阅读说明：本技术 测量高温高压多元气体混合物热导率的装置 (Device for measuring heat conductivity of high-temperature high-pressure multi-element gas mixture ) 是由 张兴 李凤仪 程思远 马维刚 于 2020-04-24 设计创作，主要内容包括：本发明公开了一种测量高温高压多元气体混合物热导率的装置,包括：测试线路用于测量气体热导率；工况监测线路用于确定测量工况信息,并将测量工况信息传递给加热控制线路；加热控制线路,用于确定温度信息与预设测试温度的差异,以校正加热功率调整温度信息；充放气管路用于将气瓶内部抽至真空,避免测量气体中含有的空气杂质,并从气瓶内取出并存储气体于储气罐、测试罐内,为气体提供测试环境；冷却管路设置于充放气管路的内部,用于压缩外界冷空气在充放气管路进行循环,以将热量带走。该装置可配制组分中含有常温下为液态工质的混合气体,并测量其高温高压超临界状态下的热导率,且导线从高温高压容器中接出不会漏气。(The invention discloses a device for measuring the heat conductivity of a high-temperature high-pressure multi-component gas mixture, which comprises: the test circuit is used for measuring the gas thermal conductivity; the working condition monitoring circuit is used for determining the information of the measuring working conditions and transmitting the information of the measuring working conditions to the heating control circuit; the heating control circuit is used for determining the difference between the temperature information and the preset test temperature so as to correct the heating power adjustment temperature information; the gas charging and discharging pipeline is used for vacuumizing the interior of the gas cylinder, so that air impurities contained in the measured gas are avoided, and gas is taken out from the gas cylinder and stored in the gas storage tank and the test tank to provide a test environment for the gas; the cooling pipeline is arranged in the charging and discharging pipeline and used for compressing the external cold air to circulate in the charging and discharging pipeline so as to take away the heat. The device can prepare the mixed gas which contains liquid working medium at normal temperature in the components, measure the heat conductivity of the mixed gas under the high-temperature high-pressure supercritical state, and lead wires are connected out from a high-temperature high-pressure container without air leakage.)

1. An apparatus for measuring thermal conductivity of a high temperature and high pressure multi-component gas mixture, comprising: a test circuit, a working condition monitoring circuit, a heating control circuit, an air charging and discharging pipeline and a cooling pipeline, wherein,

the test line is connected with the inflation and deflation pipeline and used for measuring the gas heat conductivity;

the working condition monitoring circuit is respectively connected with the heating control circuit and the charging and discharging pipeline and is used for determining measurement working condition information and transmitting temperature information in the measurement working condition information to the heating control circuit;

the heating control circuit and the charging and discharging pipeline are used for determining the difference between the temperature information and a preset test temperature so as to correct heating power and adjust the temperature information;

the charging and discharging pipeline is used for vacuumizing the interior of the gas cylinder to avoid air impurities in the measured gas; and

the cooling pipeline is arranged in the charging and discharging pipeline and used for compressing external cold air to circulate in the charging and discharging pipeline so as to take away heat.

2. The apparatus for measuring the thermal conductivity of a high temperature and high pressure multi-component gas mixture as claimed in claim 1, wherein the operating condition monitoring circuit comprises a thermocouple, a pressure gauge and a pressure display.

3. The apparatus for measuring thermal conductivity of a high temperature and high pressure multi-component gas mixture according to claim 2, wherein temperature monitoring points of the thermocouples are respectively disposed at the outside of the vessel, the inside of the vessel, and the heater to monitor temperature stability, determine the measurement condition information, and transmit the temperature information of the measurement condition information to the heating control circuit.

4. The apparatus for measuring thermal conductivity of a multi-component gas mixture under high temperature and high pressure according to claim 1, wherein the heating control circuit comprises a temperature PID control system and a heater, wherein the temperature PID control system obtains temperature information of the working condition monitoring circuit, and determines the difference between the temperature information and the preset test temperature so as to correct the heating power of the heater, so that the temperature information is raised to and stably controlled at the preset test temperature.

