Thermocouple sensor for testing temperature of explosion field

Abstract

A thermocouple sensor used for explosion field temperature testing is composed of a positive thermocouple wire, a negative thermocouple wire, a front-end conical head structure, a rear-end shell, an aluminum oxide ceramic sleeve, a compensation wire and an internal pouring sealant, the aluminum oxide ceramic sleeve is arranged in the rear-end shell, the front-end conical head structure is arranged at the front end of the rear-end shell, and the compensation wire is arranged at the rear end of the rear-end shell. The rear-end shell and the front-end conical head structure are packaged through internal pouring sealant, the positive and negative thermocouple wires penetrate through two through holes of the aluminum oxide ceramic sleeve respectively, one ends of the positive and negative thermocouple wires are connected with the corresponding positive and negative electrodes of the compensation wire, and the other ends of the positive and negative thermocouple wires extend out of the temperature measuring end face and are in direct contact with an explosion heat flow field. The utility model provides a thermocouple sensor for testing the temperature of an explosion field, and the thermocouple sensor has remarkable advantages in the aspect of testing the temperature of the explosion field.

Description

TECHNICAL FIELD

[0001] The utility model relates to sensor test field, concretely is a kind of thermocouple sensor for explosion field temperature test. BACKGROUND

[0002] Explosion field temperature is one of the key parameters in thermal damage assessment, and accurate acquisition of explosion field temperature is of great significance to weapon equipment optimization, research and development of new energy-containing materials, protective structure design and other aspects.Explosion field temperature test can be divided into non-contact temperature measurement method and contact temperature measurement method.Non-contact measurement method is based on radiation thermometry technology, and the main problems in the process of explosion field test are:1) the emissivity of explosion products is unknown, and only the brightness temperature of the object can be measured, not the true temperature;2) the emissivity changes with temperature, which easily leads to large error in calculated temperature;3) the emissivity is easily affected by the test environment;Therefore, at present, explosion field temperature is still mainly measured by contact thermocouple sensor.

[0003] At present, the conventional thermocouple sensor mainly has the following shortcomings:1) the sensor has a long dynamic response time, and it is difficult to accurately reflect the change rule of explosion flow field;2) the sensor has poor pressure resistance, and the sensor sensitive element is easily damaged and broken under the action of explosion field shock wave;3) the shell of the sensor temperature measuring end is generally designed as a plane, and the detached shock wave formed in high-speed airflow will directly act on the sensor sensitive element, affecting the temperature measurement result.

[0004] Chinese invention patent CN102818647 discloses a fast-response thermocouple for explosion field transient high pressure resistance, which fills phosphoric acid-copper oxide inorganic glue at the end of thermocouple wire extending out of the shell;Chinese utility model patent CN213579825 also discloses a thermocouple sensor for explosion field thermal convection medium temperature measurement, which fills insulating material in the middle of the welding electrode material;In this type of scheme, the positive and negative electrode structures of the sensor sensitive end are both lap joint or butt joint type, and the volume of the sensor sensitive end is large, which has certain destructive effect on the integrity of explosion flow field;At the same time, this type of scheme generally applies insulating material after preparing hot junction, in order to avoid that the filler adheres to the surface of hot junction and reduces the dynamic response performance of the sensor, additional protection is needed for the hot junction of the sensor, which increases the damage probability of the hot junction.

[0005] Chinese utility model patent CN218916575 discloses a tungsten-rhenium 5 / 26 thermocouple sensor for explosion field transient high temperature measurement, which mainly improves the insulation between the sensor shell and the thermocouple wire, but does not effectively improve the pressure resistance of the sensor sensitive element structure. UTILITY MODEL CONTENT

[0006] In view of the deficiencies of the prior art, the utility model provides a thermocouple sensor for explosion field temperature test, which has significant advantages in explosion field temperature test.

[0007] To achieve the above object, the technical scheme adopted by the utility model is:

[0008] A thermocouple sensor for explosion field temperature test, which is composed of positive and negative thermocouple wires, a front-end cone head structure, a rear-end shell, an alumina ceramic sleeve, a compensation lead and internal filling glue, the alumina ceramic sleeve is arranged in the rear-end shell, the rear-end shell has a front-end cone head structure, the rear-end shell and the front-end cone head structure are packaged by the internal filling glue, the positive and negative thermocouple wires respectively pass through two through holes of the alumina ceramic sleeve, one end is connected with the positive and negative poles of the compensation lead in correspondence, the other end extends out of the temperature measuring end surface and directly contacts with the explosion heat flow field.

