CN115266814B - Low-temperature thermal conductivity measuring device and measuring method - Google Patents
Low-temperature thermal conductivity measuring device and measuring method Download PDFInfo
- Publication number
- CN115266814B CN115266814B CN202210703822.0A CN202210703822A CN115266814B CN 115266814 B CN115266814 B CN 115266814B CN 202210703822 A CN202210703822 A CN 202210703822A CN 115266814 B CN115266814 B CN 115266814B
- Authority
- CN
- China
- Prior art keywords
- temperature
- sample
- power supply
- temperature sensor
- thermal conductivity
- 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
Abstract
The invention discloses a low-temperature thermal conductivity testing device and a measuring method.A diode cold screen is provided with a diode cold plate, one end of a sample to be tested is arranged on the diode cold plate, a copper plate is arranged at the other end of the sample to be tested, and a first temperature sensor and a first heating block are arranged on the copper plate; the second temperature sensor and the second heating block are arranged on the two-pole cold plate; the two-pole cold screen is arranged in the first-stage cold screen, and the first-stage cold screen is arranged in the vacuum cavity; the vacuum cavity and the refrigerator are fixedly arranged on the bracket, and a first-stage cold head and a second-stage cold head of the refrigerator are respectively communicated with the first-stage cold screen and the second-stage cold screen; the first temperature sensor and the second temperature sensor are both connected with the input end of the temperature controller, the output end of the temperature controller is connected with the second heating block, the first heating block is connected with the hot end heating power supply, and the first-stage cold plate of the first cold screen is connected with the quick temperature return heating power supply. The test device has less heat leakage and can accurately measure the heat conductivity.
Description
Technical Field
The invention relates to the technical field of thermal conductivity measurement at low temperature, in particular to a low-temperature thermal conductivity measurement device and a low-temperature thermal conductivity measurement method.
Background
Thermal conductivity is one of the fundamental thermophysical parameters of a substance. With the development of low-temperature technology, superconducting technology and aerospace technology and the wide application in the engineering field, the measurement of thermal conductivity is not only an important means of physical research, but also can provide necessary data for engineering design. For solid materials of the same kind, the low temperature conductivity of the solid materials still changes along with the changes of defects such as temperature, components, magazines, structures and the like, so that the measurement of the low temperature conductivity of the solid materials plays an important role.
Pages 32-36 of journal 2008 of low temperature engineering discloses a solid material thermal conductivity test system by Xu et al, and the test adopts a steady-state longitudinal heat flow method to test the low temperature heat conductivity of stainless steel, titanium alloy and magnesium alloy. Comparison with the standard sample shows that the test error is within 5%. However, the result only meets the experimental conditions of the temperature above 150k, and the thermal conductivity error gradually increases from 273k to 150k, and the thermal conductivity situation below 150k is not studied.
Pages 1-5 of journal 2011 of low temperature engineering discloses a low temperature heat conductivity measuring device developed by Liu Huiming et al, which takes a refrigerator as a cold source. The device adopts a detachable sample testing rod with an independent vacuum environment, and through the test comparison with a standard stainless steel 304 sample, the device is verified to be within 8% of the test precision of 8-300K, but the error is relatively high.
The invention patent application publication number CN104040327a discloses a method for measuring thermal conductivity. The application calculates a first thermal conductivity and a second thermal conductivity of the material in a first direction and a second direction of the material based on the shape of the isotherm and based on the first temperature and the second temperature detected at a point of the front side of the material at two points in time. There is no specific disclosure of how to reduce the thermal conductivity error.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: how to reduce the error of thermal conductivity.
In order to solve the technical problems, the invention provides the following technical scheme:
the low-temperature heat conductivity measuring device comprises a bracket, a vacuum cavity, a primary cold screen, a secondary cold screen, a refrigerator, a measuring unit and a control unit;
the two-pole cold screen is provided with a two-pole cold plate, and one end of a sample to be tested is arranged on the two-pole cold plate;
the two-pole cold screen is arranged in the primary cold screen, and the primary cold screen is arranged in the vacuum cavity;
the vacuum cavity and the refrigerator are fixedly arranged on the bracket, and a primary cold head and a secondary cold head of the refrigerator are respectively communicated with the primary cold screen and the secondary cold screen;
the vacuum cavity is also provided with an evacuation port;
the measuring unit is respectively positioned on the first-stage cold plate of the first cold screen, the second-stage cold plate of the second cold screen and the sample to be measured, and is connected with the control unit.
