A vernier type internal resistance precision measuring device for small aspect ratio flying wing layout

Abstract

This invention discloses a vernier-type precision internal resistance measurement device for low aspect ratio flying wing configurations, belonging to the field of wind tunnel testing. It includes a model to be tested on a support rod, two symmetrical support blades, one end of which is clamped to the support rod, and the other end of each support blade has a support cylinder. The axis of the support cylinder is aligned with the axis of the model to be tested. The rear section of the pressure-measuring rake is a columnar structure, which can be inserted into the support cylinder and moved along its axis. The front end of the pressure-measuring rake has several pressure-measuring holes, through which a pressure-measuring tube extends into the model to be tested. The structural improvements of this invention significantly enhance the overall performance of the support system, solving the long-standing technical bottleneck of low accuracy and poor stability in internal resistance measurement. It has significant engineering application value for promoting the development of low aspect ratio flying wing configuration aircraft.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing, and more specifically to a vernier-type precision measuring device for internal resistance of a low aspect ratio flying wing configuration. Background Technology

[0002] In the development of low aspect ratio flying wing aircraft, wind tunnel testing is the core method for obtaining their aerodynamic characteristics. In order to accurately measure the aerodynamic drag (i.e., internal resistance) of the internal flow channels of the ventilation model, the pressure rake method is usually used: a pressure rake is installed at a predetermined section inside the model, and the total pressure and static pressure distribution data are collected through multiple pressure measuring tubes, and then the internal resistance is calculated by integration.

[0003] In existing technologies, pressure-measuring rakes are typically fixed to a support rod at the rear of the model via supporting blades. However, within the confined and complex interior of the model, the following key technical challenges exist: First, the insertion depth of the pressure probe is difficult to observe directly and control precisely. Once it deviates from the design cross-section, it will directly lead to the failure of the measurement data. For example, in the published literature (CN116609027A), the pressure probe is connected by bolts and the position of the pressure probe is adjusted by threaded connection. This cannot accurately ensure the accuracy and reliability of the measured cross-section.

[0004] Secondly, the pressure gauge bundle lacks effective fixation after passing through the support blades, making it prone to swaying under high-speed airflow, affecting measurement accuracy and even causing pipeline damage. The connection between the support blades and the struts often shifts due to wind tunnel vibration and airflow impact, severely impacting measurement repeatability and stability. Existing designs are mostly simple fixing structures, failing to systematically address these problems; for example, published literature (CN113267313A) addresses this by adding connecting sleeves to ensure relative stillness between the pressure gauges. Summary of the Invention

[0005] Based on existing technologies and combined with the objective field of wind tunnel testing, this invention proposes improvements to the support structure to solve the problem of not being able to accurately adjust the relative position of the pressure measuring rake in current wind tunnel testing. At the same time, the improvement of the support structure achieves vibration suppression under high-speed airflow.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A vernier-type precision measuring device for internal resistance in a low aspect ratio flying wing configuration includes: A support rod, one end of which is connected to the model under test. The support structure includes two symmetrical support blades. One end of each support blade is clamped onto a support rod, and the other end of each support blade is fitted with a support cylinder. The axial direction of the support cylinder is aligned with the axial direction of the track of the model under test. The pressure testing rake includes a front end and a rear end. The rear end of the pressure testing rake is a columnar structure. The rear end of the pressure testing rake can be inserted into a support cylinder and move along the axial direction of the support cylinder. The front end of the pressure testing rake is provided with several pressure testing holes. The pressure testing tube passes through the pressure testing holes and extends into the model to be tested.

[0007] In the above technical solution, the side of the support cylinder is provided with a through slot along the axial direction, and a reference scale is provided on one side of the slot. The rear section of the pressure measuring rake is provided with a scale aligned with the reference scale along the axial direction.

[0008] In the above technical solution, the support cylinder is provided with a locking component for fixing the position of the support cylinder and the rear section of the pressure measuring rake.

[0009] In the above technical solution, the blade surface of the support blade is provided with several through holes for fixing the pressure measuring tube.

[0010] In the above technical solution, the inner surface of the clamp of the supporting blade is provided with a groove, and an adhesive is filled between the support rod and the groove.

[0011] In the above technical solution, there are several grooves along the axial direction of the support rod on the inner surface of the clamp.

