A thermal conductivity measurement probe and a thermal conductivity measurement method

Abstract

This invention discloses a thermal conductivity measurement probe and method, belonging to the field of thermal property measurement technology. The probe includes a probe rod, a probe head, and a watertight connector. The head end of the probe rod is threadedly connected to the probe head, and the tail end of the probe rod is threadedly connected to the watertight connector. The probe head contains a heating element and a temperature sensing element. The probe rod contains a wiring channel. The heating element is electrically connected to the watertight connector via a power supply wire, and the temperature sensing element is communicatively connected to the watertight connector via a signal wire. The method includes the following steps: Step 1, inserting the probe into the sediment to be tested; Step 2, activating the heating element; Step 3, the temperature sensing element acquiring the temperature response signal; Step 4, calculating the thermal conductivity of the sediment to be tested based on the data and the transient hot-wire method theoretical model. The segmented threaded connection method facilitates the independent processing, assembly, and replacement of the probe rod, probe head, and watertight connector, reducing costs.

Description

Technical Field

[0001] This invention relates to the field of thermal property measurement technology, and in particular to a thermal conductivity measuring probe and a thermal conductivity measuring method. Background Technology

[0002] Thermal conductivity is a crucial thermophysical property characterizing a material's ability to conduct heat, and it holds significant engineering application value in fields such as deep-sea resource development, geothermal energy utilization, nuclear waste disposal, and geotechnical engineering. Particularly important is the accurate in-situ measurement of sediment thermal conductivity under the high-pressure environment of the deep sea, which is crucial for seabed heat flow detection, natural gas hydrate resource assessment, and deep-sea engineering safety evaluation. Currently, thermal conductivity measurement methods are mainly divided into steady-state and non-steady-state methods. Among these, probe-type measurement devices based on the transient hot-wire method are widely used for testing the thermal conductivity of loose media such as soil and sediments due to their advantages of fast measurement speed, minimal sample disturbance, and wide applicability. However, existing thermal conductivity measurement probes often employ a monolithic encapsulation design, making disassembly and assembly difficult. If internal electronic components malfunction, effective replacement is challenging, often resulting in the scrapping of the entire probe and significantly increasing costs. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned technical problems and provide a thermal conductivity measurement probe and a thermal conductivity measurement method. The probe adopts a segmented threaded connection method, which facilitates the independent processing, assembly and replacement of the probe rod, probe and watertight connector, thereby reducing costs.

[0004] To achieve the above objectives, the present invention provides the following solution: The present invention discloses a thermal conductivity measuring probe, including a probe rod, a probe head, and a watertight connector. The head end of the probe rod is threadedly connected to the probe head, and the tail end of the probe rod is threadedly connected to the watertight connector. The probe head contains a heating element and a temperature sensing element. The probe rod contains a wiring channel running along its axial direction. The wiring channel contains a power supply wire and a signal wire. The heating element is electrically connected to the watertight connector via the power supply wire, and the temperature sensing element is communicatively connected to the watertight connector via the signal wire.

[0005] In one embodiment, the probe includes a connector, a heating head, and a detection head. The tail end of the connector is threaded to the head end of the probe rod. The heating head and the detection head are disposed at the head end of the connector. The heating head has a heating cavity for mounting a heating element, and the detection head has a sensing cavity for mounting the temperature sensing element. The connector has a connecting channel. The heating cavity and the sensing cavity are both connected to the wiring channel through the connecting channel. The central axes of the heating cavity and the sensing cavity are parallel to the axis of the probe rod, and there is a preset center distance between the central axes of the heating cavity and the sensing cavity. The preset center distance enables the temperature sensing element to be located on the equipotential surface of the thermal field of the heating element.

[0006] In one embodiment, the inner diameter of both the heating cavity and the induction cavity is 3mm, and the preset center-to-center distance is 6mm to 8mm.

[0007] In one embodiment, the heating element is a heating wire, and the range of the heating wire can cover the length of the heating cavity in the direction of the central axis.

[0008] In one embodiment, the temperature sensing element is a thermocouple, and the length of the thermocouple is sufficient to cover the length of the sensing cavity along the central axis.

[0009] In one embodiment, both the heating cavity and the induction cavity are filled with a highly thermally conductive insulating material.

[0010] In one embodiment, a sealing ring is provided at the threaded connection between the probe rod and the probe head, and at the threaded connection between the probe rod and the watertight connector.

