CN112782218B - Device and method for measuring thermal conductivity of wide-temperature-range material - Google Patents
Device and method for measuring thermal conductivity of wide-temperature-range material Download PDFInfo
- Publication number
- CN112782218B CN112782218B CN202110134103.7A CN202110134103A CN112782218B CN 112782218 B CN112782218 B CN 112782218B CN 202110134103 A CN202110134103 A CN 202110134103A CN 112782218 B CN112782218 B CN 112782218B
- Authority
- CN
- China
- Prior art keywords
- temperature
- vacuum
- detector
- thermal conductivity
- furnace
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
The invention provides a device and a method for measuring thermal conductivity of a wide temperature range material, belonging to the technical field of thermal conductivity measurement. The device includes the independent type sensor of third harmonic method, the signal of telecommunication gathers and processing module, high temperature vacuum heating furnace, the signal of telecommunication gathers and processing module includes high accuracy difference amplifier, lock-in amplifier, adjustable resistance case, high accuracy DC power supply, preamplifier, converter and electric capacity, be used for gathering, enlargies and handles the signal of telecommunication that the sensor produced, high temperature vacuum heating furnace includes the furnace body, the heating module, the cooling module, the vacuum module, be used for providing experimental required temperature domain environment of harmonic method and vacuum condition, the sensor passes furnace lateral wall vacuum electrode through high temperature resistant lead wire in the stove, connect external equipment, realize the circuit closure. The invention overcomes the defects that the traditional thermal characteristic testing device can not realize high-temperature measurement and the detector can not be used for many times, and the like, and ensures the reusability of the material after testing and the reutilization of the detector.
Description
Technical Field
The invention relates to the technical field of thermal conductivity measurement, in particular to a device and a method for measuring the thermal conductivity of a wide-temperature-range material.
Background
The thermophysical property parameter of the material is closely related to the temperature of the working environment. For non-metallic materials such as porous ceramic skeleton materials and phase change materials, the number of free electrons in crystal lattices is small, so that the main heat conduction mechanism is lattice vibration, namely heat conduction is carried out by depending on phonons, and under the same other conditions, the heat conductivity and the phonon mean free path are in a direct proportion relation. When the temperature rises, the possibility of interaction between phonons and phonons is increased, phonon scattering is enhanced, and the mean free path of phonons is changed, so that the thermal conductivity of the material at a high temperature has larger difference compared with the physical property at room temperature, and the thermophysical property parameter of the material measured at the room temperature environment obviously cannot actually represent the thermophysical property of the material at the working temperature. The method has important application value for accurately measuring the thermal conductivity of the material in different temperature ranges in the high-temperature technical fields of aerospace, solar thermal power generation, waste heat recovery and the like. The sensible heat porous ceramic has the advantages of high temperature resistance, high heat conductivity, low price and the like, but the heat storage capacity is low; the phase-change material utilizes phase-change latent heat for heat storage, has higher heat storage density, but has lower heat conduction capability, and has the problems of leakage and the like in the phase-change process; the porous ceramic serves as a framework material, the phase-change material serves as a core material, namely the sensible heat-latent heat composite phase-change material can further improve the heat storage density, accelerate the heat storage rate and enhance the heat conduction performance of the composite material, the porous ceramic matrix phase-change material gradually becomes an important material for the research of the field of energy storage, and the test of the heat transfer/storage performance of the porous ceramic matrix phase-change composite material becomes an important link for the development of the field of phase-change energy storage. The conventional steady-state thermophysical property testing method has larger radiation error when measuring the energy storage block material at high temperature, so that the accurate measurement of the thermal conductivity of the composite phase change material is very difficult. The third harmonic method uses a very small sample, and can effectively reduce the influence of radiation on the heat conductivity by reducing the heat exchange area, but the inside and the surface of the ceramic have a hole structure from nanometer to micron, so that the harmonic method of directly depositing a miniature detector on the surface of the material is not applicable, and the detector deposited on the surface can damage the material to a certain extent, influence other mechanism analysis on the material, and limit the multiple use of the detector, so that the method is a significant invention for nondestructive and accurate measurement of energy storage materials and other blocky materials in different temperature ranges.
Disclosure of Invention
The invention aims to provide a device and a method for measuring the thermal conductivity of a wide-temperature-range material.
