△U7 (8)

[0038] The formula for calculating yaw torque is:

[0039] △UMy=△U5-△U10 (9)

[0040] The formula for calculating resistance is:

[0041] △UX=△U5+△U10 (10)

[0042] Where △U1~△U10 represent the changes in the output signals of bridge M1~bridge M10, respectively.

[0043] Preferably, the calibration structure of the integrated parallel balance includes a calibration base, a shaped calibration support rod, an air bridge loading beam, and a loading beam connector. The calibration base is set on a static calibration platform. One end of the shaped calibration support rod is connected to the calibration base, and the other end is connected to the fixed end of the integrated parallel balance. The loading beam connector is connected to the measuring end of the integrated parallel balance. The air bridge loading beam is connected to the loading beam connector. The air inlet end of the air bridge pipe is connected to the shaped calibration support rod, and the air outlet end of the air bridge pipe is connected to the loading beam connector.

[0044] Preferably, a radial installation gap is left at the position where the loading beam connector connects to the air bridge pipe to facilitate the insertion and connection of the air bridge pipe.

[0045] The present invention has the following beneficial effects:

[0046] 1. The present invention provides a parallel air bridge balance force measurement system suitable for a central air intake model. By symmetrically arranging the integrated parallel balance, air bridge pipeline and air bridge fixed end support inside the ventilated fuselage, and adopting a layout in which the central air intake occupies the middle of the fuselage, the technical problem that the traditional internal air bridge balance system cannot be properly arranged due to insufficient internal space in the fuselage of the central air intake layout aircraft model is effectively solved. The system achieves the effect of decoupling high pressure air supply and force measurement under space-constrained conditions.

[0047] 2. The present invention provides a design method for a parallel air bridge balance force measurement system suitable for a central air intake model. Through the symmetrical arrangement and overall processing of the integrated parallel balance, the accurate calculation and pressure resistance verification of the air bridge pipeline parameters, the optimized design of the disturbance reduction unit, the gooseneck air bridge layout, and the addition of reinforcing ribs, a reasonable gap is maintained between the air bridge pipeline and the fuselage cavity and the balance. This ensures both the accuracy of the force measurement system and the sufficient rigidity of the ventilated fuselage as the main load-bearing component. Thus, this design method can systematically solve the structural design problems of wind tunnel models caused by insufficient internal space of the fuselage due to the air intake and the difficulty in arranging the air bridge balance force measurement system.

[0048] 3. The present invention provides a method for assembling an integrated parallel air bridge balance. By attaching strain gauges and temperature sensitivity compensation plates to the rectangular beams and T-beams of two symmetrically arranged six-component rod balances, ten Wheatstone bridges are formed. The six-component result is obtained by combining and calculating the output signals of the bridges. This enables accurate measurement of aerodynamic loads in a confined space. At the same time, the temperature sensitivity compensation plates ensure that the measurement accuracy is not affected by temperature changes, thereby improving the measurement reliability and environmental adaptability of the balance.

[0049] 4. The present invention provides a calibration structure for an integrated parallel air bridge balance. By setting up an irregularly shaped calibration support rod, a loading beam connector, and an air bridge loading beam, the integrated parallel balance and the air bridge pipeline can be calibrated as a whole under simulated real working conditions. The installation gap reserved at the connection position of the loading beam connector and the air bridge pipeline facilitates pipeline insertion and connection, ensuring the convenience and repeatability of calibration installation, thereby ensuring that the force measurement accuracy of the balance in wind tunnel tests meets the test requirements. Attached Figure Description

[0050] Figure 1 This is a 3D diagram of a parallel air bridge balance force measurement system; Figure 2 This is the installation diagram for a parallel air bridge balance force measurement system; Figure 3 This is a schematic diagram of the coordination of a parallel air bridge balance force measurement system; Figure 4 This is a schematic diagram of the operation of an integrated parallel balance; Figure 5 It is a bridge and road diagram of an integrated parallel balance.