[0011] In one embodiment, a rubber filler is provided in the wiring channel of the probe rod.

[0012] The present invention also discloses a method for measuring thermal conductivity, which uses the above-mentioned thermal conductivity measuring probe; Includes the following steps: Step 1: Insert the probe of the thermal conductivity measuring probe into the sediment to be tested, and connect the heating circuit and the temperature reading circuit through the watertight connector of the thermal conductivity measuring probe. Step 2: Apply constant power to the heating element inside the probe through the heating circuit to start heating; Step 3: Collect temperature response signals in real time through the temperature sensing element inside the probe and record the temperature change curve over time; Step 4: Based on the collected temperature response data and combined with the transient hot wire method theoretical model, calculate the thermal conductivity of the sediment to be tested.

[0013] In one embodiment, in step four, the calculation formula of the transient hot-wire method theoretical model is: λ=(q / 4π)×(d(lnt) / dT), where λ is the thermal conductivity, q is the heating power per unit length, t is the heating time, and T is the temperature response.

[0014] The present invention achieves the following technical effects compared to the prior art: In this invention, the probe rod, probe, and watertight connector are connected by threads, allowing for free disassembly and assembly. When any electronic component, such as the watertight connector, power supply wire, signal wire, heating element, or temperature sensing element, is damaged, the watertight connector and / or probe can be disassembled to repair the damaged electronic component. Furthermore, the segmented threaded connection method facilitates the independent processing, assembly, and replacement of the probe rod, probe, and watertight connector.

[0015] The other technical solutions of this invention achieve the following technical effects compared to the prior art: 1. In this invention, the existing probe's internal arrangement of the heating element and temperature sensing element is relatively simple, making it difficult to guarantee the relative positional accuracy between them, thus affecting the synchronization of temperature response and measurement accuracy. However, this thermal conductivity measurement probe features two independent heating heads and sensing heads, with the heating element and temperature sensing element housed separately in the heating cavity and sensing cavity, respectively. This separate cavity arrangement effectively reduces the impact of thermal interference from the heating element during the heating process on temperature measurement accuracy. Furthermore, by keeping the central axes of the heating head and sensing head parallel to each other and setting a preset center-to-center distance that ensures the temperature sensing element is located on the equipotential surface (effective heat-affected zone) of the heating element's thermal field, a fixed distance is maintained between them, ensuring both the consistency of temperature response and measurement repeatability.

[0016] 2. In this invention, both the heating cavity and the induction cavity are filled with a highly thermally conductive insulating material. This highly thermally conductive insulating material provides electrical insulation while optimizing the heat conduction path and shortening the thermal response time.

[0017] 3. In this invention, the probe rod has a rubber filler in its wiring channel, which not only fixes the power supply wires and signal wires and isolates them from the external environment to achieve a seal, but also significantly improves the probe's pressure resistance level. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained by analyzing these drawings without creative effort.

[0019] Figure 1 This is a three-dimensional structural diagram of the thermal conductivity measuring probe in an embodiment of the present invention; Figure 2 for Figure 1 A magnified schematic diagram of the probe used to measure the thermal conductivity of medium at the probe location; Figure 3 This is a front view schematic diagram of the thermal conductivity measurement probe in an embodiment of the present invention; Figure 4 This is a schematic cross-sectional view of the thermal conductivity measurement probe in an embodiment of the present invention; Figure 5 This is a cross-sectional view of the probe in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Probe rod; 11. Cable routing channels; 12. Power supply cables; 13. Signal cables; 2. Probe; 21. Connecting base; 22. Heating head; 23. Detection head; 24. Heating wire; 25. Thermocouple; 211. Connecting channel; 212. Planar area; 221. Heating cavity; 231. Induction cavity; 3. Watertight connector; 31. Connector. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments analyzed and obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide a thermal conductivity measurement probe and a thermal conductivity measurement method to solve the problems existing in the prior art. The probe rod, probe, and watertight connector are connected by threads, allowing for free disassembly and assembly. When any electronic component such as the watertight connector, power supply wire, signal wire, heating element, or temperature sensing element is damaged, the watertight connector and / or probe can be disassembled to repair the damaged electronic component. Furthermore, the segmented threaded connection method facilitates the independent processing, assembly, and replacement of the probe rod, probe, and watertight connector.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 like Figures 1 to 5As shown, this embodiment provides a thermal conductivity measurement probe, including a probe rod 1, a probe 2, and a watertight connector 3. The head end of the probe rod 1 is threaded to the probe 2, and the tail end of the probe rod 1 is threaded to the watertight connector 3, allowing the probe rod 1, probe 2, and watertight connector 3 to be freely assembled and disassembled. The probe 2 contains a heating element and a temperature sensing element. The probe rod 1 has a wiring channel 11 running along its axis. The wiring channel 11 contains a power supply wire 12 and a signal wire 13. The heating element is electrically connected to the watertight connector 3 through the power supply wire 12. The temperature sensing element is communicatively connected to the watertight connector 3 through the signal wire 13. The heating element in the probe 2 is used to heat the sediment to be tested, and the temperature sensing element collects the temperature response signal. Based on the collected temperature response data, a temperature change curve over time is recorded, and the thermal conductivity of the sediment to be tested is calculated using the transient hot-wire method theoretical model. When any of the electronic components, such as the watertight connector 3, power supply wire 12, signal wire 13, heating element, and temperature sensing element, are damaged, the watertight connector 3 and / or probe 2 can be disassembled to repair the damaged electronic component.

