Heat conductivity coefficient testing device and method

Abstract

The invention belongs to the field of testing devices, and particularly relates to a heat conductivity coefficient testing device and method. The invention provides a heat conductivity coefficient testing device. The heat conductivity coefficient testing device comprises a hot pole part, a cold pole part, a driving part, a pressure sensor and a displacement sensor, the hot electrode part comprises a hot electrode rod capable of adjusting and detecting temperature; the cold pole part comprises a cold pole rod capable of adjusting and detecting temperature; the driving part drives the cold pole part and the hot pole part to move relatively and enables the end of the cold pole rod to be close to or away from the end of the hot pole rod; the pressure sensor is arranged between the driving part and the cold pole part; the displacement sensor detects the displacement of the cold pole part relative to the hot pole part. According to the heat conductivity coefficient testing device and method provided by the invention, the device is relatively simple in structure, can be used for measuring various parameters, and is high in testing precision and wide in testing material type.

Description

Technical Field

[0001] The invention belongs to the field of testing devices, and in particular relates to a thermal conductivity testing device and method. Background Art

[0002] Thermal conductivity test device is a device that measures the relationship between the thermal conductivity of a sample and the temperature. Thermal conductivity is an important physical quantity. The determination of thermal conductivity of a poor conductor is a relatively important experiment in thermal science. Thermal conductivity is also one of the main thermal properties of thermal insulation materials and is the main indicator for identifying the thermal insulation performance of materials. In recent years, with the introduction of building energy-saving regulations, my country has attached more and more importance to building energy-saving. Therefore, it is very necessary to accurately determine this parameter, which is of great significance for the rational selection of materials.

[0003] However, the biggest problem with existing thermal conductivity test devices is that they have a single test function and can only measure one parameter. If the test function is increased, related detection devices will be added, causing the device to become bloated. In addition, existing thermal conductivity test devices also generally have problems such as low test accuracy and limited test material types. Summary of the invention

[0004] The present invention provides a thermal conductivity testing device and method, which can effectively solve the problems in the background technology.

[0005] The present invention provides a thermal conductivity testing device, comprising a hot pole part, a cold pole part, a driving part, a pressure sensor and a displacement sensor;

[0006] The hot pole part includes a hot pole rod that can adjust and detect temperature; the cold pole part includes a cold pole rod that can adjust and detect temperature; the driving part drives the cold pole part and the hot pole part to move relative to each other and makes the end of the cold pole rod approach or move away from the end of the hot pole rod; the pressure sensor is arranged between the driving part and the cold pole part; the displacement sensor detects the displacement of the cold pole part relative to the hot pole part.

[0007] As a further optimization of the present invention, the driving unit includes an electric push rod, a base, a sliding rod, a sliding block and a top seat;

[0008] The electric push rod is fixed, and the output end of the electric push rod is connected to the base; the cold pole part is fixed on the base, the slider is fixed on the base, and the slider is sleeved on the slide rod; the slide rod is vertically fixed; the top seat is fixed on the slide rod; and the hot pole part is fixed on the top seat.

[0009] As a further optimization of the present invention, it also includes a cabinet; the cabinet includes a lower cabinet and an upper cabinet;

[0010] The bottom of the lower cabinet is provided with casters, the electric push rod is fixed in the lower cabinet, and the slide bar is fixed on the lower cabinet; the upper cabinet is arranged on the lower cabinet, and the hot pole part, the cold pole part, the base and the top seat are all arranged in the upper cabinet.

[0011] As a further optimization of the present invention, a displacement sensor is fixed on the lower cabinet, and the displacement sensor detects the displacement change of the base.

[0012] As a further optimization of the present invention, it also includes a ball connection mechanism; the ball connection mechanism is arranged between the pressure sensor and the cold pole part, and the ball connection mechanism includes a connection part, a ball body and a tray;

[0013] The connecting part is connected to the pressure sensor and is provided with an upper ball groove; the tray and the cold pole part are fixed and the tray is provided with a lower ball groove; the ball is arranged in the upper ball groove and the lower ball groove, and the diameter of the ball is greater than the sum of the depths of the upper ball groove and the lower ball groove.

[0014] As a further optimization of the present invention, hot-pole temperature measuring couples are provided at the upper, middle and lower positions of the hot-pole rod; and cold-pole temperature measuring couples are provided at the upper, middle and lower positions of the cold-pole rod.

[0015] As a further optimization of the present invention, the hot pole part also includes a hot pole heat equalizer, a hot pole temperature-controlling electric couple, a hot pole insulation layer and a hot pole cover; one end of the hot pole rod is fixed to one end of the hot pole heat equalizer; the other end of the hot pole heat equalizer is fixed to one end of the hot pole insulation layer, and a hot pole temperature-controlling electric couple is provided on the hot pole heat equalizer; the hot pole cover covers the hot pole rod, the hot pole heat equalizer and the hot pole insulation layer.

[0016] As a further optimization of the present invention, the connecting end between the hot electrode rod and the hot electrode heat equalizer is umbrella-shaped.

[0017] As a further optimization of the present invention, the cold pole part also includes a cold pole temperature control box and a cold pole cover; one end of the cold pole rod is fixed to the cold pole temperature control box; and the cold pole cover is arranged on the cold pole rod.

[0018] As a further optimization of the present invention, a testing method is also included, comprising the following steps:

[0019] A1: Place a film with a known area S at the end of the cold electrode, and the pressure sensor detects the weight m of the film;

[0020] A2: The driving unit drives the cold pole and the hot pole to move relative to each other until the pressure sensor detects a pressure change, and then stops the relative movement immediately;

[0021] A3: Combine the displacement sensor to measure the film thickness h, and then calculate the film density ρ, and detect the film temperature Ti at the same time;

[0022] A4: Heat the hot rod for a certain time t, power P, and detect the interface temperature T0(t1) of the thin film at time t1;

[0023] A5: Continue to heat the hot rod until the interface of the film sheet reaches a constant temperature T;

[0024] A6: Calculate the thermal conductivity λ of the film according to the relevant thermodynamic formula;

[0025] A7: The driving unit drives the cold electrode and the hot electrode to move apart, superimpose the film sheet, and repeat steps A1-A6;

[0026] A8: Repeat steps A1-A7 several times, stack thin film sheets, and obtain a curve of thermal resistance versus thickness based on thermodynamic formulas.

[0027] The present invention provides a thermal conductivity testing device and method, the device structure is relatively simple, but can be used to measure multiple parameters, and has high testing accuracy and a wide range of test material types.

[0028] Instruction Manual

[0029] Figure 1 This is a schematic diagram of the external structure of this embodiment;

[0030] Figure 2 yes Figure 1 The schematic diagram of the cabinet structure is hidden;

[0031] Figure 3 yes Figure 2 Cutaway diagram;

[0032] Among them, the hot electrode part 1, the hot electrode rod 1a, the hot electrode heat equalizer 1b, the hot electrode insulation layer 1c, the hot electrode cover 1d, the cold electrode part 2, the cold electrode rod 2a, the cold electrode temperature control box 2b, the cold electrode cover 2c, the driving part 3, the electric push rod 3a, the base 3b, the sliding rod 3c, the slider 3d, the top seat 3e, the pressure sensor 4, the displacement sensor 5, the cabinet 6, the lower cabinet 6a, the upper cabinet 6b, the casters 6c, the ball connection mechanism 7, the connecting part 7a, the ball 7b, and the tray 7c. DETAILED DESCRIPTION

[0033] like Figure 1-3 As shown, this embodiment includes a hot pole part 1, a cold pole part 2, a driving part 3, a pressure sensor 4 and a displacement sensor 5.

[0034] The hot pole part 1 includes a hot pole rod 1a which can adjust and detect temperature, and the cold pole part 2 includes a cold pole rod 2a which can adjust and detect temperature. The driving part 3 is used to drive the cold pole part 2 to approach the hot pole part 1 so that the end of the cold pole rod 2a approaches or moves away from the end of the hot pole rod 1a.

[0035] The pressure sensor 4 is arranged between the driving part 3 and the cold pole part 2. The pressure sensor 4 can be used to detect the pressure when the cold pole rod 2a and the hot pole rod 1a are against each other, and can also detect the weight of the sample placed on the end of the cold pole rod 2a.

[0036] The displacement sensor 5 detects the displacement of the cold pole part 2 relative to the hot pole part 1, that is, detects the displacement of the cold pole rod 2a relative to the hot pole rod 1a.

