Anti-rotation coaxial thermocouple appearance structure for high-altitude high-speed flight test

Abstract

The utility model relates to an anti-rotation coaxial thermocouple appearance structure for a high-altitude high-speed flight test, which comprises a matching section, a threaded section and a tail section, and a through hole is processed on the coaxial thermocouple appearance structure to serve as a mounting hole of a core-shaped inner electrode. The top of the matching section is in a long circular shape, and the matching section is in clearance fit with a hole machined in an aircraft, so that the sensor can be prevented from rotating in the mounting or using process; threads are machined on the threaded section and used for installing a nut in the aircraft for pre-tightening, looseness and vibration are prevented, and the effect of reducing the influence of external airflow on the sensor is achieved. The appearance of the coaxial thermocouple can be installed from the outside to the inside of an aircraft, the problem that the installation process cannot be observed is solved, and the coaxial thermocouple has the advantages of being large in operation space, convenient to install and high in installation efficiency. According to the utility model, the maintenance cost and the installation cost of temperature measurement of high-speed flight equipment are greatly reduced, and the preparation efficiency and the operation efficiency of a flight test are improved.

Description

Technical Field

[0001] The utility model belongs to the field of the appearance of coaxial thermocouples, and particularly relates to an appearance structure of a coaxial thermocouple for high-altitude and high-speed flight tests that prevents rotation. Background Technique

[0002] When a high-speed flight device flies in the atmosphere, the surrounding air is strongly compressed, and there is a violent frictional effect with the surface of the aircraft. Most of the kinetic energy of the aircraft will be converted into air heat energy, resulting in a sharp rise in the air temperature. There is a huge temperature difference between the high-temperature air and the surface of the aircraft. Part of the heat energy is transferred to the surface of the aircraft through the boundary layer. This heating phenomenon is called "aerodynamic heating", that is, aerodynamic heat. Accurately grasping the energy transfer process of aerodynamic heating is the only way to effectively carry out thermal protection design and ensure flight safety. On this basis, through reasonable design, the payload efficiency and flight performance can be maximized. In high-speed flight tests, surface heat flux measurement is one of the most widely used measurement items and is also a most basic measurement technology in aerodynamic experimental research.

[0003] During the flight of an aircraft, for high-scouring areas, thermocouples with strong scouring resistance and suitable for extremely high heat flux measurement are often widely used in aerodynamic heat and thermal protection tests. Among them, coaxial thermocouples are commonly used temperature sensors for flight tests due to their small volume, high precision, and strong environmental adaptability. However, the installation space in high-speed flight devices is generally narrow. The traditional installation process inside the aircraft brings huge time costs and expensive installation costs to the installation of coaxial thermocouples. In addition, once the temperature sensor body rotates during the installation process, the internal signal line and electrode will rotate as a whole, and even interfere with the temperature measurement results. Therefore, it is extremely important to develop a new appearance of a coaxial thermocouple for high-altitude and high-speed flight tests that prevents rotation and its installation method. Designing a suitable appearance of the coaxial thermocouple and a corresponding set of installation methods will greatly reduce the maintenance cost and installation cost for temperature measurement of high-speed flight devices, and improve the preparation efficiency and operation efficiency of flight tests. Summary of the Utility Model

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and provide an appearance structure of a coaxial thermocouple for high-altitude and high-speed flight tests that prevents rotation, thereby solving the rotation problem and corresponding appearance problems that are prone to occur in coaxial thermocouples during high-altitude and high-speed flight tests, reducing time costs and installation costs, and improving the safety and reliability of coaxial thermocouples.

[0005] The above object of the utility model is mainly achieved by the following technical solutions:

[0006] The external structure of the coaxial thermocouple includes a threaded section, a mating section, and a tail section. Through holes are axially provided in the threaded section, the mating section, and the tail section, and the through holes communicate with the mounting holes serving as the inner electrodes; the mating section is mated with the hole on the aircraft body to achieve the connection between the mating section and the aircraft body; the top shape of the mating section is an oblong formed by two parallel sections and two symmetrical arc sections; the outer surface of the threaded section is provided with an external thread, the tail section is a cylindrical section, one end of the threaded section is connected to the mating section, and the other end is connected to the tail section.

[0007] The external structure of the coaxial thermocouple further includes a nut, and the nut is in threaded fit with the threaded section, and the major diameter of the threaded section is smaller than the diameter of the corresponding hole on the aircraft body.

[0008] The mounting position of the nut is between the connection part of the threaded section and the tail section and the middle 1 / 2 of the threaded section.