[0009] As a further improvement of the utility model, the positive and negative thermocouple wires adopt standard tungsten-rhenium 5-26 thermoelectric materials, the positive pole alloy theoretical mass ratio W: Re = 95: 5 wt%, and the negative pole alloy theoretical mass ratio W: Re = 74: 26 wt%.

[0010] As a further improvement of the utility model, the positive pole wire of the positive and negative thermocouple wires is designed as a cylindrical shape with an extension length of 10 to 15 mm, and the negative pole wire is designed as a spiral shape and wound on the surface of the positive pole wire; an insulating paint is applied on the surface of the positive pole wire to prepare a hot junction at the temperature measuring end of the positive and negative thermocouple wires.

[0011] As a further improvement of the utility model, the wire diameter of the positive and negative thermocouple wires is selected in the range of 0.15 to 0.2 mm, the maximum stress of the butt joint structure under 2MPa pressure loading is 63MPa, and the diameter of the prepared hot junction should be in the range of 0.4 to 0.5 mm.

[0012] As a further improvement of the utility model, the taper D:L of the front-end cone head structure is 3 / 4, and an internal through hole is processed; the rear end of the structure is a cylindrical body with a diameter of Φ10mm, and an internal thread is processed in the cylindrical body.

[0013] As a further improvement of the utility model, the rear-end shell is in a tubular shape, an external thread is processed at the front end for connecting the front-end cone head structure.

[0014] As a further improvement of the utility model, the front-end cone head structure and the rear-end shell are made of 304 stainless steel; a rubber sealing ring is used in the thread cooperation process.

[0015] As a further improvement of the utility model, the alumina ceramic sleeve is a double-hole cylindrical body as a whole; the structure is 10mm long, the hole diameter is 1mm, and the hole spacing is 2mm; the dielectric strength of the alumina ceramic material reaches 17 to 20kV / mm, and the resistivity is generally greater than 10^8Ω·cm.

[0016] As a further improvement of the utility model, the compensation wire is made of metal material with the same thermoelectric characteristics as the positive and negative thermocouple wires; during preparation, a cold welding machine is used to weld the positive and negative thermocouple wires corresponding to the positive and negative electrodes of the compensation wire.

[0017] As a further improvement of the utility model, the internal potting glue is epoxy glue, which is poured into the temperature measuring end and the tail end of the sensor respectively.

[0018] The utility model has the following beneficial effects:

[0019] High voltage resistance: by optimizing the structural design of the positive and negative thermocouple wires, especially the winding type sensitive element structure of the negative thermocouple wire wound on the surface of the positive thermocouple wire, the voltage resistance of the sensor is significantly improved. Simulation results show that the maximum stress of this structure is much lower than that of the butt joint structure under the same pressure, and it is suitable for high pressure environment such as explosion field.

[0020] Good dynamic response performance: the accurate selection of the diameters of the positive and negative thermocouple wires and the hot junction diameter ensures that the sensor has the characteristics of fast response. The time constant is less than or equal to 2ms, so that the sensor can accurately capture the temperature change in the explosion field.

[0021] Excellent insulation performance: the use of aluminum oxide ceramic sleeve and insulating paint ensures good insulation between the positive and negative thermocouple wires, avoiding measurement errors caused by short circuit.

[0022] Conical head structure improves the influence of detached shock wave: the design of the conical head structure at the front end effectively improves the range and angle of the detached shock wave, reduces the influence of the detached shock wave on the sensitive element, and improves the measurement accuracy of the sensor.

[0023] Overall sealing and impact resistance: the use of rubber sealing ring and high temperature epoxy glue improves the overall sealing, impact resistance and vibration resistance of the sensor, ensuring the stability and reliability of the sensor in harsh environment.

[0024] Easy to calibrate and maintain: the compensation wire and the thermocouple wire are welded by a cold welding machine, which ensures good connection and consistency of thermoelectric characteristics, and facilitates calibration and maintenance of the sensor. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Mechanical diagram of thermocouple sensor suitable for temperature test in explosion field;

[0026] Figure 2 The sensitive element structure formed by the positive and negative thermocouple wires wound around the temperature measuring end of the sensor;

[0027] Figure 3 The conical top structure of the sensor is shown in the schematic diagram and the mechanical diagram;

[0028] Figure 4 The simulation of the conical structure and the common plane structure under the action of 1.5 Mach, 1000K temperature airflow.