5. The device for measuring the thermal conductivity of the high-temperature high-pressure multi-component gas mixture according to claim 1, wherein the charging and discharging pipeline comprises a vacuum pump, a gas cylinder, a gas storage tank, a test tank, a gas outlet and a plurality of valves, wherein the vacuum pump is used for vacuumizing the interior of the gas cylinder to avoid air impurities contained in the measured gas, and gas samples discharged from the gas cylinder are stored in the gas storage tank and the test tank to provide a test environment for the gas.

6. The device for measuring the thermal conductivity of the high-temperature high-pressure multi-component gas mixture according to claim 5, wherein the test tank has a three-layer structure comprising a test container, a temperature equalizing container and a heat preservation container from inside to outside.

7. The apparatus for measuring the thermal conductivity of a high-temperature high-pressure multi-component gas mixture according to claim 6, wherein the test container and the thermal insulation container are both made of 625 stainless steel, the temperature equalizing container is made of high-thermal conductivity material copper, the temperature equalizing container fully surrounds the test container to provide a uniform and stable temperature field, and the thermal insulation container fully surrounds the temperature equalizing container to avoid the operator from being scalded by high temperature.

8. The device for measuring the thermal conductivity of the high-temperature high-pressure multi-component gas mixture according to claim 5, wherein the charging and discharging pipeline further comprises:

a double seal comprising a metal oxide insulated sealed tube portion comprised of 625 stainless steel tubing, magnesium oxide filler and electrical leads and a clinch nut.

9. The device for measuring the thermal conductivity of the high-temperature high-pressure multi-component gas mixture according to claim 8, wherein the metal oxide insulating sealing pipe part is manufactured by the following steps:

the electric leads are arranged in the 625 stainless steel tube in a mutual non-contact manner, the magnesium oxide filler is filled in the tube, and after the filling is finished, the 625 stainless steel tube is compressed at high temperature and high pressure, so that the whole volume is reduced, and the magnesium oxide filler is compacted.

10. The device for measuring the thermal conductivity of the high-temperature high-pressure multi-component gas mixture according to claim 1, wherein the cooling pipeline is arranged inside the gas storage tank and the test tank in the charging and discharging pipeline and comprises an air compressor and a flowmeter, wherein the air compressor is used for compressing outside cold air, the air compressor circulates in the charging and discharging pipeline, heat of a high-temperature container is taken away, the flowmeter is used for measuring and controlling the flow rate of the cold air to control the cooling speed, and a cold air outlet is arranged in the atmosphere.

Technical Field

The invention relates to the technical field of high-temperature and high-pressure gas thermophysical property testing, in particular to a device capable of testing the thermal conductivity of a high-temperature and high-pressure multi-component gas mixture.

Background

Over 80% of energy sources in modern society come from direct combustion of coal, and the combustion of coal can bring serious environmental pollution problems along withWith the global climate change aggravated, there is an increasing concern about energy efficiency and greenhouse gas emissions. In recent years, development of new energy resources such as "coal boiled in water" technology has been vigorously developed, and a clean energy of gas typified by hydrogen is expected to replace petroleum fuel. In such technologies, the production and use of gaseous fuels are typically in a high temperature, high pressure environment, and the produced gas is not a pure substance, but is accompanied by, for example, CO₂And mixed gas of supercritical water. For the correct application of such mixed working fluids, the correct measurement of their thermophysical properties is of great importance, especially as regards the thermal conductivity, which characterizes the heat transfer properties.

At present, in the field of measuring the thermal conductivity of high-temperature and high-pressure mixed gas, both a measuring method and a measuring technology are very limited, wherein two difficulties mainly exist, namely that the gas is difficult to seal under high-temperature and high-pressure, and the mixed gas containing liquid working substances at normal temperature cannot be prepared.

Therefore, it is urgently needed to develop a technology capable of solving the above two key difficult problems, so that the design of the energy reactor and the application of the new gas energy have important meanings.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.

To this end, an object of the present invention is to provide a device for measuring the thermal conductivity of a high-temperature high-pressure multi-component gas mixture, wherein the components of the gas mixture may comprise a working fluid which is liquid at normal temperature.