[0025] In one embodiment of this invention, the probe 2 includes a connecting base 21, a heating head 22, and a detection head 23. The tail end of the connecting base 21 is threaded to the head end of the probe rod 1. The heating head 22 and the detection head 23 are disposed at the head end of the connecting base 21. The heating head 22 has a heating cavity 221 for mounting a heating element. The detection head 23 has a sensing cavity 231 for mounting a temperature sensing element. The connecting base 21 has a connecting channel 211, through which both the heating cavity 221 and the sensing cavity 231 are connected to the wiring channel 11 for wiring (power supply wire 12 and signal wire 13). The central axes of the heating cavity 221 and the sensing cavity 231 are both parallel to the axis of the probe 1. That is, the central axes of the heating cavity 221 and the sensing cavity 231 are parallel to each other, and there is a preset center distance h between the central axes of the heating cavity 221 and the sensing cavity 231. The preset center distance h enables the temperature sensing element to be located on the equipotential surface (effective heat-affected zone) of the heating element's thermal field, which is beneficial to improving the consistency of temperature response and measurement repeatability.

[0026] The existing probes have a relatively simple arrangement of heating elements and temperature sensing elements, making it difficult to guarantee the relative positional accuracy between them, which affects the synchronization of temperature response and measurement accuracy. In contrast, this thermal conductivity measurement probe uses two independent heating heads 22 and sensing heads 23, with the heating element and temperature sensing element housed separately in the heating cavity 221 and sensing cavity 231. This separate cavity arrangement effectively reduces the impact of thermal interference from the heating element during the heating process on temperature measurement accuracy. Furthermore, by keeping the central axes of the heating head 22 and sensing head 23 parallel and setting a preset center-to-center distance h to ensure the temperature sensing element is located on the equipotential surface of the heating element's thermal field, the synchronization of temperature response is also guaranteed, thus improving measurement accuracy.

[0027] In one embodiment of this example, the tail end of the connector 21 is provided with a first external thread, and the head end of the wiring channel 11 is provided with a first internal thread. The connector 21 and the wiring channel 11 are threadedly connected through the first external thread and the first internal thread.

[0028] In one embodiment of this invention, two planar areas 212 are provided on the outer surface of the connector 21. The two planar areas 212 are symmetrically arranged along the central axis of the connector 21. The connector 21 can be easily rotated through the two planar areas 212 to avoid slippage during rotation.

[0029] In one embodiment of this example, the inner diameter of both the heating cavity 221 and the sensing cavity 231 is 3mm, and the preset center distance h is 6mm~8mm, so as to ensure that the temperature sensing element is located on the equipotential surface of the heating element's thermal field.

[0030] In one embodiment of this example, the lengths of the heating cavity 221 and the induction cavity 231 along the central axis are 20 mm.

[0031] In one embodiment of this invention, the heating cavity 221 and the sensing cavity 231 have the same length in the direction of the central axis, that is, the temperature sensing element and the heating element have the same arrangement range in the direction of the central axis.

[0032] In one embodiment of this invention, the heating element is a heating wire 24, and the range of the heating wire 24 can cover the length of the heating cavity 221 in the direction of the central axis.