[0009] The top shape of the mating section is an oblong formed by combining two parallel sections and two symmetrical arc sections.

[0010] The mating section includes two stepped sections with different diameters, and the smaller-diameter end of the stepped section is connected to the threaded section.

[0011] The thread of the threaded section is a fine thread.

[0012] The ratio of the total length of the external structure of the coaxial thermocouple to the aperture of the central through hole is 25 - 40:1; the ratio of the total length to the major diameter of the thread is 5 - 8:1.

[0013] The connection parts between the mating section and the threaded section and between the threaded section and the tail section are chamfered with a chamfer of R0.2 - 0.4.

[0014] The mating type between the mating section and the aircraft body is a clearance fit.

[0015] The coaxiality requirement between the mating section and the corresponding hole on the aircraft body is φ0.1mm.

[0016] The threaded section, the mating section, and the tail section are integrally formed.

[0017] The utility model has at least the following beneficial effects compared with the prior art:

[0018] (1) The external shape of the coaxial thermocouple provided by the utility model can prevent rotation during the installation or use of the sensor, solves the problem of sensor rotation that may be caused by vibration or installation of the sensor, thereby causing the internal signal line and electrode to rotate, and further causing the problem of temperature measurement distortion.

[0019] (2) The external shape of the coaxial thermocouple provided by the utility model can be installed from the outside to the inside of the aircraft or model. Compared with the current coaxial thermocouple installed from the inside to the outside, it solves the problem of being unable to observe the installation process, and has the characteristics of large operating space, convenient installation, and high installation efficiency.

[0020] (3) The present utility model preferably uses nut pre - tightening, which has the effects of preventing loosening and vibration, and reducing the influence of external air flow on the sensor. The thread section preferably uses fine - thread, which has the effect of improving the sealing performance.

[0021] (4) The overall shape of the coaxial thermocouple of the present utility model is made of the same material as the aircraft. After installation, the part of the coaxial thermocouple that is higher than the surface of the aircraft's shape is trimmed flat, which can reduce the influence of the coaxial thermocouple on the aerodynamic shape of the aircraft and restore the outer surface of the aircraft to the greatest extent. Description of the Drawings

[0022] Figure 1 is the overall structural schematic diagram after the assembly of the coaxial thermocouple's shape structure of the present utility model;

[0023] Figure 2 is the front view and top view of the coaxial thermocouple's shape structure of the present utility model;

[0024] Figure 3 is the positive tri - axial isometric view of the coaxial thermocouple's shape structure of the present utility model. Detailed Embodiment

[0025] The following further describes the present utility model in detail with reference to the drawings and specific embodiments:

[0026] As Figure 1 shown is the overall structural schematic diagram after the assembly of the coaxial thermocouple's shape structure of the present utility model, Figure 2 is the front view and top view of the coaxial thermocouple's shape structure of the present utility model, Figure 3 is the positive tri - axial isometric view of the coaxial thermocouple's shape structure of the present utility model. It can be seen from the figure that the coaxial thermocouple's shape structure of the present utility model includes a thread section 1, a mating section 6, and a tail section 7. Through - holes 2 are axially opened in the thread section 1, the mating section 6, and the tail section 7, and the through - holes 2 communicate with the installation holes serving as the inner electrodes; the mating section 6 is mated with the hole on the aircraft body 3 to realize the connection between the mating section 6 and the aircraft body 3. The mating type is clearance fit. The top shape of the mating section 6 is oblong, and the superposition of the oblong shape and the clearance fit has a better anti - rotation gain effect; the outer surface of the thread section 1 is provided with an external thread. One end of the thread section 1 is connected to the mating section 6, and the other end is connected to the tail section 7. In addition, there are coaxiality requirements between the mating section and the corresponding hole on the aircraft, generally φ0.1mm. At the same time, there are symmetry requirements for the oblong hole at the top of the mating section, generally 0.04mm. When the mating section meets the limiting conditions of coaxiality and symmetry, the coaxial thermocouple has the beneficial effect of avoiding assembly interference caused by misalignment with the center of the aircraft's assembly hole.

[0027] The forming method of the thread section 1, the mating section 6, and the tail section 7 is integral forming.

[0028] Threads are machined on the threaded section 1 for installing and pre-tightening nuts inside the aircraft, and its outer diameter is smaller than the corresponding threaded hole machined on the aircraft.

[0029] The installation position of the nut 4 is between the connection part of the threaded section 1 and the tail section 7 and the middle 1 / 2 of the threaded section 1.