In order to achieve the above object, an embodiment of the present invention provides an apparatus for measuring thermal conductivity of a high-temperature and high-pressure multi-component gas mixture, including: the device comprises a test circuit, a working condition monitoring circuit, a heating control circuit, an air charging and discharging pipeline and a cooling pipeline, wherein the test circuit is connected with the air charging and discharging pipeline and is used for measuring the air heat conductivity; the working condition monitoring circuit is connected with the heating control circuit and the charging and discharging pipeline and is used for determining measurement working condition information and transmitting temperature information in the measurement working condition information to the heating control circuit; the heating control circuit is used for determining the difference between the temperature information and a preset test temperature so as to correct the heating power and adjust the temperature information; the charging and discharging pipeline is used for vacuumizing the interior of the gas cylinder to avoid air impurities in the measured gas; the cooling pipeline is arranged in the charging and discharging pipeline and used for compressing external cold air to circulate in the charging and discharging pipeline so as to take away heat.

The device for measuring the heat conductivity of the high-temperature high-pressure multi-element gas mixture can prepare the mixed gas which contains the liquid working medium at normal temperature, measure the heat conductivity of the mixed gas in a high-temperature high-pressure supercritical state, and connect the lead out of a high-temperature high-pressure container without air leakage by using the sealing device with good sealing performance at high temperature and high pressure.

In addition, the device for measuring the thermal conductivity of the high-temperature high-pressure multi-component gas mixture according to the above embodiment of the invention may also have the following additional technical features:

further, in one embodiment of the present invention, the operating condition monitoring circuit includes a thermocouple, a pressure gauge and a pressure display.

Further, in one embodiment of the present invention, temperature monitoring points of the thermocouples are disposed at the outside of the vessel, the inside of the vessel, and the heater, respectively, to monitor temperature stability, determine the measured condition information, and transmit the temperature information of the measured condition information to the heating control circuit.

Further, in an embodiment of the present invention, the heating control circuit includes a temperature PID control system and a heater, where the temperature PID control system obtains temperature information of the operating condition monitoring circuit, and determines a difference between the temperature information and the preset test temperature to correct the heating power of the heater, so that the temperature information is raised to and stably controlled at the preset test temperature.

Further, in an embodiment of the present invention, the charging and discharging pipeline includes a vacuum pump, a gas cylinder, a gas storage tank, a testing tank, a gas discharging port, and a plurality of valves, wherein the vacuum pump is used to evacuate the gas cylinder to avoid measuring air impurities contained in the gas, and the gas samples discharged from the gas cylinder are stored in the gas storage tank and the testing tank to provide a testing environment for the gas.

Further, in an embodiment of the present invention, the test tank has a three-layer structure, which includes a test container, a temperature equalizing container and a heat insulating container from inside to outside, the test container and the heat insulating container are both made of 625 stainless steel, the temperature equalizing container is made of high thermal conductive material copper, the temperature equalizing container fully encloses the test container to provide a uniform and stable temperature field, and the heat insulating container fully encloses the temperature equalizing container to prevent an operator from being scalded by high temperature.

Further, in an embodiment of the present invention, the charging and discharging pipeline further includes: a double seal comprising a metal oxide insulated sealed tube portion comprised of 625 stainless steel tubing, magnesium oxide filler and electrical leads, and a clinch nut.

Further, in an embodiment of the present invention, the metal oxide insulating sealing tube part is manufactured by the following process: the electric leads are arranged in the 625 stainless steel tube in a mutual non-contact manner, the magnesium oxide filler is filled in the tube, and after the filling is finished, the 625 stainless steel tube is compressed under high temperature and high pressure, so that the whole volume is reduced, and the magnesium oxide filler is compacted.

Further, in an embodiment of the present invention, the cooling pipeline is disposed inside the air storage tank and the test tank in the air charging and discharging pipeline, and includes an air compressor and a flow meter, wherein the air compressor is configured to compress outside cold air, circulates in the air charging and discharging pipeline, takes away heat of the high temperature container, and controls a flow rate of the cold air by the flow meter to control a cooling speed, and the cold air outlet is disposed in the atmosphere.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of an apparatus for measuring thermal conductivity of a high-temperature high-pressure multi-component gas mixture according to an embodiment of the invention;

FIG. 2 is a schematic diagram illustrating a detailed structure of an apparatus for measuring thermal conductivity of a high-temperature high-pressure multi-component gas mixture according to an embodiment of the invention;

FIG. 3 is a schematic diagram of a specific structure of a test tank in the inflation/deflation line according to an embodiment of the present invention;

FIG. 4 is a diagram of a double seal assembly model according to one embodiment of the present invention;

FIG. 5 is a schematic view of the inflation and deflation lines according to one embodiment of the present invention;

FIG. 6 is a schematic diagram of a test circuit according to an embodiment of the present invention.