[0012] This invention discloses a method for using a vernier-type precision internal resistance measuring device for a low aspect ratio flying wing configuration, comprising the following steps: Step 1: Connect the support structure to the support rod using clamps, and fill the groove with adhesive to fix the support structure to the support rod; Step 2: Connect the rear section of the pressure testing rake to the support cylinder, and extend one end of the pressure testing tube through the pressure testing hole at the front end of the pressure testing rake into the model to be tested; Step 3: Using the scale on the pressure testing rake, adjust the relative position of the pressure testing rake and the model being tested to ensure that the front end of each pressure testing tube is accurately positioned on the same measuring section; Step 4: Secure several pressure testing tubes to the support blades by bundling them together through the through holes; Step 5: Use locking devices to fix the support cylinder to the rear section of the pressure measuring rake.

[0013] In the above technical solution, after each set of test measurements is completed, the fixed position of the rear section of the pressure measuring rake and the support cylinder is readjusted using a ruler to realize the replacement of the measurement section in the model to be tested.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention innovatively applies the principle of vernier calipers to the installation and adjustment of wind tunnel pressure gauges. By coordinating the vernier scale on the pressure gauge with the reference marks on the support blades, the problem of depth adjustment, which was originally invisible and unmeasurable inside the model, is transformed into a displacement measurement problem that is visible and can be accurately read from outside the model. This shift in design concept overcomes the technical prejudice of those skilled in the art that "precise measurement is difficult in confined spaces," achieving a positioning accuracy of up to 0.02 mm, laying a solid foundation for high-precision measurement of internal resistance.

[0015] This invention innovatively solves the problem that traditional pressure rakes cannot be adjusted due to the angle between the support rod and the model's track, by designing the axial direction of the support cylinder to be consistent with the axial direction of the intake channel. This ensures that the pressure rake remains consistent with the thrust axis of the intake channel before and after position adjustment.

[0016] This invention features through holes on the support blades for securing the pressure measuring tube, effectively solving the problem of loose pressure measuring tubes affecting the flow field in traditional solutions. Furthermore, the design of the pressure measuring hole at the front end of the pressure measuring rake solves the problem of fixing the pressure measuring tube. The structure is extremely simple, with significant effects, overcoming the shortcomings of traditional designs where the pipeline is prone to shaking and damage.

[0017] This invention employs a method of adding grooves to the inner surface of the clamp structure for adhesive injection. This not only increases the adhesion between the support blade and the support rod, but also increases the contact area between the support rod and the support blade in the radial direction by using the adhesive-fixed structure. The adhesive effectively suppresses the impact of high-frequency vibration and strong airflow impact in wind tunnel tests on the support blade, ensuring the stable operation of the pressure measuring rake.

[0018] The invention features ingenious structural improvements that significantly enhance the overall performance of the support system. It solves the long-standing technical bottleneck of low accuracy and poor stability in internal resistance measurement, and has significant engineering application value for promoting the development of low aspect ratio flying wing aircraft. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the support structure for the pressure-measuring rake. Figure 2 This is a schematic diagram of the overall support structure of the experimental model; Figure 3 This is a schematic diagram of the structure of the rear section of the pressure rake; Figure 4 Schematic diagram of a fixed pressure gauge tube; The attached diagram shows the markings and corresponding component names: 1 is the support rod, 2 is the front end of the pressure measuring rake, 3 is the rear end of the pressure measuring rake, 4 is the support cylinder, 5 is the clamp, 6 is the support blade, 7 is the through hole, 8 is the groove, 9 is the model to be tested, 10 is the pressure measuring tube, 11 is the locking component, 12 is the scale, 13 is the reference scale, and 14 is the locking band. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0021] Example 1 The experimental model support structure in this embodiment is as follows: Figure 2 As shown, the test model 9 is connected to a support rod 1 via a voltage level. One end of the support rod 1 is connected to a curved mechanism used for wind tunnel testing. A support mechanism is provided between the support rod and the test model 9 to support the pressure measuring rake. The pressure measuring tube 10 extends into the test model 9 through the pressure measuring rake to complete the test.

[0022] In this embodiment, the main objective is to achieve pressure measurement at different air intake sections within the model 9 under test during the measurement process, thereby improving the pressure measuring rake.

[0023] like Figure 1 As shown, this embodiment divides the traditionally fixed pressure rake into two parts. One part is a support structure, including two symmetrical support blades 6. One end of the support blades 6 is clamped to each other 5, and the two support blades 6 are locked to the support rod 1 by the clamps 5. The other end of the support blades 6 is provided with a support cylinder 4, which is used to movably connect the rear section 3 of the pressure rake. The rear section 3 of the pressure rake is a cylindrical structure that can move along the axial direction of the support cylinder 4. The front end of the rear section 3 of the pressure rake is a one-piece pressure rake front end 2, which is provided with several pressure measuring holes that pass through both ends for the pressure measuring tube 10 to pass through.