[0033] In one embodiment of this invention, the heating wire 24 forms at least two circuit loops, and the heating wire 24 is connected to the watertight connector 3 via the power supply wire 12. This multi-loop heating wire structure enables uniform and stable heat output within a limited space.

[0034] In one embodiment of this invention, the heating wire 24 is wound into a U-shaped circuit loop within the heating cavity 221.

[0035] In one embodiment of this invention, the heating wire 24 is made of nickel-chromium alloy and has a diameter of 0.2 mm to 0.4 mm. This material has advantages such as stable resistivity, good oxidation resistance, and uniform heat output, making it suitable for long-term repeated use.

[0036] In one embodiment of this invention, the temperature sensing element is a thermocouple 25. The thermocouple 25 is connected to the watertight connector 3 via a signal wire 13. The length of the thermocouple 25 covers the length of the sensing cavity 231 along its central axis. That is, the length of the thermocouple 25 along its central axis is the same as the length of the heating wire 24, for example, both are 20 mm.

[0037] In one embodiment of this invention, thermocouple 25 is a type K thermocouple with a time constant of no more than 0.12 s and a dissipation constant of no more than 0.045 mW / ℃. By selecting a type K thermocouple with high response speed and low dissipation, the ability to capture transient temperature changes is significantly improved, meeting the temperature acquisition accuracy requirements of the transient hot-wire method.

[0038] In one embodiment of this invention, both the heating cavity 221 and the sensing cavity 231 are filled with a highly thermally conductive insulating material. This highly thermally conductive insulating material provides electrical insulation while optimizing the heat conduction path and shortening the thermal response time. For example, the highly thermally conductive insulating material in the heating cavity 221 ensures rapid heat transfer from the heating element. The highly thermally conductive insulating material in the sensing cavity 231 ensures that the temperature sensing element responds quickly to temperature changes in the deposit.

[0039] In one embodiment of this example, the high thermal conductivity insulating material is filled and compacted using magnesium oxide powder.

[0040] In one embodiment of this invention, sealing rings are provided at the threaded connection between probe 1 and probe 2, and at the threaded connection between probe 1 and watertight connector 3, forming a sealing structure.

[0041] In one embodiment of this invention, the wiring channel 11 of the probe 1 is provided with a rubber filler. This further improves the overall sealing and pressure resistance of the internal structure, making it suitable for harsh environments with high pressure, such as deep sea.

[0042] In one embodiment of this invention, a vulcanization encapsulation process is used to form a dense rubber filler in the wiring channel 11 of the probe 1 to fill the gaps between the components.

[0043] In one embodiment of this invention, a sealing ring and a rubber filler are included. Through the threaded connection and the multiple sealing designs of the sealing ring and the rubber filler, moisture is effectively prevented from seeping into the probe under high pressure, thus ensuring the long-term stability and reliability of the measurement system.

[0044] In one embodiment of this invention, the rubber filler is silicone rubber.

[0045] In one embodiment of this invention, the probe 1 is made of stainless steel with an overall outer diameter not exceeding 16 mm. Its internal hollow structure forms a wiring channel 11 for laying power supply wires 12 and signal wires 13. Stainless steel possesses excellent mechanical strength and corrosion resistance. The hollow structure facilitates internal wire routing, and the small overall outer diameter makes it suitable for in-situ measurements of fine-particle sediments and in confined spaces. The probe 1 has an outer diameter not exceeding 16 mm, and the probe 2 has a compact internal cavity structure, making it suitable for in-situ micro-area measurements of fine-particle sediments and in confined spaces.

[0046] In one embodiment of this invention, the head end of the watertight connector 3 is provided with a connector 31, which has a second external thread. The tail end of the wiring channel 11 is provided with a second internal thread, which mates with the second external thread. The probe 1 and the watertight connector 3 are threadedly connected through the second internal thread and the second external thread. By threading the connector 31 into the wiring channel 11, a sealed environment can be effectively formed.

[0047] In one embodiment of this invention, the diameter of the connector 31 is smaller than the diameter of the head end of the watertight connector 3, forming a stepped shaft shape. A sealing ring can be fitted onto the connector 31 and conforms between the head end face of the watertight connector 3 and the tail end face of the probe 1.