[0037] After the sample is placed into the end of the cold pole rod 2a, the driving unit 3 drives the cold pole rod 2a to move relative to the hot pole rod 1a. When the end of the hot pole rod 1a fits against the sample, the pressure sensor 4 detects the pressure fluctuation, and it can be known that the sample is just clamped. The driving unit 3 stops driving, and the test conditions are just met at this time.

[0038] The displacement sensor 5 sets an initial position, which is the distance between the end of the cold pole 2a and the end of the hot pole 1a. Then, the displacement of the cold pole 2a is detected, and the thickness of the sample is obtained by subtracting the displacement from the data of the initial position.

[0039] When the sample area is known, the density of the sample can be obtained by measuring the weight and thickness of the sample.

[0040] This embodiment cleverly utilizes the pressure sensor 4 and the displacement sensor 5 to obtain the thickness and density of the sample, and provides a method for testing the thermal conductivity of thin films whose thickness is difficult to measure. This embodiment is particularly convenient when testing the relationship between film thickness and thermal resistance.

[0041] The following is an explanation through specific cases:

[0042] Take a circular sample with a diameter of d=60 mm as an example, place the sample on the end of the cold electrode 2a, and the pressure sensor 4 detects the mass m of the sample.

[0043] The driving unit 3 drives the cold electrode 2a and the hot electrode 1a to move relative to each other until the pressure sensor 4 detects a pressure change, and then immediately stops the relative movement.

[0044] The thickness of the film h = 10 mm is measured by the displacement sensor 5, and the density of the film ρ = 3965 kg / m2 is calculated. At the same time, the temperature of the film Ti = 23.00°C is detected.

[0045] Heat the hot rod 1a, set it to heat for 120s, power P = 15.0W; when heating to t1 = 30s, the sample interface temperature T0(t1) = 24.57°C is detected;

[0046] Continue to heat the hot electrode 1a until the sample heating time is much longer than 30s and the sample interface approaches a constant temperature T = 33.5°C.

[0047] According to the energy conservation formula, the specific heat capacity of the sample can be obtained:

[0048] C=(15*120) / 2*3965*((3.14*0.060*0.060) / 4)*0.01*(33.5-23)=765J / (kg·k);

[0049] We can also calculate the heat flux density Q = 15 / 2*((3.14*0.06*0.06) / 4) = 2653W / ㎡;

[0050] And the thermal conductivity λ=(30 / (3.14*3965*765))*((2*2653) / (24.57-23))=36W / MK.

[0051] It can be seen from this that this embodiment can obtain parameters such as specific heat capacity and thermal conductivity of the sample.

[0052] When the sample is a thin film, the relationship between the thermal resistance and thickness change of the thin film can be obtained by continuing the following method.

[0053] The driving unit 3 drives the cold pole 2a and the hot pole 1a to move apart, and the thin film sheets are superimposed again, and the above steps are repeated to obtain λ2.

[0054] Repeat the above steps several times to obtain λn. According to the formula of thermal resistance R and thermal conductivity, obtain the curve of thermal resistance R changing with thickness and fit the slope of the curve.

[0055] This embodiment makes full use of the pressure sensor 4. The pressure sensor 4 can detect the weight of the sample on the one hand, and can be used as a critical test to meet the test conditions on the other hand. At the same time, it can be used in conjunction with the displacement sensor 5 to detect the thickness of the sample. It can be said that it has three uses in one device, which greatly optimizes the structure of the device and saves some cumbersome detection devices. Especially when testing the thermal resistance of the thin film and its thickness, it can greatly reduce the measurement steps and improve the test efficiency.

[0056] Furthermore, the driving part 3 in this embodiment includes an electric push rod 3a, a base 3b, a slide bar 3c, a slider 3d and a top seat 3e. In addition, a cabinet 6 is provided, and the cabinet 6 also includes a lower cabinet 6a and an upper cabinet 6b. A caster 6c is provided at the bottom of the lower cabinet 6a, the electric push rod 3a is fixed in the lower cabinet 6a, and the slide bar 3c is vertically fixed on the lower cabinet 6a. The upper cabinet 6b is arranged on the lower cabinet 6a, and the hot pole part 1, the cold pole part 2, the base 3b and the top seat 3e are all arranged in the upper cabinet 6b.

