A device and method for testing thermal conductivity of frozen clay in semi-infinite space

Abstract

The present invention relates to a semi-infinite space frozen clay thermal conductivity test device and test method, including a first low-temperature water supply water area device, a second low-temperature water supply water area device, an inner thermostatic box, a soil body, and an outer thermostatic box, wherein the inner thermostatic box, the soil body, and the outer thermostatic box are all annular columnar structures, and the inner side wall of the soil body fits with the outer side wall of the inner thermostatic box, and the outer side wall of the soil body fits with the inner side wall of the outer thermostatic box; the interior of the soil body is inserted with freezing pipes at equal intervals along the circumferential direction, the first low-temperature water supply water area device is connected to the outer thermostatic box, and the second low-temperature water supply water area device is connected to the inner thermostatic box. The present invention has a reasonable structural design, adopts an annular structural design to simulate a traditional infinite plane, realizes the test of the thermal conductivity of clay, and makes up for the gaps in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of clay thermal conductivity testing, in particular to a semi-infinite space frozen clay thermal conductivity testing device and a testing method. Background Art

[0002] Thermal conductivity refers to the amount of heat transferred through an area of ​​1 square meter in 1 second under stable heat transfer conditions when the temperature difference between the two surfaces of a 1m thick material is 1 degree K, ℃. The unit is Watt / meter·degree W / (m·K), where K can be replaced by ℃.

[0003] Thermal conductivity only applies to heat transfer forms where conduction exists. When there are other forms of heat transfer, such as radiation, convection, and mass transfer, this property is usually called apparent thermal conductivity, explicit thermal conductivity, or effective thermal conductivity.

[0004] The existing thermal conductivity of clay remains at the theoretical derivation stage. The main reason is that an infinite plane is defined when the thermal conductivity is derived. However, in reality, an infinite plane does not exist, and it cannot be demonstrated using experimental equipment. Therefore, there is an urgent need for a device that can simulate the thermal conductivity of clay. Summary of the invention

[0005] In view of the defects of the above-mentioned technology, the present invention proposes a semi-infinite space frozen clay thermal conductivity testing device and testing method.

[0006] A device for testing thermal conductivity of frozen clay in a semi-infinite space comprises a first low-temperature water supply water area device, a second low-temperature water supply water area device, an inner thermostatic box, a soil body, and an outer thermostatic box, wherein the inner thermostatic box, the soil body, and the outer thermostatic box are all annular columnar structures, and the inner wall of the soil body is in contact with the outer wall of the inner thermostatic box, and the outer wall of the soil body is in contact with the inner wall of the outer thermostatic box; freezing pipes are inserted into the interior of the soil body at equal intervals along the circumferential direction, the first low-temperature water supply water area device is connected to the outer thermostatic box, and the second low-temperature water supply water area device is connected to the inner thermostatic box.

[0007] The first low-temperature water supply water area device and the second low-temperature water supply water area device have the same structure, both of which include a low-temperature cold water area, a heating pipe, a solenoid valve, a condenser, a compressor, and a water pump. The heating pipe is installed in the low-temperature cold water area, and the output end of the compressor is connected in series with the condenser and the solenoid valve through pipelines in turn and connected to the low-temperature cold water area, and then connected from the low-temperature cold water area to the input end of the compressor through a pipeline; the output end of the low-temperature cold water area of ​​the first low-temperature water supply water area device is connected in series with the water pump through a pipeline and then connected to an external constant temperature box, and the input end of the low-temperature cold water area of ​​the first low-temperature water supply water area device is connected to the external constant temperature box through a pipeline; the output end of the low-temperature cold water area of ​​the second low-temperature water supply water area device is connected in series with the water pump through a pipeline and then connected to an internal constant temperature box, and the input end of the second low-temperature water supply water area device is connected to the internal constant temperature box through a pipeline.

[0008] The axial direction of the freezing pipe is parallel to the axial direction of the soil body.

[0009] The soil body includes a paraffin layer with a circular structure and a frozen clay layer with a circular structure wrapped on the outer wall of the paraffin layer. The inner wall and the outer wall of the paraffin layer are respectively installed with a first thermocouple temperature measuring end and a second thermocouple temperature measuring end, and the inner wall and the outer wall of the frozen clay layer are respectively installed with a third thermocouple temperature measuring end and a fourth thermocouple temperature measuring end.

