Carbon dioxide porous medium flow heat transfer experiment system and experiment method

Abstract

The invention relates to the technical field of fluid porous medium flow heat transfer experiments, and provides a carbon dioxide porous medium flow heat transfer experiment system and experiment method. The experiment system comprises a storage pressure regulating assembly used for providing carbon dioxide; the injection pressurizing assembly is connected to an outlet of the storage pressure regulating assembly; the clamp holder assembly is connected to an outlet of the injection pressurizing assembly; the control assembly is electrically connected with the storage pressure regulating assembly, the injection pressurizing assembly and the clamping device assembly, and the control assembly is used for controlling the clamping device assembly to obtain flowing heat transfer data of the carbon dioxide; under the condition of low pressure demand, the control assembly is used for controlling the storage pressure regulating assembly or the injection pressurizing assembly to regulate the pressure of the carbon dioxide; under the condition of middle and high pressure requirements, the control assembly is used for controlling the storage pressure adjusting assembly and the injection pressurizing assembly to jointly adjust the pressure of the carbon dioxide. According to the experimental system provided by the invention, the pressure operation working condition from subcritical pressure to supercritical ultrahigh pressure can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of fluid porous medium flow heat transfer experiments, and in particular to a carbon dioxide porous medium flow heat transfer experiment system and an experiment method. Background Art

[0002] Since carbon dioxide has a low critical temperature, it is easier to reach a supercritical state during application. At the same time, due to its advantages such as low viscosity, high thermal diffusion coefficient, and significant critical effect in the supercritical state, the flow and heat transfer process of carbon dioxide in porous media under supercritical pressure has also attracted much attention.

[0003] However, existing experimental devices mostly focus on subcritical phase change or supercritical flow heat transfer processes separately, and the pressure control range is limited. It is impossible to achieve pressure operating conditions as low as subcritical pressure and as high as supercritical ultra-high pressure on the same experimental equipment. At the same time, it is impossible to guarantee the pressure accuracy and stable flow requirements within a large pressure range. Summary of the invention

[0004] The first aspect of the present invention provides a carbon dioxide porous medium flow heat transfer experimental system to solve the defects of the experimental equipment in the prior art. By setting a storage pressure regulating component and an injection pressurizing component, pressure operating conditions as low as subcritical pressure and as high as supercritical and ultra-high pressure can be achieved on the same experimental equipment, while ensuring the pressure accuracy and stable flow requirements within a large pressure range, effectively improving the versatility of the carbon dioxide porous medium flow heat transfer experimental system.

[0005] A first aspect of the present invention provides a carbon dioxide porous media flow heat transfer experimental method.

[0006] The carbon dioxide porous medium flow heat transfer experimental system provided by the present invention comprises: A storage pressure regulating assembly for providing carbon dioxide; An injection pressurizing component connected to the outlet of the storage pressure regulating component; A clamp assembly connected to the outlet of the injection pressurizing assembly; a control component, electrically connected to the storage pressure regulating component, the injection pressurizing component and the clamp component, respectively, and used for controlling the clamp component to obtain the flow heat transfer data of the carbon dioxide; Wherein, in the case of low pressure demand, the control component is used to control the storage pressure regulating component or the injection pressurizing component to adjust the pressure of the carbon dioxide; In the case of medium or high pressure demand, the control component is used to control the storage pressure regulating component and the injection pressurizing component to jointly regulate the pressure of the carbon dioxide.

[0007] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the injection pressurization component comprises: At least one injection constant speed and constant pressure pump, the inlet of the injection constant speed and constant pressure pump is connected to the outlet of the storage pressure regulating component, the injection constant speed and constant pressure pump is electrically connected to the control component, the injection constant speed and constant pressure pump is used to adjust the pressure of the carbon dioxide, and in the case where a plurality of the injection constant speed and constant pressure pumps are provided, the plurality of the injection constant speed and constant pressure pumps are arranged in parallel; A preheater, wherein the outlet of the injection constant speed and constant pressure pump is connected to the inlet of the preheater, and the outlet of the preheater is connected to the inlet of the clamp assembly, and the preheater is used to heat the carbon dioxide.

[0008] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the injection pressurization assembly further includes a back pressure control pump and a back pressure valve, the inlet of the back pressure valve is connected to the outlet of the injection constant speed and constant pressure pump, and the outlet of the back pressure valve is connected to the inlet of the preheater; The back-pressure control pump is connected to the back-pressure valve and electrically connected to the control assembly, and the back-pressure control pump is used to control the opening of the back-pressure valve.

[0009] The carbon dioxide porous medium flow heat transfer experimental system provided by the present invention also includes a pretreatment component; The pretreatment component includes a low-temperature bath, a high-pressure storage tank and a filter. The high-pressure storage tank is arranged inside the low-temperature bath. The inlet of the high-pressure storage tank is connected to the outlet of the storage pressure regulating component. The outlet of the high-pressure storage tank is connected to the filter. The outlet of the filter is connected to the inlet of the injection constant speed and constant pressure pump. The low-temperature bath and the high-pressure storage tank are used to convert the carbon dioxide from a gaseous state to a liquid state.

[0010] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the storage and pressure regulating assembly comprises a carbon dioxide storage tank, a pressure regulating heater and a first low-temperature cooling circuit, the outlet of the carbon dioxide storage tank is connected to the inlet of the high-pressure storage tank, and the carbon dioxide storage tank is used to provide carbon dioxide; The pressure regulating heater and the first low-temperature cooling circuit are arranged on the outside of the carbon dioxide storage tank and are electrically connected to the control component respectively. The first low-temperature cooling circuit is connected to the low-temperature bath. The pressure regulating heater and the first low-temperature cooling circuit are used to adjust the temperature of the carbon dioxide storage tank.

[0011] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the injection pressurization component further includes a second low-temperature cooling circuit; One end of the second low-temperature cooling circuit is connected to the injection constant speed and constant pressure pump, and the other end is connected to the low-temperature bath. The second low-temperature cooling circuit is used to cool the injection constant speed and constant pressure pump.

[0012] The carbon dioxide porous medium flow heat transfer experimental system provided by the present invention also includes a condenser and a back pressure valve; The inlet of the condenser is connected to the outlet of the clamper assembly, the outlet of the condenser is connected to the inlet of the back pressure valve, and the outlet of the back pressure valve is connected to the inlet of the injection pressurizing assembly.

[0013] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the clamp assembly comprises: A clamping component, connected to the outlet of the preheater, and used to fix the porous medium sample; A confining pressure tracking pump connected to the clamping component, the confining pressure tracking pump is used to provide confining pressure to the clamping component; A clamp heater, provided on the clamping component, for heating the fixed porous medium sample; The temperature and pressure monitoring component is used to detect the temperature of the clamping component and the carbon dioxide and the pressure of the carbon dioxide.

[0014] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the clamping component comprises a cylinder, a rubber sleeve and two sealing components, the rubber sleeve is arranged inside the cylinder, and the two sealing components are respectively arranged at the openings at both ends of the rubber sleeve; The rubber sleeve and the cylinder body enclose a confining pressure space, the sealing component is used to seal the openings of the confining pressure space and the rubber sleeve, and the rubber sleeve is used to fix the porous medium sample; the outlet of the preheater is connected to the rubber sleeve through one of the two sealing components, the outlet of the confining pressure tracking pump is connected to the confining pressure space, the clamper heater is arranged on the outside of the cylinder body, and the contact piece of the temperature and pressure monitoring component is arranged inside the rubber sleeve after passing through the cylinder body.

[0015] According to the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the sealing component includes a core plug, a tapered sleeve, a connecting sleeve, a large pressure cap and a small pressure cap, the core plug is arranged at the opening of the rubber sleeve, and the core plug is used to fix the porous medium sample; The connecting sleeve abuts against one end of the core plug away from the rubber sleeve, the tapered sleeve is arranged on the outside of the core plug and the connecting sleeve, and abuts against the rubber sleeve, the small pressure cap abuts against one end of the connecting sleeve away from the core plug, and the large pressure cap is arranged on the outside of the connecting sleeve and the small pressure cap.

[0016] The carbon dioxide porous medium flow heat transfer experimental method provided by the present invention comprises: installing the porous media sample into the holder assembly; Turn on the confining pressure tracking pump and set the confining pressure; Open the storage pressure regulating assembly to supply carbon dioxide to the main pipeline, and set the preset flow rate and preset pressure of carbon dioxide; The injection pressurizing assembly is opened, the carbon dioxide is pressurized through the storage pressure regulating assembly and / or the injection pressurizing assembly, and the opening of the back pressure valve is adjusted until the flow rate and pressure of the carbon dioxide reach a preset flow rate and a preset pressure, respectively.

