Thermal shrinkage sheet-based transient temperature field heat flux testing device and method

Abstract

The application discloses a kind of transient temperature field heat flux testing device and method based on heat shrinkage piece, purpose is to solve the shortcomings of existing non-contact temperature measurement method, which is greatly influenced by the emissivity of measured object, insufficient response speed, and interference of measured temperature field.The testing device is composed of packaging shell, heat transfer element, heat shrinkage piece, thermal resistance block, screw and movable bolt.The heat transfer element, thermal resistance block and packaging shell are coaxially installed.The heat shrinkage piece and thermal resistance block are located in the packaging shell, the heat shrinkage piece is located in the groove at both ends of the thermal resistance block, and the thermal resistance block is tightly attached to the left end surface of the heat transfer element.The outer wall of the packaging shell is attached with a thermal insulation layer.The testing method is to quantitatively convert the heat flux into the quantitative plastic deformation of the heat shrinkage piece by plastic deformation of the heat shrinkage piece, to realize the rapid quantitative passive measurement of transient temperature field heat flux.The application is not influenced by the emissivity of measured object, has small measurement error, fast response speed, and is not interfered by measured temperature field, so that the quantitative measurement of transient temperature field heat flux can be accurately completed.

Description

Technical Field

[0001] This invention belongs to the field of measurement and testing, specifically relating to a test device for measuring transient temperature field heat flux. It is a passive test device that uses the deformation characteristics of heat shrink sheet to measure transient temperature field heat flux. Background Technology

[0002] Currently, with the development of science and technology, transient temperature fields (transient temperature fields refer to temperature fields whose existence time is on the order of seconds or even milliseconds) are often formed in some application scenarios, such as explosive explosions, gas explosions, and mine blasting. In these cases, measuring the heat flux of the transient temperature field can effectively assess the destructive effect of the temperature field on surrounding people or objects, which is of great significance for practical applications. Therefore, research on the measurement of heat flux of transient temperature fields has become an increasingly popular research topic.

[0003] Based on the relationship between the temperature sensing element and the target temperature field during measurement, temperature measurement is divided into contact and non-contact methods. Non-contact temperature measurement mainly includes: infrared radiation thermometry, fluorescence thermometry, dual-spectral thermometry, and acoustic thermometry. Infrared radiation thermometry can be further divided into total radiation thermometry and monochromatic methods, dual-band thermometry and multi-band thermometry. The basic principle of infrared radiation thermometry is the blackbody radiation law. Total radiation thermometry and monochromatic methods determine the temperature of an object by measuring the light emitted by the object at different wavelengths. However, this method is greatly affected by the emissivity of the object being measured, making it difficult to accurately measure the temperature in actual measurement. Dual-band thermometry and multi-band thermometry obtain the temperature of the object being measured based on the radiation power of two or more given wavelengths using a ratio method. This method is suitable for objects with unknown emissivity, but its application is limited to objects with high radiation energy density. Fluorescence thermometry uses the ratio of fluorescence intensity or fluorescence lifetime emitted by a fluorescent substance to measure temperature. The advantages of non-contact temperature measurement include small sensor size, no metallic materials, complete electrical insulation, immunity to high voltage and strong electromagnetic fields, resistance to chemical corrosion, and no pollution. However, because the transient temperature field is in a dynamic state, fluorescent materials cannot be applied, making fluorescence thermometry unsuitable for transient temperature field measurement. Based on atomic emission spectroscopy theory, when excited atoms transition from high to low energy levels, they produce specific atomic spectra. Dual-line thermometry calculates the transient temperature field temperature by measuring the energy of the atomic spectral radiation. This method can be used for transient temperature field measurement; however, band selection is difficult, requiring the selection of an appropriate band based on the transient temperature field.

[0004] Contact temperature measurement methods mainly include pressure temperature measurement, fiber optic temperature measurement, and thermoelectric temperature measurement. In contact temperature measurement, the sensing element must directly contact the target. According to the thermodynamic equilibrium law, the sensor receives heat through thermal conduction. Based on the temperature difference between the hot and cold ends, the electrical signal output by the sensing element is converted into temperature by an integrated circuit. Contact temperature measurement utilizes heat conduction and heat exchange. According to the first law of thermodynamics, the temperature of the sensing element at thermal equilibrium can be considered as the temperature of the measured medium. Contact temperature measurement has advantages such as simple operation and intuitive visualization. However, during the measurement process, the sensing element needs to be in full contact with the object being measured and reach thermal equilibrium. Its disadvantages are also quite obvious: the heat transfer process between the sensing element and the object being measured limits the response speed; simultaneously, the contact between the sensing element and the object being measured interferes with the measured temperature field.

[0005] In summary, existing measurement methods have at least the following technical problems:

[0006] 1. Existing non-contact temperature measurement methods have problems such as being greatly affected by the emissivity of the object being measured, being easily interfered with by other factors, measuring the temperature as the surface temperature of the object being measured, and the surrounding medium easily causing measurement errors, making it impossible to accurately measure the heat flux of the transient temperature field.

[0007] 2. Existing contact temperature measurement methods have problems such as insufficient response speed and interference with temperature field measurement due to contact with the object being measured, which leads to errors in the measurement results.