[0048] In one embodiment of this invention, the connection area between the tail end of the probe 1 and the connector 31 is thickened, with a thickness greater than that of the rest of the probe 1. This improves the connection stability between the tail end of the probe 1 and the connector 31.

[0049] In one embodiment of this invention, the head end of the watertight connector 3 is provided with a coaxially arranged polygonal prism protrusion to facilitate rotation of the watertight connector 3 and prevent slippage. The polygonal prism protrusion can be a square prism, pentagonal prism, hexagonal prism, octagonal prism, etc.

[0050] In one embodiment of this example, several reference examples are provided: Reference Example 1 Specifically, in this thermal conductivity measurement probe: The probe rod 1 is made of 316L stainless steel, with an overall outer diameter of 16mm and a length of 200mm. Its hollow interior forms a wiring channel 11 for laying power supply wires 12 and signal wires 13. The wiring channel 11 of the probe rod 1 is filled with a dense rubber filling material, silicone rubber, through a vulcanization process to fill the gaps between components and improve overall pressure resistance and sealing performance.

[0051] The probe 2 is made of 316L stainless steel, the same material as the probe rod 1. The outer diameter of the connecting seat 21 is 12mm, and the axial length of the connecting seat 21 is 20mm. The axial length of the heating cavity 221 and the sensing cavity 231 are both 20mm, and their inner diameters are both 3mm. Heating elements and temperature sensing elements are installed thereon, respectively. The heating element is a heating wire 24, connected to the power supply wire 12. The heating wire has a diameter of 0.3mm and is wound into a U-shaped circuit loop inside the heating cavity 221. The loop length is consistent with the axial length of the heating cavity 221, ensuring uniform heating along the axis of the probe 2. The heating wire 24 is made of nickel-chromium alloy. The power supply wire 12 is a high-temperature resistant wire. The temperature sensing element is a K-type thermocouple with a time constant of 0.10s and a dissipation constant of 0.040mW / ℃. The thermocouple 25 and the heating element are both 20mm long, and their center-to-center distance (preset center-to-center distance h) is 7mm. The gap between the heating cavity 221 and the heating wire 24 is filled with a high thermal conductivity insulating material, and the gap between the induction cavity 231 and the K-type thermocouple is filled with a high thermal conductivity insulating material. The high thermal conductivity insulating material is made of magnesium oxide powder, which is compacted. This material has a high thermal conductivity and good insulation performance, which can ensure that the thermocouple 25 responds quickly to temperature changes in the deposit.

[0052] The watertight connector 3 uses a dedicated underwater multi-core watertight connector to achieve external connection between the heating circuit and the temperature reading circuit. Power supply wire 12 and signal wire 13 are led out from inside the watertight connector 3, respectively connecting to the heating element and temperature sensing element inside the probe 2.

[0053] O-rings are provided at the connection between the watertight connector 3 and the probe rod 1, and at the connection between the probe rod 1 and the probe 2, forming a double sealing structure to ensure that the probe does not leak under high pressure.

[0054] See Example 2 This reference example is essentially the same as Reference Example 1, with the difference lying in some dimensional parameters and material selection. In this example, the diameter of the heating wire 24 is 0.2 mm, and the center-to-center distance (preset center-to-center distance h) between the thermocouple 25 and the heating element is 6 mm. The outer diameter of the probe rod 1 is 12 mm, further reducing the overall size of the probe and making it suitable for micro-area measurements of finer-particle sediments. Testing showed that the response speed and measurement accuracy of this probe size are comparable to those in Reference Example 1, meeting the measurement needs of different types of sediments.

[0055] See Example 3 This reference example is essentially the same as Reference Example 1, except that the diameter of the heating wire 24 is 0.4 mm, and the center-to-center distance (preset center-to-center distance h) between the thermocouple 25 and the heating element is 8 mm. With this configuration, the heating wire 24 has higher mechanical strength, making it suitable for measurement scenarios involving frequent insertion and removal or coarse-grained sediments. Simultaneously, appropriately increasing the distance between the thermocouple 25 and the heating element can further reduce direct thermal radiation interference that may exist during heating, thereby improving the accuracy of temperature measurement.

[0056] The above reference examples aim to provide a thermal conductivity measurement probe that is compact, has good pressure resistance, high measurement accuracy, and fast response speed.