The advantages are that: the testing device is used for ensuring the environment required by the test through the vacuum cavity and the arranged evacuation port, so that the testing process is more accurate. And set up one-level cold screen and dipolar cold screen, be favorable to reducing the system heat leakage for the heat of heating is close to the true value more. Meanwhile, the primary cold screen and the secondary cold screen are respectively connected to the primary cold head and the secondary cold head of the refrigerator, so that heat leakage of the system is reduced. Therefore, the test device has less heat leakage and can accurately measure the heat conductivity.
Preferably, the control unit comprises a hot end heating power supply, a rapid temperature return heating power supply and a temperature controller;
the measuring unit comprises a first temperature sensor, a second temperature sensor, a first heating block and a second heating block;
the first temperature sensor and the second temperature sensor are both connected with the input end of the temperature controller, the output end of the temperature controller is connected with the second heating block, the first heating block is connected with the hot end heating power supply, and the first-stage cold plate of the first cold screen is connected with the rapid temperature return heating power supply;
the first temperature sensor and the first heating block are arranged at the other end of the sample to be measured; the second temperature sensor and the second heating block are mounted on the two-pole cold plate.
Preferably, the temperature sensor further comprises a copper plate fixedly arranged at the other end of the sample to be measured, and the first temperature sensor and the first heating block are arranged on the copper plate.
Preferably, the thickness of the copper plate is 2mm.
Preferably, the bracket is of a rectangular frame structure, and the temperature controller, the hot end heating power supply and the rapid temperature return heating power supply are all arranged in the bracket.
Preferably, further comprises an electrical connector and a wire; the hot end heating power supply is connected with the first heating block through an electric connector and a wire, the quick temperature return heating power supply and the wire are connected with the first cold plate through the electric connector, and the temperature controller is connected with the first temperature sensor and the second temperature sensor through the electric connector and the wire respectively.
Preferably, the wire is subjected to heat sink treatment and is wound on the outer side wall of the diode cold screen.
Preferably, the first temperature sensor and the second temperature sensor are both of the model numbers DT670; the model of the refrigerator is GM210.
Preferably, the type of the hot-end heating power supply is PS3003D, and the type of the rapid temperature-return heating power supply is PS6005D; the model of the temperature controller is Lakeshore336.
The invention also discloses a measuring method using the low-temperature thermal conductivity testing device, which comprises the following steps:
s1, fixedly mounting the bottom of a sample to be measured on a diode cold plate, loading an indium sheet on a contact surface, and measuring the diameter D and the height L;
s2, fixedly mounting a copper plate at the upper end of a sample to be tested, and loading an indium sheet on a contact surface;
s3, a first temperature sensor and a first heating block are arranged at the upper end of the copper plate, and temperature measurement and heating are respectively carried out to obtain the loading power Q and the hot end temperature T1 of the heating power supply;
s4, a second temperature sensor and a second heating block are arranged on the cold plate, and temperature measurement and temperature control are respectively carried out to obtain the temperature T2 of the lower end face; and obtaining a contact area A according to the first temperature sensor and the first heating block;
s5, performing simulation analysis on the sample to be detected to obtain the temperature T of the upper surface of the sample table under ideal conditions; and obtaining equivalent thermal resistance R according to the loading power Q of the heating power supply; wherein, the calculation formula is:
wherein R is equivalent thermal resistance generated by the contact of the first temperature sensor 8, the first heating block 10 and the copper plate 15, T1 is the temperature of the upper surface of the sample to be detected, T is the temperature of the upper surface of the sample to be detected in an ideal state, and Q is the loading power of a heating power supply;
s6, in the calculation process, the thermal resistance is considered to obtain the real thermal conductivity lambda, wherein the calculation formula is as follows:
wherein lambda is the calculated true thermal conductivity, T1 is the temperature of the upper surface of the sample to be measured, T2 is the temperature of the lower surface of the sample to be measured, Q is the loading power of a heating power supply, R is the thermal resistance, L is the height of the sample to be measured, and A is the contact area of the first temperature sensor, the first heating block and the copper plate.
Compared with the prior art, the invention has the beneficial effects that:
(1) The testing device provided by the invention adopts the vacuum cavity and the arranged evacuation port to ensure the environment required by the test, so that the testing process is more accurate. And set up one-level cold screen and dipolar cold screen, be favorable to reducing the system heat leakage for the heat of heating is close to the true value more. Meanwhile, the primary cold screen and the secondary cold screen are respectively connected to the primary cold head and the secondary cold head of the refrigerator, so that heat leakage of the system is reduced. Therefore, the test device has less heat leakage and can accurately measure the heat conductivity.
(2) According to the testing device, the related wires are subjected to heat sink and wound on the outer side wall of the diode cold screen, so that solid heat conduction and leakage can be ignored.