[0024] In the traditional design, the support cylinder 4 is fixed coaxially with the support rod 1. However, there is an angle between the axis of the support rod and the thrust axis of the intake duct. Therefore, in the traditional design, the pressure measuring rake can only complete one test after being fixed, and it is impossible to perform accurate measurements of multiple sections. This embodiment addresses this issue by improving the support cylinder 4 that supports the pressure measuring rake. The axis of the support cylinder 4 is aligned with the thrust axis of the intake duct of the model under test 9. When the position of the rear section 3 of the pressure measuring rake relative to the support cylinder 4 is adjusted, the front end 2 of the pressure measuring rake can be adjusted along the axis of the model under test 9, ensuring that the cross-section of the front end of all pressure measuring tubes remains unchanged.

[0025] Based on the improvement of the support cylinder 4 structure, in order to achieve precise position adjustment, a groove is opened on the side of the support cylinder 4 along the axial direction, and a reference scale 13 is set on one side of the groove. At the same time, a scale 12 is set on the rear section 3 of the pressure measuring rake. The scale 12 is used to align with the reference scale 13, thereby achieving precise adjustment of the position of the front end 2 of the pressure measuring rake. Figure 3 As shown.

[0026] The above improvements precisely solve the objective problem that the position of the pressure gauge end in the model can only be blindly adjusted in the current wind tunnel test. At the same time, the precise calibration of the scale solves the problem of uniformity of the pressure gauge position change and prevents the pressure gauge end face from deviating from the designed measurement section.

[0027] To ensure that the rear section 3 of the pressure measuring rake is fixed in position with the support cylinder 4, a set of locking parts 11 is installed on the support cylinder 4 to lock it. The locking parts 11 can be locking rings or clamp-like structures to achieve the clamping of the rear section 3 of the pressure measuring rake by the support cylinder 4.

[0028] In this embodiment, in order to ensure axial accuracy, the internal dimensions of the rear section 3 of the pressure measuring rake and the support cylinder 4 are kept as consistent as possible to prevent excessive gaps from causing changes in the axial direction.

[0029] The further improvement to the support structure in this embodiment addresses the connection between the support structure and the support rod 1. In this embodiment, a clamp 5 is used to fix the support blade 6 to the support rod 1. To prevent vibration and displacement of the support blade 6 under high-speed airflow, several grooves 8 are provided on the inner surface of the clamp 5 along the axial direction of the support rod 1. Adhesive is then injected into the grooves 8, allowing the adhesive to bond with the surface of the support rod 1 and the grooves, increasing the contact force between the clamp 5 and the surface of the support rod 1. Simultaneously, because a support arm can be formed radially into the groove 8 after adhesive fixation, increasing the contact area between the clamp 5 and the support rod 1, the physical properties of the cured adhesive can, to a certain extent, dampen vibrations in the clamp 5.

[0030] This embodiment further improves the support blade 6 for fixing the pressure measuring tube 10, such as... Figure 1 and Figure 4 As shown, several through holes 7 are provided on the support blade 6. When the pressure measuring tube 10 passes through the front end 2 of the pressure measuring rake, the scattered pressure measuring tube is fixed to the through hole 7 by the locking band 14. This structure design can avoid the need to design a structure specifically for fixing the pressure measuring tube, reduce the structure on the support blade 6, and prevent excessive vibration of the structure under high-speed airflow.

[0031] Example 2 Based on the structure of Embodiment 1, this embodiment proposes the usage process of this structure in actual measurement: First, through experimental design, the position for fixing the support blade 6 is found. Then, the clamps 5 of the two support blades 6 are fastened to the support rod 1, and glue is poured into the groove 8. Wait for the glue to cure to form a stable base.

[0032] Then, the front end of the pressure measuring tube is passed through the pressure measuring hole on the front end 2 of the pressure measuring rake, and all pressure measuring tubes are fixedly installed and extended into the model 9 to be tested. Then, the rear section 3 of the pressure measuring rake is inserted into the support cylinder 4. According to the test requirements, the relative position of the scale 12 on the rear section 3 of the pressure measuring rake and the reference scale 13 is adjusted to accurately move the front end 2 of the pressure measuring rake axially.