The device comprises a linear heater/detector module, a high-temperature resistant substrate, a high-temperature vacuum heating furnace and an electric signal acquisition and processing module, wherein the linear heater/detector module is arranged on the high-temperature resistant substrate; the linear heater/detector module comprises a linear heater/detector, a first current lead element, a first detection voltage lead element, a second detection voltage lead element and a second current lead element, the electric signal acquisition and processing module comprises a signal generator, a microcomputer control and data acquisition system, a signal processing system, a preamplifier, a lock-in amplifier, an adjustable resistor, a first current lead end, a first voltage lead end, a second voltage lead end and a second current lead end, the signal processing system comprises a converter, a first operational amplifier, a second operational amplifier, a first low-temperature drift resistor, a second low-temperature drift resistor, a third low-temperature drift resistor, a fourth low-temperature drift resistor, a fifth low-temperature drift resistor, a sixth low-temperature drift resistor, a seventh low-temperature drift resistor and an eighth low-temperature drift resistor, the high-temperature vacuum heating furnace comprises a heat insulation material, a furnace body supporting material, a furnace body, a, Furnace qianmen, vacuum pipe, lobe pump, mechanical pump, heating element, lead wire device, pipeline flange, the furnace body lower part is the furnace body support, sets up insulation material in the furnace body, and the furnace body openly sets up the furnace qianmen, and the furnace body rear portion passes through vacuum pipe and connects the lobe pump, sets up the pipeline flange between furnace body rear portion and the vacuum pipe, and the furnace body lower part sets up mechanical pump, and furnace body upper portion sets up the lead wire device, sets up heating element in the insulation material.
The linear heater/detector module and the high-temperature resistant substrate form a third harmonic method independent sensor, the third harmonic method independent sensor is based on an asymmetric heat conduction model, a high-temperature resistant insulating material is used as a sensor substrate, and a metal detector is deposited on the substrate with a smooth and flat surface by adopting a mask plate physical deposition method; the surface of the detector is plated with a layer of wear-resistant insulating protective film, and the third harmonic method independent sensor structure comprises a high-temperature-resistant substrate, a linear heater/detector module and a wear-resistant insulating protective film from bottom to top respectively, wherein the wear-resistant insulating protective film is silicon nitride.
The linear heater/detector is in the shape of four pads of a linear thin strip, the four pads are respectively connected with a first current lead wire, a first detection voltage lead wire, a second detection voltage lead wire and a second current lead wire, wherein the linear thin strip has the length range of 8-30mm and the width range of 8-700 mu m, the linear heater/detector is made of one of nickel, platinum and gold, the resistance temperature coefficient is large, and the thickness is 50-200 nm.
The first current lead element, the first detection voltage lead element, the second current lead element and the second detection voltage lead element are made of molybdenum wires, the melting point is 2620 ℃, and the diameter is 300 mu m.
The first current lead wire, the first detection voltage lead wire, the second detection voltage lead wire and the second current lead wire are respectively connected with a first current lead wire end, a first voltage lead wire end, a second voltage lead wire end and a second current lead wire end, the first current lead wire end is connected with a first operational amplifier, a signal generator and a microcomputer control and data acquisition system through an adjustable resistor, the first current lead wire end is connected with the first operational amplifier through a second low temperature drift resistor, a first low temperature drift resistor is arranged between the adjustable resistor and the first operational amplifier, a converter is arranged between the adjustable resistor and the signal generator, the signal generator is connected with the microcomputer control and data acquisition system, the microcomputer control and data acquisition system and the signal generator are both connected with a phase-locked amplifier, the first voltage lead wire end is connected with the second operational amplifier through a third low temperature drift resistor, the second voltage lead wire end is connected with the second operational amplifier through a fourth low temperature drift resistor, the first operational amplifier is connected with the preamplifier, the first operational amplifier is connected with the seventh low-temperature drift resistor in parallel, the second operational amplifier is connected with the preamplifier, the second operational amplifier is connected with the eighth low-temperature drift resistor in parallel, the preamplifier is connected with the phase-locked amplifier, and the second current lead wire is connected to the ground through the second current lead wire end.
The high-temperature vacuum heating furnace adopts an electric heating mode, and the highest working temperature is up to 1200 ℃; a two-stage vacuum pumping mode of a 2X-70 mechanical pump and a Roots pump is adopted to realize a high vacuum environment, the pressure of the vacuum environment is less than 1Pa, the whole external furnace body is made of stainless steel, the hearth is made of an alumina polycrystalline fiberboard, and heating elements are respectively installed on the periphery inside the hearth in a suspension manner; the furnace body is provided with a lead device for leading out a high-temperature lead in the hearth to external equipment; the double-layer furnace body structure is characterized in that a cooling water system is used for cooling an inner furnace door, a B-type double platinum-rhodium thermocouple is used for monitoring the inner temperature of a hearth, and the heating power is controlled and adjusted according to a PID controller, wherein the temperature measuring range of the B-type double platinum-rhodium thermocouple is normal temperature-1820 ℃.
The method specifically comprises the following steps:
s1: and placing a material sample to be detected on the surface of the third harmonic method independent sensor, fixing the material sample by using a sample clamp, and then placing the material sample in a high-temperature vacuum heating furnace. The linear heater/detector module is connected with the external electric signal acquisition and processing module through a vacuum electrode;
s2: starting a vacuum system, vacuumizing the high-temperature vacuum heating furnace, and setting the vacuum degree to be less than 1 Pa;
s3: when the vacuum degree meets the requirement, starting a heating module of the high-temperature vacuum furnace, setting the temperature, and heating the material to be measured in the furnace;
s4: when the set temperature is reached, introducing sinusoidal alternating current at different frequencies to the linear heater/detector module to obtain third harmonic and fundamental voltage of the sensor at different frequencies, and fitting according to a harmonic method test principle to obtain the thermal conductivity of the material measured by the sensor at the set temperature;
s5: the set temperature of the heating module is changed, and S1-S4 are repeated, and the thermal conductivity of the sample in a wide temperature range is measured.