[0010] A testing method for a semi-infinite space frozen clay thermal conductivity testing device, the testing method steps are as follows:

[0011] Step 1: Start two circulating cold baths, namely the first low-temperature water supply water area device and the second low-temperature water supply water area device, and set the cold shower circulating liquid temperature to -10℃ and -25℃ respectively;

[0012] Step 2: After the cold bath circulating fluid reaches the required temperature, run for another 8 hours, start temperature measurement, measure the temperature of the walls on both sides of the standard sample and the frozen soil sample every 10 minutes, and record; when the difference between the temperatures of each point measured three times in a row is 0.1℃, the test ends;

[0013] Step 3: Calculate the thermal conductivity of frozen clay using the following formula:

[0014]

[0015] Where λ is the thermal conductivity of frozen clay;

[0016] λ0 is the thermal conductivity of paraffin;

[0017] Δθ is the temperature difference between the two walls of the frozen clay layer;

[0018] Δθ0 is the temperature difference between the two walls of the paraffin layer.

[0019] The beneficial effects of the present invention are as follows: the present invention has a reasonable structural design, adopts a ring-shaped structural design to simulate a traditional infinite plane, realizes the test of the thermal conductivity of clay, and fills the gap in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the connection of the inner thermostatic box, soil, freezing pipe and outer thermostatic box of the present invention;

[0023] Figure 3 yes Figure 2 A partial enlarged view of I. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below.

[0025] like Figures 1 to 3 As shown, a semi-infinite space frozen clay thermal conductivity test device includes a first low-temperature water supply water area device, a second low-temperature water supply water area device, an inner thermostatic box 1, a soil body 2, and an outer thermostatic box 4. The inner thermostatic box 1, the soil body 2, and the outer thermostatic box 4 are all annular columnar structures, and the inner wall of the soil body 2 fits with the outer wall of the inner thermostatic box 1, and the outer wall of the soil body 2 fits with the inner wall of the outer thermostatic box 4; the interior of the soil body 2 is inserted with freezing pipes 3 at equal intervals along the circumferential direction, the first low-temperature water supply water area device is connected to the outer thermostatic box 4, and the second low-temperature water supply water area device is connected to the inner thermostatic box 1. The present invention can control the outer thermostatic box 4 and the inner thermostatic box 1 to work separately through the first low-temperature water supply water area device and the second low-temperature water supply water area device to form a specific working temperature.

[0026] The first low-temperature water supply water area device and the second low-temperature water supply water area device have the same structure, both of which include a low-temperature cold water area 11, a heating pipe 12, a solenoid valve 13, a condenser 14, a compressor 15, and a water pump 16. The heating pipe 12 is installed in the low-temperature cold water area 11, and the output end of the compressor 15 is connected in series with the condenser 14 and the solenoid valve 13 through pipelines in sequence and connected to the low-temperature cold water area 11, and then connected from the low-temperature cold water area 11 to the input end of the compressor 15 through a pipeline; the output end of the low-temperature cold water area 11 of the first low-temperature water supply water area device is connected in series with the water pump 16 through a pipeline and then connected to the external constant temperature box 4, and the input end of the low-temperature cold water area 11 of the first low-temperature water supply water area device is connected to the external constant temperature box 4 through a pipeline; the output end of the low-temperature cold water area 11 of the second low-temperature water supply water area device is connected in series with the water pump 16 through a pipeline and then connected to the internal constant temperature box 1, and the input end of the second low-temperature water supply water area device is connected to the internal constant temperature box 1 through a pipeline.

[0027] The axial direction of the freezing pipe 3 is parallel to the axial direction of the soil 2 .

[0028] The soil body 2 includes a paraffin layer 5 with a circular structure and a frozen clay layer 6 with a circular structure wrapped on the outer wall of the paraffin layer 5. The inner wall and outer wall of the paraffin layer 5 are respectively installed with a first thermocouple temperature measuring end 7 and a second thermocouple temperature measuring end 8. The inner wall and outer wall of the frozen clay layer 6 are respectively installed with a third thermocouple temperature measuring end 9 and a fourth thermocouple temperature measuring end 10.