(3) According to the invention, the influence of contact thermal resistance is larger through experiments and simulations, the sensor, the heater and the like are calibrated, and the heat leakage can be reduced to the minimum through the arrangement of the testing device, but the thermal resistance cannot be eliminated even by adopting the modes of indium sheets, smearing heat conduction grease and the like. Therefore, the invention provides an optimization method based on heat resistance elimination, and experiments prove that the heat conductivity error is far smaller than the error in the literature, the accuracy is improved by more than 100%, in any material test, if the heat resistance between contact surfaces can be obtained, the test error is greatly reduced, and if the material is unknown, the heat resistance error caused by the heater sensor can be eliminated by itself. Therefore, the test method has high accuracy.
Drawings
FIG. 1 is a schematic overall structure of a first embodiment of the present invention;
fig. 2 is a schematic view showing an internal structure of a vacuum chamber according to a first embodiment of the present invention;
FIG. 3 is a schematic diagram of a sample to be tested of a testing device according to a first embodiment of the present invention;
fig. 4 is a schematic structural view of a stainless steel according to a second embodiment of the present invention;
FIG. 5 is a schematic diagram showing simulation results of stainless steel according to a second embodiment of the present invention;
FIG. 6 is a schematic diagram of thermal conductivity and error of stainless steel according to embodiment II of the present invention;
fig. 7 is a schematic structural diagram of oxygen-free copper according to a second embodiment of the present invention;
fig. 8 is a schematic diagram of thermal conductivity and error of oxygen free copper of example two of the present invention.
Detailed Description
In order to facilitate the understanding of the technical scheme of the present invention by those skilled in the art, the technical scheme of the present invention will be further described with reference to the accompanying drawings.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Example 1
Referring to fig. 1, the embodiment discloses a low-temperature thermal conductivity measuring device, which comprises a bracket 1, a vacuum cavity 5, a primary cold screen 6, a secondary cold screen 7, a refrigerator 12, a control unit and a measuring unit.
The control unit comprises a hot end heating power supply 2, a rapid temperature return heating power supply 3 and a temperature controller 4; the measuring unit comprises a first temperature sensor 8, a second temperature sensor 9, a first heating block 10 and a second heating block 11. The bracket 1 is of a rectangular frame structure, and the hot end heating power supply 2, the rapid temperature return heating power supply 3 and the temperature controller 4 are all arranged in the bracket 1.
Referring to fig. 2 and 3, a vacuum chamber 5 is fixedly installed at the upper end of a bracket 1, a primary cold screen 6 is installed in the vacuum chamber 5, a secondary cold screen 7 is installed in the primary cold screen 6, and a sample 14 to be measured is installed in the secondary cold screen 7. Specifically, the vacuum cavity 5, the primary cold screen 6 and the secondary cold screen 7 are all in cylindrical structures, the vacuum cavity 5, the primary cold screen 6 and the secondary cold screen 7 can be arranged to be coaxial shafts and the rotating shafts are in vertical directions, the primary cold screen 6 is located in the middle of the vacuum cavity 5, and the secondary cold screen 7 is located in the middle of the primary cold screen 6. Further, the vacuum chamber 5 may be mounted on the bracket 1 by screw connection. The first-stage cold screen 6, the second-stage cold screen 7 and the corresponding connection modes are adopted, so that system heat leakage is reduced, and the heating heat is as close to a true value as possible.
Meanwhile, the refrigerator 12 is fixedly arranged at the bottom of the vacuum cavity 5, and a primary cold head 121 and a secondary cold head of the refrigerator 12 are respectively connected to the primary cold screen 6 and the secondary cold screen 7, so that heat leakage of the system is reduced, and measurement errors are reduced.
The bottom of the diode cooling screen 7 is provided with a diode cooling plate 701, the bottom of the sample 14 to be tested is arranged on the diode cooling plate 701 in a threaded connection mode, and the upper end of the sample 14 to be tested is provided with a copper plate 15 in a threaded connection mode.
The first temperature sensor 8 and the first heating block 10 are fixedly installed on the copper plate 15, and the second temperature sensor 9 and the second heating block 11 are installed on the side of the dipolar cold plate 701 where the sample 14 to be measured is installed. The thickness of the copper plate 15 in this embodiment is 2mm, and the temperature error of the two sides of the copper plate 15 is small, so that the default testing temperature of the steel plate is the temperature of the upper end face of the sample 14 to be tested.