The applicable temperature range of the test method is as follows: 25-1000 ℃;
in the experiment, the thermal conductivity of the material is calculated by mainly utilizing the frequency dependence of temperature fluctuation and utilizing the relationship between the temperature fluctuation and the frequency, and the calculation formula of the thermal conductivity is as follows:
wherein k is the thermal conductivity (W.m) of the material to be measured-1·K-1)；ksThermal conductivity of the substrate material (W.m.)-1·K-1) (ii) a P-the detector power (W),
r-resistance of heating/detector (Ω, 25 ℃); l-length of heating/detector (m); u shape1ω-a first harmonic voltage (V); omega-angular frequency (rad/s); u shape3ω-third harmonic voltage (V); alpha is alphaCR-temperature coefficient of resistance (1/K) of the heating/detector.
The technical scheme of the invention has the following beneficial effects:
(1) according to the invention, the metal sensor is deposited on the high-temperature-resistant substrate, a mechanical compression mode is adopted, and a test scheme of material thermal conductivity at a non-temperature is directly measured, so that the defects that the conventional thermal characteristic test device cannot realize high-temperature measurement and a detector cannot be used for multiple times are overcome, and the reusability of the material after testing and the reuse of the detector are ensured;
(2) a high-precision direct-current power supply (+ -15V, the power supply voltage regulation rate is less than or equal to 0.5%, and the ripple wave is less than 10mV), a differential amplifier is used for changing the original AMP03 into an AD620 chip with higher precision, capacitors of 10pF, 1 muF and 100 muF are added to the power supply input end and used for filtering high-frequency and low-frequency clutter signals, the signal measurement fluctuation quantity is reduced, the harmonic fluctuation quantity under different frequencies is less than 0.0004mV, and the high-precision measurement of the heat conductivity of the material under different temperature ranges is ensured.
Drawings
FIG. 1 is a schematic diagram of an independent sensor of the third harmonic method of the present invention;
FIG. 2 is a schematic diagram of a third harmonic method independent sensor of the present invention contacting a sample for signal detection;
FIG. 3 is a diagram of a detection system for thermal conductivity using the third harmonic method of the present invention;
FIG. 4 is a three-dimensional view showing the structure of a high-temperature vacuum furnace according to the present invention, wherein (a) is a front view, (b) is a left side view, and (c) is a top view.
Wherein: 1-a linear heater/detector module, 11-a linear heater/detector, 12 a-a first current lead member, 12 b-a first detection voltage lead member, 12 c-a second detection voltage lead member, 12 d-a second current lead member, 2-a high temperature resistant substrate, 3-a material sample to be measured, 4-a high temperature vacuum heating furnace, 51-a signal generator, 52-a microcomputer control and data acquisition system, 53-a signal processing system, 54-a preamplifier, 55-a lock-in amplifier, R9-an adjustable resistor, 5 a-a first current lead terminal, 5 b-a first voltage lead terminal, 5 c-a second voltage lead terminal, 5 d-a second current lead terminal, 531-a converter, 532-a first operational amplifier, 533-second operational amplifier, R1-first low temperature drift resistor, R2-second low temperature drift resistor, R3-third low temperature drift resistor, R4-fourth low temperature drift resistor, R5-fifth low temperature drift resistor, R6-sixth low temperature drift resistor, R7-seventh low temperature drift resistor, R8-eighth low temperature drift resistor, R9-adjustable resistor, 41-thermal insulation material, 42-furnace body support, 43-furnace front door, 44-vacuum pipeline, 45-roots pump, 46-mechanical pump, 47-heating element, 48-lead device, 49-pipeline flange.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
The invention provides a device and a method for measuring the thermal conductivity of a wide temperature range material.