[0017] According to the carbon dioxide porous medium flow heat transfer experimental method provided by the present invention, the step of opening the injection pressurizing component and pressurizing the carbon dioxide through the storage pressure regulating component and / or the injection pressurizing component comprises: In the case of low pressure demand, three injection constant speed and constant pressure pumps are on standby, and the pressure of the carbon dioxide is regulated by the storage pressure regulating component; In the case of medium and high pressure demand, a corresponding number of the injection constant speed and pressure pumps are started according to the flow demand, and the pressure of the carbon dioxide is regulated jointly by the storage pressure regulating component and the injection constant speed and pressure pump.

[0018] According to the carbon dioxide porous medium flow heat transfer experimental method provided by the present invention, the step of starting a corresponding number of injection constant speed and pressure pumps according to flow requirements under the condition of medium and high pressure requirements includes: In the case of medium and low flow demand, two of the three injection constant speed and constant pressure pumps are operated, and the two injection constant speed and constant pressure pumps are operated in turns; In case of high flow demand, the three injection constant speed and constant pressure pumps are operated, and the three injection constant speed and constant pressure pumps are operated in turns.

[0019] The carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the control component, storage pressure regulating component, injection pressurizing component and clamping component and other components work together to achieve a comprehensive and accurate test of the flow heat transfer performance of carbon dioxide in porous media. Among them, the storage pressure regulating component and the injection pressurizing component can pressurize the carbon dioxide respectively, and the cooperation of the two can provide a variety of optional methods for heating carbon dioxide, thereby meeting different pressurization requirements for carbon dioxide; for example, under low pressure requirements, the injection pressurizing component is on standby, and the pressurization operation is not started, and the pressure can be adjusted only by the storage pressure regulating component; under medium and high pressure requirements, the carbon dioxide can be further pressurized by the injection pressurizing component on the basis of the storage pressure regulating component pressurizing the carbon dioxide; such a setting can make the carbon dioxide porous medium flow heat transfer experimental system cover the operating range of subcritical to supercritical pressure (3 to 50MPa), which can meet the high-performance flow heat transfer test experimental requirements of carbon dioxide porous media.

[0020] Compared with the prior art, the carbon dioxide porous medium flow heat transfer experimental system provided by the present invention, the arrangement of the storage pressure regulating component and the injection pressurizing component, can achieve pressure operating conditions as low as subcritical pressure and as high as supercritical and ultra-high pressure on the same experimental equipment, while ensuring the pressure accuracy and stable flow requirements within a large pressure range, effectively improving the versatility of the carbon dioxide porous medium flow heat transfer experimental system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of a carbon dioxide porous medium flow heat transfer experimental system provided by an embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure of the clamping component provided by an embodiment of the present invention.

[0024] Figure 3 It is a schematic flow chart of a carbon dioxide porous medium flow heat transfer experimental method provided in an embodiment of the present invention.

[0025] Reference numerals: 100: storage pressure regulating assembly; 110: carbon dioxide storage tank; 120: pressure regulating heater; 130: first low temperature cooling circuit; 140: first valve; 200: injection pressurizing assembly; 210: injection constant speed constant pressure pump; 220: back pressure control pump; 230: back pressure valve; 240: second low temperature cooling circuit; 300: preheater; 400: holder assembly; 410: holder component; 411: barrel; 412: rubber sleeve; 413: sealing component; 4131: core plug; 4132: taper sleeve; 4133: connecting sleeve; 4134: large pressure cap; 4135: small pressure cap; 414: confining pressure space; 420: confining pressure tracking pump; 430: holder heater; 440: temperature and pressure monitoring component; 4410: first pressure sensor; 4411: second pressure sensor; 4412: third pressure sensor; 4 413: fourth pressure sensor; 4414: fifth pressure sensor; 4415: sixth pressure sensor; 4420: first temperature sensor; 4421: second temperature sensor; 4422: third temperature sensor; 4423: fourth temperature sensor; 4424: fifth temperature sensor; 4425: sixth temperature sensor; 4426: seventh temperature sensor; 4427: eighth temperature sensor; 450: third valve; 460: fourth valve; 470: fifth valve; 500: control component; 510: data acquisition component; 520: temperature and pressure display device; 600: pretreatment component; 610: low temperature bath; 620: high pressure storage tank; 630: filter; 640: second valve; 700: condenser; 800: back pressure valve; 900: porous medium sample. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0028] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0030] Many of these scenarios involve the key physical process of carbon dioxide flowing and transferring heat in porous media, including carbon dioxide enhanced geothermal systems, carbon dioxide porous media sensible heat storage systems, carbon dioxide porous media phase change sweating cooling systems, etc. Clarifying the process and mechanism of carbon dioxide flowing and transferring heat in porous media plays a key role in the efficient implementation of related scenarios. Since carbon dioxide has a low critical temperature, it is easier to reach a supercritical state during the application process. At the same time, due to its advantages such as low viscosity, high thermal diffusion coefficient, and significant critical effect in the supercritical state, the process of carbon dioxide flowing and transferring heat in porous media under supercritical pressure has also attracted much attention.

[0031] However, most existing experimental devices focus on subcritical phase change or supercritical flow heat transfer processes separately, and the pressure control range is limited. It is impossible to achieve pressure operation conditions as low as subcritical pressure (<7.38MPa) and as high as supercritical ultra-high pressure (50MPa) on the same experimental equipment, and it is also impossible to guarantee the pressure accuracy and stable flow requirements within a large pressure range. Therefore, it is necessary to design a carbon dioxide porous media flow heat transfer experimental system that can achieve a large pressure control range based on the pressure requirements in different application scenarios, including the pressure operation range and accuracy requirements.

[0032] Figure 1 It is a schematic diagram of a carbon dioxide porous medium flow heat transfer experimental system provided by an embodiment of the present invention.

[0033] See also Figure 1 The first aspect of the embodiment of the present invention provides a carbon dioxide porous medium flow heat transfer experimental system. For the convenience of explanation, the experimental system is referred to as the experimental system throughout the text; the experimental system includes a main line and a control component 500. The main line can be made of metal pipes such as copper pipes, and a plurality of corresponding interfaces are provided, which are further used to provide a storage pressure regulating component 100, an injection pressurizing component 200, a preheater 300 and a clamping component 400.

[0034] The storage and pressure regulating component 100 is used to provide carbon dioxide and regulate the pressure of carbon dioxide, wherein the carbon dioxide may be in a gaseous state in some optional embodiments and in a liquid state in some optional embodiments; the pressure of carbon dioxide may be regulated by compression or by indirectly regulating the temperature of carbon dioxide. The storage and pressure regulating component 100 may adjust the pressure of carbon dioxide within the range of low pressure requirements (3-6MPa).

[0035] The inlet of the injection and pressurizing assembly 200 is connected to the outlet of the storage and pressure regulating assembly 100. The injection and pressurizing assembly 200 is used to further adjust the pressure of the carbon dioxide. Specifically, on the basis of the storage and pressure regulating assembly 100 pressurizing the carbon dioxide, the injection and pressurizing assembly 200 can further pressurize the carbon dioxide within the range of medium and high pressure requirements (6-50MPa); in an optional embodiment of the present invention, within the range of low pressure requirements (3-6MPa), the injection and pressurizing assembly 200 can also be used as a carbon dioxide pressurization tool. In other words, either the storage and pressure regulating assembly 100 or the injection and pressurizing assembly 200 can be adaptively selected according to actual working conditions, or both can be enabled at the same time.

[0036] The inlet of the preheater 300 is connected to the outlet of the injection pressurizing component 200. The preheater 300 is used to heat the carbon dioxide. The preheater 300 can use direct heating or indirect heating, for example, directly heating the carbon dioxide through an electric heating plate. This heating method has a fast heating speed and precise temperature control, and can meet the heating power required by different experiments; or, the main pipeline is wrapped with a heat-conducting medium connected to the heat source, thereby indirectly heating the carbon dioxide. In other words, the heat of other heat media is transferred to the carbon dioxide through a heat exchanger. This method can efficiently utilize energy and different heat media can be selected as needed, such as hot water, hot oil, etc.; in an optional embodiment of the present invention, the preheater 300 can also be integrated into any one of the clamping component 400 and the injection pressurizing component 200. Specifically, it can be adaptively selected according to actual conditions. In this embodiment, a single preheater 300 is taken as an example for example and explanation.