[0029] Component name:

[0030] 1. Positive and negative thermocouple wires; 2. Front end cone head structure; 3. Rear end shell; 4. Alumina ceramic sleeve; 5. Compensation wire; 6. Internal filling glue. DETAILED DESCRIPTION

[0031] The utility model will be described in further detail in combination with the drawings and specific embodiments:

[0032] The utility model discloses a thermocouple sensor for explosion field temperature test as shown in the mechanical drawing Figure 1 The sensor temperature measuring end, the sensitive element structure formed by the winding of positive and negative thermocouple wires is as shown in the mechanical drawing Figure 2 The sensor cone top structure schematic diagram and mechanical drawing are as shown in the mechanical drawing Figure 3 The simulation of the conical structure and the common plane structure under the action of 1.5 Mach, 1000K temperature airflow is as shown in the mechanical drawing Figure 4 A kind of thermocouple sensor for explosion field temperature test, the sensor is composed of positive and negative thermocouple wires 1, front end cone head structure 2, rear end shell 3, alumina ceramic sleeve 4, compensation wire 5, internal filling glue 6.

[0033] The positive and negative thermocouple wires adopt standard tungsten-rhenium 5-26 thermoelectric material, the positive electrode alloy theoretical mass ratio W:Re =95:5wt%, the negative electrode alloy theoretical mass ratio W:Re =74:26wt%, the positive and negative thermocouple wires respectively pass through the two through holes of alumina ceramic sleeve, one end is connected with the positive and negative poles corresponding to compensation wire, the other end extends out temperature measuring end face, directly contacts with explosion heat flow field;

[0034] Further, in order to improve the pressure resistance of the sensor, the positive and negative thermoelectric electrode wire structure exposed at the temperature measuring end of the sensor is optimized and designed; the positive electrode wire is designed as a column shape with a length of 10 to 15 mm; the negative electrode wire is designed as a spiral shape and wound on the surface of the positive electrode wire; the surface of the positive electrode wire is coated with insulating paint to ensure the insulation of the negative electrode wire in the winding part with the positive electrode wire; a hot junction is prepared at the end of the positive and negative electrode wires at the temperature measuring end; compared with the butt joint type sensitive element structure disclosed in CN218916575, CN102818647 and CN213579825, the winding type sensitive element structure has higher strength; the pressure resistance of the two structures is calculated by using simulation software, the diameter of the wire is 0.2 mm, and the maximum stress of the butt joint type structure is 63 MPa under the pressure of 2 MPa; the maximum stress of the winding type structure is about 5.9 MPa, which proves that the structure can effectively improve the strength of the sensor sensitive element and is suitable for explosive environment.

[0035] Further, in order to ensure the dynamic response performance and the strength of the sensitive element, the diameters of the positive and negative electrode wires are selected in the range of 0.15 to 0.2 mm; the diameter of the prepared hot junction should be in the range of 0.4 to 0.5 mm; the dynamic response parameters of the sensor are calibrated based on the water bath method, and the time constant of the sensor is measured to be less than or equal to 2 ms.

[0036] Further, in order to improve the mutual insulation of the positive and negative electrode wire winding parts, the insulating layer can be made of high temperature epoxy resin and high temperature insulating paint.

[0037] The front end cone head structure is as shown in Figure 3 The front end part of the structure is designed as a conical frustum with a taper D:L=3 / 4, and a through hole is processed in the inside; the rear end is a cylindrical body with a diameter of 10 mm, and an internal thread is processed in the inside; according to the simulation results Figure 4 It can be found that the detached shock wave area formed at the sensitive end is larger under the high speed and high temperature airflow excitation, and directly acts on the sensitive element structure; compared with the above, the cone head structure designed in the application can effectively improve the acting range and angle of the detached shock wave, and reduce the influence of the detached shock wave on the sensitive element to a certain extent.

[0038] The rear end shell is designed as a tube shape, and the front end is processed with external threads for connecting the front end cone head structure; further, the front end cone head structure and the rear end shell are made of 304 stainless steel; during the thread cooperation process, a rubber sealing ring is used to improve the overall sealing performance of the structure.

[0039] The alumina ceramic sleeve is a double-hole cylinder as a whole, the structure length is 10 mm, the opening diameter is 1 mm, and the hole spacing is 2 mm; the dielectric strength of the alumina ceramic material can reach 17-20 kV / mm, the resistivity is generally greater than 10^8 ohm*cm, and the insulation of the positive and negative thermocouple wires passing through the two through-holes can be ensured.

[0040] The compensation wires are made of metal materials with the same thermoelectric characteristics as the positive and negative thermocouple wires; during preparation, a cold welding machine is used to weld the positive and negative thermocouple wires corresponding to the positive and negative poles of the compensation wires.

[0041] The internal potting glue is high-temperature epoxy glue, which is filled into the temperature measuring end and the tail end of the sensor respectively, and after high-temperature curing, the impact and vibration resistance of the internal structure of the sensor can be effectively improved.

[0042] The above is only a preferred embodiment of the present application, and does not limit the present application in any other form, and any modification or equivalent change made according to the technical essence of the present application still falls within the scope of the present application.

Claims

1. A thermocouple sensor for explosion field temperature testing, comprising positive and negative thermocouple wires (1), a front end cone structure (2), a rear end housing (3), an alumina ceramic sleeve (4), a compensation wire (5) and an internal potting compound (6), characterized in that: The alumina ceramic sleeve (4) is arranged in the rear end shell (3), and the front end of the rear end shell (3) has a front end cone head structure (2). The rear end shell and the front end cone head structure (2) are encapsulated by an internal potting glue (6). The positive and negative thermocouple wires (1) respectively pass through the two through holes of the alumina ceramic sleeve (4), one end is connected to the positive and negative electrodes corresponding to the compensation wire (5), and the other end extends out of the temperature measuring end face and directly contacts the explosion heat flow field.

2. A thermocouple sensor for explosion field temperature testing according to claim 1, characterized in that: The positive and negative thermocouple wires (1) are made of standard tungsten-rhenium 5-26 thermoelectric material, with a positive electrode alloy theoretical mass ratio of W:Re = 95:5 wt%; and a negative electrode alloy theoretical mass ratio of W:Re = 74:26 wt%.

3. The thermocouple sensor for explosion field temperature testing according to claim 1, characterized in that: The positive electrode wire of the positive and negative thermocouple wires (1) extending from the temperature measuring end is designed to be cylindrical, with an extension length of 10 to 15 mm; the negative electrode wire extending from the temperature measuring end is designed to be spiral, and is wound around the surface of the positive electrode wire; an insulating coating is applied to the surface of the positive electrode wire, and a hot junction is prepared at the temperature measuring end at the end of the positive and negative thermocouple wires (1).

4. A thermocouple sensor for explosion field temperature testing according to claim 3, characterized in that: The diameter of the positive and negative thermocouple wires (1) is selected in the range of 0.15 to 0.2 mm. Under a pressure load of 2 MPa, the maximum stress of the butt-jointed structure is 63 MPa, and the diameter of the prepared hot junction should be in the range of 0.4 to 0.5 mm.

5. The thermocouple sensor for explosion field temperature testing according to claim 1, characterized in that: The front end cone head structure (2) has a taper D: L=3 / 4, and a through hole is machined inside; the rear end of the structure is a cylinder with a diameter of Φ10mm, and an internal thread is machined inside the cylinder.

6. The thermocouple sensor for explosion field temperature testing according to claim 5, characterized in that: The rear end housing (3) is tubular, and the front end is processed with an external thread for connecting to the front end cone head structure.

7. The thermocouple sensor for explosion field temperature testing according to claim 6, characterized in that: The front end cone head structure (2) and the rear end housing (3) are made of 304 stainless steel; during the thread matching process, a rubber sealing ring is used.

8. The thermocouple sensor for explosion field temperature testing according to claim 1, characterized in that: The alumina ceramic sleeve (4) is a double-hole cylinder as a whole; the structure is 10 mm long, the opening diameter is 1 mm, and the hole spacing is 2 mm; the dielectric strength of the alumina ceramic material reaches 17-20 kV / mm, and the resistivity is generally greater than 10^8 Ω·cm.

9. The thermocouple sensor for explosion field temperature testing according to claim 1, characterized in that: The compensation wire (5) is made of a metal material having the same thermoelectric properties as the positive and negative thermocouple wires (1); during preparation, a cold welding machine is used to weld the positive and negative thermocouple wires (1) corresponding to the positive and negative poles of the compensation wire (5).

10. The thermocouple sensor for explosion field temperature testing according to claim 1, characterized in that: The internal potting glue (6) is epoxy glue, which is poured into the sensor from the temperature measuring end and the tail end respectively.

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