As shown in fig. 2 and fig. 3, the device comprises a linear heater/detector module 1, a high temperature resistant substrate 2, a material sample 3 to be measured, a high temperature vacuum heating furnace 4, and an electric signal collecting and processing module 5, wherein the linear heater/detector module 1 is arranged on the high temperature resistant substrate 2, one side of the high temperature resistant substrate 2 provided with the linear heater/detector module 1 is pressed towards the material sample 3 to be measured, the high temperature resistant substrate 2 is arranged in the high temperature vacuum heating furnace 4, and the linear heater/detector module 1 is connected with the electric signal collecting and processing module;
as shown in fig. 1, the linear heater/detector module 1 includes a linear heater/detector 11, a first current lead 12a, a first detection voltage lead 12b, a second detection voltage lead 12c, and a second current lead 12d, the electrical signal collecting and processing module includes a signal generator 51, a microcomputer control and data collecting system 52, a signal processing system 53, a preamplifier 54, a lock-in amplifier 55, an adjustable resistor R9, a first current lead 5a, a first voltage lead 5b, a second voltage lead 5c, and a second current lead 5d, the signal processing system 53 includes a converter 531, a first operational amplifier 532, a second operational amplifier 533, a first low temperature drift resistor R1, a second low temperature drift resistor R2, a third low temperature drift resistor R3, a fourth low temperature drift resistor R4, a fifth low temperature drift resistor R5, a sixth low temperature drift resistor R6, A seventh low temperature drift resistor R7 and an eighth low temperature drift resistor R8, wherein the high-temperature vacuum heating furnace 4 comprises a heat insulation material 41, a furnace body support 42, a furnace front door 43, a vacuum pipeline 44, a roots pump 45, a mechanical pump 46, a heating element 47, a lead device 48 and a pipeline flange 49.
The linear heater/detector module 1 and the high temperature resistant substrate 2 form a third harmonic method independent sensor, linear plusThe heater/detector 11 is in the shape of linear thin belt, has a length of 8-20 mm and a width of 8-100 μm, is made of metal nickel or gold or platinum, has a thickness of 200nm and a temperature coefficient of resistance of 0.0064 deg.C-1The device has the functions of uniformly heating the porous composite energy storage material sample 3 and receiving a sample feedback voltage signal with high precision. The high-temperature resistant substrate 2 is a mica sheet material, the thickness of the mica sheet material is 0.1-0.3 mm, the maximum service temperature is 1000 ℃, and the mica sheet material has good insulating and high-temperature resistant characteristics. The micro linear heater/detector module is covered on one side of the micro linear heater/detector module 1, and plays a role in protecting and depositing the detector and improving the service temperature of the independent detector. The third harmonic method independent sensor can measure the wide temperature range of the material sample 3 to be measured, and the bonding effect of the sensor and the sample is good. The first current lead wire 12a, the first detection voltage lead wire 12b, the second detection voltage lead wire 12c and the second current lead wire 12d at the end of the linear heater/detector are connected with a high temperature resistant molybdenum wire in a mechanical compression mode to form the miniature linear heater/detector module 1. During measurement, the first current lead element 12a, the first detection voltage lead element 12b, the second detection voltage lead element 12c and the second current lead element 12d are respectively connected with the first current lead terminal 5a, the first voltage lead terminal 5b, the second voltage lead terminal 5c and the second current lead terminal 5d which are positioned outside the hearth through vacuum electrodes.
The main measurement principle of the triple harmonic method independent sensor is that after a micro linear heater/detector 11 is introduced with 1 omega sine alternating current, a linear heater/detector module 1 generates 2 omega heat wave signals under the action of Joule to heat a material sample 3 to be measured, the material sample 3 to be measured generates frequency domain heat waves according to the relation between the heat wave frequency generated by the sample and the material physical property, the linear heater/detector 11 receives the heat waves and converts the heat waves into corresponding voltage signals, and the voltage signals are output to an electric signal acquisition and processing system through a metal lead wire to indirectly obtain temperature fluctuation signals.
The electric signal acquisition and processing system receives fundamental wave signals and third harmonic voltage signals detected by the independent sensor based on the third harmonic method, records the resistance R of the sensor under the temperature to be measured and the third harmonic voltage U under different frequencies f under the control of the host3ωFundamental wave voltage U1ωAnd the like.
Fig. 2 and 3 contain the main structural information of the electrical signal acquisition and processing system, including the signal generator 51, the microcomputer control and data acquisition system 52, the signal processing system 53, the preamplifier 54, the lock-in amplifier 54, the adjustable resistance box R9, the first current lead terminal 5a, the first voltage lead terminal 5b, the second voltage lead terminal 5c and the second current lead terminal 5 d.
The lead terminal connecting method comprises the following steps: the first current lead member 121 is electrically connected to the first current lead terminal 5a, the second current lead member 124 is electrically connected to the second current lead terminal 5d, and the first detection voltage lead member 122 and the second detection voltage lead member 123 are electrically connected to the first voltage lead terminal 5c and the second voltage lead terminal 5d, respectively.
The signal generator 51 outputs an ac voltage signal, which is converted into a current signal by the converter 531, the current signal passes through the adjustable resistor R9, and is connected to the first current lead 12a of the independent detector through the first current lead 5a, the voltage signal of the adjustable resistor box and the voltage signal of the detector are connected to the first operational amplifier 532 and the second operational amplifier 533, respectively, and the voltage signal is converted into a differential signal, converged to the preamplifier 54, and then input to the lock-in amplifier 55.