[0008] In practice, the measurement of transient temperature field heat flux can be obtained by measuring the degree of deformation of certain heat shrink sheets. With proper design, the thermal deformation process of heat shrink sheets can be stable and controllable. Some shape memory polymers with a large deformation range are ideal materials for measuring transient temperature fields. Heat shrink sheets refer to polymers mixed in a certain proportion, pre-formed into a certain shape at a programmed temperature, and gradually returning to their original state under heating conditions. They exhibit the characteristic that the degree of deformation changes with temperature; the temperature at which the shape changes is called the deformation temperature. During the thermal deformation process, within a certain range, there is a definite functional relationship between the temperature of the heat shrink sheet and the amount of plastic deformation of the shape memory polymer. This temperature-deformation correspondence makes it suitable for quantitative measurement of transient temperature field heat flux. Heat shrink sheets are generally elongated strips, and shape memory polymers of different sizes can be used to construct various measurement structures, corresponding to transient temperature fields of different intensities to achieve relatively accurate measurements. By selecting shape memory polymer materials with stable performance and a wide deformation temperature range, structurally stable and reliable transient temperature field heat flux measurement devices can be fabricated.

[0009] Currently, shape memory polymers are mainly used in aerospace and biomedicine fields, and there are no public reports on the use of shape memory polymer materials to prepare transient temperature field heat flux measurement devices. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a heat flux testing device and method for transient temperature field based on heat shrink sheets, which solves the problems existing in existing non-contact temperature measurement methods, such as being greatly affected by the emissivity of the measured object, being easily affected by other factors, the measured temperature being the surface temperature of the object, and surrounding media easily causing measurement errors; it compensates for the shortcomings of existing contact temperature measurement methods such as insufficient response speed and interference to the measured temperature field caused by contact with the measured object. The provided testing device has the characteristics of simple structure, low cost, strong anti-interference ability, rapid deployment, convenient post-result processing and high measurement accuracy, and can be used for measuring heat flux of transient temperature fields with different intensity grades, providing a new reference option for heat flux measurement of transient temperature fields. The testing method quantitatively converts heat flux into quantitative plastic deformation of the heat shrink sheet by using the plastic deformation of the heat shrink sheet, thereby realizing rapid quantitative passive testing of heat flux in transient temperature field. The testing method is not affected by the emissivity of the measured object, has small testing error, fast response speed, and is not interfered by the measured temperature field.

[0011] The heat flux testing device for transient temperature field based on heat shrink sheet of the present invention consists of an encapsulation shell, a heat transfer element, a heat shrink sheet, a thermal resistance block, screws, and a movable bolt. Define the end close to the heat transfer element as the right end, and the end far away from the heat transfer element as the left end; the heat transfer element, the thermal resistance block and the encapsulation shell are installed coaxially; the heat shrink sheet and the thermal resistance block are located in the encapsulation shell, the heat shrink sheet is arranged in the grooves at both ends of the thermal resistance block, and the thermal resistance block is closely attached to the left end face of the heat transfer element.

[0012] The encapsulation shell is used for loading and fixing other components, and is cylindrical in shape. The outer diameter D1 of the encapsulation shell satisfies 0.01m<D1<0.5m, the wall thickness t1 satisfies 0.02m<t1<0.1m, the inner diameter d1 satisfies d1=D1-2t1, and the length L1 satisfies 0.01m<L1<2m; the distance between the center of 4 evenly distributed screw holes processed on the right end face of the encapsulation shell and the center of the end face of the encapsulation shell satisfies r1=(D1+d1) / 4, the pitch diameter Φ1 of the screw holes satisfies 0.005m<Φ1<t1, the depth t of the screw holes 11 satisfies 0.02m<t 11<0.1 m, the heat transfer element is fixed through the connection between screw holes and screws; an internal thread is processed on the left end face, the pitch diameter of the internal thread Φ2=d1, the thread length t2 satisfies 0.02m<t2<0.03m, and the movable bolt is fixed through the internal thread. A heat insulation layer is adhered to the outer wall of the packaging shell, the thickness t9 of the heat insulation layer satisfies 0.00001m<t9<0.001m, so that there is no heat exchange between the inside and outside of the packaging shell, thereby achieving the heat insulation effect. The thermal conductivity λ1 of the heat insulation layer satisfies 0.01W / (m·K)<λ1<0.04W / (m·K). The packaging shell is made of metal material or polymethyl methacrylate, and the material is required to satisfy: yield strength σ1>150MPa, density ρ1>1.0g / cm 3 , the requirement is that the packaging shell does not produce plastic deformation when subjected to external impact.

[0013] The heat transfer element is used to conduct the heat of the transient temperature field to the heat shrinkable sheet and the thermal resistance block. Its shape is composed of a circular sheet and a cylinder, the thicknesses t3 and t4 of the circular sheet and the cylinder satisfy 0.001m<t3<0.1m and 0.005m<t4<0.03m respectively, which need to be adjusted according to actual measurement requirements; 4 screw through holes are processed on the right end face of the circular sheet, the distance r2 from the center of each screw hole to the center of the circular sheet satisfies r2=(D1+d1) / 4, the diameter of the screw through hole is Φ1; the heat transfer element is fixed on the right end of the packaging shell by screws; the heat transfer element is made of a material with good thermal conductivity, and the material is required not to produce plastic deformation under external impact, specifically the material is required to satisfy: yield strength σ2>200MPa, density ρ2>2.0g / cm 3 , thermal conductivity λ2≥100W / (m·K), and can withstand high temperature of 1000℃~10000℃ for 1 second to 10 minutes. The heat transfer element can be fixed and disassembled through screws, so that a new heat shrinkable sheet can be reloaded, and the test device can be reused.