The first temperature sensor 8 and the second temperature sensor 9 are connected with the input end of the temperature controller 4 through an electric connector 13 and an internal heating wire, and the second heating block 11 is connected with the output end of the temperature controller 4 through the electric connector 13 and the internal heating wire; the first connecting block is connected with the hot end heating power supply 2 through an electric connector 13 and an internal heating wire; the first-stage cold plate 601 at the lower end of the first-stage cold screen 6 is connected with the rapid temperature-return heating power supply 3.
The hot-end heating power supply 2 of the embodiment heats the copper plate 15 through the first heating block 10, and the rapid temperature-return heating power supply 3 is connected with the primary cold plate 601 of the primary cold screen 6 to enable the whole system to rapidly return to temperature. The temperature controller 4 receives temperature signals of the first temperature sensor 8 and the second temperature sensor 9, and then controls the temperature of the lower end of the sample 14 to be measured.
Meanwhile, the lower end of the vacuum chamber 5 is further provided with an evacuation port 501, and the inside of the vacuum chamber 5 is subjected to a vacuum evacuation process by connecting an external evacuation device at the evacuation port 501, so that the inside of the vacuum chamber 5 can be maintained in a vacuum state.
In some embodiments, all the connecting wires are heat-sinking and wound around the outer side wall of the secondary cold screen, so that the temperature of the conducting wires led out from the inside of the sample stage is almost equal to the temperature of the secondary cold head 122 of the refrigerator 12, so as to eliminate the influence caused by conduction heat leakage, and thus the testing process of the embodiment can ignore solid heat conduction heat leakage.
In some embodiments, the model number of the chiller 12 is GM210. The GM210 refrigerator 12 can meet the thermal conductivity measurement in the 20K-300K temperature region, and can meet the thermal conductivity measurement requirements of the present embodiment.
Meanwhile, the first temperature sensor 8 and the second temperature sensor 9 are both of the type DT670. The type of the hot end heating power supply 2 is PS3003D, and the type of the rapid temperature return heating power supply 3 is PS6005D. The model of temperature controller 4 is Lakeshore336.
In some embodiments, wheels 101 for movement are also mounted at the four ends of the stand 1, facilitating movement of the entire testing device.
The testing device of the embodiment heats and returns the temperature of the sample 14 to be tested through the hot end heating power supply 2 and the quick temperature return heating power supply 3, and simultaneously controls the temperature of the lower end of the sample 14 to be tested through the temperature controller 4. And the structural designs of the primary cold screen 6 and the secondary cold screen 7 are adopted, so that the error of the whole device in the measuring process is reduced as much as possible.
Example two
The implementation also discloses a measuring method of the low-temperature thermal conductivity measuring device of the first application embodiment, which comprises the following steps:
s1, fixedly mounting the bottom of a sample 14 to be measured on a diode cold plate 701, loading an indium sheet on a contact surface, and measuring the diameter D and the height L;
s2, fixedly mounting a copper plate 15 at the upper end of a sample 14 to be tested, and loading an indium sheet on a contact surface;
s3, a first temperature sensor 8 and a first heating block 10 are arranged at the upper end of the copper plate 15, and are used for respectively measuring temperature and heating to obtain loading power Q and hot end temperature T1 of a heating power supply;
s4, a second temperature sensor 9 and a second heating block 11 are arranged on the cold plate, and temperature measurement and temperature control are respectively carried out to obtain the temperature T2 of the lower end face; and the contact area a is obtained from the first temperature sensor 8 and the second temperature sensor 9 used.
S5, performing simulation analysis on the sample 14 to be detected to obtain the temperature T of the upper surface of the sample table under ideal conditions; and obtaining equivalent thermal resistance R according to the loading power Q of the heating power supply; wherein, the calculation formula is:
wherein R is equivalent thermal resistance generated by the contact of the first temperature sensor 8, the first heating block 10 and the copper plate 15, T1 is the temperature of the upper surface of the sample 14 to be measured, T is the temperature of the upper surface of the sample 14 to be measured in an ideal state, and Q is the loading power of a heating power supply.
S6, in the calculation process, the thermal resistance is considered to obtain the real thermal conductivity lambda, wherein the calculation formula is as follows:
where λ is the calculated true thermal conductivity, T1 is the temperature of the upper surface of the sample 14 to be measured, T2 is the temperature of the lower surface of the sample 14 to be measured, Q is the loading power of the heating power supply, R is the thermal resistance, L is the height of the sample 14 to be measured, and a is the contact area of the first temperature sensor 8, the first heating block 10, and the copper plate 15.
In steps S1 and S2, the sample 14 to be measured is fixedly mounted on the cold plate and the copper plate 15, respectively, by means of threaded connection.