For the harmonic method measurement unit 53, it can be subdivided into: the circuit comprises a converter 531, a first differential amplifier 532, a second differential amplifier 533, a first low-temperature drift resistor R1, a second low-temperature drift resistor R2, a third low-temperature drift resistor R3, a fourth low-temperature drift resistor R4, a fifth low-temperature drift resistor R5, a sixth low-temperature drift resistor R6, a seventh low-temperature drift resistor R7, an eighth low-temperature drift resistor R8 and an adjustable resistor R9. The model of the high-precision differential amplifier is AD 620.
The converter is connected with the signal generator and the adjustable resistor and is used for converting the voltage signal into a current signal; the first differential amplifier is connected to two ends of the adjustable resistance box and used for converting voltage signals of the adjustable resistance box into differential signals; the second differential amplifier is connected to the first voltage lead piece and the second voltage lead piece of the sensor and used for converting the voltage signal of the detector into a differential signal; the preamplifier is respectively connected with the first differential amplifier and the second differential amplifier and is used for amplifying the output signals of the differential amplifiers; the phase-locked amplifier is connected with the preamplifier and the signal generator and used for extracting the voltage signal.
Fig. 4 is a three-dimensional view of a high-temperature vacuum furnace including the main components of the furnace body. The furnace comprises a heat insulation material 41, a furnace body support 42, a furnace front door 43, a vacuum pipeline 44, a Roots pump 45, a mechanical pump 46, a heating element 47, a lead device 48 and a pipeline flange 49, wherein the furnace body support 42 is arranged at the lower part of the furnace body, the heat insulation material 41 is arranged in the furnace body, the furnace front door 43 is arranged on the front surface of the furnace body, the rear part of the furnace body is connected with the Roots pump 45 through the vacuum pipeline 44, the pipeline flange 49 is arranged between the rear part of the furnace body and the vacuum pipeline 44, the mechanical pump 46 is arranged at the lower part of the furnace body, the lead device 48 is arranged at the upper part of the furnace body, and the heating element is arranged in the heat insulation material 41. And finishing the high-temperature and vacuum environment required by the high-temperature harmonic method experiment of the porous composite phase-change material. Wherein the size of the heating area is 350 multiplied by 350 mm; the heat insulation material adopts a polycrystalline alumina fiberboard; the heating element adopts a nickel-rhodium alloy belt (a resistance wire heating mode), and the temperature rise range is 25-1200 ℃; the experimental steps mainly comprise the steps of starting a secondary vacuum system to meet the requirement of set vacuum degree, setting the required temperature, heating the material to be measured, changing the frequency, collecting fundamental wave voltage and third harmonic voltage under different frequencies by combining a harmonic method measuring unit, and obtaining the thermal conductivity of the porous composite phase change material at the temperature to be measured according to a harmonic method theoretical formula.
The data processing module adopts a main formula of a harmonic method test principle to calculate, and the calculation formula is as follows:
wherein k is the thermal conductivity (W.m) of the material to be measured-1·K-1)；
ksThermal conductivity of the substrate material (W.m.)-1·K-1)；
P-the detector power (W),
r-resistance of heating/detector (Ω, 25 ℃);
l-length of heating/detector (m);
U1ω-a first harmonic voltage (V);
U3ω-a third harmonic voltage (V);
omega-angular frequency (rad/s);
αCRtemperature coefficient of resistance (1/K) of the heating/detector.
Based on the harmonic method principle calculation formula, the device has the following detailed testing method for the porous composite phase change energy storage material:
(1) and (3) placing the third harmonic method independent sensor on a sample clamp, then placing the material sample 3 to be detected on the top of the sensor, and fixing the device by utilizing the function of applying top pressure after the bonding is confirmed to be complete. It should be noted that, when the sensor and the sample are fixed, the sensor cannot be deformed by an angle greater than 15 ° so as to avoid damaging the sensor;
(2) and (3) placing the fixed third harmonic method independent sensor and the material sample to be detected (3) (comprising a fixing device) in a high-temperature vacuum furnace cavity. The first current lead member 12a, the first detection voltage lead member 12b, the second detection voltage lead member 12c and the second current lead member 12d of the sensor are connected to a high temperature lead inside the high temperature vacuum furnace. It should be noted that the lead connection is mechanical. The first current lead wire 12a, the first detection voltage lead wire 12b, the second detection voltage lead wire 12c and the second current lead wire 12d are connected with the first current lead terminal 5a, the first voltage lead terminal 5b, the second voltage lead terminal 5c and the second current lead terminal 5d of the harmonic method measuring unit in a mechanical compression mode and are connected with an external circuit through vacuum electrodes;
(3) and starting a secondary vacuum cavity system, and vacuumizing the air in the furnace body by using a mechanical pump and a roots pump outside the hearth. When the vacuum pumping is finished, the pressure in the vacuum heating furnace can be less than 1 Pa. Before the vacuum pumping operation, whether a power supply system of the vacuum pump is abnormal or not needs to be checked;
(4) when the vacuum degree meets the requirement and is kept constant, setting a target temperature (25-1000 ℃), starting a high-temperature vacuum furnace heating module to heat a sample, and starting a furnace body cooling water system to protect a furnace body and prevent temperature fluctuation;