[0057] In one embodiment of this example, the probe assembly and sealing process is as follows: During assembly, the heating wire 24 and thermocouple 25 are first installed in the heating cavity 221 and sensing cavity 231 of the probe 2, respectively, and then filled and compacted layer by layer with a high thermal conductivity insulating material to ensure that there are no gaps between the components and the inner wall of the probe 2. The probe 2 and probe rod 1 are then screwed together, and an O-ring is installed at the threaded connection. After the power supply wire 12 and signal wire 13 are laid through the wiring channel 11 of the probe rod 1, liquid silicone rubber is injected into the wiring channel 11 of the probe rod 1 using a vulcanization encapsulation process. Under high temperature and high pressure conditions, it is vulcanized to form a dense rubber filler. This rubber filler completely fills the wiring channel 11 of the probe rod 1, fixing the power supply wire 12 and signal wire 13 and isolating them from the external environment, significantly improving the probe's pressure resistance.

[0058] Example 2 like Figures 1 to 5 As shown, this embodiment provides a method for measuring thermal conductivity, which uses the thermal conductivity measuring probe from Embodiment 1; Includes the following steps: Step 1: Insert the probe 2 of the thermal conductivity measuring probe into the sediment to be tested, and connect the heating circuit and the temperature reading circuit through the watertight connector 3 of the thermal conductivity measuring probe. Step 2: Apply constant power to the heating element inside probe 2 through the heating circuit to start heating; Step 3: Collect the temperature response signal in real time through the temperature sensing element inside probe 2 and record the temperature change curve over time; Step 4: Based on the collected temperature response data and combined with the transient hot wire method theoretical model, calculate the thermal conductivity of the sediment to be tested.

[0059] In one embodiment of this invention: In step four, the calculation formula for the transient hot-wire method theoretical model is: λ=(q / 4π)×(d(lnt) / dT), where λ is the thermal conductivity, q is the heating power per unit length, t is the heating time, and T is the temperature response. The calculation formula is derived from the slope of the linear segment of the temperature-time curve. This calculation model, based on the transient hot-wire method theory, is applicable to one-dimensional radial heat conduction processes in infinitely large media, and features a solid theoretical foundation, simple calculation, and reliable results.

[0060] In one embodiment of this invention: in step two, the applied constant power ranges from 0.5W to 5W, and the heating duration is from 10s to 60s. This parameter range has been optimized to ensure sufficient temperature rise while avoiding changes in the physical properties of the medium or thermal interference caused by overheating.

[0061] In one embodiment of this invention: In step three, the temperature sensing element acquires the temperature response signal in real time at a sampling frequency of not less than 10Hz. A high sampling frequency can effectively capture key characteristics of transient temperature changes and improve the data quality for thermal conductivity calculation.

[0062] By rationally setting the heating power, heating duration, and sampling frequency, and combining this with the transient hot-wire method theoretical model, high-precision and highly repeatable measurements of the thermal conductivity of sediments were achieved. The thermal conductivity measurement probe, combined with optimized heating power, heating duration, and sampling frequency parameters, and based on the transient hot-wire method theoretical model, enables high-precision and highly repeatable measurements of the thermal conductivity of sediments.

[0063] In one embodiment of this example, several reference examples are provided: Reference Example 1 This reference example provides a method for measuring thermal conductivity, which specifically includes the following steps: Step 1: Insert the probe into the sediment to be tested, ensuring that the probe 2 is completely submerged in the sediment. Connect the external heating circuit and the temperature reading circuit through the watertight connector 3 respectively, and check the reliability of the circuit connection.

[0064] Step 2: Apply constant power to the heating element through the heating circuit. Set the heating power to 2W and the heating duration to 30s. During the heating process, control the power output through a precision constant current source to ensure that the power fluctuation does not exceed ±1%.

[0065] Step 3: The temperature response signal is collected in real time through the temperature sensing element. The temperature value output by thermocouple 25 is continuously recorded at a sampling frequency of 20Hz using a data acquisition card. The heating time is recorded simultaneously to form a response curve of temperature change over time. Step 4: Based on the collected temperature response data and combined with the transient hot-wire method theoretical model, calculate the thermal conductivity of the sediment to be tested. Specifically, extract the temperature-time data from the second second after the start of heating to the end of heating, plot the relationship curve between temperature T and the logarithm of time lnt, select the linear segment of the curve to calculate the slope d(lnt) / dT, and substitute it into the formula λ=(q / 4π)×(d(lnt) / dT) to calculate the thermal conductivity, where q is the heating power per unit length.

[0066] See Example 2 This reference example is essentially the same as Reference Example 1, except for the setting of the measurement parameters. In this example, based on the differences in the thermophysical properties of the sediments to be measured, the heating power is set to 0.5W, the heating duration is set to 60s, and the sampling frequency is set to 10Hz. For sediments with low thermal conductivity, using a lower heating power can avoid changes in the properties of the medium caused by local overheating; for sediments with high thermal conductivity, appropriately extending the heating time can ensure a sufficient temperature rise and improve the signal-to-noise ratio.

[0067] See Example 3 This reference example is essentially the same as Reference Example 1, except for the setting of the measurement parameters. In this example, the heating power is set to 5W, the heating duration to 10s, and the sampling frequency to 50Hz. These parameters are suitable for media with high thermal conductivity or for use in situations where measurement time is limited. The high sampling frequency can effectively capture the dynamic response during the rapid temperature rise phase in the initial stage of heating, ensuring sufficient data points for the linear segment and calculation accuracy.

[0068] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A probe for measuring thermal conductivity, characterized in that: The device includes a probe rod, a probe, and a watertight connector. The head end of the probe rod is threadedly connected to the probe, and the tail end of the probe rod is threadedly connected to the watertight connector. The probe contains a heating element and a temperature sensing element. The probe rod has a wiring channel running along its axis, and the wiring channel contains a power supply wire and a signal wire. The heating element is electrically connected to the watertight connector through the power supply wire, and the temperature sensing element is communicatively connected to the watertight connector through the signal wire.

2. The thermal conductivity measuring probe according to claim 1, characterized in that: The probe includes a connector, a heating head, and a detection head. The tail end of the connector is threaded to the head end of the probe rod. The heating head and the detection head are located at the head end of the connector. The heating head has a heating cavity for mounting a heating element, and the detection head has a sensing cavity for mounting the temperature sensing element. The connector has a connecting channel. The heating cavity and the sensing cavity are both connected to the wiring channel through the connecting channel. The central axes of the heating cavity and the sensing cavity are parallel to the axis of the probe rod, and there is a preset center distance between the central axes of the heating cavity and the sensing cavity. The preset center distance allows the temperature sensing element to be located on the equipotential surface of the thermal field of the heating element.

3. The thermal conductivity measuring probe according to claim 2, characterized in that: The inner diameter of both the heating cavity and the induction cavity is 3mm, and the preset center-to-center distance is 6mm~8mm.

4. The thermal conductivity measuring probe according to claim 2, characterized in that: The heating element is an electric heating wire, and the range of the electric heating wire can cover the length of the heating cavity along the central axis.

5. The thermal conductivity measuring probe according to claim 2, characterized in that: The temperature sensing element is a thermocouple, and the length of the thermocouple is sufficient to cover the length of the sensing cavity along the central axis.

6. The thermal conductivity measuring probe according to claim 2, characterized in that: Both the heating cavity and the induction cavity are filled with highly thermally conductive insulating material.

7. The thermal conductivity measuring probe according to claim 1, characterized in that: Sealing rings are provided at the threaded connection between the probe rod and the probe head, and at the threaded connection between the probe rod and the watertight connector.

8. The thermal conductivity measuring probe according to claim 1 or 7, characterized in that: The probe's wiring channel is filled with a rubber filler.

9. A method for measuring thermal conductivity, characterized in that, The thermal conductivity measurement probe as described in any one of claims 1-8 was used; Includes the following steps: Step 1: Insert the probe of the thermal conductivity measuring probe into the sediment to be tested, and connect the heating circuit and the temperature reading circuit through the watertight connector of the thermal conductivity measuring probe. Step 2: Apply constant power to the heating element inside the probe through the heating circuit to start heating; Step 3: Collect temperature response signals in real time through the temperature sensing element inside the probe and record the temperature change curve over time; Step 4: Based on the collected temperature response data and combined with the transient hot wire method theoretical model, calculate the thermal conductivity of the sediment to be tested.

10. The method for measuring thermal conductivity according to claim 9, characterized in that: In step four, the calculation formula of the transient hot wire method theoretical model is: λ=(q / 4π)×(d(lnt) / dT), where λ is the thermal conductivity, q is the heating power per unit length, t is the heating time, and T is the temperature response.

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