Systematic errors originate from a number of directions: systematic errors of instruments and meters, solid heat conduction of wires and thermal resistance between contact surfaces.
Thermal contact resistance refers to the difference between the two interfacial surface temperatures divided by the heat flux.
The system heat leakage is ignored, the second-stage cold screen and the first-stage cold screen 6 are respectively consistent with the respective cold head temperatures, and the radiation heat leakage can be ignored; the wire is wound on the cold screen to be used as a heat sink, so that the heat leakage of the wire can be ignored, the reading error of an instrument is 1%, and the comprehensive error is very small and can be ignored.
The effect of the contact thermal resistance is optimized, the contact thermal resistance generates temperature errors on the contact surface, the thermal resistance between the contact surfaces of the wall surfaces cannot be realized no matter the indium sheet is loaded or the silver paste is coated, and particularly in the material test with higher thermal conductivity, the extremely small temperature difference can cause great thermal conductivity errors, so the thermal resistance cannot be ignored. After optimizing the contact thermal resistance, only the tiny heat leakage is remained, and the thermal conductivity result is more accurate.
In this embodiment, stainless steel is used as the sample 14 to be tested for design:
first, the structure of the stainless steel of the present embodiment is shown in fig. 4. Stainless steel has better thermal conductivity stability in a full temperature area, and has standard database comparison. Facilitating comparison.
The stainless steel is then placed in a measuring device, the bottom of the stainless steel is fixedly mounted on the bipolar cold plate 701, and the contact surface is loaded with indium flakes while measuring the diameter D and the height L of the stainless steel. Specifically, the diameter D and the height L are obtained by averaging from a plurality of measurements.
The perforated copper plate 15 is then fixed to the upper end of the stainless steel by external threads, the contact surface is loaded with indium flakes, and the contact is increased by loading indium flakes on the contact surface, reducing the measurement error.
The first temperature sensor 8 and the first heating block 10 are arranged at the upper end of the copper plate 15, and are used for respectively measuring temperature and heating to obtain loading power Q and hot end temperature T1 of a heating power supply. The thickness of the copper plate 15 in this embodiment is 2mm, the temperature error of the two sides of the copper plate 15 is small, and the default test temperature is the temperature of the upper end face of the stainless steel.
The second temperature sensor 9 and the second heating block 11 are mounted on the cold plate, and temperature measurement and temperature control are performed respectively to obtain the lower end face temperature T2.
The temperature T of the upper surface of the stainless steel under ideal conditions is obtained by carrying out simulation analysis on the stainless steel; FIG. 5 is a simulation result of stainless steel at a cold end 77K, and according to real data T1 measured in an experiment, an equivalent thermal resistance R is obtained according to loading power Q of a heating power supply; wherein, the calculation formula is:
wherein R is equivalent thermal resistance generated by the contact of the first temperature sensor 8, the first heating block 10 and the copper plate 15, T1 is the temperature of the upper surface of the sample 14 to be measured, T is the temperature of the upper surface of the sample 14 to be measured in an ideal state, and Q is the loading power of a heating power supply.
The heating block of the present embodiment has a size of 10X10 mm, and the contact area of the first temperature sensor 8 and the second temperature sensor 9 is 40.77mm 2 And according to the proportion of the contact thermal resistance and the contact surface area, the equivalent thermal group value generated by the hot end of the stainless steel sample piece is analyzed and calculated to be 0.69K/W, and the error is far greater than other factors, so that the thermal resistance needs to be considered.
Finally, taking thermal resistance into consideration during calculation to obtain the real thermal conductivity lambda, wherein a calculation formula is as follows:
where λ is the calculated true thermal conductivity, T1 is the temperature of the upper surface of the sample 14 to be measured, T2 is the temperature of the lower surface of the sample 14 to be measured, Q is the loading power of the heating power supply, R is the thermal resistance, L is the height of the sample 14 to be measured, and a is the contact area of the first temperature sensor 8, the first heating block 10, and the copper plate 15.
The calculation is carried out through the formula of the heat conductivity and the measured data, the result is shown in fig. 6, square scattered points represent theoretical values of stainless steel, and curve 1 is a heat conductivity correction value corresponding to the theoretical values; the triangular scattered points represent the relative error between the correction value and the theoretical value, the curve 2 is the average error of a plurality of measured thermal conductivities at the fixed temperature corresponding to the correction value, and the graph clearly shows that the corrected thermal conductivities of the embodiment have high coincidence in the measured temperature region, and meanwhile, the thermal conductivity error at a single temperature is less than 3%, and the average thermal conductivity is about 1%.