(5) after the set temperature is reached, the signal generator 51, the microcomputer control and data acquisition system 52 and the lock-in amplifier 55 are started, and weak sine periodic alternating current I is introduced into the sensor1ω. The sensor resistance is measured by an adjustable resistance box R9, and the initial resistance value R of the sensor is obtained. The input frequency f is changed by the phase-locked amplifier 55, and under the differential amplification effect of the signal generator 51, the converter 531, the first differential amplifier 532, the second differential amplifier 533 and the phase-locked amplifier 55 on the weak electric signals, the third harmonic voltage U with different frequencies at the set temperature is obtained by the microcomputer control and data acquisition system 523ωAnd fundamental wave voltage U1ω；
(6) Fitting a calculation formula according to a harmonic method test principle to obtain the normal phase thermal conductivity of the material to be measured at the set temperature measured by the sensor, wherein the length l of the metal thin belt of the detector and the thermal conductivity k of the substrate in the calculation formula are shown in the specificationsAre measured in the experimental preparation stage;
(7) after changing the set temperature, repeating the steps (1) to (6), and measuring the thermal conductivity of the sample at other temperatures;
(8) according to the measurement results of the steps (5) and (6), combining a third harmonic method test mechanism to obtain the thermal conductivity of the material without temperature;
(9) considering the high temperature resistance of the substrate material, the temperature range measured by the material to be measured is as follows: 25-1000 ℃.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. A device for measuring the thermal conductivity of a wide temperature range material is characterized in that: the device comprises a linear heater/detector module (1), a high-temperature resistant substrate (2), a high-temperature vacuum heating furnace (4) and an electric signal acquisition and processing module, wherein the linear heater/detector module (1) is arranged on the high-temperature resistant substrate (2), one surface of the high-temperature resistant substrate (2) provided with the linear heater/detector module (1) is pressed to a material sample (3) to be detected, the high-temperature resistant substrate (2) is arranged in the high-temperature vacuum heating furnace (4), and the linear heater/detector module (1) is connected with the electric signal acquisition and processing module;
the linear heater/detector module (1) comprises a linear heater/detector (11), a first current lead element (12a), a first detection voltage lead element (12b), a second detection voltage lead element (12c) and a second current lead element (12d), the electric signal acquisition and processing module comprises a signal generator (51), a microcomputer control and data acquisition system (52), a signal processing system (53), a preamplifier (54), a lock-in amplifier (55), an adjustable resistor (R9), a first current lead end (5a), a first voltage lead end (5b), a second voltage lead end (5c) and a second current lead end (5d), the signal processing system (53) comprises a converter (531), a first operational amplifier (532), a second operational amplifier (533), a first low-temperature drift resistor (R1), a second low-temperature drift resistor (R2), A third low-temperature drift resistor (R3), a fourth low-temperature drift resistor (R4), a fifth low-temperature drift resistor (R5), a sixth low-temperature drift resistor (R6), a seventh low-temperature drift resistor (R7) and an eighth low-temperature drift resistor (R8), wherein the high-temperature vacuum heating furnace (4) comprises a heat insulation material (41), a furnace body support (42), a furnace front door (43), a vacuum pipeline (44), a Roots pump (45), a mechanical pump (46), a heating element (47), a lead device (48) and a pipeline flange (49), the lower part of the furnace body is the furnace body support (42), the heat insulation material (41) is arranged in the furnace body, the front side of the furnace body is provided with the furnace front door (43), the rear part of the furnace body is connected with the Roots pump (45) through the vacuum pipeline (44), the pipeline flange (49) is arranged between the rear part of the furnace body and the vacuum pipeline (44), the lower part of the furnace body is provided with the mechanical pump (46), the lead device (48) is arranged on the upper part of the furnace body, a heating element (47) is arranged in the heat insulation material (41);
the shape of the linear heater/detector (11) is a linear thin strip four-pad, the four pads are respectively connected with a first current lead wire (12a), a first detection voltage lead wire (12b), a second detection voltage lead wire (12c) and a second current lead wire (12d), wherein the linear thin strip is 8-30mm in length and 8-700 mu m in width, the linear heater/detector is made of one of nickel, platinum and gold and is 50-200nm in thickness;
the high-temperature resistant substrate (2) is made of a mica sheet material, the thickness of the mica sheet material is 0.1-0.3 mm, and the maximum service temperature is 1000 ℃.
2. The apparatus for measuring thermal conductivity of a wide temperature range material according to claim 1, wherein: the linear heater/detector module (1) and the high-temperature resistant substrate (2) form a third harmonic method independent sensor, the third harmonic method independent sensor is based on an asymmetric heat conduction model, and a metal detector is deposited on the high-temperature resistant substrate (2) by adopting a mask plate physical deposition method; the surface of the detector is plated with a layer of wear-resistant insulating protective film, and the third harmonic method independent sensor structure comprises a high-temperature-resistant substrate (2), a linear heater/detector module (1) and a wear-resistant insulating protective film from bottom to top, wherein the wear-resistant insulating protective film is silicon nitride.