[0029] A testing method for a semi-infinite space frozen clay thermal conductivity testing device, the testing method steps are as follows:

[0030] Step 1: Start two circulating cold baths, namely the first low-temperature water supply water area device and the second low-temperature water supply water area device, and set the cold shower circulating liquid temperature to -10℃ and -25℃ respectively;

[0031] Step 2: After the cold bath circulating fluid reaches the required temperature, run for another 8 hours, start temperature measurement, measure the temperature of the walls on both sides of the standard sample and the frozen soil sample every 10 minutes, and record; when the difference between the temperatures of each point measured three times in a row is 0.1℃, the test ends;

[0032] Step 3: Calculate the thermal conductivity of frozen clay using the following formula:

[0033]

[0034] Where λ is the thermal conductivity of frozen clay;

[0035] λ0 is the thermal conductivity of paraffin;

[0036] Δθ is the temperature difference between the two walls of the frozen clay layer 6;

[0037] Δθ0 is the temperature difference between the two walls of the paraffin layer 5.

[0038] In addition, the present invention can also control the freezing pipe 3 to simulate the change of the ambient temperature, so it is suitable for testing the thermal conductivity under different ambient temperatures.

[0039] According to the above test device and following the above test method, the thermal conductivity of the semi-infinite space frozen clay can be tested.

[0040] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A semi-infinite space frozen clay thermal conductivity testing device, comprising a first low-temperature water supply water area device, a second low-temperature water supply water area device, an inner constant temperature box (1), a soil body (2), and an outer constant temperature box (4), characterized in that: The inner thermostatic box (1), the soil body (2), and the outer thermostatic box (4) are all annular columnar structures, and the inner wall of the soil body (2) fits with the outer wall of the inner thermostatic box (1), and the outer wall of the soil body (2) fits with the inner wall of the outer thermostatic box (4); freezing pipes (3) are inserted into the interior of the soil body (2) at equal intervals along the circumferential direction; the first low-temperature water supply water area device is connected to the outer thermostatic box (4), and the second low-temperature water supply water area device is connected to the inner thermostatic box (1); the first low-temperature water supply water area device and the second low-temperature water supply water area device have the same structure, and both include a low-temperature cold water area (11), a heating pipe (12), an electromagnetic valve (13), a condenser (14), a compressor (15), and a water pump (16); the heating pipe (12) is installed in the low-temperature cold water area (11), and the output of the compressor (15) is connected to the outer thermostatic box (4). The end is connected in series with the condenser (14) and the solenoid valve (13) through pipelines in sequence and connected to the low-temperature cold water area (11), and then connected to the input end of the compressor (15) through the pipeline from the low-temperature cold water area (11); the output end of the low-temperature cold water area (11) of the first low-temperature water supply water area device is connected in series with the water pump (16) through pipelines and then connected to the external thermostatic box (4), and the input end of the low-temperature cold water area (11) of the first low-temperature water supply water area device is connected to the external thermostatic box (4) through pipelines; the output end of the low-temperature cold water area (11) of the second low-temperature water supply water area device is connected in series with the water pump (16) through pipelines and then connected to the internal thermostatic box (1), and the input end of the second low-temperature water supply water area device is connected to the internal thermostatic box (1) through pipelines; the axial direction of the freezing pipe (3) is parallel to the axial direction of the soil (2).

2. A semi-infinite space frozen clay thermal conductivity testing device according to claim 1, characterized in that: The soil body (2) comprises a paraffin layer (5) with a circular structure, and a frozen clay layer (6) with a circular structure wrapped on the outer wall of the paraffin layer (5); a first thermocouple temperature measuring end (7) and a second thermocouple temperature measuring end (8) are respectively installed on the inner wall and the outer wall of the paraffin layer (5); and a third thermocouple temperature measuring end (9) and a fourth thermocouple temperature measuring end (10) are respectively installed on the inner wall and the outer wall of the frozen clay layer (6).

3. A testing method for a semi-infinite space frozen clay thermal conductivity testing device according to any one of claims 1 to 2, characterized in that: The test method steps are as follows: Step 1: Start two circulating cold baths, namely the first low-temperature water supply water area device and the second low-temperature water supply water area device, and set the cold shower circulating liquid temperature to -10℃ and -25℃ respectively; Step 2: After the cold bath circulating fluid reaches the required temperature, run for another 8 hours, start temperature measurement, measure the temperature of the walls on both sides of the standard sample and the frozen soil sample every 10 minutes, and record; when the difference between the temperatures of each point measured three times in a row is 0.1℃, the test ends; Step 3: Calculate the thermal conductivity of frozen clay using the following formula: Where λ is the thermal conductivity of frozen clay; λ0 is the thermal conductivity of paraffin; Δθ is the temperature difference between the two walls of the frozen clay layer 6; Δθ0 is the temperature difference between the two walls of the paraffin layer 5.

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