[0051] In the diagram: 1-ventilation body, 2-central air intake, 3-upper reinforcing rib, 4-integrated parallel balance, 5-air bridge pipeline, 6-air bridge fixed end support, 7-belly support rod, 8-lower reinforcing rib, 9-calibration base, 10-irregular calibration support rod, 11-air bridge loading beam, 12-loading beam connector, 401-six-component lever balance, 402-integrated measuring structure, 403-integrated fixed structure, 411-first rectangular beam, 412-first T-beam, 413-second T-beam, 414-second rectangular beam. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0053] Example 1: Combination Figures 1-2 This embodiment describes a parallel air bridge balance force measurement system suitable for a central air intake model, comprising a ventilation body 1, a central air intake 2, an integrated parallel balance 4, air bridge pipes 5, air bridge fixed end supports 6, and abdominal support rods 7.

[0054] A central air intake duct 2 is provided in the middle of the ventilation body 1, and an integrated parallel balance 4 is installed inside the ventilation body 1. The fixed end of the integrated parallel balance 4 is connected to the abdominal support rod 7, and the measuring end of the integrated parallel balance 4 is connected to the ventilation body 1.

[0055] The fixed end support 6 of the air bridge is connected to the fixed end of the integrated parallel balance 4. The air inlet of the air bridge pipe 5 is connected to the fixed end support 6, and the air outlet of the air bridge pipe 5 is connected to the ventilation body 1. A gap is left between the air bridge pipe 5 and the ventilation body 1 to ensure that the air bridge pipe 5 does not come into contact with the ventilation body 1 under load or no load conditions, thereby reducing interference with the force measurement of the balance.

[0056] High-pressure air flows from the intake end of the air bridge pipe 5 through two symmetrically arranged air bridge pipes 5 and then enters the corresponding connecting pipe of the ventilation body 1 to provide driving gas for the engine simulation device.

[0057] To enhance the rigidity of the ventilator body 1, an upper reinforcing rib 3 and a lower reinforcing rib 8 are provided on the ventilator body 1. The upper reinforcing rib 3 and the lower reinforcing rib 8 are only connected to the ventilator body 1 and do not come into contact with other components, so as to avoid the reinforcing ribs affecting the force measurement of the balance.

[0058] The integrated parallel balance 4 adopts two symmetrically arranged sets of six-component lever balances 401. To avoid the influence of assembly errors and assembly stress, the measuring ends of the two sets of six-component lever balances are integrally machined as a single measuring structure 402, and the fixed ends of the two sets of six-component lever balances are integrally machined as a single fixing structure 403. The fixed end interface of the balance is designed to match the belly support rod 7, and the measuring end interface of the balance is designed to match the ventilator body 1.

[0059] Each set of six-component lever balances 401 includes a first rectangular beam 411, a first T-beam 412, a second T-beam 413, and a second rectangular beam 414, arranged in a front-to-back sequence, i.e., front and back double rectangular beams and two sets of T-beams. Strain gauges and temperature sensitivity compensation plates are attached to the first rectangular beam 411, the first T-beam 412, the second T-beam 413, and the second rectangular beam 414 to sense strain changes caused by loads and convert them into electrical signals for output.

[0060] This embodiment effectively solves the technical problem that the traditional internal air bridge balance system cannot be properly arranged due to insufficient internal space in the fuselage of the aircraft model with the central air intake duct 2 occupying the middle of the fuselage by symmetrically arranging the integrated parallel balance 4, air bridge pipeline 5 and air bridge fixed end support 6 inside the ventilated fuselage 1.

[0061] Example 2: Combination Figures 1-2This embodiment describes a design method for a parallel air bridge balance force measurement system suitable for a central air intake model. The method, used to design the parallel air bridge balance force measurement system described in Example 1, includes the following steps:

[0062] Step 1: Integrated Parallel Balance Structure Design. The integrated parallel balance 4 adopts two symmetrically arranged sets of six-component lever balances 401. To avoid the influence of assembly errors and assembly stress, both the fixed end and the measuring end of the integrated parallel balance 4 are integrally machined. The fixed end interface of the integrated parallel balance 4 is matched with the web support rod 7, and the measuring end interface of the integrated parallel balance 4 is matched with the ventilation body 1. The strain element of each lever balance consists of front and rear double rectangular beams and two sets of T-beams.