[0037] The clamp assembly 400 is connected to the outlet of the preheater 300, and the clamp assembly 400 is used to obtain the flow heat transfer data of carbon dioxide; the control assembly 500 is electrically connected to the storage pressure regulating assembly 100, the injection pressurizing assembly 200, the preheater 300 and the clamp assembly 400 respectively, and the control assembly 500 is built with a preset control method. The control assembly 500 can control various components of the carbon dioxide porous medium flow heat transfer experimental system according to the preset control method, and based on the aforementioned flow heat transfer data, key thermal parameters such as the heat transfer coefficient and permeability performance of the convective heat transfer between carbon dioxide and the porous medium sample 900 are obtained.

[0038] See also Figure 1 It can be understood that the carbon dioxide porous medium flow heat transfer experimental system provided by the embodiment of the present invention, the control component 500, the storage pressure regulating component 100, the injection pressurizing component 200, the preheater 300 and the clamping component 400 and other components work together to achieve a comprehensive and accurate test of the flow heat transfer performance of carbon dioxide in porous media. Among them, the storage pressure regulating component 100 and the injection pressurizing component 200 can pressurize the carbon dioxide respectively, and the coordinated cooperation of the two can provide a variety of optional methods for heating the carbon dioxide, thereby meeting different pressurization requirements for carbon dioxide; for example, under low pressure requirements, the injection pressurizing component 200 is on standby, and the pressurization operation is not started, and the pressure can be adjusted only by the storage pressure regulating component 100; under medium and high pressure requirements, the carbon dioxide can be further pressurized by the injection pressurizing component 200 on the basis of the pressurization of the carbon dioxide by the storage pressure regulating component 100; this setting can make the carbon dioxide porous medium flow heat transfer experimental system cover the operating range of subcritical to supercritical pressure (3 to 50MPa), which can meet the requirements of high-performance flow heat transfer test experiments of carbon dioxide porous media.

[0039] Compared with the prior art, the carbon dioxide porous medium flow heat transfer experimental system provided in the embodiment of the present invention, the arrangement of the storage pressure regulating component 100 and the injection pressurizing component 200, can achieve pressure operating conditions as low as subcritical pressure and as high as supercritical and ultra-high pressure on the same experimental equipment, while ensuring the pressure accuracy and stable flow requirements within a wide pressure range, effectively improving the versatility of the carbon dioxide porous medium flow heat transfer experimental system.

[0040] Continuing to refer to 1, in an optional embodiment of the present invention, the injection pressurizing assembly 200 includes at least one injection constant speed and constant pressure pump 210, the inlet of the injection constant speed and constant pressure pump 210 is connected to the outlet of the storage pressure regulating assembly 100, and the outlet of the injection constant speed and constant pressure pump 210 is connected to the inlet of the preheater 300. In actual applications, when the system needs to pressurize carbon dioxide, the injection constant speed and constant pressure pump 210 can start working according to pre-set parameters.

[0041] In the case where multiple injection constant speed and constant pressure pumps 210 are provided, the multiple pumps are arranged in parallel. It can be understood that this design brings many advantages to the experimental system. First, it greatly increases the pressure regulation flexibility of the experimental system. For example, when facing different experimental pressure requirements, precise pressure regulation can be achieved by controlling the start and operation status of different injection constant speed and constant pressure pumps 210. When low pressure is required, some injection constant speed and constant pressure pumps 210 can be started to avoid excessive pressure; when high pressure is required, multiple injection constant speed and constant pressure pumps 210 can be started at the same time to ensure that the required high pressure state can be achieved.

[0042] Secondly, the injection constant speed and constant pressure pumps 210 arranged in parallel improve the reliability of the experimental system. Specifically, if one of the injection constant speed and constant pressure pumps 210 fails, the other injection constant speed and constant pressure pumps 210 can continue to work to ensure the normal progress of the experiment, thus playing the role of redundant design. In this way, during long and complex experiments, experimental interruptions and data errors caused by equipment failures can be effectively reduced.

[0043] In summary, multiple injection constant speed and constant pressure pumps 210 can effectively adjust the pressure of carbon dioxide to meet the needs of different experiments. At the same time, they have high reliability and stability, and can provide a strong guarantee for the smooth progress of carbon dioxide porous medium flow heat transfer experiments. This article takes the three injection constant speed and constant pressure pumps 210 shown in the figure as examples for examples and explanations.

[0044] Continue reading Figure 1 In an optional embodiment of the present invention, based on the aforementioned claims, in this embodiment, the injection pressurizing component 200 also includes a back pressure control pump 220 and a back pressure valve 230, the inlet of the back pressure valve 230 is connected to the outlet of the injection constant speed and constant pressure pump 210, the outlet of the back pressure valve 230 is connected to the inlet of the preheater 300, the back pressure control pump 220 is connected to the back pressure valve 230, and is electrically connected to the control component 500, the back pressure control pump 220 can accurately control the opening size of the back pressure valve 230 according to experimental requirements.

[0045] It is understandable that during the experiment, when the pressure of carbon dioxide needs to be adjusted, the back pressure control pump 220 intelligently adjusts the opening of the back pressure valve 230 according to the pressure signal fed back by the system. This precise pressure control capability greatly improves the accuracy and reliability of the experimental results.

[0046] It can also be understood that compared with relying solely on the injection of the constant speed and constant pressure pump 210 or the storage pressure regulating assembly 100 for pressure regulation, the addition of the back pressure control pump 220 and the back pressure valve 230 can make the pressure regulation more flexible and precise. Specifically, in some complex experimental scenarios, it may be necessary to adjust the pressure of carbon dioxide quickly and frequently. The back pressure control pump 220 and the back pressure valve 230 can respond quickly and achieve precise regulation. The setting of the back pressure control pump 220 and the back pressure valve 230 significantly improves the system's ability to regulate the carbon dioxide pressure, providing a more stable and precise pressure environment for carbon dioxide porous medium flow heat transfer experiments.

[0047] Continue reading Figure 1 In an optional embodiment of the present invention, the experimental system also includes a pretreatment component 600. The pretreatment component 600 is mainly used when the initial state of carbon dioxide is gas and the injection constant speed and constant pressure pump 210 is a liquid pump. The pretreatment component 600 includes a low-temperature bath 610, a high-pressure storage tank 620 and a filter 630. The high-pressure storage tank 620 is arranged inside the low-temperature bath 610. The inlet of the high-pressure storage tank 620 is connected to the outlet of the storage pressure regulating component 100, and the outlet of the high-pressure storage tank 620 is connected to the filter 630. The outlet of the filter 630 is connected to the inlet of the injection constant speed and constant pressure pump 210. The low-temperature bath 610 can work together with the high-pressure storage tank 620 to convert carbon dioxide from gas to liquid.

[0048] It is understandable that during the experiment, the low-temperature bath 610 can provide a low-temperature environment for the high-pressure storage tank 620. The specific temperature of the low-temperature environment can meet the condensation of carbon dioxide. After the carbon dioxide gas output by the storage pressure regulating component 100 enters the high-pressure storage tank 620, it can remain in the high-pressure storage tank 620 for a period of time. The high-pressure storage tank 620 can perform heat exchange with the carbon dioxide, thereby causing the carbon dioxide to condense into a liquid state and accumulate in the high-pressure storage tank 620.

[0049] The liquefied carbon dioxide is then filtered through a filter 630, which can effectively remove impurities and particles in the carbon dioxide, ensuring that the carbon dioxide entering the injection pressurization assembly 200 is of high purity. The carbon dioxide processed by the filter 630 has a greatly reduced impurity content, which can avoid the interference of impurities on the experimental results and improve the accuracy of the experimental data. In an optional embodiment of the present invention, when there is a circulation loop, the impurity content in the carbon dioxide recycled for the second time will be greatly increased. The filter 630 provided in this embodiment can effectively remove impurities and particles in the carbon dioxide recycled for the second time, which can avoid the impact of recycling on subsequent experimental results.

[0050] It can also be understood that the temperature of the carbon dioxide treated by the pretreatment component 600 is relatively low, the movement of carbon dioxide molecules in the low temperature state is relatively slow, and its viscosity will be reduced accordingly. In this way, the flow resistance encountered by the carbon dioxide when passing through the injection constant speed and constant pressure pump 210 will be reduced, thereby reducing the workload of the injection constant speed and constant pressure pump 210. In other words, the pretreated low-temperature carbon dioxide can be more smoothly injected into and discharged by the constant speed and constant pressure pump 210, reducing the wear and energy consumption of the injection constant speed and constant pressure pump 210, and extending the service life of the injection constant speed and constant pressure pump 210.

[0051] Secondly, lower temperatures help improve the working efficiency of the injection constant speed and constant pressure pump 210. Due to the reduced viscosity of carbon dioxide, the injection constant speed and constant pressure pump 210 can more efficiently pressurize carbon dioxide to the required pressure value when transporting it, reducing pressure fluctuations caused by energy loss, and making the output pressure of the injection constant speed and constant pressure pump 210 more stable.

[0052] In addition, the injection constant speed and constant pressure pump 210 will generate a certain amount of heat due to the conversion of mechanical energy when working. If the temperature of carbon dioxide is too high, it may aggravate the heating of the injection constant speed and constant pressure pump 210 and affect the performance and stability of the injection constant speed and constant pressure pump 210. The pre-treated low-temperature carbon dioxide can effectively absorb and take away part of the heat, play a role in cooling the pump body, and further ensure the normal operation of the injection constant speed and constant pressure pump 210.

[0053] Continue reading Figure 1 In an optional embodiment of the present invention, the storage pressure regulating assembly 100 includes a carbon dioxide storage tank 110, a pressure regulating heater 120 and a first low-temperature cooling circuit 130. The outlet of the carbon dioxide storage tank 110 is connected to the inlet of the high-pressure storage tank 620. The carbon dioxide storage tank 110 is a storage container for carbon dioxide, which provides a stable gas source for the entire experimental system. The pressure regulating heater 120 is arranged on the outside of the carbon dioxide storage tank 110, and the first low-temperature cooling circuit 130 is arranged around the outside of the carbon dioxide storage tank 110. The inlet and outlet of the first low-temperature cooling circuit 130 are both connected to the low-temperature bath 610. The pressure regulating heater 120 and the first low-temperature cooling circuit 130 are used to adjust the temperature of the carbon dioxide storage tank 110.

[0054] Specifically, when the pressure of carbon dioxide needs to be increased, the pressure regulating heater 120 starts working. The pressure regulating heater 120 heats the carbon dioxide in the carbon dioxide storage tank 110. According to the ideal gas state equation, an increase in temperature will cause an increase in gas pressure. By precisely controlling the heating power of the pressure regulating heater 120, the pressure of carbon dioxide can be adjusted to the specific value required for the experiment.

[0055] On the contrary, when the pressure of carbon dioxide needs to be reduced, the first low-temperature cooling loop 130 starts to work. The first low-temperature cooling loop 130 reduces the temperature of carbon dioxide by cooling the carbon dioxide storage tank 110. According to the ideal gas state equation, the temperature reduction will cause the gas pressure to decrease, and the pressure of carbon dioxide can be adjusted to the specific value required for the experiment.

[0056] It can be understood that, through the effective cooperation of the carbon dioxide storage tank 110, the pressure regulating heater 120 and the first low-temperature cooling circuit 130, the storage pressure regulating assembly 100 can flexibly adjust the pressure of carbon dioxide according to experimental requirements, providing stable and reliable pressure conditions for subsequent experimental links.

[0057] In addition, the low-temperature bath 610 itself has a stable low-temperature environment and precise temperature control capabilities. By connecting the first low-temperature cooling circuit 130 to the first low-temperature cooling circuit 130, the low-temperature refrigerant of the low-temperature bath 610 can be directly utilized without the need to set up additional complex refrigeration equipment. This not only simplifies the system structure, but also reduces the equipment's footprint and cost investment.

[0058] Secondly, the refrigerant temperature of the low-temperature bath 610 is usually low and relatively stable. When the first low-temperature cooling circuit 130 is connected to the low-temperature bath 610, a lower and more stable refrigerant can be provided to the carbon dioxide storage tank 110, thereby effectively reducing the temperature of the carbon dioxide, and further more accurately controlling the pressure of the carbon dioxide. Furthermore, the low-temperature bath 610 has good temperature uniformity and heat exchange efficiency. The design of the low-temperature bath 610 allows the refrigerant to fully circulate and exchange heat in the tank, ensuring the consistency of the refrigerant temperature. After being connected to the first low-temperature cooling circuit 130, the cooled carbon dioxide can also maintain good temperature uniformity in the circuit, avoiding the adverse effects of excessively high or low local temperatures on pressure regulation.

[0059] Continue reading Figure 1 In an optional embodiment of the present invention, the injection pressurizing component 200 also includes a second low-temperature cooling circuit 240, one end of the second low-temperature cooling circuit 240 is connected to the injection constant speed and constant pressure pump 210, and the other end is connected to the low-temperature bath 610. The second low-temperature cooling circuit 240 is used to cool the injection constant speed and constant pressure pump 210.

[0060] It is understandable that during the experiment, the injection constant speed and constant pressure pump 210 generates heat when pressurizing carbon dioxide. If the heat cannot be dissipated in time, it may cause the performance of the pump to deteriorate or even be damaged. In the embodiment of the present invention, the low-temperature coolant in the low-temperature bath 610 can circulate through the second low-temperature cooling circuit 240 to take away the heat generated by the injection constant speed and constant pressure pump 210. In this way, the temperature of the injection constant speed and constant pressure pump 210 can be effectively controlled within a reasonable range to ensure its stable operation.

[0061] It can also be understood that, similar to the first low-temperature cooling loop 130 in the aforementioned embodiment, the second low-temperature cooling loop 240 is connected to the low-temperature bath 610, and can utilize the existing low-temperature environment and stable temperature control of the low-temperature bath 610, without the need to set up a special refrigeration device, which effectively simplifies the system structure and reduces equipment costs and maintenance complexity.

[0062] Secondly, a separately installed refrigeration device may have problems such as large temperature fluctuations and unstable refrigerant supply, which will affect the cooling effect on the injection constant speed and pressure pump 210. In this embodiment, the low-temperature bath 610 can provide continuous and stable low-temperature refrigerant. When multiple injection constant speed and pressure pumps 210 are provided, the consistency and reliability of the cooling effect of the second low-temperature cooling circuit 240 on the injection constant speed and pressure pump 210 can be ensured.

[0063] Continue reading Figure 1 In an optional embodiment of the present invention, the experimental system also includes a condenser 700 and a back pressure valve 800, the inlet of the condenser 700 is connected to the outlet of the clamp assembly 400, the outlet of the condenser 700 is connected to the inlet of the back pressure valve 800, and the outlet of the back pressure valve 800 is connected to the inlet of the injection pressurizing assembly 200.

[0064] It is understandable that when the carbon dioxide flows out of the clamp assembly 400, the temperature is relatively high. To avoid damage to the back pressure valve 800 due to excessive outlet temperature, the temperature of the carbon dioxide can be rapidly reduced through the condenser 700, thereby ensuring the safe operation of the back pressure valve 800. Secondly, the back pressure valve 800 can control the pressure of the carbon dioxide to keep it in a stable flow state in the system. During the experiment, by adjusting the opening of the back pressure valve 800, combined with the aforementioned storage pressure regulating assembly 100 and injection pressurizing assembly 200, the pressure of the carbon dioxide can be precisely regulated.

[0065] In addition, through the coordinated work of the condenser 700 and the back pressure valve 800, the closed circulation of carbon dioxide in the experimental system can be realized, which is the circulation loop mentioned above. The design of the circulation loop not only improves the utilization rate of carbon dioxide, reduces resource waste, but also reduces experimental costs.

[0066] Continue reading Figure 1In an optional embodiment of the present invention, the clamp assembly 400 includes a clamping component 410, a confining pressure tracking pump 420, a clamping heater 430 and a temperature and pressure monitoring component 440. The clamping component 410 is connected to the outlet of the preheater 300 and is used to fix the porous medium sample 900; the confining pressure tracking pump 420 is connected to the clamping component 410, and the confining pressure tracking pump 420 is used to provide confining pressure to the clamping component 410; the clamping heater 430 is provided on the clamping component 410 and is used to heat the porous medium sample 900; the temperature and pressure monitoring component 440 is used to detect the temperature of the clamping component 410 and carbon dioxide and the pressure of carbon dioxide.

[0067] It can be understood that the pressure of the carbon dioxide after being treated by the storage pressure regulating component 100 and the injection pressurizing component 200 is relatively high, much greater than the atmospheric pressure. This pressure difference will generate huge pressure on the clamping component 410 used for the clamping component 410. In this embodiment, the confining pressure tracking pump 420 can accurately apply confining pressure to the clamping component 410 according to the preset experimental conditions, so that it maintains a stable structural form and prevents the clamping component 410 from being deformed, ruptured or the pore structure changed due to factors such as internal pressure changes or fluid flow during the experiment.

[0068] In addition, appropriate confining pressure can also ensure the fit between the clamping component 410 and the porous medium sample 900, thereby ensuring that all carbon dioxide passes through the porous medium sample 900 and preventing carbon dioxide from passing through the gap between the clamping component 410 and the porous medium sample 900. Based on this, the accuracy of the experimental results can be guaranteed.

[0069] The clamp heater 430 can quickly raise the temperature of the porous medium sample 900 to the set value according to the experimental requirements, and accurately control the temperature fluctuation within a very small range during the entire experiment, thereby creating a specific temperature environment and providing a stable high-temperature environment for the flow and heat transfer experiment of carbon dioxide in porous media. In addition, by changing the power of the clamp heater 430, the temperature requirements under different experimental conditions can also be met.

[0070] The temperature and pressure monitoring component 440 includes a plurality of temperature sensors and pressure sensors, which are distributed at corresponding positions such as before the inlet and after the outlet of the clamping component 410 and inside the clamping component 410, and can be adaptively adjusted according to actual conditions. The temperature and pressure monitoring component 440 is used to obtain all temperature data and pressure data of carbon dioxide in the heat transfer experiment, so as to obtain key thermal parameters such as the heat transfer coefficient and permeability performance of the convective heat transfer between carbon dioxide and the porous medium sample 900.

[0071] Figure 2 It is a schematic diagram of the structure of the clamping component provided by an embodiment of the present invention.

[0072] See also Figure 2 In an optional embodiment of the present invention, the clamping component 410 includes a cylinder 411, a rubber sleeve 412 and two sealing components 413. The rubber sleeve 412 is arranged inside the cylinder 411. Both ends of the cylinder 411 are open structures. Both ends of the rubber sleeve 412 are also open structures. The rubber sleeve 412 and the cylinder 411 are coaxially arranged. The two sealing components 413 are respectively arranged at the openings at both ends of the rubber sleeve 412, that is, at the openings at both ends of the cylinder 411; the rubber sleeve 412 is used to fix the porous medium sample 900. The rubber sleeve 412 can be made of materials such as fluororubber. 12 and the cylinder 411 have some space left, thereby enclosing a confining pressure space 414, and the outlet of the confining pressure tracking pump 420 is connected to the confining pressure space 414. During the experiment, the confining pressure tracking pump 420 can inject liquid or gas into the confining pressure space 414 to apply confining pressure to the rubber sleeve 412, so that the rubber sleeve 412 is subjected to uniform pressure, thereby ensuring the fit between the rubber sleeve 412 and the porous medium sample 900 inside the rubber sleeve 412, and tightly wrapping the porous medium sample 900. It should be noted that the confining pressure and the fluid pressure difference need to be maintained at 3-5MPa.

[0073] The sealing component 413 is used to seal the openings of the confining pressure space 414 and the rubber sleeve 412. The sealing component 413 can effectively seal the openings of the confining pressure space 414 and the rubber sleeve 412 to prevent leakage of the confining pressure medium and ensure the stability of the confining pressure. At the same time, the rubber sleeve 412 and the porous medium sample 900 are firmly confined inside the cylinder 411 to ensure the stability of the structure. In addition, the pipeline inside the sealing component 413 can be connected to the rubber sleeve 412, and the outlet of the preheater 300 is connected to the rubber sleeve 412 through one of the two sealing components 413, and the other of the two sealing components 413 is connected to the inlet of the aforementioned condenser 700, thereby ensuring the smoothness of the main pipeline.

[0074] The clamp heater 430 is arranged on the outside of the cylinder 411 and is used to heat the cylinder 411. The clamp heater 430 can also extend into the confined pressure space 414 to heat the fluid inside the confined pressure space 414, thereby ensuring the heating of the porous medium sample 900; a plurality of detection ports are provided on the cylinder 411 and the rubber sleeve 412, and the contact parts of the temperature and pressure monitoring part can pass through the cylinder 411 through these detection ports and then be arranged inside the rubber sleeve 412, thereby realizing temperature monitoring of carbon dioxide and the porous medium sample 900.

[0075] It can be understood that, through the synergistic effect of the rubber sleeve 412, the sealing component 413 and the confining pressure tracking pump 420, the fluid can be effectively prevented from flowing in the gap between the porous medium sample 900 and the cylinder 411, thereby ensuring the sealing of the experimental system and reducing experimental errors.

[0076] Continue reading Figure 2 In an optional embodiment of the present invention, the sealing component 413 includes a core plug 4131, a tapered sleeve 4132, a connecting sleeve 4133, a large pressure cap 4134 and a small pressure cap 4135. The core plug 4131 is arranged at the opening of the rubber sleeve 412, and the core plug 4131 is used to abut against the porous medium sample 900; the connecting sleeve 4133 abuts against the end of the core plug 4131 away from the rubber sleeve 412, the tapered sleeve 4132 is sleeved on the outside of the core plug 4131 and the connecting sleeve 4133, and abuts against the rubber sleeve 412, the small pressure cap 4135 abuts against the end of the connecting sleeve 4133 away from the core plug 4131, and the large pressure cap 4134 is sleeved on the outside of the connecting sleeve 4133 and the small pressure cap 4135.

[0077] Specifically, the core plug 4131 is located at the opening of the rubber sleeve 412, and its main function is to tightly abut the porous medium sample 900 to prevent the porous medium sample 900 from being displaced during the experiment. The connecting sleeve 4133 abuts against the end of the core plug 4131 away from the rubber sleeve 412 to provide support for the core plug 4131. The tapered sleeve 4132 is sleeved on the outside of the core plug 4131 and the connecting sleeve 4133, and is tightly abutted against the rubber sleeve 412. The design of the tapered sleeve 4132 cleverly utilizes its tapered characteristics. When tightening the large pressure cap 4134 and the small pressure cap 4135, the tapered sleeve 4132 will be squeezed, so that it fits tightly against the inner wall of the cylinder 411, further enhancing the sealing effect on the confining pressure space 414. The small pressing cap 4135 abuts against one end of the connecting sleeve 4133, and the large pressing cap 4134 is sleeved on the outside of the connecting sleeve 4133 and the small pressing cap 4135. By tightening the large pressing cap 4134 and the small pressing cap 4135, the various components can be tightly combined to form a reliable sealing structure.

[0078] In the actual installation process, the porous medium sample 900 that has been pre-processed in size can be first placed in the rubber sleeve 412, and then the core plug 4131 is placed at the opening of the rubber sleeve 412 so that it is in close contact with the porous medium sample 900, and then the connecting sleeve 4133 is sleeved on the outside of the core plug 4131, and it is ensured that the connection between the connecting sleeve 4133 and the core plug 4131 is firm. Next, the tapered sleeve 4132 is sleeved on the outside of the core plug 4131 and the connecting sleeve 4133, and the tapered sleeve 4132 is tightly abutted against the rubber sleeve 412. Finally, the small pressure cap 4135 and the large pressure cap 4134 are sequentially installed on the outside of the connecting sleeve 4133, and by tightening the large pressure cap 4134 and the small pressure cap 4135, the entire sealing component 413 achieves the best sealing effect.

[0079] The temperature sensor, pressure sensor, injection constant speed and pressure pump 210, preheater 300, condenser 700, clamp heater 430, back pressure valve 800 and other components used in the present invention are all connected to the logic circuit of the data acquisition component 510 in the control component 500. Each temperature and pressure sensor feeds back the system working parameters to the logic circuit. The logic circuit controls the working frequency of the injection constant speed and pressure pump 210, the heating power of the preheater 300, the cooling power of the condenser 700, the heating power of the clamp heater 430 and the opening of the back pressure valve 800. The back pressure valve 800 and the injection constant speed and pressure pump 210 cooperate with the logic circuit embedded with the above-mentioned operation strategy to control the working pressure and flow rate of carbon dioxide entering the experimental section (i.e., inside the clamp assembly 400). The preheater 300 cooperates with the logic circuit to control the temperature of carbon dioxide entering the experimental section (i.e., inside the clamp assembly 400). The clamp heater 430 cooperates with the logic circuit to control the temperature or heat flux density in the clamp. The temperature sensor parameters, pressure sensor parameters, and flow rate parameters can also be displayed in real time and visually through the temperature and pressure display device 520 in the control component 500.

[0080] See also Figure 1 and Figure 2 The following is a summary of the specific connectors of a specific embodiment of the carbon dioxide porous medium flow heat transfer experimental system provided in an embodiment of the present invention.

[0081] The carbon dioxide storage tank 110 is connected to the main pipeline through the first valve 140 via a pipeline, and a first pressure sensor 4410 is installed on the carbon dioxide storage tank 110. The first valve 140 is sequentially connected to the high-pressure storage tank 620, the filter 630, three parallel injection constant speed and constant pressure pumps 210, the back pressure valve 230, the preheater 300, the third valve 450, the clamp assembly 400 (including the clamping component 410, the clamp heater 430, the confining pressure tracking pump 420, the porous medium sample 900), the fourth valve 460, the condenser 700 and the back pressure valve 800 through the pipeline. The circulation pipeline after the back pressure valve 800 merges with the pipeline led out from the outlet of the first valve 140, and after the merger, the main pipeline is connected to the high-pressure storage tank 620 again to form a closed circulation loop.

[0082] Among them, the outlet of the high-pressure storage tank 620 is connected to a second pressure sensor 4411 and a second valve 640 through a branch. The second valve 640 is a safety valve used to ensure the safety of various components in the main pipeline; a branch is led out from the back pressure valve 230 to connect the back pressure control pump 220 and the third pressure sensor 4412; a first temperature sensor 4420 is arranged on the preheater 300; a second temperature sensor 4421 and a fourth pressure sensor 4413 are connected between the third valve 450 and the clamp assembly 400 through a branch; a third temperature sensor 4422, a fourth temperature sensor 4423 and a fifth temperature sensor 4424 are arranged on the clamping component 410 to measure the solid temperature of the porous medium sample 900 along the flow direction, and a fifth valve 470 is arranged on the branch connecting the clamping component 410 and the confining pressure tracking pump 420.

[0083] A sixth temperature sensor 4425 and a fifth pressure sensor 4414 are also provided on the clamping component 410. The sixth temperature sensor 4425 is used to detect the temperature of the clamping component 410, and the fifth pressure sensor 4414 is used to detect the confining pressure. A branch is provided between the clamping component 410 and the fourth valve 460 for connecting the seventh temperature sensor 4426, the sixth pressure sensor 4415 and the fifth valve 470. The fifth valve 470 is a pressure relief valve. An eighth temperature sensor 4427 is provided on the condenser 700.

[0084] The flow path of carbon dioxide is shown below.

[0085] After the carbon dioxide comes out of the carbon dioxide storage tank 110, it enters the main pipeline, first passes through the high-pressure storage tank 620, is cooled into a liquid state in the high-pressure storage tank 620, and then enters the three parallel injection constant speed and pressure pumps 210 after being filtered by the filter 630 to be pressurized to the pressure parameters required for the experiment. After the carbon dioxide is injected from the constant speed and pressure pump 210, it enters the preheater 300 through the back pressure valve 230 and is heated to the set temperature. Thereafter, the carbon dioxide enters the experimental section of the porous medium flow heat transfer experimental system, i.e., the clamp assembly 400, at the set temperature, pressure, and flow rate.

[0086] The carbon dioxide flows through the internal pores of the porous medium sample 900 heated by the clamp heater 430, performs convection heat exchange with the solid skeleton of the porous medium sample 900, and flows out of the clamp assembly 400 with increased temperature and reduced pressure, and enters the condenser 700.

[0087] During the convective heat exchange process between carbon dioxide and the porous medium sample 900, the second temperature sensor 4421 and the seventh temperature sensor 4426 are used to measure the fluid temperature before and after the carbon dioxide flows through the porous medium sample 900, the fourth pressure sensor 4413 and the sixth pressure sensor 4415 are used to measure the fluid pressure before and after the carbon dioxide flows through the porous medium sample 900, and the third temperature sensor 4422, the fourth temperature sensor 4423 and the fifth temperature sensor 4424 are used to measure the solid temperature of the porous medium sample 900 along the flow direction.

[0088] According to the above temperature parameters and pressure parameters, key thermal parameters such as heat transfer coefficient and permeability performance of the convective heat transfer between carbon dioxide and the porous medium sample 900 can be obtained. Finally, the carbon dioxide passes through the back pressure valve 800 and enters the circulation pipeline at the outlet of the main pipeline to realize its closed circulation use.

[0089] Figure 3 It is a schematic flow chart of a carbon dioxide porous medium flow heat transfer experimental method provided in an embodiment of the present invention.

[0090] See also Figure 3 A second aspect of an embodiment of the present invention provides a carbon dioxide porous medium flow heat transfer experimental method, which specifically includes the following steps.

[0091] S100 : Mounting the porous medium sample 900 to the holder assembly 400 .

[0092] Specifically, the small pressure cap 4135, the large pressure cap 4134, the connecting sleeve 4133, the taper sleeve 4132, the core plug 4131 and other components are opened in sequence, the rubber sleeve 412 is taken out from the cylinder 411, and the porous medium sample 900 which has been pre-processed in size is placed in the rubber sleeve 412. Then the cylinder 411 is put back, the temperature sensor measuring points of the rubber sleeve 412 and the cylinder 411 are aligned, and the core plug 4131, the taper sleeve 4132, the connecting sleeve 4133, the large pressure cap 4134, the small pressure cap 4135 and other components are tightened in sequence. Through such operations, the porous medium sample 900 can be firmly fixed in the clamp assembly 400, and at the same time, the temperature sensor can accurately measure the temperature of the sample.

[0093] S200: Turn on the confining pressure tracking pump 420 and set the confining pressure.

[0094] Specifically, the fifth valve 470 is opened, and the confining pressure tracking pump 420 is started to add water and pressurize the confining pressure space 414. The function of the confining pressure tracking pump 420 is to provide confining pressure for the porous medium sample 900. The pressure difference between the confining pressure and carbon dioxide causes the rubber sleeve 412 to deform, thereby ensuring that there is no gap between the porous medium sample 900 and the wall of the rubber sleeve 412, and the high-pressure fluid only flows through the internal cracks of the porous medium sample 900.

[0095] The confining pressure is such that the difference between the confining pressure and the fluid pressure is maintained at 3-5 MPa. The appropriate confining pressure can ensure the structural stability of the rubber sleeve 412 and prevent it from being deformed or damaged during the experiment. It also helps to accurately measure the flow and heat transfer characteristics of carbon dioxide in porous media.

[0096] S300: Open the storage pressure regulating assembly 100, supply carbon dioxide to the main pipeline, and set a preset flow rate and a preset pressure of carbon dioxide.

[0097] Specifically, close the second valve 640 and the fifth valve 470, open the first valve 140, the third valve 450, and the fourth valve 460, make the gas source and the main pipeline unblocked, and set the flow rate and working pressure of carbon dioxide. This step can ensure that carbon dioxide can smoothly enter the experimental system from the storage and pressure regulating assembly 100, providing a stable gas source for subsequent experimental operations.

[0098] S400: Open the injection pressurizing assembly 200, pressurize the carbon dioxide through the storage pressure regulating assembly 100 and / or the injection pressurizing assembly 200, and adjust the opening of the back pressure valve 800 until the flow rate and pressure of the carbon dioxide reach the preset flow rate and preset pressure respectively.

[0099] Specifically, the storage pressure regulating assembly 100 or the injection constant speed and pressure pump 210 is turned on. The storage pressure regulating assembly 100 and the injection constant speed and pressure pump 210 can accurately control the flow and pressure of carbon dioxide to meet the requirements of the experiment for different working conditions. The opening of the back pressure valve 800 is adjusted, and the operating state of the injection constant speed and pressure pump 210 is further adjusted to adjust the mass flow of carbon dioxide. It can be understood that by adjusting the opening of the back pressure valve 800, the pressure distribution in the experimental system can be controlled to ensure the flow and pressure stability of carbon dioxide in the experimental section.

[0100] S500: Setting the temperature of the preheater 300 and the temperature of the clamper assembly 400 until the temperatures of both reach a designated temperature.

[0101] Specifically, the temperature of the preheater 300 and the temperature or heat flux of the holder heater 430 are set to heat the carbon dioxide in front of the holder assembly 400 and the porous medium sample 900 in the holder assembly 400. The function of the preheater 300 is to heat the carbon dioxide to the set temperature so that it has a suitable temperature condition when entering the experimental section, and the holder heater 430 is used to heat the holder assembly 400 to ensure that the temperature of the porous medium sample 900 is stable during the experiment.

[0102] Until each temperature sensor reaches a specified temperature, or the heating power of each temperature sensor and the holder heater 430 reaches a specified value. By accurately controlling the temperature, the flow and heat transfer process of carbon dioxide in porous media under different temperature conditions can be simulated, and the influence of temperature on the flow and heat transfer characteristics can be studied.

[0103] Among them, the heating process is considered stable only when all temperatures change no more than 0.2°C within 20 minutes and the heating power of the clamp heater 430 changes no more than 1% within 20 minutes. A stable heating process is an important prerequisite for ensuring the accuracy of the experimental results.

[0104] This step also includes setting the cooler temperature to control the outlet temperature of the experimental system to avoid damage to components such as the back pressure valve 800 due to excessive temperature.

[0105] S600: Acquire flow heat transfer data of the carbon dioxide, and perform data analysis based on the flow heat transfer data.

[0106] Specifically, after all parameters such as temperature, pressure, heating power and flow rate are stable, the control component 500 starts data acquisition and records the values ​​of various flow heat transfer data, which include all temperature parameters, pressure parameters, heating power parameters and flow rate parameters.

[0107] By analyzing the collected flow heat transfer data, key thermal parameters such as heat transfer coefficient and permeability performance of convective heat transfer between carbon dioxide and porous medium sample 900 can be obtained. By analyzing and studying these parameters, the flow heat transfer mechanism of carbon dioxide in porous media can be deeply understood, providing theoretical support for applications in related fields.

[0108] In an optional embodiment of the present invention, the steps of opening the injection pressurizing component 200, setting the carbon dioxide flow rate and working pressure, and adjusting the opening of the back pressure valve 800 until the flow and pressure in the main line are stable include: in the case of low pressure demand, three injection constant speed and constant pressure pumps 210 are on standby, and the pressure of carbon dioxide is regulated by the storage pressure regulating component 100; in the case of medium and high pressure demand, a corresponding number of injection constant speed and constant pressure pumps 210 are started according to the flow demand, and the pressure of carbon dioxide is regulated jointly by the storage pressure regulating component 100 and the injection constant speed and constant pressure pump 210.

[0109] Specifically, under low pressure requirements (such as 3-6MPa), the three injection constant speed and constant pressure pumps 210 are on standby. At this time, the pressure of carbon dioxide is mainly regulated by the storage pressure regulating component 100. This is because within the low pressure range, the storage pressure regulating component 100 can accurately control the pressure. By adjusting the relevant parameters in the storage pressure regulating component 100, such as the working state of the pressure regulating heater 120 and the first low-temperature cooling circuit 130, the temperature and pressure in the carbon dioxide storage tank 110 can be adjusted, thereby achieving the regulation of carbon dioxide pressure and meeting the experimental requirements for low pressure conditions.

[0110] Under medium and high pressure requirements (such as 6-50MPa), a corresponding number of injection constant speed and pressure pumps 210 are started according to the flow requirements, and the pressure of carbon dioxide is regulated jointly by the storage pressure regulating component 100 and the injection constant speed and pressure pump 210. This is because within the medium and high pressure range, the storage pressure regulating component 100 alone may not be able to meet the requirements of pressure regulation accuracy and stability, and the synergistic effect of the injection constant speed and pressure pump 210 is required.

[0111] At the same time, during the entire process, the pressure of the main line can be controlled by steadily and slightly adjusting the opening of the back pressure valve 800 through the control system, which helps to ensure that the pressure difference before and after the clamp assembly 400 is maintained within a lower parameter range, so that the pressure rises steadily until the set pressure is reached, thereby achieving stability of the flow and pressure in the main line.

[0112] In summary, by adopting different adjustment methods according to different pressure requirements, making full use of the advantages of the storage pressure regulating assembly 100 and the injection constant speed and pressure pump 210, and combining the precise control of the back pressure valve 800, it can ensure that the experimental system can achieve stable flow and pressure conditions under different working conditions, providing a guarantee for accurately measuring the flow and heat transfer characteristics of carbon dioxide in porous media.

[0113] In an optional embodiment of the present invention, under the condition of medium and high pressure demand, the step of starting a corresponding number of injection constant speed and constant pressure pumps 210 according to the flow demand includes running two of the three injection constant speed and constant pressure pumps 210 under the condition of medium and low flow demand; and running three injection constant speed and constant pressure pumps 210 under the condition of high flow demand, and the three injection constant speed and constant pressure pumps 210 are run in turns.

[0114] Specifically, under medium and low flow requirements (1-30ml / min, the flow value is for reference only, and the flow range of different pump models is different), two of the three injection constant speed and constant pressure pumps 210 are operated, and one of the injection constant speed and constant pressure pumps 210 is used as the main pump for pressurized operation. It uses its own working principle to transport carbon dioxide into the system at a certain pressure and flow rate.

[0115] At the same time, another injection constant speed constant pressure pump 210 works as a fluid replenishment pump. When the main pump delivers carbon dioxide, the pressure in the system will gradually decrease, and the fluid replenishment pump will start in time to replenish carbon dioxide into the system to maintain the flow rate in the system stable. Through this operation mode of one pump for pressurization and one pump for fluid replenishment, the flow rate and pressure of carbon dioxide can be effectively controlled under low and medium flow requirements to ensure the stable operation of the experimental system.

[0116] Under high flow demand (30-50 ml / min), three injection constant speed and constant pressure pumps 210 need to be operated, and the three pumps operate in turn. When one of the pumps is running, it undertakes the main task of pressurizing and transporting carbon dioxide, and delivers a large amount of carbon dioxide into the system at a higher pressure and flow rate.

[0117] At the same time, the other two pumps start to replenish fluid. As the pumps run, the carbon dioxide in the system is gradually consumed and the pressure drops. At this time, the replenishment pump will start in time to replenish carbon dioxide into the system, ensuring that the flow rate in the system always meets the high flow demand.

[0118] When the running pump is about to run out of liquid, the next pump will start running immediately, taking over the work of the previous pump, and continue to pressurize and transport carbon dioxide. In this way, the three pumps run in turn, achieving continuous and stable supply under high flow demand.

[0119] It is understandable that, in the whole process, whether it is a medium or low flow demand or a high flow demand, the coordinated work of the three injection constant speed and constant pressure pumps 210, and the cooperation with other components (such as the storage pressure regulating component 100, the back pressure valve 800, etc.), jointly maintain the stable flow and pressure of carbon dioxide in the experimental system. By accurately controlling the operating state of each pump and the opening of the back pressure valve 800, the experimental conditions can be accurately adjusted, providing a reliable experimental environment for studying the flow and heat transfer characteristics of carbon dioxide in porous media.

[0120] It can also be understood that, through the carbon dioxide porous medium flow heat transfer experimental method provided by the embodiment of the present invention, the ultra-high pressure parameters of the experimental section can be achieved by using a low compression ratio, and at the same time, high-precision, stable regulation and operation can be met in a large pressure range of 3-50MPa. It should be noted that the number of parallel pumps is not limited to three. When more than three pumps are operated in combination, under medium-high pressure and high flow requirements, they can be operated in turns, or a combination of multiple simultaneous operations and multiple fluid replenishment.

[0121] In an optional embodiment of the present invention, after obtaining the flow heat transfer data of the carbon dioxide and performing data analysis based on the flow heat transfer data, it is necessary to close various components in the carbon dioxide porous medium flow heat transfer experimental system, specifically, turn off the preheater 300, the clamp heater 430, the injection constant speed and constant pressure pump 210, and the first valve 140 in sequence, and after the temperature cools to room temperature, close the third valve 450 and the fourth valve 460, open the fifth valve 470 to release the pressure of the clamp assembly 400, and synchronously adjust the confining pressure tracking pump 420 and the fifth valve 470. It is necessary to ensure that the confining pressure and the fluid pressure difference are maintained at 3-5MPa to avoid the rubber sleeve 412 from rupturing due to excessive internal and external pressure difference. Finally, the confining pressure drops to normal pressure, and the confining pressure tracking pump 420 and the fifth valve 470 are closed. Next, the porous medium sample 900 can be taken out from the clamp assembly 400, and according to the above steps, other porous medium samples 900 are replaced in the same way to carry out the convective heat transfer experiment.

[0122] It should be noted that the technical solutions in various embodiments of the present invention can be combined with each other, but the basis for the mutual combination is that it can be implemented by ordinary technicians in the field; when the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist, that is, it does not belong to the protection scope of the present invention.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon dioxide porous medium flow heat transfer experimental system, characterized in that: include: A storage and pressure regulating component (100) for providing carbon dioxide; An injection pressurizing component (200) connected to the outlet of the storage pressure regulating component (100); A clamp assembly (400) connected to the outlet of the injection pressurizing assembly (200); a control component (500) electrically connected to the storage pressure regulating component (100), the injection pressurizing component (200) and the holder component (400), respectively, the control component (500) being used to control the holder component (400) to obtain flow heat transfer data of the carbon dioxide; Wherein, in the case of low pressure demand, the control component (500) is used to control the storage pressure regulating component (100) or the injection pressurizing component (200) to adjust the pressure of the carbon dioxide; In the case of medium or high pressure demand, the control component (500) is used to control the storage pressure regulating component (100) and the injection pressurizing component (200) to jointly regulate the pressure of the carbon dioxide.

2. The carbon dioxide porous media flow heat transfer experimental system according to claim 1, characterized in that: The injection pressurizing assembly (200) comprises: at least one injection constant speed and constant pressure pump (210), the inlet of the injection constant speed and constant pressure pump (210) being connected to the outlet of the storage pressure regulating assembly (100), the injection constant speed and constant pressure pump (210) being electrically connected to the control assembly (500), the injection constant speed and constant pressure pump (210) being used to regulate the pressure of the carbon dioxide, and in the case where a plurality of the injection constant speed and constant pressure pumps (210) are provided, the plurality of the injection constant speed and constant pressure pumps (210) are arranged in parallel; A preheater (300), wherein the outlet of the injection constant speed and constant pressure pump (210) is connected to the inlet of the preheater (300), and the outlet of the preheater (300) is connected to the inlet of the clamp assembly (400), and the preheater (300) is used to heat the carbon dioxide.

3. The carbon dioxide porous medium flow heat transfer experimental system according to claim 2, characterized in that: The injection pressurizing assembly (200) further comprises a back pressure control pump (220) and a back pressure valve (230), wherein the inlet of the back pressure valve (230) is connected to the outlet of the injection constant speed and constant pressure pump (210), and the outlet of the back pressure valve (230) is connected to the inlet of the preheater (300); The back pressure control pump (220) is connected to the back pressure valve (230) and is electrically connected to the control assembly (500). The back pressure control pump (220) is used to control the opening of the back pressure valve (230).

4. The carbon dioxide porous media flow heat transfer experimental system according to claim 2, characterized in that: Also included is a pre-processing component (600); The pretreatment component (600) comprises a low-temperature bath (610), a high-pressure storage tank (620) and a filter (630); the high-pressure storage tank (620) is arranged inside the low-temperature bath (610); the inlet of the high-pressure storage tank (620) is connected to the outlet of the storage pressure regulating component (100); the outlet of the high-pressure storage tank (620) is connected to the filter (630); and the outlet of the filter (630) is connected to the inlet of the injection constant speed and constant pressure pump (210); The low-temperature bath (610) and the high-pressure storage tank (620) are used to convert the carbon dioxide from a gaseous state into a liquid state.

5. The carbon dioxide porous media flow heat transfer experimental system according to claim 4, characterized in that: The storage pressure regulating assembly (100) comprises a carbon dioxide storage tank (110), a pressure regulating heater (120) and a first low-temperature cooling circuit (130); the outlet of the carbon dioxide storage tank (110) is connected to the inlet of the high-pressure storage tank (620); and the carbon dioxide storage tank (110) is used to provide carbon dioxide; The pressure regulating heater (120) and the first low-temperature cooling circuit (130) are arranged outside the carbon dioxide storage tank (110) and are electrically connected to the control component (500) respectively; the first low-temperature cooling circuit (130) is connected to the low-temperature bath (610); the pressure regulating heater (120) and the first low-temperature cooling circuit (130) are used to adjust the temperature of the carbon dioxide storage tank (110).

6. The carbon dioxide porous media flow heat transfer experimental system according to claim 4, characterized in that: The injection pressurization assembly (200) further comprises a second low-temperature cooling circuit (240); One end of the second low-temperature cooling circuit (240) is connected to the injection constant-speed and constant-pressure pump (210), and the other end is connected to the low-temperature bath (610). The second low-temperature cooling circuit (240) is used to cool the injection constant-speed and constant-pressure pump (210).

7. The carbon dioxide porous media flow heat transfer experimental system according to any one of claims 1 to 6, characterized in that: Also includes a condenser (700) and a back pressure valve (800); The inlet of the condenser (700) is connected to the outlet of the clamp assembly (400), the outlet of the condenser (700) is connected to the inlet of the back pressure valve (800), and the outlet of the back pressure valve (800) is connected to the inlet of the injection pressurizing assembly (200).

8. The carbon dioxide porous media flow heat transfer experimental system according to any one of claims 2 to 6, characterized in that: The clamp assembly (400) comprises: A clamping component (410), connected to the outlet of the preheater (300), and used to fix the porous medium sample (900); A confining pressure tracking pump (420) connected to the clamping component (410), the confining pressure tracking pump (420) being used to provide confining pressure to the clamping component (410); A clamp heater (430), provided on the clamping component (410), and used for heating the fixed porous medium sample (900); The temperature and pressure monitoring component (440) is used to detect the temperature of the clamping component (410) and the carbon dioxide, and the pressure of the carbon dioxide.

9. The carbon dioxide porous media flow heat transfer experimental system according to claim 8, characterized in that: The clamping component (410) comprises a cylinder (411), a rubber sleeve (412) and two sealing components (413); the rubber sleeve (412) is arranged inside the cylinder (411), and the two sealing components (413) are respectively arranged at openings at both ends of the rubber sleeve (412); The rubber sleeve (412) and the cylinder (411) enclose a confined pressure space (414); the sealing component (413) is used to seal the openings of the confined pressure space (414) and the rubber sleeve (412); the rubber sleeve (412) is used to fix the porous medium sample (900); the outlet of the preheater (300) is connected to the rubber sleeve (412) through one of the two sealing components (413); the outlet of the confining pressure tracking pump (420) is connected to the confining pressure space (414); the clamp heater (430) is arranged on the outside of the cylinder (411); and the contact member of the temperature and pressure monitoring component (440) passes through the cylinder (411) and is arranged inside the rubber sleeve (412).

10. The carbon dioxide porous medium flow heat transfer experimental system according to claim 9, characterized in that: The sealing component (413) comprises a core plug (4131), a tapered sleeve (4132), a connecting sleeve (4133), a large pressure cap (4134) and a small pressure cap (4135); the core plug (4131) is arranged at the opening of the rubber sleeve (412); the core plug (4131) is used to fix the porous medium sample (900); The connecting sleeve (4133) abuts against one end of the core plug (4131) away from the rubber sleeve (412); the tapered sleeve (4132) is sleeved on the outer sides of the core plug (4131) and the connecting sleeve (4133) and abuts against the rubber sleeve (412); the small pressure cap (4135) abuts against one end of the connecting sleeve (4133) away from the core plug (4131); and the large pressure cap (4134) is sleeved on the outer sides of the connecting sleeve (4133) and the small pressure cap (4135).

11. A carbon dioxide porous medium flow heat transfer experimental method, characterized in that: include: Mounting the porous medium sample (900) to the holder assembly (400); Turn on the confining pressure tracking pump (420) and set the confining pressure; Opening the storage pressure regulating assembly (100), supplying carbon dioxide to the main pipeline, and setting a preset flow rate and a preset pressure of the carbon dioxide; The injection pressurizing assembly (200) is opened, the carbon dioxide is pressurized through the storage pressure regulating assembly (100) and / or the injection pressurizing assembly (200), and the opening of the back pressure valve (800) is adjusted until the flow rate and pressure of the carbon dioxide reach a preset flow rate and a preset pressure, respectively.

12. The carbon dioxide porous media flow heat transfer experimental method according to claim 11, characterized in that: The step of opening the injection pressurizing component (200) and pressurizing the carbon dioxide via the storage pressure regulating component (100) and / or the injection pressurizing component (200) comprises: In the case of low pressure demand, the three injection constant speed and constant pressure pumps (210) are on standby, and the pressure of the carbon dioxide is regulated by the storage pressure regulating assembly (100); In the case of medium to high pressure demand, a corresponding number of the injection constant speed and pressure pumps (210) are started according to the flow demand, and the pressure of the carbon dioxide is regulated by the storage pressure regulating component (100) and the injection constant speed and pressure pumps (210).

13. The carbon dioxide porous media flow heat transfer experimental method according to claim 12, characterized in that: In the case of medium and high pressure requirements, the step of starting a corresponding number of injection constant speed and constant pressure pumps (210) according to flow requirements comprises: In the case of medium or low flow demand, two of the three injection constant speed and constant pressure pumps (210) are operated, and the two injection constant speed and constant pressure pumps (210) are operated in turns; In the case of high flow demand, the three injection constant speed and constant pressure pumps (210) are operated, and the three injection constant speed and constant pressure pumps (210) are operated in turns.

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