[0033] In this step, the minimum precision of machining is limited to 0.02mm, so the minimum precision of the scale is also 0.02mm. This allows the axial displacement of the pressure measuring tube at the front end 2 of the pressure measuring rake 2 inside the model to be tested 9 to be adjusted by 0.02mm, which can accurately position the front end of the pressure measuring tube within the theoretically designed measurement section inside the model to be tested.

[0034] Secondly, the loose pressure measuring tubes are tied and fixed by passing the locking strap 14 through the through hole 7 to prevent them from shaking under high-speed airflow.

[0035] Finally, the rear section 3 of the pressure measuring rake and the support cylinder 4 are fixed by locking the locking element 11, thus completing the installation of the entire device.

[0036] When starting an experiment, after completing one set of data measurements, it is not necessary to adjust the entire pressure rake support structure before proceeding to the next set of experiments. Simply loosen the locking piece 11, and then adjust the rear section 3 of the pressure rake according to the experimental design requirements. By aligning the scale, the position of the front end of the pressure tube within the model to be tested 9 can be precisely adjusted to ensure that the next theoretical measurement section can be tested.

[0037] This embodiment successfully solves three major technical problems in internal resistance measurement: inaccurate control of the pressure measuring tube depth, easy pipe shaking, and easy loosening of the support structure, thus achieving high-precision and high-reliability internal resistance measurement.

[0038] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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 vernier-type precision measuring device for internal resistance in a low aspect ratio flying wing configuration, characterized in that, include: A support rod, one end of which is connected to the model under test. The support structure includes two symmetrical support blades. One end of each support blade is clamped onto a support rod, and the other end of each support blade is fitted with a support cylinder. The axial direction of the support cylinder is aligned with the axial direction of the track of the model under test. The pressure testing rake includes a front end and a rear end. The rear end of the pressure testing rake is a columnar structure. The rear end of the pressure testing rake can be inserted into a support cylinder and move along the axial direction of the support cylinder. The front end of the pressure testing rake is provided with several pressure testing holes. The pressure testing tube passes through the pressure testing holes and extends into the model to be tested.

2. The vernier-type internal resistance precision measuring device for a low aspect ratio flying wing configuration according to claim 1, characterized in that, The side of the support cylinder has a through slot along the axial direction, and a reference scale is provided on one side of the slot. The rear section of the pressure measuring rake has a scale aligned with the reference scale along the axial direction.

3. The vernier-type internal resistance precision measuring device for a low aspect ratio flying wing configuration according to claim 2, characterized in that, The support cylinder is equipped with a locking device to fix the position of the support cylinder and the rear section of the pressure measuring rake.

4. The vernier-type internal resistance precision measuring device for a low aspect ratio flying wing configuration according to claim 1, characterized in that, The support blade has several through holes on its surface for fixing the pressure measuring tube.

5. A vernier-type precision measuring device for internal resistance in a low aspect ratio flying wing configuration according to claim 1, characterized in that, The inner surface of the clamp of the supporting blade is provided with a groove, and adhesive is filled between the support rod and the groove.

6. A vernier-type precision measuring device for internal resistance in a low aspect ratio flying wing configuration according to claim 5, characterized in that, Several grooves begin to appear on the inner surface of the clamp along the axial direction of the support rod.

7. A method of using a vernier-type internal resistance precision measuring device for a low aspect ratio flying wing configuration as described in claim 1, characterized in that, Includes the following steps: Step 1: Connect the support structure to the support rod using clamps, and fill the groove with adhesive to fix the support structure to the support rod; Step 2: Connect the rear section of the pressure testing rake to the support cylinder, and extend one end of the pressure testing tube through the pressure testing hole at the front end of the pressure testing rake into the model to be tested; Step 3: Using the scale on the pressure testing rake, adjust the relative position of the pressure testing rake and the model being tested to ensure that the front end of each pressure testing tube is accurately positioned on the same measuring section; Step 4: Secure several pressure testing tubes to the support blades by bundling them together through the through holes; Step 5: Use locking devices to fix the support cylinder to the rear section of the pressure measuring rake.

8. The method of using the vernier-type internal resistance precision measuring device for a low aspect ratio flying wing configuration according to claim 7, characterized in that, After each set of test measurements is completed, the fixed position of the rear section of the pressure measuring rake and the support cylinder is readjusted using a ruler to allow the measurement section of the end of the pressure measuring tube to be replaced within the model to be tested.

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