[0063] Step 2: Calculate the air bridge piping parameters. Based on parameters such as the maximum design pressure, mass flow rate, and gas constant, calculate the inner diameter and wall thickness of air bridge piping 5, and perform pressure resistance verification. The specific calculation formula is as follows:

[0064] (1)

[0065] In the formula Where is the air density, P is the maximum design pressure of the pipeline, m is the molar mass of air, R is the universal gas constant, and T is the Kelvin temperature;

[0066] (2)

[0067] In the formula S For the air bridge pipe (5) flow area, M This refers to the mass flow rate of a single air bridge tube. The velocity of air flowing within the air bridge duct;

[0068] The air bridge piping is a circular pipe, therefore:

[0069] (3)

[0070] In the formula, D is the inner diameter of the air bridge pipe, and π is pi.

[0071] Based on the performance of the air bridge piping material, welding requirements, piping weight, and the connection thickness and sealing requirements of other components, the piping wall thickness t is selected. Then, the pressure resistance of the pipe wall thickness is checked, requiring the actual selected wall thickness to be greater than the minimum pressure-resistant wall thickness. The formula for calculating the minimum pressure-resistant wall thickness is:

[0072] (4)

[0073] In the formula, t is the minimum pressure-resistant wall thickness, and D1 is the outer diameter of the pipe. Let t1 be the allowable stress of the pipeline material, Ej be the welding coefficient (1 for seamless steel pipes), and Y be the influence coefficient; where D1 = D + 2 * t1.

[0074] Step 3: Disturbance Suppression Unit Design. The disturbance suppression unit employs elastic rubber rings or bellows for pipeline sealing and elastic disturbance suppression. The form of the disturbance suppression unit is selected to meet the internal space requirements of the powered full-mold, ensuring a gap between the air bridge pipeline 5, the inner cavity of the ventilation body 1, and the integrated parallel balance 4, thus guaranteeing the reliability of the internal air bridge balance. The dimensions of the air bridge disturbance suppression units and their distances are optimized to reduce the impact of the air bridge system on the balance's stiffness.

[0075] Step 4: Air Bridge Piping Layout Design. The air bridge piping layout design adopts a two-inlet gooseneck air bridge layout to ensure reasonable arrangement of piping within a limited space and good interference reduction effect.

[0076] Step 5: System Integration and Layout. The designed air bridge piping 5, air bridge fixed end support 6, and integrated parallel balance 4 are symmetrically arranged within the ventilation unit 1, ensuring that the air bridge fixed end support 6 does not collide with the ventilation unit 1. Simultaneously, by adding upper reinforcing ribs 3 and lower reinforcing ribs 8, sufficient rigidity and strength are ensured for the ventilation unit 1, as the main load-bearing component, to meet the test requirements.

[0077] This embodiment achieves a reasonable gap between the air bridge pipe 5 and the inner cavity of the ventilation fuselage 1 and the integrated parallel balance 4 through symmetrical arrangement and overall processing of the integrated parallel balance 4, precise calculation and pressure resistance verification of the parameters of the air bridge pipe 5, optimized design of the disturbance reduction unit, gooseneck air bridge layout, and addition of reinforcing ribs. This ensures the accuracy of the force measurement system and the sufficient rigidity of the ventilation fuselage 1 as the main load-bearing component. Thus, it systematically solves the structural design problem of wind tunnel model caused by insufficient internal space of the fuselage due to the air intake and the difficulty in arranging the air bridge balance force measurement system.

[0078] Example 3: Combination Figures 1-5 This embodiment describes a method for assembling a parallel air bridge balance. The integrated parallel balance 4 consists of two symmetrically arranged sets of six-component lever balances 401. The strain elements of each set of six-component lever balances 401 include a first rectangular beam 411, a first T-beam 412, a second T-beam 413, and a second rectangular beam 414.

[0079] Strain gauges and temperature sensitivity compensation plates are attached to the first rectangular beam 411, the first T-beam 412, the second T-beam 413, and the second rectangular beam 414.