Therefore, the optimum results for the test values of this example were about 1% error at temperatures of 20-300K. The accuracy of thermal conductivity measurement is improved.
The thermal conductivity of the oxygen-free copper is greatly changed at low temperature, and the thermal conductivity result caused by adopting the oxygen-free copper to conduct contact thermal resistance is verified. Thus, oxygen-free copper is used as the sample 14 to be tested for auxiliary verification. The specific experimental process is the same as that of stainless steel, and will not be described in detail here.
FIG. 7 shows a structure of a test sample of oxygen-free copper, wherein a middle thin rod is used as the test sample, a model of the oxygen-free copper is different from a stainless steel structure, the middle thin rod is integrated with the upper surface and the lower surface to reduce the contact thermal resistance of the sample, and the diameter of the test sample is smaller due to larger heat conductivity of the oxygen-free copper, and a temperature division area is required to design the size, so that the model is suitable for temperature test of more than 100K. The thermal resistance in the model is generated on the lower surface of the cold plate and the copper body, and the heater, the sensor and the upper surface of the copper body. According to the analysis of stainless steel above, the thermal resistance generated by the cold plate and the lower surface of the sample, together with other errors, produced about 1% of the errors, and therefore the thermal contact resistance of the sensor and the heater was the main factor. The contact thermal resistance is proportional to the contact area, the stainless steel thermal resistance calculated by the method is 0.69K/W, and the area of the heating block is 100mm 2 The contact area of the sensor is 40.77mm 2 Total contact area of upper and lower surfaces of test article 1036mm 2 Therefore, the contact thermal resistance between the heating block and the sensor can be distributed to be 0.3K/W according to the contact area. Wherein, table 1 is partial verification data of oxygen free copper.
TABLE 1
Fig. 8 is a schematic diagram for verifying the thermal conductivity of oxygen-free copper, wherein curve 3 is the corrected thermal conductivity, curve 4 is the theoretical thermal conductivity, and fig. 8, calculated by combining the data in table 1, shows that the error of the thermal conductivity of oxygen-free copper applying the method is less than 2.9% when the temperature is 100-200 k.
Therefore, the present embodiment provides an optimization method based on eliminating the influence of thermal resistance, so that there is high accuracy in measuring physical properties of any unknown material by using the thermal conductivity of the same heater and sensor as in the present embodiment.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
The above-described embodiments merely represent embodiments of the invention, the scope of the invention is not limited to the above-described embodiments, and it is obvious to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.
Claims (7)
1. A low temperature thermal conductivity measuring method is characterized in that: the device comprises a bracket (1), a vacuum cavity (5), a primary cold screen (6), a secondary cold screen (7), a refrigerator (12), a copper plate (15), a measuring unit and a control unit;
the diode cooling screen (7) is provided with a diode cooling plate (701), and one end of a sample (14) to be tested is arranged on the diode cooling plate (701);
the two-pole cold screen (7) is arranged in the first-stage cold screen (6), and the first-stage cold screen (6) is arranged in the vacuum cavity (5);
the vacuum cavity (5) and the refrigerator (12) are fixedly arranged on the bracket (1), and a primary cold head (121) and a secondary cold head of the refrigerator (12) are respectively communicated with the primary cold screen (6) and the secondary cold screen (7);
an evacuation port (501) is also arranged on the vacuum cavity (5);
the measuring unit is respectively positioned on the first-stage cold plate (601) of the first cold screen (6), the second-stage cold plate (701) of the second cold screen (7) and the sample (14) to be measured, and is connected with the control unit;
the control unit comprises a hot end heating power supply (2), a rapid temperature return heating power supply (3) and a temperature controller (4);
the measuring unit comprises a first temperature sensor (8), a second temperature sensor (9), a first heating block (10) and a second heating block (11);
the first temperature sensor (8) and the second temperature sensor (9) are both connected with the input end of the temperature controller (4), the output end of the temperature controller (4) is connected with the second heating block (11), the first heating block (10) is connected with the hot end heating power supply (2), and the first-stage cold plate (601) of the first cold screen (6) is connected with the rapid temperature return heating power supply (3);
the copper plate (15) is fixedly arranged at the other end of the sample (14) to be detected, and the first temperature sensor (8) and the first heating block (10) are arranged on the copper plate (15); the method comprises the steps of carrying out a first treatment on the surface of the The second temperature sensor (9) and the second heating block (11) are arranged on the two-pole cold plate (701);