[0057] The output end of the electric push rod 3a is connected to the base 3b, the cold pole part 2 is fixed on the base 3b, the slider 3d is fixed on the base 3b, and the slider 3d is sleeved on the slide bar 3c. The top seat 3e is fixed on the slide bar 3c, and the hot pole part 1 is fixed on the top seat 3e. In this embodiment, the base 3b and the top seat 3e are both rectangular, and there are four slide bars 3c, which are respectively arranged at the four corners of the base 3b and the top seat 3e.

[0058] The electric push rod 3a pushes the base 3b to move upward, and the base 3b drives the cold pole part 2 to move upward.

[0059] Furthermore, the displacement sensor 5 is fixed on the lower cabinet 6 a , and the displacement sensor 5 detects the displacement change of the base 3 b , that is, detects the displacement of the cold pole part 2 relative to the hot pole part 1 .

[0060] Furthermore, the present embodiment also includes a ball connection mechanism 7. The ball connection mechanism 7 is arranged between the pressure sensor 4 and the cold pole part 2, and the ball connection mechanism 7 includes a connection part 7a, a ball 7b and a tray 7c. The lower end of the connection part 7a is connected to the pressure sensor 4, and the upper end of the connection part 7a is provided with an upper ball groove. The upper end of the tray 7c is fixed to the base 3b, and the upper end of the tray 7c in other embodiments can also be directly fixed to the cold pole part 2. In the present embodiment, the lower end of the tray 7c is provided with a lower ball groove. The ball 7b is arranged in the upper ball groove and the lower ball groove, and the diameter of the ball 7b is greater than the sum of the depths of the upper ball groove and the lower ball groove.

[0061] The ball connection mechanism 7 makes the pressure sensor 4 and the cold pole part 2 in a non-fixed relationship. The cold pole part 2 is pressed on the pressure sensor 4 due to gravity, and the cold pole part 2 and the pressure sensor 4 can be separated by external force. This structure can ensure the accuracy of the measurement of the pressure sensor 4.

[0062] Furthermore, in this embodiment, hot pole temperature measuring couples are provided at the top, middle and bottom of the hot pole 1a; cold pole temperature measuring couples are provided at the top, middle and bottom of the cold pole 2a to ensure the accuracy of the temperature control effect of the hot pole 1a and the cold pole 2a.

[0063] Furthermore, the hot electrode part 1 also includes a hot electrode heat balancing body 1b, a hot electrode temperature-controlling electric couple, a hot electrode heat insulation layer 1c and a hot electrode cover 1d. One end of the hot electrode rod 1a is fixed to one end of the hot electrode heat balancing body 1b. Specifically, the hot electrode heat balancing body 1b is provided with an umbrella-shaped groove, and the hot electrode rod 1a is provided in an umbrella shape corresponding to the groove. The umbrella-shaped structure can increase the contact area between the hot electrode rod 1a and the hot electrode heat balancing body 1b, improve the heat transfer effect, and on the other hand, can prevent the hot electrode rod 1a and the hot electrode heat balancing body 1b from relative movement when the fault is stressed, which affects the later test data.

[0064] The hot pole heat-controlling electric couple is provided on the hot pole heat-controlling electric couple, and the hot pole heat-controlling electric couple is used to heat and control the temperature of the hot pole heat-controlling electric couple. The other end of the hot pole heat-controlling electric couple 1b is fixed to one end of the hot pole heat-insulating layer 1c, and the hot pole heat-insulating layer 1c is made of mullite material, and the hot pole heat-insulating layer 1c is fixed on the top seat 3e. The hot pole cover 1d covers the hot pole rod 1a, the hot pole heat-controlling electric couple 1b and the hot pole heat-insulating layer 1c, which plays a role in enhancing the temperature control effect.

[0065] Furthermore, the cold pole part 2 also includes a cold pole temperature control box 2b and a cold pole cover 2c. One end of the cold pole rod 2a is fixed to the cold pole temperature control box 2b, and the cold pole temperature control box 2b uses water circulation to control the temperature. The cold pole cover 2c is set on the cold pole rod 2a to control the temperature of the cold pole rod 2a.