[0080] The specific surface mount and bridging methods are as follows:

[0081] Two strain gauges are symmetrically attached to the upper and lower surfaces of the first rectangular beam 411, i.e., two on the upper surface and two on the lower surface. These four strain gauges, together with two temperature compensation gauges attached to the beam, form a Wheatstone bridge M1, which is used to measure the load component related to the normal force. Two strain gauges are symmetrically attached to the left and right sides of the first rectangular beam 411, i.e., two on the left side and two on the right side. These four strain gauges, together with two other temperature compensation gauges attached to the beam, form a Wheatstone bridge M3, which is used to measure the load component related to the lateral force.

[0082] Two strain gauges are symmetrically attached to the upper and lower surfaces of the second rectangular beam 414, i.e., two on the upper surface and two on the lower surface. These four strain gauges, together with two temperature compensation gauges attached to the beam, form a Wheatstone bridge M2. Two strain gauges are symmetrically attached to the left and right sides of the second rectangular beam 414, i.e., two on the left side and two on the right side. These four strain gauges, together with two other temperature compensation gauges attached to the beam, form a Wheatstone bridge M4.

[0083] A strain gauge is attached to both the front and rear sides of the root of the first T-beam 412, and a strain gauge is attached to both the front and rear sides of the root of the second T-beam 413, for a total of four strain gauges. At the same time, a temperature compensation gauge is attached to the outer side of the first T-beam 412, and a temperature compensation gauge is attached to the outer side of the second T-beam 413. The above four strain gauges and two temperature compensation gauges together form a Wheatstone bridge M5, which is used to measure the load components related to axial force.

[0084] The second group of balances is assembled in the same way as the first group, that is, strain gauges and temperature compensation gauges are attached to the first rectangular beam, the second rectangular beam, the first T-beam, and the second T-beam in the same way, and they are respectively formed into Wheatstone bridges M6, M7, M8, M9, and M10.

[0085] Bridges M1 to M10 output signals, denoted as ΔU1 to ΔU10. By combining and calculating these ten output signals, the six-component load result of the integrated parallel balance can be obtained. The specific calculation formula is as follows:

[0086] The formula for calculating lift ΔUY is:

[0087] △UY=△U1+△U6-△U2-△U7 (5)

[0088] The formula for calculating the pitch moment ΔUMz is:

[0089] △UMz=△U1+△U2+△U6+△U7 (6)

[0090] The formula for calculating lateral force is:

[0091] △UZ=△U4+△U9-△U3-△U8 (7)

[0092] The formula for calculating rolling torque is:

[0093] △UMx=△U1+△U2-△U6-△U7 (8)

[0094] The formula for calculating yaw torque is:

[0095] △UMy=△U5-△U10 (9)

[0096] The formula for calculating resistance is:

[0097] △UX=△U5+△U10 (10)

[0098] Where △U1~△U10 represent the changes in the output signals of bridge M1~bridge M10, respectively.

[0099] This embodiment achieves precise measurement of aerodynamic loads in a confined space by arranging strain gauges on the rectangular and T-beams of each balance as described above and forming ten Wheatstone bridges. These bridges are then combined to obtain a six-component output, enabling accurate measurement of aerodynamic loads. The use of temperature compensation plates effectively eliminates the influence of temperature changes on the measurement results, ensuring the balance's measurement accuracy and reliability.

[0100] Example 4: Combination Figures 1-3 This embodiment describes a calibration structure for a parallel air-bridge balance. The calibration structure includes a calibration base 9, a shaped calibration support rod 10, an air-bridge loading beam 11, and a loading beam connector 12. The calibration base 9 is mounted on a static calibration platform. One end of the shaped calibration support rod 10 is connected to the calibration base 9, and the other end is connected to the fixed end of the integrated parallel balance 4. The loading beam connector 12 is connected to the measuring end of the integrated parallel balance 4, and the air-bridge loading beam 11 is connected to the loading beam connector 12. The air inlet of the air-bridge pipe 5 is connected to the shaped calibration support rod 10, and the air outlet of the air-bridge pipe 5 is connected to the loading beam connector 12.

[0101] A radial installation gap is left at the position where the loading beam connector 12 connects to the air bridge pipe 5, so as to facilitate the insertion and connection of the air bridge pipe 5.

[0102] The specific installation steps are as follows:

[0103] Step 1: First, connect the irregularly shaped calibration support rod 10 to the calibration base 9 installed on the calibration platform. Use the six-degree-of-freedom displacement adjustment capability of the calibration platform to adjust the angle and displacement of the irregularly shaped calibration support rod 10.

[0104] Step 2: Using the positioning stop and connecting screws, connect and fasten the integrated parallel balance 4 to the irregular calibration support rod 10.

[0105] Step 3: Using the positioning stop and connecting screws, connect the air bridge pipes 5 on the left and right sides to the irregular calibration support rod 10, and adjust the direction of the air bridge pipes for subsequent installation.

[0106] Step 4: Connect the loading beam connector 12 to the air bridge loading beam 11. The two beams will then be hoisted and installed as a whole.

[0107] Step 5: Simultaneously connect the loading beam connector 12 and the air bridge loading beam 11 to the integrated parallel balance 4 and the air bridge pipe 5, and secure them reliably. During installation, the middle of the loading beam connector 12 is positioned with the integrated parallel balance 4 using a stop. Sufficient installation clearance is left radially on both sides of the loading beam connector 12 at the connection positions with the air bridge pipe 5 to allow the air bridge pipe 5 to be smoothly inserted into the holes of the loading beam connector 12.

[0108] The above steps complete the calibration and installation of the balance, enabling subsequent balance calibration work.

[0109] This embodiment, by setting up an irregularly shaped calibration support rod 10, a loading beam connector 12, and an air bridge loading beam 11, enables the integrated parallel balance 4 and the air bridge pipeline 5 to be calibrated as a whole under simulated real working conditions. The installation gap reserved at the connection position of the loading beam connector 12 and the air bridge pipeline 5 facilitates pipeline insertion and connection, ensuring the convenience and repeatability of calibration installation, thereby ensuring that the force measurement accuracy of the balance in the wind tunnel test meets the test requirements.

[0110] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A parallel air bridge balance force measurement system, characterized in that, It includes a ventilation body (1), a central air intake (2), an integrated parallel balance (4), an air bridge pipeline (5), an air bridge fixed end support (6), and a belly support rod (7); the central air intake (2) is provided in the middle of the ventilation body (1), the integrated parallel balance (4) is located inside the ventilation body (1), the fixed end of the integrated parallel balance (4) is connected to the belly support rod (7), the measuring end of the integrated parallel balance (4) is connected to the ventilation body (1), the air bridge fixed end support (6) is connected to the fixed end of the integrated parallel balance (4), the air intake end of the air bridge pipeline (5) is connected to the air bridge fixed end support (6), the air outlet end of the air bridge pipeline (5) is connected to the ventilation body (1), and there is a gap between the air bridge pipeline (5) and the ventilation body (1).

2. The parallel air bridge balance force measurement system according to claim 1, characterized in that: The ventilation body (1) is provided with an upper reinforcing rib (3) and a lower reinforcing rib (8), which are only connected to the ventilation body (1).

3. The parallel air bridge balance force measurement system according to claim 1, characterized in that: The integrated parallel balance (4) adopts two sets of six-component lever balances (401) arranged symmetrically. The measuring ends of the two sets of six-component lever balances are integrally machined from an integrated measuring structure (402), and the fixed ends of the two sets of six-component lever balances are integrally machined from an integrated fixing structure (403).

4. The parallel air bridge balance force measurement system according to claim 3, characterized in that: Each set of six-component bar balances (401) includes a first rectangular beam (411), a first T-beam (412), a second T-beam (413), and a second rectangular beam (414) with strain gauges and temperature sensitivity compensation plates attached to the first rectangular beam (411), the first T-beam (412), the second T-beam (413), and the second rectangular beam (414).

5. A design method for a parallel air bridge balance force measurement system, wherein the parallel air bridge balance force measurement system is the parallel air bridge balance force measurement system as described in claim 4, characterized in that, Includes the following steps: Step 1: The integrated parallel balance (4) adopts two sets of six-component bar balances (401) arranged symmetrically. The fixed end interface of the integrated parallel balance (4) is matched with the belly support rod (7), and the measuring end interface of the integrated parallel balance (4) is matched with the ventilation body (1). Step 2: Calculate the air bridge piping parameters. （1） In the formula Where is the air density, P is the maximum design pressure of the pipeline, m is the molar mass of air, R is the universal gas constant, and T is the Kelvin temperature; （2） In the formula S For the air bridge pipe (5) flow area, M This refers to the mass flow rate of a single air bridge tube. The airflow velocity within the air bridge duct; The air bridge pipe (5) is a circular pipe, therefore: （3） In the formula, D is the inner diameter of the air bridge pipe, and π is pi. Based on the performance of the air bridge piping material, welding requirements, piping weight, and the thickness and sealing requirements of other component connections, a piping wall thickness t1 is selected. Subsequently, a pressure resistance check of the piping wall thickness is performed, requiring that the actual selected wall thickness t1 be greater than the minimum pressure-resistant wall thickness t. （4） In the formula, t is the minimum pressure-resistant wall thickness, and D1 is the outer diameter of the pipe, where D1 = D + 2 * t1. Let Ej be the allowable stress of the pipeline material, Ej be the welding coefficient (1 for seamless steel pipes), and Y be the influence coefficient.

6. The design method of the parallel air bridge balance force measurement system according to claim 5, characterized in that, The bridging method of the integrated parallel balance (4) includes: Strain gauges and temperature sensitivity compensation plates are attached to the first rectangular beam (411), the first T-beam (412), the second T-beam (413), and the second rectangular beam (414) of each group of six-component bar balances (401) to form a Wheatstone bridge. In the first group of six-component bar balances (401), the strain gauges on the first rectangular beam (411) are grouped into groups of four, forming bridge M1 and bridge M3; in the first group of six-component bar balances (401), the strain gauges on the second rectangular beam (414) are grouped into groups of four, forming bridge M2 and bridge M4; the strain gauges on the first T-beam (412) and the second T-beam (413) are grouped into groups of four, forming bridge M5; In the second group of six-component bar balances (401), the strain gauges on the first rectangular beam (411) are grouped into groups of four, forming bridges M6 and M7; in the first group of six-component bar balances (401), the strain gauges on the second rectangular beam (414) are grouped into groups of four, forming bridges M8 and M9; the strain gauges on the first T-beam (412) and the second T-beam (413) are grouped into groups of four, forming bridge M10. By performing combined calculations on bridges M1 to M10, the six-component output results of the integrated parallel balance are obtained.

7. The design method of the parallel air bridge balance force measurement system according to claim 5, characterized in that: The formula for calculating the six-component output result is as follows: The formula for calculating lift ΔUY is: △UY=△U1+△U6-△U2-△U7 (5) The formula for calculating the pitch moment ΔUMz is: △UMz=△U1+△U2+△U6+△U7 (6) The formula for calculating lateral force is: △UZ=△U4+△U9-△U3-△U8 (7) The formula for calculating rolling torque is: △UMx=△U1+△U2-△U6-△U7 (8) The formula for calculating yaw torque is: △UMy=△U5-△U10 (9) The formula for calculating resistance is: △UX=△U5+△U10 (10) Where △U1~△U10 represent the changes in the output signals of bridge M1~bridge M10, respectively.

8. The design method of the parallel air bridge balance force measurement system according to claim 5, including the calibration structure of the integrated parallel balance (4), is characterized in that, The system includes a calibration base (9), a shaped calibration support rod (10), an air bridge loading beam (11), and a loading beam connector (12). The calibration base (9) is set on a static calibration platform. One end of the shaped calibration support rod (10) is connected to the calibration base (9), and the other end is connected to the fixed end of an integrated parallel balance (4). The loading beam connector (12) is connected to the measuring end of the integrated parallel balance (4). The air bridge loading beam (11) is connected to the loading beam connector (12). The air inlet of the air bridge pipe (5) is connected to the shaped calibration support rod (10), and the air outlet of the air bridge pipe (5) is connected to the loading beam connector (12).

9. The design method of the parallel air bridge balance force measurement system according to claim 8, characterized in that: The loading beam connector (12) has a radial installation gap at the connection point with the air bridge pipe (5) to facilitate the insertion and connection of the air bridge pipe (5).

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