the measuring method using the low temperature thermal conductivity testing device comprises the following steps:
s1, fixedly mounting the bottom of a sample (14) to be measured on a diode cold plate (701), loading an indium sheet on the contact surface of the sample (14) to be measured, and measuring the diameter D and the height L of the sample (14) to be measured;
s2, fixedly mounting a copper plate (15) at the upper end of a sample (14) to be tested, and loading an indium sheet on the contact surface of the sample (14) to be tested;
s3, a first temperature sensor (8) and a first heating block (10) are arranged at the upper end of the copper plate (15) to respectively measure temperature and heat so as to obtain loading power Q and hot end temperature T1 of a heating power supply;
s4, a second temperature sensor (9) and a second heating block (11) are arranged on the two-pole cold plate (701) to respectively perform temperature control and temperature control to obtain the temperature T2 of the lower end face; and the contact area A is obtained according to the first temperature sensor (8) and the first heating block (10) which are used;
s5, performing simulation analysis on the sample (14) to be detected to obtain the temperature T of the upper surface of the sample stage under ideal conditions; and obtaining equivalent thermal resistance R according to the loading power Q of the heating power supply; wherein, the calculation formula is:
wherein R is equivalent thermal resistance generated by contact of a first temperature sensor (8), a first heating block (10) and a copper plate (15), T1 is the temperature of the upper surface of a sample (14) to be detected, T is the temperature of the upper surface of the sample (14) to be detected in an ideal state, and Q is the loading power of a heating power supply;
s6, in the calculation process, the thermal resistance is considered to obtain the real thermal conductivity lambda, wherein the calculation formula is as follows:
wherein lambda is the calculated true thermal conductivity, T1 is the temperature of the upper surface of the sample (14) to be measured, T2 is the temperature of the lower surface of the sample (14) to be measured, Q is the loading power of a heating power supply, R is the thermal resistance, L is the height of the sample (14) to be measured, and A is the contact area of the first temperature sensor (8), the first heating block (10) and the copper plate (15).
2. The low temperature thermal conductivity measurement method according to claim 1, wherein: the thickness of the copper plate (15) is 2mm.
3. The low temperature thermal conductivity measurement method according to claim 1, wherein: the bracket (1) is of a rectangular frame structure, and the temperature controller (4), the hot end heating power supply (2) and the rapid temperature return heating power supply (3) are all arranged in the bracket (1).
4. The low temperature thermal conductivity measurement method according to claim 1, wherein: also comprises an electric connector (13) and a wire; the hot end heating power supply (2) is connected with the first heating block (10) through the electric connector (13) and the lead, the quick temperature return heating power supply (3) and the lead are connected with the first cold plate through the electric connector (13), and the temperature controller (4) is connected with the first temperature sensor (8) and the second temperature sensor (9) through the electric connector (13) and the lead respectively.
5. The low temperature thermal conductivity measurement method according to claim 4, wherein: and the lead is subjected to heat sink treatment and is wound on the outer side wall of the diode cold screen (7).
6. The low temperature thermal conductivity measurement method according to claim 1, wherein: the model numbers of the first temperature sensor (8) and the second temperature sensor (9) are DT670; the model of the refrigerator (12) is GM210.
7. The low temperature thermal conductivity measurement method according to claim 1, wherein: the type of the hot-end heating power supply (2) is PS3003D, and the type of the rapid temperature-return heating power supply (3) is PS6005D; the model of the temperature controller (4) is Lakeshore336.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210703822.0A CN115266814B (en) | 2022-06-21 | 2022-06-21 | Low-temperature thermal conductivity measuring device and measuring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210703822.0A CN115266814B (en) | 2022-06-21 | 2022-06-21 | Low-temperature thermal conductivity measuring device and measuring method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115266814A CN115266814A (en) | 2022-11-01 |
| CN115266814B true CN115266814B (en) | 2023-06-27 |
Family
ID=83762420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210703822.0A Active CN115266814B (en) | 2022-06-21 | 2022-06-21 | Low-temperature thermal conductivity measuring device and measuring method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115266814B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104535609A (en) * | 2014-12-26 | 2015-04-22 | 怡维怡橡胶研究院有限公司 | Device for determining heat-conductivity coefficient |
| CN109085199A (en) * | 2018-09-17 | 2018-12-25 | 成都市科创节能材料有限公司 | Detect the device and method of insulating mold coating equivalent thermal resistance and Equivalent Thermal Conductivities |
| CN208766130U (en) * | 2018-09-04 | 2019-04-19 | 成都市科创节能材料有限公司 | A kind of equivalent thermal resistance and thermal coefficient detection device of insulating mold coating for building |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102998424B (en) * | 2012-11-29 | 2014-11-05 | 安徽万瑞冷电科技有限公司 | High temperature and low temperature testing device |
| KR101322183B1 (en) * | 2013-06-13 | 2013-10-28 | 한국지질자원연구원 | Vertical type device for measuring thermal conductivity of rocks and using method of the same |
| DE202015102305U1 (en) * | 2015-05-06 | 2016-08-09 | G.U.N.T. Gerätebau GmbH | Experimental device for the investigation of heat conduction in specimens of metal or other material |
| CN106153672A (en) * | 2016-06-08 | 2016-11-23 | 东南大学 | Voluminous powder material thermal conductivity measurement apparatus based on one-dimensional heat conduction principle and method |
| CN110308752A (en) * | 2018-03-27 | 2019-10-08 | 中国科学院理化技术研究所 | A kind of superhigh precision thermostat |
| CN110118451A (en) * | 2019-04-09 | 2019-08-13 | 上海交通大学 | The profound hypothermia high accuracy temperature control device of thermal capacitance thermal resistance economic benefits and social benefits coupling |
| JP7332413B2 (en) * | 2019-09-27 | 2023-08-23 | 明星工業株式会社 | Low temperature thermal conductivity measuring device |
| CN112129810A (en) * | 2020-09-15 | 2020-12-25 | 中国科学院上海技术物理研究所 | Contact thermal resistance test system with variable pressure and temperature in deep low temperature region |
-
2022
- 2022-06-21 CN CN202210703822.0A patent/CN115266814B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104535609A (en) * | 2014-12-26 | 2015-04-22 | 怡维怡橡胶研究院有限公司 | Device for determining heat-conductivity coefficient |
| CN208766130U (en) * | 2018-09-04 | 2019-04-19 | 成都市科创节能材料有限公司 | A kind of equivalent thermal resistance and thermal coefficient detection device of insulating mold coating for building |
| CN109085199A (en) * | 2018-09-17 | 2018-12-25 | 成都市科创节能材料有限公司 | Detect the device and method of insulating mold coating equivalent thermal resistance and Equivalent Thermal Conductivities |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115266814A (en) | 2022-11-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109001252A (en) | Test device of thermal conductivity coefficient | |
| Solé et al. | Review of the T-history method to determine thermophysical properties of phase change materials (PCM) | |
| Zhang et al. | A high-precision instrumentation of measuring thermal contact resistance using reversible heat flux | |
| CN108303443A (en) | A kind of sheeting is towards heat conductivility steady-state method of test | |
| CN101320007A (en) | Material thermal conductivity measurement apparatus by probe method | |
| CN206832722U (en) | A kind of flat-plate heat pipe testing device for heat transferring performance of tilt adjustable | |
| CN102072916A (en) | Method and device for measuring total hemispherical emissivity of non-metallic material | |
| CN101788513A (en) | Measurement device of thermal conductivity of materials and method thereof | |
| CN109613051B (en) | Device and method for measuring Seebeck coefficient of material by using contrast method | |
| CN110927212A (en) | Testing device for thermal conductivity and contact thermal resistance of gas diffusion layer in compression state | |
| CN102539472A (en) | Method for measuring heat conductivity of poor conductor by using steady-state comparison | |
| CN111157574A (en) | Experimental device for measuring contact thermal resistance | |
| CN104749214B (en) | A kind of constant temperature hot bath device that liquid thermal conductivity factor is measured based on Adsorbent By Using Transient Plane Source Technique | |
| CN114544699B (en) | Method for testing thermal resistance and thermal conductivity coefficient of material | |
| Hejtmánek et al. | Test system for thermoelectric modules and materials | |
| CN115266814B (en) | Low-temperature thermal conductivity measuring device and measuring method | |
| CN107917929A (en) | A kind of parallel hot line heat conduction coefficient tester of high accuracy unstable state and its test method | |
| CN107144597B (en) | Test device and method for measuring heat conductivity coefficient of building material in service state | |
| CN115616030B (en) | Measurement method of heat conductivity coefficient | |
| CN104006983A (en) | Intelligent test system for heat resistance of CPU radiator and test method of intelligent test system | |
| Luo et al. | An experimental investigation on thermal contact resistance across metal contact interfaces | |
| CN111474204A (en) | Method for testing heat conductivity coefficient of cylindrical sample by punching method | |
| Zhang et al. | Thermal conductivity measurement of the epoxies and composite material for low temperature superconducting magnet design | |
| Kanagaraj et al. | Simultaneous measurements of thermal expansion and thermal conductivity of FRPs by employing a hybrid measuring head on a GM refrigerator | |
| CN201222042Y (en) | Apparatus for measuring material thermal conductivity parameter |
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 |