[0014] The heat-shrinkable sheet is used to characterize the received heat and is in the shape of a long strip, the length L2 of which satisfies 0.008m<L2<0.02m, the width W1 satisfies 0.001m<W1<0.005m, and the thickness t5 satisfies 0.0005m<t5<0.001m. The heat-shrinkable sheet is made of shape memory polymer. It is required that before the transient temperature field heat flux test, the heat-shrinkable sheet is prefabricated into a long strip at the programming temperature. When the heat-shrinkable sheet is heated, as the temperature rises, the heat-shrinkable sheet undergoes plastic deformation of different degrees according to different temperatures, and there is a quantitative relationship between the deformation degree and temperature; shape memory polymers with different lengths and different materials can form temperature-measurement structures of various specifications with accurate correspondence between different temperatures and deformation degrees, which can achieve relatively accurate measurement for transient temperature fields of different intensities. At the same time, using shape memory polymer materials with stable properties can prepare a transient temperature field heat flux testing device with stable structure, reliable performance, and can be stored and used for a long time. The shape memory polymer material is required to meet: yield strength σ3<1000MPa, density ρ3<1.0g / cm 3 , and the temperature indicating range satisfies 303K<T<503K; the heat-shrinkable sheet is fixed through the grooves at both ends of the thermal resistance block, and new heat-shrinkable sheets can be reloaded, realizing recycling of the testing device.

[0015] Working mechanism of the heat-shrinkable sheet: when a transient temperature field occurs, the heat it carries propagates in space and loads the heat transfer element. The heat of the transient temperature field is transferred to the heat transfer element and converted into the internal energy of the heat transfer element. The heat of the heat transfer element is further transferred to the heat-shrinkable sheet and the thermal resistance block, and the shape of the heat-shrinkable sheet changes. The heat insulation layers on the inner and outer walls of the packaging shell block the heat exchange between the inner and outer spaces, and do not affect the shape change of the heat-shrinkable sheet.

[0016] The thermal resistance block is cylindrical, the cylinder diameter d2 satisfies d2=D1-2t1, the thickness l2 satisfies l2=L1-t2-t4, and the two ends of the thermal resistance block are parallel to each other and perpendicular to the central axis of the packaging shell. Each end plane of the thermal resistance block is provided with a groove, the groove is a cuboid, the center of which coincides with the central axis of the thermal resistance block, the width w1 of the groove is the same as the width W1 of the heat-shrinkable sheet, the length l3 is the same as the length L2 of the heat-shrinkable sheet, the depth t6 is the same as the thickness t5 of the heat-shrinkable sheet, and the two grooves are symmetrical about the center of the thermal resistance block. The thermal resistance block is made of inorganic materials, polymer materials or metal oxides, and the materials are required to meet: yield strength σ4<1000MPa, density ρ4>2.0g / cm 3 , thermal conductivity λ3 satisfies λ3≤250W / (m·K), and thermal expansion coefficient satisfies k≤3×10 -5 / ℃.

[0017] Before transient temperature field loading, the length of the heat-shrinkable sheet is x1. After transient temperature field loading, remove the screws, take off the heat transfer element, and measure the length of the heat-shrinkable sheet as x2, then obtain the strain of the heat-shrinkable sheet ε=(x1-x2) / x1. During interpretation, it shall be ensured that the interface between the heat transfer element and the packaging shell is in close contact. The corresponding relationship between temperature (T) and strain (ε) in the present invention is calibrated through a temperature-strain calibration experiment. The temperature difference ΔT between the two heat-shrinkable sheets can be calculated according to the strains of the heat-shrinkable sheets before and after transient temperature field loading. Combined with the thermal conductivity λ3 and thickness l2 of the thermal resistance block, the heat flux Ψ of the transient temperature field can be obtained as Ψ=λ3·ΔT / l2 (in W / m 2 ), thereby realizing rapid passive quantitative measurement of heat flux in a transient temperature field.

[0018] For the movable bolt, the diameter D4 of the left-end circular disc satisfies d1<D4<1.2D1, and the thickness t8 satisfies 0.01m<t8<0.05m. The length t7 of the external thread at the right end is the same as the length t2 of the internal thread on the left end face of the packaging shell, and the pitch diameter Φ3 of the thread is the same as the pitch diameter Φ2 of the internal thread on the left end face of the packaging shell. A central screw hole is processed on the left end face of the movable bolt, and the testing device is fixed through the connection between the central screw hole and a fixture. One central screw hole is processed at the center of the left end face of the movable bolt, the diameter Φ4 of the central screw hole satisfies 0.005m<Φ4<0.03m, and the length L3 of the screw hole satisfies 0.002m<L3<0.5t2. The sensor device is fixed through the connection between the central screw hole and a fixture. The movable bolt is made of metal material, and the material is required to meet: yield strength σ5>200MPa, density ρ5>2.0g / cm 3 .

[0019] The method for measuring heat flux in a transient temperature field by using the heat-shrinkable sheet-based testing device for heat flux in a transient temperature field of the present invention is as follows:

[0020] In the first step, the corresponding relationship between temperature (T) and strain (ε) of the testing device is calibrated through a temperature-strain calibration experiment.

[0021] In the second step, mount the movable bolt (6) on the left end of the packaging shell (1), place two heat-shrinkable sheets (3) in the grooves (41) at two ends of the thermal resistance block (4) respectively, and place the thermal resistance block (4) inside the packaging shell (1); the heat transfer element (2) is fixed at the right end of the packaging shell (1) with screws (5) to form the testing device, and the testing device is firmly fixed on the ground or a firm support through the central screw hole (61) of the movable bolt (6).

[0022] In the third step, check whether there is close contact between the heat transfer element (2) and the packaging shell (1), and whether the heat-shrinkable sheets (3) are completely placed in the grooves (41) at two ends of the thermal resistance block (4). Measure and record the lengths of the two heat-shrinkable sheets (3) at the left end and the right end of the thermal resistance block (4) before explosive detonation respectively, and denote the length of the one at the left end as x 11 , and denote the length of the one at the right end as x 21 .

[0023] The fourth step involves obtaining a transient temperature field by detonating the explosive. After the transient temperature field ends, the lengths of the two heat-shrink sheets 3 at the left and right ends of the thermal resistance block 4 are measured respectively. Let the length of the left end be x. 12 Let the value on the right be x. 22 .

[0024] Step 5: Calculate the strain ε1 of the heat shrink sheet 3 at the left end of the thermal resistance block 4, ε1=(x 11 -x 12 ) / x 11 Calculate the strain ε2 of the heat shrink sheet 3 at the right end of the thermal resistance block 4, ε2=(x 21 -x 22 ) / x 21 .

[0025] Step 6: Based on the strains ε1 and ε2 of the two heat shrink sheets 3 before and after the transient temperature field loading, the temperatures of the two heat shrink sheets 3 are found to be T1 and T2 respectively according to the correspondence between temperature (T) and strain (ε).

[0026] Step 7: Calculate the temperature difference ΔT across the thermal resistance block, ΔT = |T1 - T2|.

[0027] Step 8: Combining the thermal conductivity λ3 and thickness l2 of thermal resistance block 4, the heat flux Ψ of the transient temperature field is obtained, Ψ=λ3·ΔT / l2 (unit is W / m). 2 This enables rapid, passive, quantitative measurement of heat flux in transient temperature fields.

[0028] The ninth step is to remove the screws 5 and movable bolts 6 of the heat transfer element 2 and replace them with new heat shrink sheet 3, thereby enabling the test device to be reused.

[0029] The following technical effects can be achieved by using this invention:

[0030] 1. This invention can obtain the heat passing through the thermal resistance block by measuring the strain of the heat shrink sheet before and after the experiment, and can conveniently obtain the heat flux of the transient temperature field at the sensor, thus completing the quantitative test of the heat flux of the transient temperature field.

[0031] 2. The heat shrink sheet of this invention can be made of different materials, allowing for a wide variety of specifications. Based on the thermal conductivity of the thermal resistance block and the temperature range indicated by the heat shrink sheet, it can achieve a high response speed to transient temperature fields of high, medium, and low temperatures, thus enabling rapid measurement of heat flux in different types of transient temperature fields. The testing device can be placed within the temperature field to measure the heat flux at a given location, unaffected by complex electromagnetic interference; the testing device does not need to reach the temperature of the transient temperature field to perform the measurement, reducing interference to the measured temperature field.

[0032] 3. This invention has the characteristics of simple structure, no power supply required, convenient deployment and use, simple and intuitive results, low cost, and reusability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0034] Figure 2 This is an axial sectional view of the present invention.

[0035] Figure 3 This is a three-dimensional schematic diagram of the encapsulation housing 1.

[0036] Figure 4 This is a three-dimensional schematic diagram of heat transfer element 2.

[0037] Figure 5 This is a three-dimensional schematic diagram of heat shrink sheet 3.

[0038] Figure 6 This is a three-dimensional schematic diagram of thermal resistance block 4.

[0039] Figure 7 This is a three-dimensional schematic diagram of the movable bolt 6.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Encapsulation housing, 2. Heat transfer element, 3. Heat shrink sheet, 4. Thermal resistance block, 5. Screw, 6. Adjustable bolt, 7. Insulation layer. Detailed Implementation

[0042] To facilitate understanding and implementation of this invention by those skilled in the art, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure 1 As shown, this invention comprises a housing 1, a heat transfer element 2, two heat-shrink sheets 3, a thermal resistance block 4, screws 5, and a movable bolt 6. The end closer to the heat transfer element 2 is defined as the right end, and the end farther from the heat transfer element 2 is defined as the left end. The heat transfer element 2 is fixed to the right end of the housing 1 by screws 5, thus encapsulating the right end of the housing 1. The two heat-shrink sheets 3 and the thermal resistance block 4 are embedded within the housing 1, and the heat transfer element 2, thermal resistance block 4, and housing 1 are coaxially mounted. The two heat-shrink sheets 3 are respectively fixed in the grooves at both ends of the thermal resistance block 4. The movable bolt 6 is threadedly fixed to the left end of the housing 1, thus encapsulating the left end of the housing 1.

[0044] Figure 2 This is an axial sectional view of the present invention. Figure 3 This is a three-dimensional schematic diagram of the enclosure housing 1. (See diagram below.) Figure 2 and Figure 3As shown, the packaging shell 1 is cylindrical. The outer diameter D1 of the packaging shell 1 satisfies 0.01m<D1<0.5m, the wall thickness t1 satisfies 0.02m<t1<0.1m, the inner diameter d1 satisfies d1=D1-2t1, and the length L1 satisfies 0.01m<L1<2m; four screw holes 11 are uniformly processed along the circumferential direction on the right end face of the packaging shell 1, the distance r1 from the center of the four screw holes 11 to the center of the right end face of the packaging shell 1 satisfies r1=(D1+d1) / 4, the pitch diameter Φ1 of the four screw holes 11 satisfies 0.005<Φ1<t1, the depth t of the four screw holes 11 11 satisfies 0.02m<t 11 <0.1m, the heat transfer element 2 is fixed to the right end of the packaging shell 1 by screws 5 passing through the four screw holes 11; an internal thread 12 is processed at the center of the left end face of the packaging shell 1, the pitch diameter Φ2 of the internal thread 12 is d1, the length t2 of the internal thread 12 satisfies 0.002m<t2<0.003m, a movable bolt 6 is inserted into the internal thread 12, and the movable bolt 6 is fixed to the left end of the packaging shell 1 through the internal thread 12. A heat insulation layer 7 is attached to the outer wall of the packaging shell 1, so that there is no heat exchange between the inside and the outside of the packaging shell 1, thereby achieving a heat insulation effect. The thickness t9 of the heat insulation layer 7 satisfies 0.00001m<t9<0.001m, and the thermal conductivity λ1 satisfies 0.01W / (m·K)<λ2<0.04W / (m·K). The packaging shell 1 is made of metal material or organic glass, and the material is required to satisfy: yield strength σ1>150MPa, density ρ1>1.0g / cm 3 , the requirement principle is that the packaging shell 1 will not produce plastic deformation when subjected to external impact.

[0045] Figure 4 is a three-dimensional schematic diagram of the heat transfer element 2. As Figure 2 and Figure 4As shown, the heat transfer element 2 is configured to conduct heat of the transient temperature field to the heat shrinkable sheet 3 and the thermal resistance block 4. The heat transfer element 2 is shaped as a two-stage stepped cylinder, and is composed of a cylinder 21 and a disk 22. The thickness t3 of the disk 22 satisfies 0.001m<t3<0.1m, which needs to be adjusted according to actual measurement requirements, and the diameter D2 of the disk 22 is equal to the outer diameter D1 of the packaging housing 1. The length t4 of the cylinder 21 satisfies 0.005m<t4<0.03m, which needs to be adjusted according to actual measurement requirements, and the diameter D3 of the cylinder 21 is equal to the inner diameter d1 of the packaging housing 1. Four screw through holes 23 are uniformly processed along the circumferential direction on the right end face of the disk 22, the distance from the center of each screw through hole 23 to the center of the disk 22 is r2, where r2=(D2+D3) / 4, and the diameter of the screw through hole 23 is Φ1; four screws 5 pass through the screw through holes 23 and the screw holes 11 to fix the heat transfer element 2 on the right end of the packaging housing 1; the heat transfer element 2 is made of a material with good thermal conductivity, and the material does not produce plastic deformation under external impact, specifically the material meets the following requirements: yield strength σ2>200MPa, density ρ2>2.0g / cm 3 , thermal conductivity λ2≥100W / (m·K), and can withstand high temperatures from 1000°C to 10000°C for 1 second to 10 minutes. The heat transfer element 2 is fixed and disassembled via the screws 5, so that a new heat shrinkable sheet 3 can be reloaded, realizing reuse of the test device.

[0046] Figure 5 is a three-dimensional schematic diagram of the heat shrinkable sheet 3. As Figure 2 and Figure 5 shown, the heat shrinkable sheet 3 is configured to characterize received heat, is shaped as a strip, has a length L2 satisfying 0.008m<L2<0.02m, a width W1 satisfying 0.001m<W1<0.005m, and a thickness t5 satisfying 0.0005m<t5<0.001m. The heat shrinkable sheet 3 is made of shape memory polymer, and it is required that the heat shrinkable sheet 3 is prefabricated into a strip at a programming temperature before the transient temperature field heat flux test. When the heat shrinkable sheet 3 is heated, as the temperature rises, the heat shrinkable sheet 3 undergoes plastic deformation of different degrees according to different temperatures, and there is a quantitative relationship between the deformation degree and the temperature; shape memory polymers with different lengths and different materials can form measurement structures of various specifications with accurate correspondence between different temperatures and deformation degrees, which can achieve relatively accurate measurement for transient temperature fields of different intensities. Meanwhile, the use of shape memory polymer materials with stable properties can manufacture a transient temperature field heat flux sensor device with stable structure, reliable performance, and capable of long-term storage and use. The shape memory polymer material is required to satisfy: yield strength σ3<1000MPa, density ρ3<1.0g / cm 3, and the temperature indicating range satisfies 303K<T<503K; two pieces of heat-shrinkable sheets 3 are respectively fixed in the grooves 41 at both ends of the thermal resistance block 4, so that new heat-shrinkable sheets 3 can be reloaded, realizing cyclic utilization of the testing device.

[0047] Figure 6 is a three-dimensional schematic diagram of the thermal resistance block 4. As shown in Figure 2 and Figure 6 , the thermal resistance block 4 is cylindrical, the cylindrical diameter d2 satisfies d2=D1-2t1, and the length l2 satisfies l2=L1-t2-t4. Two ends of the thermal resistance block 4 are parallel to each other and perpendicular to the central axis of the packaging shell 1. A groove 41 is respectively dug on two end faces of the thermal resistance block, the groove 41 is a cuboid, the center of which coincides with the central axis of the thermal resistance block, the width w1 of the groove 41 is equal to the width W1 of the heat-shrinkable sheet 3, the length l3 of the groove 41 is equal to the length L2 of the heat-shrinkable sheet, and the depth t6 of the groove 41 is equal to the thickness t5 of the heat-shrinkable sheet 3. One piece of heat-shrinkable sheet 3 is respectively embedded in the two grooves 41. The thermal resistance block 4 is made of inorganic materials, polymer materials or metal oxides, and the materials are required to satisfy: yield strength σ4<1000MPa, density ρ4>2.0g / cm 3 , thermal conductivity λ3 satisfies λ3≤250W / (m·K), and thermal expansion coefficient satisfies k≤3×10 -5 / °C.

[0048] Figure 7 is a three-dimensional schematic diagram of the movable bolt 6. As shown in Figure 2 and Figure 7 , the length of the external thread at the right end of the movable bolt 6 t7 is equal to the length t2 of the internal thread 12 on the left end face of the packaging shell 1, the pitch diameter Φ3 of the thread is equal to the pitch diameter Φ2 of the internal thread on the left end face of the packaging shell 1, a central screw hole 61 is processed on the left end face of the movable bolt 6, and the testing device is fixed by connecting the central screw hole 61 with a fixture. The diameter D4 of the left-end cylinder of the movable bolt 6 satisfies d1<D4<1.2D1, the diameter Φ4 of the central screw hole 61 satisfies 0.005m<Φ4<0.03m, the length L3 of the central screw hole 61 satisfies 0.002m<L3<0.5t2, and the testing device is fixed by connecting the central screw hole 61 with a fixture. The movable bolt 6 is made of metal materials, and the materials are required to satisfy: yield strength σ5>200MPa, density ρ5>2.0g / cm 3 .

[0049] The main parameters of one embodiment of the present invention are as follows: D1 = 0.2m, t1 = 0.025m, d1 = 0.15m, L1 = 0.043m, r1 = 0.0875m, Φ1 = 0.01m, Φ2 = 0.15m, t2 = 0.027m, t3 = 0.002m, t4 = 0.006m, r2 = 0.0875m, L2 = 0.01m, W1 = 0.004m, t5 = 0.006m, t6 = 0.006m, d2 = 0.15m, l2 = 0.01m, D4 = 0.2m, t7 = 0.027m, t8 = 0.015m, Φ4 = 0.02m, L3 = 0.012m, t9 = 0.0003m. Both the housing 1 and the movable bolt 6 are made of steel, with a yield strength σ1 = 300 MPa and a density ρ1 = 7.8 g / cm³. 3 The heat transfer element 2 is made of copper, with a yield strength of σ2 = 315 MPa and a density of ρ1 = 8.96 g / cm³. 3 The thermal conductivity is λ2 = 401 W / (m·K); the heat shrink sheet 3 material used is a BMIP / DABA / BMI-PTMO system composition, ρ3 = 0.9 g / cm³. 3 The temperature measurement range is 303K~500K, and the correlation between temperature (T) and strain (ε) of the heat shrink sheet is obtained. The thermal resistance block 4 is made of aluminum alloy 1070 with a density of ρ4=2.7g / cm³. 3 The thermal conductivity is λ3 = 236 W / (m·K), and the coefficient of thermal expansion is K = 2.36 × 10⁻⁶. -5 / ℃.

[0050] The measuring device designed based on the above parameters was used to test the transient temperature field heat flux. The equivalent TNT of a certain explosive is 30 kg. After the measuring device was assembled, it was placed on a fixed support 3 m away from the explosive, with the right end of the measuring device facing the center of the explosive (i.e., the center of the explosive and the axis of the measuring device are on the same straight line 2). After installation, it was checked whether the heat transfer element 2 and the encapsulation shell 1 were in tight contact, and whether the heat shrink sheet 3 was completely placed in the grooves 41 at both ends of the thermal resistance block 4. The lengths of the two heat shrink sheets 3 at the left and right ends of the thermal resistance block 4 before the explosive was detonated were measured and recorded respectively. Let the length of the left end be x. 11 =0.01m, let the right-hand side be x 21 =0.01m. After completing the pre-test preparations, the explosive is detonated. The heat shrink sheet 3 shrinks due to heat. After removing the test device from the fixed support, the two heat shrink sheets 3 are taken out. The lengths of the two heat shrink sheets 3 at the left and right ends of the thermal resistance block 4 are measured using vernier calipers, and are respectively x 12 =0.00923m and x 22 =0.00882m, the calculated strains are ε1=(x 11 -x12 ) / x 11 =0.077 and ε2=(x 21 -x 22 ) / x 21 =0.118. Comparing the correspondence between temperature (T) and strain (ε), the temperatures sensed by the two heat shrink sheets are T1 = 72.3℃ and T2 = 83.5℃, respectively, with a temperature difference of ΔT = |T1 - T2| = 11.2℃. Therefore, the heat flux generated by the explosion of 30kg TNT 3 meters from the detonation point is Ψ = λ³·ΔT / l² = 264.32kW / m². 2 The heat flux measurement method of this invention has a simple process and a clear physical process. It can be used to measure the heat flux of explosive explosions, gas explosions, and other complex and harsh temperature fields, providing a new option for heat flux measurement.

[0051] For near-field explosion heat flux tests at different explosives and different detonation distances, the heat flux passive measurement can be completed quickly, conveniently and accurately by using the transient temperature field heat flux testing device and method based on heat shrink sheet of this invention.

[0052] The above embodiments are merely one implementation of the present invention. The specific structure and dimensions can be adjusted according to actual needs. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention patent.

Claims

1. A transient temperature field heat flux testing device based on heat shrink sheet, characterized in that... The transient temperature field heat flux testing device based on heat shrink sheet consists of a housing (1), a heat transfer element (2), two heat shrink sheets (3), a thermal resistance block (4), screws (5), and a movable bolt (6). The end closer to the heat transfer element (2) is defined as the right end, and the end farther away from the heat transfer element (2) is defined as the left end. The heat transfer element (2) is fixed to the right end of the housing (1) by screws (5) to encapsulate the right end of the housing (1). The two heat shrink sheets (3) and the thermal resistance block (4) are embedded in the housing (1), and the heat transfer element (2), the thermal resistance block (4), and the housing (1) are coaxially installed. The two heat shrink sheets (3) are fixed in the grooves at both ends of the thermal resistance block (4). The movable bolt (6) is fixed to the left end of the housing (1) by threads to encapsulate the left end of the housing (1). The encapsulation housing (1) is cylindrical; the outer diameter of the encapsulation housing (1) is D1, the wall thickness is t1, the inner diameter is d1, and the length is L1; four screw holes (11) are uniformly machined along the circumference on the right end face of the encapsulation housing (1), the middle diameter of the screw holes (11) is Φ1, and the heat transfer element (2) is fixed to the right end of the encapsulation housing (1) by passing through the four screw holes (11) with screws (5); an internal thread (12) is machined at the center of the left end face of the encapsulation housing (1), and a movable bolt (6) is inserted in the internal thread (12), and the movable bolt (6) is fixed to the left end of the encapsulation housing (1) by the internal thread (12); a heat insulation layer (7) is attached to the outer wall of the encapsulation housing (1), the thickness of the heat insulation layer (7) is t9, and the encapsulation housing (1) is made of metal or plexiglass, and the encapsulation housing (1) is required not to undergo plastic deformation under external impact; The heat transfer element (2) is used to conduct heat from the transient temperature field to the heat shrink sheet (3) and the thermal resistance block (4); the heat transfer element (2) is a two-stage stepped cylinder, consisting of a cylinder (21) and a disk (22); the thickness of the disk (22) is t3, and the diameter D2 of the disk (22) is equal to the outer diameter D1 of the encapsulation shell (1); the length of the cylinder (21) is t4, and the diameter D3 of the cylinder (21) is equal to the inner diameter d1 of the encapsulation shell (1); four screw through holes (23) are uniformly machined along the circumference on the right end face of the disk (22); four screws (5) pass through the screw through holes (23) and screw holes (11) to fix the heat transfer element (2) to the right end of the encapsulation shell (1); the heat transfer element (2) is made of a material with a thermal conductivity λ2≥100W / (m·K), and the material satisfies that it does not produce plastic deformation under external impact; the heat transfer element (2) is fixed or disassembled by screws (5); The heat-shrinkable sheet (3) is used for characterizing received heat, is in the shape of an elongated strip, has a length of L2, a width of W1 and a thickness of t5; the heat-shrinkable sheet (3) is made of shape memory polymer, and it is required that the heat-shrinkable sheet (3) is preformed into an elongated strip at a programming temperature before the transient temperature field heat flux test. When the heat-shrinkable sheet (3) is heated, as the temperature rises, the heat-shrinkable sheet (3) undergoes plastic deformation of different degrees according to different temperatures, and there is a quantitative relationship between the deformation degree and the temperature; two heat-shrinkable sheets (3) are respectively fixed in the grooves (41) at both ends of the thermal resistance block (4); The thermal resistance block (4) is cylindrical, has a diameter of d2 and a length of l2, and two ends of the thermal resistance block (4) are parallel to each other and perpendicular to the central axis of the packaging shell (1); a groove (41) is dug on each of two end faces of the thermal resistance block, the groove (41) is a cuboid, and the center of the groove coincides with the central axis of the thermal resistance block; one heat-shrinkable sheet (3) is embedded in each of the two grooves (41); the thermal resistance block (4) is made of inorganic materials, polymer materials or metal oxides; The length t7 of the external thread at the right end of the movable bolt (6) is equal to the length t2 of the internal thread (12) on the left end face of the packaging shell (1), the pitch diameter Φ3 of the thread is equal to the pitch diameter Φ2 of the internal thread on the left end face of the packaging shell (1), a central screw hole (61) is processed on the left end face of the movable bolt (6), and the transient temperature field heat flux testing device based on the heat-shrinkable sheet is fixed by connecting the central screw hole (61) with a fixed object; the movable bolt (6) is made of a metal material.

2. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The outer diameter D1 of the packaging housing (1) satisfies 0.01m < D1 < 0.5m, the wall thickness t1 satisfies 0.02m < t1 < 0.1m, the inner diameter d1 satisfies d1=D1-2t1, and the length L1 satisfies 0.01m < L1 < 2m; the distance r1 between the center of the screw hole (11) and the center of the right end face of the packaging housing (1) satisfies r1=(D1+d1) / 4, the pitch diameter Φ1 of the 4 screw holes (11) satisfies 0.005m < Φ1 < t1, the depth t of the 4 screw holes (11) 11 satisfies 0.02m < t 11 < 0.1m; the pitch diameter Φ2 of the internal thread (12) is d1, and the length t2 of the internal thread (12) satisfies 0.002m < t2 < 0.003m.

3. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The thickness t9 of the heat insulation layer (7) satisfies 0.00001m<t9<0.001m.

4. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The thickness t3 of the disc (22) satisfies 0.001m<t3<0.1m, the length t4 of the cylinder (21) satisfies 0.005m<t4<0.03m, the distance r2 between the center of the screw through hole (23) and the center of the disc (22) is (D2+ D3) / 4, and the diameter of the screw through hole (23) is Φ1.

5. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The length L2 of the heat-shrinkable sheet (3) satisfies 0.008m<L2<0.02m, the width W1 satisfies 0.001m<W1<0.005m, and the thickness t5 satisfies 0.0005m<t5<0.001m.

6. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The diameter d2 of the thermal resistance block (4) satisfies d2=D1-2t1, and the length l2 satisfies l2=L1-t2-t4; the width w1 of the groove (41) is equal to the width W1 of the heat-shrinkable sheet (3), the length l3 of the groove (41) is equal to the length L2 of the heat-shrinkable sheet, and the depth t6 of the groove (41) is equal to the thickness t5 of the heat-shrinkable sheet (3).

7. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The diameter D4 of the cylinder at the left end of the movable bolt (6) satisfies d1<D4<1.2D1, the diameter Φ4 of the central screw hole (61) satisfies 0.005m<Φ4<0.03m, and the length L3 of the central screw hole (61) satisfies 0.002m< L3<0.5t2.

8. The transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... The metal material or organic glass used for preparing the packaging shell (1) satisfies: yield strength σ1>150MPa, density ρ1>1.0g / cm 3 ; The material for preparing the heat transfer element (2) satisfies: yield strength σ2>200MPa, density ρ2>2.0g / cm 3 , and can withstand high temperature of 1000°C~10000°C for 1 second to 10 minutes; the shape memory polymer material for preparing the heat-shrinkable sheet (3) satisfies: yield strength σ3<1000MPa, density ρ3<1.0g / cm 3 , and the temperature indicating range satisfies 303K<T<503K; the material used for preparing the thermal resistance block (4) satisfies: yield strength σ4<1000MPa, density ρ4>2.0g / cm 3 , thermal conductivity λ3 satisfies λ3≤250W / (m·K), and thermal expansion coefficient satisfies k≤3×10 -5 / ℃; The material for preparing the movable bolt (6) satisfies: yield strength σ5>200MPa, density ρ5>2.0g / cm 3 ; the thermal conductivity λ1 of the heat insulating layer (7) satisfies 0.01W / (m·K)<λ1<0.04W / (m·K).

9. A method for testing the heat flux of a transient temperature field using the transient temperature field heat flux testing device based on heat shrink sheet as described in claim 1, characterized in that... comprises the following steps: in the first step, the corresponding relationship between temperature (T) and strain (ε) of the testing device is calibrated through a temperature-strain calibration experiment; The second step is to install the movable bolt (6) on the left end of the encapsulation housing (1), place the two heat shrink sheets (3) in the grooves (41) at both ends of the thermal resistance block (4), and place the thermal resistance block (4) inside the encapsulation housing (1); the heat transfer element (2) is fixed to the right end of the encapsulation housing (1) by screws (5) to form a test device, and the test device is firmly fixed to the ground or a solid support by the central screw hole (61) of the movable bolt (6); The third step is to check whether the heat transfer element (2) and the encapsulation shell (1) are in close contact, and whether the heat shrink sheet (3) is completely placed in the grooves (41) at both ends of the thermal resistance block (4). Measure and record the lengths of the two heat shrink sheets (3) at the left and right ends of the thermal resistance block (4) before the explosive is detonated. Let the length of the heat shrink sheet at the left end before the explosive is detonated be x. 11 Let the length of the heat-shrink sheet at the right end of the explosive be x. 21 ; The fourth step is to obtain a transient temperature field by detonating the explosive. After the transient temperature field ends, the lengths of the two heat shrink sheets (3) at the left and right ends of the thermal resistance block (4) are measured respectively. Let the length of the heat shrink sheet at the left end be x. 12 Let the length of the heat shrink sheet on the right end be x. 22 ; Step 5: Calculate the strain ε1 of the heat-shrinkable sheet at the left end of the thermal resistance block (4), ε1=(x 11 -x 12 ) / x 11 Calculate the strain ε2 of the heat shrink sheet at the right end of the thermal resistance block (4), ε2=(x 21 -x 22 ) / x 21 ; Step 6: Based on the strains ε1 and ε2 of the two heat shrink sheets (3) before and after the transient temperature field loading, the temperatures of the two heat shrink sheets (3) are found to be T1 and T2 respectively according to the correspondence between temperature (T) and strain (ε); Step 7: Calculate the temperature difference ΔT across the thermal resistance block, ΔT = |T1 - T2|; Step 8: Combining the thermal conductivity λ3 of the thermal resistance block (4) and the length l2 of the thermal resistance block (4), the heat flux Ψ of the transient temperature field is obtained, Ψ=λ3·ΔT / l2, where the unit of Ψ is W / m. 2 ; In the ninth step, the screws (5) and movable bolts (6) of the heat transfer element (2) are removed and replaced with new heat shrink sheet (3) to enable the test device to be used again.

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