[0030] The top shape of the mating section 6 is an oblong composed of two parallel sections and two symmetric arc sections.

[0031] The mating section 6 includes two stepped sections with different diameters, and the smaller-diameter end of the stepped section is connected to the threaded section 1.

[0032] The thread of the threaded section 1 is a fine thread.

[0033] For the external shape structure of the coaxial thermocouple, the ratio of the total length to the diameter of the central through hole is 25 - 40:1, and the ratio of the total length to the major diameter of the thread is 5 - 8:1; the chamfers at the connection part between the mating section 6 and the threaded section 1 and the connection part between the threaded section 1 and the tail section 7 are R0.2 - 0.4.

[0034] The tail section 7 is a cylindrical section, and its main function is to serve as a transition for the connection between the sensor and the connector. Since the temperature outside the aircraft is relatively high, and the temperature drops more significantly the farther away from the end face of the sensor, the cylindrical section is used for temperature cooling so as not to affect the use of the connector.

[0035] The working principle of the present utility model is as follows:

[0036] First, the external shape of the coaxial thermocouple is installed from the outside of the aircraft and inserted into the hole machined on the aircraft; second, after insertion, the top of the coaxial thermocouple is slightly higher than the aircraft surface by 0.01 mm - 0.05 mm. At this time, tighten the nut inside the aircraft to generate a certain pre-tightening force, and the external shape of the coaxial thermocouple will drop a certain height axially but still be higher than the aircraft surface; finally, grind the part of the top of the coaxial thermocouple that is higher than the aircraft surface until it is flush with the aircraft surface. After grinding and making it flush, the sensor can minimize the influence brought by the protrusions and grooves of the aerodynamic characteristics, and at the same time ensure the conduction of the heat flow sensor to ensure the correctness of the test results.

[0037] The design result of the external shape of the coaxial thermocouple of the present utility model can pass tests such as temperature screening test, high-temperature tolerance test, high and low temperature working test, shock test, vibration test, etc. with a relatively high qualification rate, and mass production has now been achieved and it has been applied in flight tests.

[0038] The above are only the best specific implementation manners of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present utility model should be covered within the protection scope of the present utility model.

[0039] The content not detailedly described in the specification of the present utility model belongs to the well-known technology of those skilled in the art.

Claims

1. A coaxial thermocouple shape structure for anti-rotation high-altitude high-speed flight test, characterized in that: The coaxial thermocouple outer structure (5) comprises a threaded section (1), a mating section (6) and a tail section (7); the threaded section (1), the mating section (6) and the tail section (7) are all provided with a through hole (2) along the axial direction, and the through hole (2) is connected to the mounting hole of the inner electrode; the mating section (6) is matched with the hole on the aircraft body (3) to realize the connection between the mating section (6) and the aircraft body (3); the top shape of the mating section (6) is an oblong, the outer surface of the threaded section (1) is provided with an external thread, and the tail section (7) is a cylindrical section, one end of the threaded section (1) is connected to the mating section (6), and the other end is connected to the tail section (7); The top shape of the matching section (6) is an oblong shape formed by combining two parallel sections and two symmetrical arc sections; The type of fit between the fitting section (6) and the aircraft body (3) is clearance fit.

2. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 1 is characterized in that: The coaxial thermocouple outer structure (5) also includes a nut (4), the nut (4) is threadedly matched with the threaded section (1), and the major diameter of the threaded section (1) is smaller than the diameter of the corresponding hole on the aircraft body (3).

3. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 2 is characterized in that: The nut (4) is installed at a position between the connection between the threaded section (1) and the tail section (7) and the middle 1 / 2 of the threaded section (1).

4. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 1 is characterized by: The matching section (6) comprises two step sections with different diameters, and the end of the step section with a smaller diameter is connected to the threaded section (1).

5. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 1 is characterized in that: The thread of the threaded section (1) is a fine pitch thread.

6. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 1 is characterized by: The ratio of the total length of the coaxial thermocouple outer structure (5) to the diameter of the central through hole is 25 to 40:1; the ratio of the total length to the major diameter of the thread is 5 to 8:

1.

7. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 1 is characterized by: The chamfer angles of the connection parts between the matching section (6) and the threaded section (1) and the connection parts between the threaded section (1) and the tail section (7) are R0.2 to 0.

4.

8. The anti-rotation high-altitude high-speed flight test coaxial thermocouple appearance structure according to claim 1 is characterized by: The coaxiality requirement between the matching section (6) and the corresponding hole on the aircraft body (3) is φ0.1 mm.

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