3. The apparatus for measuring thermal conductivity of a wide temperature range material according to claim 1, wherein: the first current lead element (12a), the first detection voltage lead element (12b), the second current lead element (12d) and the second detection voltage lead element (12c) are made of molybdenum wires, the melting point is 2620 ℃, and the diameter is 300 mu m.
4. The apparatus for measuring thermal conductivity of a wide temperature range material according to claim 1, wherein: the first current lead wire (12a), the first detection voltage lead wire (12b), the second detection voltage lead wire (12c) and the second current lead wire (12d) are respectively connected with a first current lead end (5a), a first voltage lead end (5b), a second voltage lead end (5c) and a second current lead end (5d), the first current lead end (5a) is connected with a first operational amplifier (532), a signal generator (51) and a microcomputer control and data acquisition system (52) through an adjustable resistor (R9), the first current lead end (5a) is connected with a first operational amplifier (532) through a second low temperature drift resistor (R2), a first low temperature drift resistor (R1) is arranged between the adjustable resistor (R9) and the first operational amplifier (532), a converter (531) is arranged between the adjustable resistor (R9) and the signal generator (51), the signal generator (51) is connected with the microcomputer control and data acquisition system (52), the microcomputer control and data acquisition system (52) and the signal generator (51) are both connected with the phase-locked amplifier (55), the first voltage lead end (5b) is connected with the second operational amplifier (533) through the third low-temperature drift resistor (R3), the second voltage lead end (5c) is connected with the second operational amplifier (533) through the fourth low-temperature drift resistor (R4), the first operational amplifier (532) is connected with the preamplifier (54), the first operational amplifier (532) and the seventh low-temperature drift resistor (R7) are connected in parallel, the second operational amplifier (533) is connected with the preamplifier (54), the second operational amplifier (533) and the eighth low-temperature drift resistor (R8) are connected in parallel, the preamplifier (54) is connected with the phase-locked amplifier (55), and the second current lead piece (12d) is connected with the ground through the second current lead end (5 d).
5. The apparatus for measuring thermal conductivity of a wide temperature range material according to claim 1, wherein: the high-temperature vacuum heating furnace (4) adopts an electric heating mode, and the highest working temperature is 1200 ℃; a two-stage vacuum pumping mode of a 2X-70 mechanical pump (46) and a Roots pump (45) is adopted, the pressure of a vacuum environment is less than 1Pa, the whole external furnace body is made of stainless steel, a hearth material is made of an alumina polycrystalline fiberboard, and heating elements are respectively installed on the periphery inside the hearth in a suspension mode; the furnace body is provided with a lead device for leading out a high-temperature lead in the hearth to external equipment; the furnace adopts a double-layer furnace body structure, a cooling water system is used for cooling the inner furnace door, a B-type double platinum-rhodium thermocouple is used for monitoring the inner temperature of the hearth, and the heating power is controlled and regulated according to a PID controller, wherein the temperature measuring range of the B-type double platinum-rhodium thermocouple is between normal temperature and 1820 ℃.
6. The method for applying the device for measuring the thermal conductivity of the wide temperature range material according to claim 1 is characterized in that: the method comprises the following steps:
s1: placing a material sample (3) to be detected on the surface of the third harmonic method independent sensor, fixing the material sample by using a sample clamp, and then placing the material sample in a high-temperature vacuum heating furnace (4), wherein the linear heater/detector module (1) is connected with an external electric signal acquisition and processing module through a vacuum electrode;
s2: starting a vacuum system, vacuumizing the high-temperature vacuum heating furnace (4), and setting the vacuum degree to be less than 1 Pa;
s3: when the vacuum degree meets the requirement, starting a heating module of the high-temperature vacuum furnace, setting the temperature, and heating the material to be measured in the furnace;
s4: when the set temperature is reached, introducing sinusoidal alternating current at different frequencies to the linear heater/detector module (1) to obtain third harmonic and fundamental voltage of the sensor at different frequencies, and fitting according to a harmonic method test principle to obtain the thermal conductivity of the material measured by the sensor at the set temperature;
s5: the set temperature of the heating module is changed, and S1-S4 are repeated, and the thermal conductivity of the sample in a wide temperature range is measured.
7. The method of measuring thermal conductivity of a wide temperature range material of claim 6, wherein: the applicable temperature range of the method is as follows: 25-1000 ℃.