[0066] This embodiment can be used to detect the thermal conductivity of other materials such as ceramics, insulating materials, composite materials, and non-metallic materials.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A thermal conductivity testing device, characterized in that: It includes a hot pole part, a cold pole part, a driving part, a pressure sensor and a displacement sensor; The hot pole part includes a hot pole rod that can adjust and detect temperature; the cold pole part includes a cold pole rod that can adjust and detect temperature; the driving part drives the cold pole part and the hot pole part to move relative to each other and makes the end of the cold pole rod approach or move away from the end of the hot pole rod; the pressure sensor is arranged between the driving part and the cold pole part; the displacement sensor detects the displacement of the cold pole part relative to the hot pole part.

2. A thermal conductivity testing device according to claim 1, characterized in that: The driving part includes an electric push rod, a base, a sliding rod, a sliding block and a top seat; The electric push rod is fixed, and the output end of the electric push rod is connected to the base; the cold pole part is fixed on the base, the slider is fixed on the base, and the slider is sleeved on the slide rod; the slide rod is vertically fixed; the top seat is fixed on the slide rod; and the hot pole part is fixed on the top seat.

3. A thermal conductivity testing device according to claim 2, characterized in that: It also includes a cabinet; the cabinet includes a lower cabinet and an upper cabinet; The bottom of the lower cabinet is provided with casters, the electric push rod is fixed in the lower cabinet, and the slide bar is fixed on the lower cabinet; the upper cabinet is arranged on the lower cabinet, and the hot pole part, the cold pole part, the base and the top seat are all arranged in the upper cabinet.

4. A thermal conductivity testing device according to claim 3, characterized in that: The displacement sensor is fixed on the lower cabinet, and the displacement sensor detects the displacement change of the base.

5. A thermal conductivity testing device according to claim 1, characterized in that: It also includes a ball connection mechanism; the ball connection mechanism is arranged between the pressure sensor and the cold pole part, and the ball connection mechanism includes a connection part, a ball body and a tray; The connecting part is connected to the pressure sensor and is provided with an upper ball groove; the tray and the cold pole part are fixed and the tray is provided with a lower ball groove; the ball is arranged in the upper ball groove and the lower ball groove, and the diameter of the ball is greater than the sum of the depths of the upper ball groove and the lower ball groove.

6. A thermal conductivity testing device according to claim 1, characterized in that: The hot pole rod is provided with hot pole temperature measuring couples at the upper, middle and lower positions; the cold pole rod is provided with cold pole temperature measuring couples at the upper, middle and lower positions.

7. A thermal conductivity testing device according to claim 1, characterized in that: The hot electrode part also includes a hot electrode heat equalizer, a hot electrode temperature control couple, a hot electrode insulation layer and a hot electrode cover; One end of the hot electrode rod is fixed to one end of the hot electrode heat equalizer; the other end of the hot electrode heat equalizer is fixed to one end of the hot electrode insulation layer, and the hot electrode temperature control electric couple is arranged on the hot electrode heat equalizer; The hot pole cover is provided with the hot pole rod, the hot pole heat-sparing body and the hot pole heat-insulating layer.

8. A thermal conductivity testing device according to claim 7, characterized in that: The connection end between the hot electrode rod and the hot electrode heat equalizer is umbrella-shaped.

9. A thermal conductivity testing device according to claim 1, characterized in that: The cold pole part also includes a cold pole temperature control box and a cold pole cover; one end of the cold pole rod is fixed on the cold pole temperature control box; and the cold pole cover is arranged on the cold pole rod.

10. A thermal conductivity testing device according to claim 1, characterized in that: Also included is a testing method comprising the following steps: A1: Place a film with a known area S at the end of the cold electrode, and the pressure sensor detects the weight m of the film; A2: The driving unit drives the cold pole and the hot pole to move relative to each other until the pressure sensor detects a pressure change, and then stops the relative movement immediately; A3: Combine the displacement sensor to measure the film thickness h, and then calculate the film density ρ, and detect the film temperature Ti at the same time; A4: Heat the hot rod for a certain time t, power P, and detect the interface temperature T0(t1) of the thin film at time t1; A5: Continue to heat the hot rod until the interface of the film sheet reaches a constant temperature T; A6: Calculate the thermal conductivity λ of the film according to the relevant thermodynamic formula; A7: The driving unit drives the cold electrode and the hot electrode to move apart, superimpose the film sheet, and repeat steps A1-A6; A8: Repeat steps A1-A7 several times, stack thin film sheets, and obtain a curve of thermal resistance versus thickness based on thermodynamic formulas.

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