Description of reference numerals:

100-test circuit, 200-working condition monitoring circuit, 300-heating control circuit, 400-charging and discharging pipeline, 500-cooling pipeline, 1-personal computer, 2-direct current power supply, 3-standard resistor, 4-data acquisition system, 5-pressure display, 6-pressure gauge, 7-thermocouple, 8-temperature PID control system, 9-heater, 10-air compressor, 11-flowmeter, 12-gas cylinder, 13-vacuum pump, 14-multiple valves, 15-gas storage tank, 16-test tank, 17-lead sealing device, 18-test line, 19-heat preservation container, 20-temperature equalization container, 21-heating rod, 22-test container, 23-electric lead, 24-ceramic base, 25-support column, 26-test line, 27-625 stainless steel tube, 28-magnesia filler and 29-expansion nut.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

An apparatus for measuring thermal conductivity of a high-temperature and high-pressure multi-component gas mixture according to an embodiment of the present invention will be described with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of an apparatus for measuring thermal conductivity of a high-temperature high-pressure multi-component gas mixture according to an embodiment of the invention.

As shown in fig. 1, the apparatus for measuring the thermal conductivity of a high-temperature high-pressure multi-component gas mixture comprises: the device comprises a test line 100, a working condition monitoring line 200, a heating control line 300, an air charging and discharging line 400 and a cooling line 500.

The test line 100 is connected to the inflation/deflation line 400, and is used for measuring the gas thermal conductivity.

Specifically, as shown in fig. 2, the test line 100 is represented by a red dotted line and a dark black dotted line, and the test line represents that a constant current is output by the dc power supply 2, and returns to the dc power supply 2 after passing through the standard resistor 3 and the test short hot wire 18 in the test tank 16, the voltage drop between the standard resistor 3 and the test short hot wire 18 is collected by the data collection system 4, and the collection parameter setting and the collection result are displayed in the personal computer 1.

Further, the working condition monitoring circuit 200 is connected to the heating control circuit 300 and the charging and discharging pipeline 400, and is configured to determine the measured working condition information and transmit the temperature information in the measured working condition information to the heating control circuit.

Specifically, as shown in fig. 2, the operation condition monitoring circuit 200 includes a thermocouple 7, a pressure gauge 6 and a pressure display 5, wherein thermocouple 7 temperature monitoring points are respectively disposed at the outside of the vessel, the inside of the vessel and the heating rod to monitor temperature stability, determine measurement condition information, and transmit the temperature information in the measurement condition information to the heating control circuit 300.

The heating control circuit 300 is used to determine a difference between the temperature information and a preset test temperature to correct the heating power adjustment temperature information.

Further, in the embodiment of the present invention, the heating control circuit 300 includes a temperature PID (proportional integral derivative control) control system 8 and a heater 9.

Specifically, as shown in fig. 2, the temperature PID control system 8 obtains temperature information from the thermocouple 7, and corrects the heating power of the heater 9 by the difference between the current temperature and the set temperature, thereby increasing and stably controlling to the set test temperature. The heater 9 is a heating rod heater, and compared with a common heating wire heater, the heating rod heater is slower in temperature rise, higher in stability and easier in insulation treatment.

And the charging and discharging pipeline 400 is used for vacuumizing the interior of the gas cylinder to avoid measuring air impurities contained in the gas.

Further, in an embodiment of the present invention, the gas charging and discharging pipeline 400 includes a vacuum pump 13, a gas cylinder 12, a gas storage tank 15, a test tank 16, a gas discharging port, and a plurality of valves 14, wherein the inside of the gas cylinder 12 is pumped to a vacuum by the vacuum pump, so as to avoid measuring air impurities contained in the gas, and the gas cylinder 12 is taken out and the gas storage tank 15 and the test tank 16 are stored to provide a test environment for the gas.

Specifically, as shown in fig. 2, the charging and discharging pipeline 400 is connected to a vacuum pump 13, an air bottle 12, an air storage tank 15, a testing tank 16, a gas outlet and a plurality of valves 14, the vacuum pump 13 is used for evacuating the interior of the container, and if the interior of the container is not evacuated, air impurities are contained in the measuring gas. If the measuring gas contains hydrogen, dangerous accidents are easily caused by oxygen in the air, so that the vacuumizing is necessary. Meanwhile, the air tightness of the device can be detected in the vacuumizing process, and if an air leakage point exists, the pressure in the device cannot be reduced to below 10Pa after the device is vacuumized.

It should be noted that the air storage tank 15 is similar to the test tank 16 in structure, but has no other devices inside, wherein, as shown in fig. 3, the inside of the test tank 16 is specifically configured as follows: the test tank 16 has a three-layer structure, and comprises a test container 22, a temperature equalizing container 20 and a heat preservation container 19 from inside to outside. The test container 22 is made of 625 stainless steel, has good high-temperature and high-pressure resistance, is of a flange structure as a whole, and has good sealing performance. The temperature equalizing container 20 is made of high heat conduction material copper, the test container 22 is completely surrounded to provide a uniform and stable temperature field, a heating rod 21 is embedded in the temperature equalizing container for heating the test container 22, and the heating power is determined by the temperature PID control system 8. The heat preservation container 19 is made of 625 stainless steel, has good heat preservation performance and higher safety factor, and avoids users from being scalded by high temperature. The test container 22 is provided inside with a test stub wire 26, the test stub wire 26 is made of a platinum wire, both ends of which are welded to support pillars 25, the support pillars 25 are also made of platinum, and are fixed to the ceramic base 24. A ceramic base 24 is secured to the top of the test vessel 22 by a nut to provide support and to define the location of the test line 26. The voltage drop signal at the two ends of the test wire 26 is output to the data acquisition system 4 through the electric lead 23, and in order to avoid the inaccurate voltage signal caused by the contamination of dissimilar metals, the electric lead 23 is also made of a platinum wire.

Further, as shown in fig. 4, the inflation/deflation pipeline 400 in the embodiment of the present invention further includes:

a double seal device for leading out a lead wire from a container containing high-temperature and high-pressure gas without leakage of the gas, which is composed of two parts including a metal oxide insulating seal tube part composed of a 625 stainless steel tube 27, a magnesium oxide filler 28 and an electric lead 23, and a tension nut 29.

The manufacturing process of the metal oxide insulating sealing pipe part comprises the steps of placing four electric leads 23 in a 625 stainless steel pipe in a mutual non-contact mode, filling magnesium oxide filler 28 into the pipe, compressing the 625 stainless steel pipe 27 at high temperature and high pressure after filling is completed, reducing the whole volume, compacting the magnesium oxide filler, and accordingly achieving the sealing effect, and meanwhile the magnesium oxide filler 28 also achieves the insulating effect among the electric leads 23. After the manufacturing is finished, the top of the part is connected with the expansion nut 29 to be used as a second double seal, the sealing effect is enhanced, and the double sealing device has the following three advantages: (1) insulation: the four wires are filled with the magnesium oxide filler 28, so that good insulation is achieved, and the wires are prevented from being contacted with each other to generate signal interference. (2) Cooling: the metal oxide insulating sealing tube is longer in part, can extend out of the interior of the container, is exposed to the atmosphere at the tail end, is lower in temperature, is smaller in expansion deformation of materials, and is beneficial to sealing. (3) And (3) reducing the pressure: the metal oxide insulating sealing tube is longer in part and is equivalent to a pressure relief tube, and even if air leaks from the outlet, the outlet can be blocked by a second resealing, namely an expansion nut 29.

The cooling pipe 500 is disposed inside the air charging and discharging pipe 400, and is used for compressing the external cold air to circulate through the air charging and discharging pipe to take away the heat.

Further, as shown in fig. 2, the cooling pipeline 500 is disposed inside the air storage tank 15 and the test tank 16 in the air charging and discharging pipeline 400, and includes an air compressor 10 and a flow meter 11, wherein the air compressor 10 is used for compressing the external cold air, circulates in the air charging and discharging pipeline 400, takes away the heat of the high temperature container, and controls the flow rate of the cold air by the flow meter 11 to control the cooling speed, and the cold air outlet is disposed in the atmosphere.

The following examples are provided to further illustrate the apparatus for measuring thermal conductivity of a high-temperature and high-pressure multi-component gas mixture according to the embodiments of the present invention.

Example one, a mixed gas containing a working medium which is liquid at normal temperature is prepared

As shown in FIG. 5, the gas charging/discharging pipeline 400 comprises a vacuum pump 13, a gas cylinder 12, a gas storage tank 15, a test tank 16 and a gas outlet, wherein 7 valves, labeled A-G, are installed in the system, and when a mixed gas (such as H) containing a working medium which is liquid at normal temperature needs to be configured₂-H₂Mixed gas of O), the specific operation steps are as follows:

step 1, determining the components of the mixed gas, and mixing the components (such as H) which are gaseous at normal temperature₂) Is flushed into the gas cylinder 12 and is connected to the left side of the valve G.

And 2, closing the valve G, slightly opening the gas cylinder 12 and then closing the valve G, and confirming that the gas does not leak from a connecting port on the left side of the valve.

And 3, closing the valve E and the valve D, opening the valve G and the valve F, and discharging the gas flushed in the step 2.

And 4, closing the valve A and the valve F, opening the valve B, the valve C, the valve D, the valve E and the valve G, opening the vacuum pump 13, and pumping the whole pipeline.

And 5, when the vacuum pump displays that the pressure is lower than 10Pa, closing the valve D, opening the gas valve of the gas cylinder 12, filling gas into the container, and closing the gas valve of the gas cylinder 12 after the gas is filled to the preset pressure.

And 6, closing the valve C, opening the valve F, discharging the gas in the gas storage tank 15 and the pipeline connected with the gas storage tank, keeping the gas in the test tank at the moment, closing the valve F and the valve G after the gas discharge is finished, and removing the gas bottle 12.

And 7, opening the valve D, opening the vacuum pump 13 again, and pumping away the gas in the gas storage tank and the connecting pipeline thereof.

And 8, closing the valve D and the valve E when the vacuum pump displays that the pressure is lower than 10 Pa.

Step 9, sucking another component (e.g. H) which is liquid at room temperature into the syringe₂O), connecting the needle tube to the valve A, slowly opening the valve A, sucking the liquid in the needle tube into the air storage tank 15 under the action of pressure difference, closing the valve A when the suction amount reaches the pre-metering amount, and removing the needle tube.

And step 10, opening a valve F, and discharging redundant gas in the pipeline.

And step 11, turning on the power supply, turning on the temperature PID control system 8, setting the predicted temperature, turning on the heater 9, and starting to heat the two tanks.

Step 12, when the temperature rises to the gasification point (such as H) of the working medium in the gas storage tank 15₂And O is 374 degrees), after the temperature is stabilized, opening the valve B and the valve C, and fully mixing the two tanks to complete the preparation of the mixed gas.

Step 13, a specific test flow is set forth in example two.

And 14, after the experiment is finished, closing the temperature PID control system 8, closing the heater 9, opening the air compressor 10, controlling the cooling speed through the flow meter 11, and reducing the temperature to the room temperature.

And step 15, opening all the valves except the valve D, and exhausting the internal gas. After the exhaust is completed, the temperature PID control system 8 is turned on again to set a higher temperature (e.g., H)₂O is 100 degrees), the heater 9 is turned on, the temperature is controlled for one day, and the working medium which is liquid at the normal temperature inside is evaporated and discharged out of the container.

And step 16, turning off the temperature PID control system 8, turning off the heater 9, cutting off the power supply, and finishing the test.

Example two, a test procedure is described in further detail, wherein the method of measuring thermal conductivity is a short hot wire method.

Briefly describing the measurement principle of the short-hot-wire method, which is proposed based on the cylindrical system heat conduction differential equation, the electrified test wire 26 generates joule heat, and the heat exchange process with the surrounding medium is described by the following equation:

in the formula, r₀Is the radius of the test wire 26, q is the joule heat power of the test wire 26, L is the wire length of the test wire 26, ρ, c, λ are density, heat capacity and thermal conductivity, respectively, as can be seen from the equation, the thermal conductivity of the test working medium affects the temperature rise of the test wire 26 after being electrified, and the test wire 26 is a good resistance thermometer, so that the thermal conductivity of the test medium can be deduced by measuring the resistance change after being electrified.

As shown in FIG. 3, in the test tank 16 according to the embodiment of the present invention, a test wire 26 made of a platinum wire having a diameter of 25 μm is selected, the test wire has a length of about 23mm, both ends of the test wire are welded to a supporting platinum column 25 having a diameter of 1.5mm, and the test wire is fixed to a ceramic base 24 made of alumina, the ceramic base 24 is fixed to the top of the test container 22, and four electrical leads 23 are welded to the other end of the supporting platinum column 25 for measuring the voltage of the test wire 26, and in order to prevent contamination of dissimilar metals, the electrical leads 23 are made of platinum and connected to the data acquisition system 4 through a double sealing device.

As shown in fig. 6, the testing device is composed of a dc power supply 2, a standard resistor 3, a testing tank 16 and a data acquisition system 4. In the example, the direct current power supply 2 selects ADCMT6243, the resistance value of the standard resistor 3 is 10 omega, the data acquisition system 4 consists of NI-5900 and NI-5922, the acquisition frequency is 50k points per second, and the accuracy is 24 bits.

When the test environment temperature is stable, the test is started, and the specific flow of the example is as follows:

step 1, connecting wires as shown in fig. 6, and connecting the direct current power supply 2 and the data acquisition system 4 to a power supply.

And 2, firstly, introducing a micro current to the test line 26 to measure the reference temperature of the test line 26. The dc power supply 2 is set to the constant current mode, and the upper limit of the output voltage is set to 800mV, and then the output current is set to 20 mA. The data acquisition system 4 was set to test 3s at 50k acquisition points per second. The personal computer 1 is turned on and the readings of the thermocouple 7, the pressure gauge 6 and the pressure display 5 are continuously monitored.

And step 3, after the setting is finished, firstly turning on the data acquisition system 4 to start data acquisition, and then immediately turning on the switch of the direct current power supply 2 to introduce constant current into the test circuit.

And 4, after the acquisition is finished, turning off the direct current power supply 2, exporting data in the data acquisition system 4, observing the voltage change of the two ends of the test wire 26, if the voltage change is not obvious, judging that the test wire 26 has no temperature rise, and acquiring the data to obtain the reference temperature of the test wire 26.

Step 5, a large current is introduced into the test wire 26, so that the test wire has a temperature rise to measure the thermal conductivity of the surrounding medium. The direct current power supply 2 is set to be in a constant current mode, the upper limit of the output voltage is set to be 800mV, and then the output current is set to be 200 mA. The data acquisition system 4 was set to test 3s at 50k acquisition points per second.

And 6, after the setting is finished, firstly turning on the data acquisition system 4 to start data acquisition, and then immediately turning on a switch of the direct current power supply 2 to introduce constant current into the test circuit.

And 7, after the acquisition is finished, turning off the direct current power supply 2, exporting data in the data acquisition system 4, and calculating the thermal conductivity of the measured gas according to the data.

And 8, repeating the steps 2 to 7, wherein each experiment is separated by five minutes, and measuring for multiple times to verify the repeatability.

And 9, after the measurement is finished, turning off the direct current power supply 2, turning off the data acquisition system 4, turning off the personal computer 1, turning off the main power supply and dismounting the connecting lead.

According to the device for measuring the thermal conductivity of the high-temperature high-pressure multi-element gas mixture, provided by the embodiment of the invention, the mixed gas containing the liquid working medium at normal temperature can be prepared, the thermal conductivity of the mixed gas in a high-temperature high-pressure supercritical state can be measured, and meanwhile, the sealing device with good sealing performance at high temperature and high pressure can be used for connecting a lead out of a high-temperature high-pressure container without air leakage.

Furthermore, the terms "first", "second" and "first" 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 defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.