8. The method of measuring thermal conductivity of a wide temperature range material of claim 6, wherein: the calculation formula of the thermal conductivity is as follows:
wherein k is the thermal conductivity of the material to be measured, and the unit is W.m-1·K-1；ksThermal conductivity of the substrate material, in W.m-1·K-1(ii) a P-detector power, in units of W,
r-resistance of heating/detector, unit is omega; l-length of heating/detector, unit is m; u shape1ω-first harmonic voltage, in units V; omega-angular frequency in rad/s; u shape3ωThird harmonicVoltage in units of V; alpha is alphaCRTemperature coefficient of resistance of the heating/detector, in units of 1/K.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110134103.7A CN112782218B (en) | 2021-01-28 | 2021-01-28 | Device and method for measuring thermal conductivity of wide-temperature-range material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110134103.7A CN112782218B (en) | 2021-01-28 | 2021-01-28 | Device and method for measuring thermal conductivity of wide-temperature-range material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112782218A CN112782218A (en) | 2021-05-11 |
| CN112782218B true CN112782218B (en) | 2021-10-22 |
Family
ID=75760133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110134103.7A Active CN112782218B (en) | 2021-01-28 | 2021-01-28 | Device and method for measuring thermal conductivity of wide-temperature-range material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112782218B (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101481786A (en) * | 2009-02-21 | 2009-07-15 | 奉化市光亮热处理电炉有限公司 | Vacuum heat treatment furnace for metallic titanium coiled material and heat treatment method thereof |
| CN102279204B (en) * | 2010-06-09 | 2013-05-08 | 中国科学院工程热物理研究所 | Detection method for thermal conductivity and thermal diffusivity of anisotropic material |
| KR20150053488A (en) * | 2013-11-08 | 2015-05-18 | 한국전자통신연구원 | thermoelectric conductivity measurement instrument of thermoelectric device and measuring method of the same |
| CN105954319B (en) * | 2016-07-21 | 2018-09-14 | 北京科技大学 | The device and method that energy-saving heat-insulating material thermal conductivity scene is accurately tested |
| US11193901B2 (en) * | 2016-11-29 | 2021-12-07 | Eko Instruments Co., Ltd. | Thermal conductivity measuring device, thermal conductivity measuring method and vacuum evaluation device |
| CN109115830B (en) * | 2018-10-18 | 2024-04-19 | 北京科技大学 | Nondestructive testing device and method for three-dimensional anisotropic thermal conductivity of material |
-
2021
- 2021-01-28 CN CN202110134103.7A patent/CN112782218B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112782218A (en) | 2021-05-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102305807B (en) | Method for measuring Seebeck coefficient of micro/nano thermoelectric materials or devices | |
| Martin | Apparatus for the high temperature measurement of the Seebeck coefficient in thermoelectric materials | |
| CN102692427B (en) | Nano-thermoelectric multi-parameter in-situ quantitative characterization device based on atomic force microscope | |
| MXPA05002782A (en) | Tunneling-effect energy converters. | |
| CN110907493B (en) | Method for testing high-temperature thermal conductivity | |
| CN103344790B (en) | A kind of device based on scanning calorifics microscope in-situ characterization nanometer thermoelectric Seebeck coefficient | |
| CN104502400A (en) | Heat barrier material high temperature heat conductivity plane heat source test system and method | |
| CN112034002B (en) | Device and method for measuring Seebeck coefficient of thermoelectric material | |
| CN103698357B (en) | A kind of thermal conductivity based on MEMS double-heater and thermal diffusion coefficient sensor | |
| CN112782218B (en) | Device and method for measuring thermal conductivity of wide-temperature-range material | |
| CN101149403A (en) | Method for sensing and measuring current through electric-thermal conversion and dedicated electric-thermal conversion sensor | |
| CN211528262U (en) | Material heat conductivity testing system | |
| CN114264695A (en) | Method and system for measuring heat conductivity coefficient of trace liquid | |
| Li et al. | Complex thermal analysis of supercapacitor by thermal impedance spectroscopy | |
| CN215525613U (en) | Micro-nano material thermoelectric performance in-situ comprehensive measurement device based on harmonic detection | |
| MacLeod et al. | High-temperature high-pressure calorimeter for studying gram-scale heterogeneous chemical reactions | |
| CN102590274B (en) | System and method used for testing heat conductivity of thin film thermoelectric material | |
| CN106686771B (en) | A kind of coating has the thick film element of high thermal conductivity ability | |
| CN105954319B (en) | The device and method that energy-saving heat-insulating material thermal conductivity scene is accurately tested | |
| CN112595749A (en) | Near-field heat radiation independent detector, preparation method and measurement method | |
| CN106686770B (en) | A kind of coating substrate has the thick film element of high thermal conductivity ability | |
| CN215525614U (en) | Device for directly and comprehensively measuring thermoelectric performance of micro-nano material in situ | |
| CN214277971U (en) | Near-field thermal radiation detector based on transient plane heat source | |
| Klems et al. | Large‐area, high‐sensitivity heat‐flow sensor | |
| Zheng et al. | Stethoscope-type 3ω independent detector for fast measurement of material thermal conductivity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |