Molten salt-carbon dioxide-water thermal hydraulic testing device and method

Abstract

The invention discloses a fused salt-carbon dioxide-water thermal hydraulic testing device and method, an outlet of a carbon dioxide storage tank is divided into two paths, one path is communicated with an inlet of a carbon dioxide compressor through a fourth flow regulating valve, and the other path is communicated with an outlet of a carbon dioxide compressor through a fourth flow regulating valve; the other path is communicated with an inlet of a carbon dioxide storage tank through a pressure regulating valve, a carbon dioxide heating temperature control module, a carbon dioxide side of the fused salt-carbon dioxide heat transfer test element and a carbon dioxide side of the carbon dioxide-water heat transfer test element; the outlet of the cooling tower is divided into three paths after passing through a water pump, the first path is communicated with the inlet of the water pump through a sixth flow regulating valve, the second path is communicated with the inlet of the cooling tower through the water side of the fused salt-water heat transfer test element, and the third path is communicated with the inlet of the cooling tower through the water side of the carbon dioxide-water heat transfer test element; the device and the method can be adapted to a pairwise coupling environment of three-phase media, cover multi-dimensional test parameters, and can also meet thermotechnical hydraulic test requirements with flexible working conditions.

Description

Technical Field

[0001] This invention belongs to the field of new energy thermal testing technology, and relates to a thermal hydraulic testing device and method for molten salt-carbon dioxide-water. Background Technology

[0002] Currently, emerging energy technologies such as molten salt energy storage, supercritical CO2 power generation, concentrated solar power (CSP), and hydrogen production and storage are developing rapidly. These technologies generally involve heat transfer processes between three-phase media: molten salt, CO2, and water. For example, the main heat exchanger in a CSP supercritical CO2 power generation system involves the heat transfer characteristics between molten salt and carbon dioxide, molten salt cooling requires consideration of the heat transfer characteristics between molten salt and water, and the cooling system of a supercritical CO2 heat exchanger needs to take into account the CO2-water heat transfer process.

[0003] Current technologies for multi-media thermal-hydraulic testing have significant limitations: Poor media compatibility: Existing testing devices are often only designed for a single medium and cannot simulate the real and complex working conditions when three media are coupled in pairs.

[0004] Incomplete test parameters: Existing methods mostly only measure basic parameters such as temperature and pressure, making it difficult to simultaneously obtain key thermal-hydraulic characteristics such as the flow resistance coefficient and heat transfer coefficient of the three-phase medium, resulting in insufficient data dimensions.

[0005] The simulated operating conditions are limited: the flow rate ratio, temperature gradient, and pressure level of the three components cannot be flexibly adjusted, making it difficult to reproduce the changing operating conditions in actual engineering projects.

[0006] Therefore, there is an urgent need to develop a thermal-hydraulic testing method and device that can adapt to the pairwise coupling environment of three-phase media, cover multi-dimensional test parameters, and be flexible in operating conditions. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a molten salt-carbon dioxide-water thermal hydraulic testing device and method. This device and method can adapt to the three-phase medium pairwise coupling environment, cover multi-dimensional test parameters, and meet the flexible thermal hydraulic testing needs.

[0008] To achieve the above objectives, the present invention discloses a thermal hydraulic testing device for molten salt-carbon dioxide-water, comprising a molten salt storage tank, a carbon dioxide storage tank, and a cooling tower. The molten salt storage tank is equipped with a main heat tracing device. The outlet of the molten salt storage tank is divided into three paths after passing through the molten salt pump. The first path is connected to the inlet of the molten salt pump via the first flow regulating valve. The second path is connected to the inlet of the molten salt storage tank via the third flow regulating valve, the second molten salt heating and temperature control module, and the molten salt side of the molten salt-carbon dioxide heat transfer test element. The third path is connected to the inlet of the molten salt storage tank via the second flow regulating valve, the first molten salt heating and temperature control module, and the molten salt side of the molten salt-water heat transfer test element. The outlet of the carbon dioxide storage tank is divided into two paths after passing through the carbon dioxide compressor and the fifth flow regulating valve. One path is connected to the inlet of the carbon dioxide compressor via the fourth flow regulating valve, and the other path is connected to the inlet of the carbon dioxide storage tank via the pressure regulating valve, the carbon dioxide heating and temperature control module, the carbon dioxide side of the molten salt-carbon dioxide heat transfer test element and the carbon dioxide side of the carbon dioxide-water heat transfer test element. The outlet of the cooling tower is divided into three paths after passing through the water pump. The first path is connected to the inlet of the water pump via the sixth flow regulating valve. The second path is connected to the inlet of the cooling tower via the water side of the molten salt-water heat transfer test element. The third path is connected to the inlet of the cooling tower via the seventh flow regulating valve and the water side of the carbon dioxide-water heat transfer test element.

[0009] Furthermore, the outlet of the molten salt storage tank is divided into three paths after passing through the molten salt pump. The first path is connected to the inlet of the molten salt pump via a first flow regulating valve. The second path is connected to the inlet of the molten salt storage tank via a third flow regulating valve, a second molten salt heating and temperature control module, a third molten salt stirrer, a third temperature sensor, a third pressure sensor, the molten salt side of the molten salt-carbon dioxide heat transfer test element, a fourth molten salt stirrer, a fourth temperature sensor, a fourth pressure sensor, and a second molten salt flow meter. The third path is connected to the inlet of the molten salt storage tank via a second flow regulating valve, a first molten salt heating and temperature control module, a first molten salt stirrer, a first temperature sensor, a second pressure sensor, the molten salt side of the molten salt-water heat transfer test element, a second molten salt stirrer, a second temperature sensor, a second pressure sensor, and a first molten salt flow meter.

[0010] Furthermore, the outlet of the carbon dioxide storage tank is divided into two paths after passing through the carbon dioxide compressor and the fifth flow regulating valve. One path is connected to the inlet of the carbon dioxide compressor via the fourth flow regulating valve, and the other path is connected to the inlet of the carbon dioxide storage tank via a carbon dioxide flow meter, a pressure regulating valve, a carbon dioxide heating and temperature control module, a fifth temperature sensor, a fifth pressure sensor, the carbon dioxide side of the molten salt-carbon dioxide heat transfer test element, a sixth temperature sensor, a sixth pressure sensor, the carbon dioxide side of the carbon dioxide-water heat transfer test element, a seventh pressure sensor, and a seventh temperature sensor.

[0011] Furthermore, the outlet of the cooling tower is divided into three paths after passing through the water pump. The first path is connected to the inlet of the water pump via the sixth flow regulating valve. The second path is connected to the inlet of the cooling tower via the first water flow meter, the eighth temperature sensor, the eighth pressure sensor, the water side of the molten salt-water heat transfer test element, the ninth temperature sensor, and the ninth pressure sensor. The third path is connected to the inlet of the cooling tower via the seventh flow regulating valve, the second water flow meter, the tenth temperature sensor, the tenth pressure sensor, the water side of the carbon dioxide-water heat transfer test element, the eleventh temperature sensor, and the eleventh pressure sensor.

[0012] This invention discloses a thermal hydraulic testing method for molten salt-carbon dioxide-water, comprising the following steps: Preheating preparation stage; Adjustment to the testing phase; Data processing stage.

[0013] Furthermore, in the data processing stage, the heat release Q of the working fluid on the high-temperature side of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element is calculated according to the law of conservation of energy. H Heat absorption Q of the working fluid on the low-temperature side L When the deviation between the two does not exceed 5%, the heat transfer Q of the test element is calculated. Calculate the overall heat transfer coefficient U of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element according to the heat transfer equation; The flow resistance coefficients f of the working fluids on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element are calculated based on the fluid internal flow resistance formula. H f L .

[0014] Furthermore, the heat release Q of the working fluid on the high-temperature side of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element are further analyzed. H Heat absorption Q of the working fluid on the low-temperature side L for: Q H = m H (H Hin -H Hout ) Q L = m L (H Lout -H Lin ) Where, m H m LThese are the mass flow rates of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element, respectively; H Hin H Hout These are the inlet and outlet enthalpies of the working fluid on the high-temperature side, respectively; H Lin H Lout These are the inlet and outlet enthalpies of the working fluid on the low-temperature side, respectively.

[0015] Furthermore, the heat transfer Q of the test element is: Q = 0.5(Q H +Q L ) Furthermore, the overall heat transfer coefficient U of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element is: U = Q / A / T LM Where A is the heat transfer area of ​​the heat transfer test element; T LM This represents the logarithmic heat transfer temperature difference of the heat transfer test element.

[0016] Furthermore, the flow resistance coefficient f of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element are further investigated. H f L :

[0017]

[0018] in, p H , p L These are the pressure differences between the inlet and outlet of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element, respectively; ρ H ρ L These represent the working fluid densities on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element, respectively. H u L These represent the high-temperature and low-temperature working fluid flow rates in the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element, respectively; D H D L These are the equivalent diameters of the high-temperature and low-temperature side channels in the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element, respectively; L H LL These refer to the lengths of the high-temperature and low-temperature side channels in the molten salt-water heat transfer test element, the molten salt-carbon dioxide heat transfer test element, and the carbon dioxide-water heat transfer test element, respectively.

[0019] The present invention has the following beneficial effects: In specific operation, the molten salt-carbon dioxide-water thermal hydraulic testing device and method of the present invention utilizes molten salt-water heat transfer testing elements, molten salt-carbon dioxide heat transfer testing elements, and carbon dioxide-water heat transfer testing elements to achieve coupling of molten salt, water, and carbon dioxide. This adapts to the two-to-two coupling environment of three-phase media, covers multi-dimensional test parameters, and provides flexible thermal hydraulic testing under various operating conditions. The structure is simple and highly practical.

[0020] Furthermore, it measures thermal-hydraulic parameters such as temperature, pressure, flow rate, heat transfer coefficient, and resistance coefficient, providing a more comprehensive basis for equipment optimization and system design. It supports precise parameter adjustment and dynamic operating condition simulation, and the operating condition matrix can be flexibly defined according to needs. Its application scope covers multiple fields such as molten salt energy storage, supercritical CO2 power generation, and nuclear energy. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a structural diagram of the present invention.

[0023] Among them, 1 is a molten salt storage tank, 2 is a molten salt pump, 3 is a main heat tracing device, 4 is a first molten salt heating and temperature control module, 5 is a first molten salt stirrer, 6 is a molten salt-water heat transfer testing element, 7 is a second molten salt stirrer, 8 is a first molten salt flow meter, 9 is a second molten salt heating and temperature control module, 10 is a third molten salt stirrer, 11 is a molten salt-carbon dioxide heat transfer testing element, 12 is a fourth molten salt stirrer, 13 is a second molten salt flow meter, 14 is a carbon dioxide storage tank, 15 is a carbon dioxide compressor, 16 is a carbon dioxide flow meter, 17 is a carbon dioxide heating and temperature control module, 18 is a carbon dioxide-water heat transfer testing element, 19 is a cooling tower, 20 is a water pump, 21 is a first water flow meter, 22 is a second water flow meter, 23a is a first flow regulating valve, 23b is a second flow regulating valve, 23c is a third flow regulating valve, 23d is a fourth flow regulating valve, 23e is a fifth flow regulating valve, and 23g is a sixth flow regulating valve. Flow control valve, 23h is the seventh flow control valve, 23f is the pressure control valve, 24a is the first temperature sensor, 24b is the second temperature sensor, 24c is the third temperature sensor, 24d is the fourth temperature sensor, 24e is the fifth temperature sensor, 24f is the sixth temperature sensor, 24g is the seventh temperature sensor, 24h is the eighth temperature sensor, 24i is the ninth temperature sensor, 24j is the tenth temperature sensor, 24k is the eleventh temperature sensor, 25a is the first pressure sensor, 25b is the second pressure sensor, 25c is the third pressure sensor, 25d is the fourth pressure sensor, 25e is the fifth pressure sensor, 25f is the sixth pressure sensor, 25g is the seventh pressure sensor, 25h is the eighth pressure sensor, 25i is the ninth pressure sensor, 25j is the tenth pressure sensor, 25k is the eleventh pressure sensor, and 26 is the pipe heat tracing device. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0028] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0029] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0031] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0032] refer to Figure 1 The thermal-hydraulic testing device for molten salt-carbon dioxide-water described in this invention includes a molten salt storage tank 1, a molten salt pump 2, a main heat tracing unit 3, a first molten salt heating and temperature control module 4, a first molten salt stirrer 5, a molten salt-water heat transfer testing element 6, a second molten salt stirrer 7, a first molten salt flow meter 8, a second molten salt heating and temperature control module 9, a third molten salt stirrer 10, a molten salt-carbon dioxide heat transfer testing element 11, a fourth molten salt stirrer 12, a second molten salt flow meter 13, a carbon dioxide storage tank 14, a carbon dioxide compressor 15, a carbon dioxide flow meter 16, a carbon dioxide heating and temperature control module 17, a carbon dioxide-water heat transfer testing element 18, a cooling tower 19, a water pump 20, a first water flow meter 21, a second water flow meter 22, a first flow regulating valve 23a, a second flow regulating valve 23b, a third flow regulating valve 23c, a fourth flow regulating valve 23d, and a fifth flow regulating valve. Valve 23e, sixth flow regulating valve 23g, seventh flow regulating valve 23h, pressure regulating valve 23f, first temperature sensor 24a, second temperature sensor 24b, third temperature sensor 24c, fourth temperature sensor 24d, fifth temperature sensor 24e, sixth temperature sensor 24f, seventh temperature sensor 24g, eighth temperature sensor 24h, ninth temperature sensor 24i, tenth temperature sensor 24j, eleventh temperature sensor 24k, first pressure sensor 25a, second pressure sensor 25b, third pressure sensor 25c, fourth pressure sensor 25d, fifth pressure sensor 25e, sixth pressure sensor 25f, seventh pressure sensor 25g, eighth pressure sensor 25h, ninth pressure sensor 25i, tenth pressure sensor 25j, eleventh pressure sensor 25k, and pipe heat tracing device 26; A main heat tracing device 3 is installed inside the molten salt storage tank 1. The outlet of the molten salt storage tank 1 is divided into three paths after passing through the molten salt pump 2. The first path is connected to the inlet of the molten salt pump 2 via the first flow regulating valve 23a. The second path is connected to the inlet of the molten salt storage tank 1 via the third flow regulating valve 23c, the second molten salt heating and temperature control module 9, the third molten salt stirrer 10, the third temperature sensor 24c, the third pressure sensor 25c, the molten salt side of the molten salt-carbon dioxide heat transfer test element 11, the fourth molten salt stirrer 12, the fourth temperature sensor 24d, the fourth pressure sensor 25d, and the second molten salt flow meter 13. The third path is connected to the inlet of the molten salt storage tank 1 via the second flow regulating valve 23b, the first molten salt heating and temperature control module 4, the first molten salt stirrer 5, the first temperature sensor 24a, the second pressure sensor 25b, the molten salt side of the molten salt-water heat transfer test element 6, the second molten salt stirrer 7, the second temperature sensor 24b, the second pressure sensor 25b, and the first molten salt flow meter 8.

[0033] The outlet of the carbon dioxide storage tank 14 is divided into two paths after passing through the carbon dioxide compressor 15 and the fifth flow regulating valve 23e. One path is connected to the inlet of the carbon dioxide compressor 15 via the fourth flow regulating valve 23d. The other path is connected to the inlet of the carbon dioxide storage tank 14 via the carbon dioxide flow meter 16, the pressure regulating valve 23f, the carbon dioxide heating and temperature control module 17, the fifth temperature sensor 24e, the fifth pressure sensor 25e, the carbon dioxide side of the molten salt-carbon dioxide heat transfer test element 11, the sixth temperature sensor 24f, the sixth pressure sensor 25f, the carbon dioxide side of the carbon dioxide-water heat transfer test element 18, the seventh pressure sensor 25g, and the seventh temperature sensor 24g.

[0034] The outlet of cooling tower 19 is divided into three paths after passing through water pump 20. The first path is connected to the inlet of water pump 20 via the sixth flow regulating valve 23g. The second path is connected to the inlet of cooling tower 19 via the first water flow meter 21, the eighth temperature sensor 24h, the eighth pressure sensor 25h, the water side of molten salt-water heat transfer test element 6, the ninth temperature sensor 24i, and the ninth pressure sensor 25i. The third path is connected to the inlet of cooling tower 19 via the seventh flow regulating valve 23h, the second water flow meter 22, the tenth temperature sensor 24j, the tenth pressure sensor 25j, the water side of carbon dioxide-water heat transfer test element 18, the eleventh temperature sensor 24k, and the eleventh pressure sensor 25k.

[0035] like Figure 1 As shown, the testing device includes a molten salt circuit, a carbon dioxide circuit, a water circuit, a heat transfer testing section, and a data acquisition and storage module.

[0036] Molten salt circuit: Composed of molten salt storage tank 1, molten salt pump 2, main heat tracing device 3, first molten salt heating and temperature control module 4, second molten salt heating and temperature control module 9, first molten salt stirrer 5, second molten salt stirrer 7, third molten salt stirrer 10, fourth molten salt stirrer 12, first molten salt flow meter 8, second molten salt flow meter 13, first flow regulating valve 23a, second flow regulating valve 23b, third flow regulating valve 23c, first temperature sensor 24a, second temperature sensor 24b, third temperature sensor 24c, fourth temperature sensor 24d, first pressure sensor 25a, second pressure sensor 25b, third pressure sensor 25c, fourth pressure sensor 25d, and pipeline heat tracing device 26. Molten salt pump 2 is used to overcome the resistance of the circulation loop and establish molten salt circulation; main heat tracing device 3 is used to preheat the molten salt and prevent the molten salt in molten salt storage tank 1 from cooling and condensing; first molten salt heating and temperature control module 4 and second molten salt heating and temperature control module 9 are used to adjust the molten salt inlet temperature to meet the requirements of heat transfer testing; first molten salt agitator 5, second molten salt agitator 7, third molten salt agitator 10 and fourth molten salt agitator 12 promote molten salt mixing through mechanical stirring, and are used to eliminate the molten salt temperature gradient so as to accurately measure the average temperature of the molten salt; first flow regulating valve 23a and second flow regulating valve 23a... The throttle valve 23b and the third flow regulating valve 23c work together to achieve precise control of the molten salt flow rate by adjusting the flow distribution of each branch; the first temperature sensor 24a, the second temperature sensor 24b, the third temperature sensor 24c, the fourth temperature sensor 24d, the first pressure sensor 25a, the second pressure sensor 25b, the third pressure sensor 25c, and the fourth pressure sensor 25d are used to measure the temperature and pressure changes of the molten salt at the inlet and outlet of the heat transfer test section; the pipe heat tracing device 26 is used to heat the molten salt in the pipe to prevent the molten salt in the molten salt circuit pipe from cooling and condensing.

[0037] The carbon dioxide circuit consists of a carbon dioxide storage tank 14, a carbon dioxide compressor 15, a carbon dioxide flow meter 16, a carbon dioxide heating and temperature control module 17, a fourth flow regulating valve 23d, a fifth flow regulating valve 23e, a pressure regulating valve 23f, a fifth temperature sensor 24e, a sixth temperature sensor 24f, a seventh temperature sensor 24g, a fifth pressure sensor 25e, a sixth pressure sensor 25f, and a seventh pressure sensor 25g. The carbon dioxide compressor 15 is used to pressurize and overcome the resistance of the circulation loop, establishing a carbon dioxide circulation. The carbon dioxide heating and temperature control module 17 directly heats the carbon dioxide, precisely controlling the carbon dioxide inlet temperature to meet the requirements of the heat transfer test. The fourth and fifth flow regulating valves 23d and 23e work together to achieve precise control of the carbon dioxide flow rate by adjusting the main and bypass flow distribution. The pressure regulating valve 23f is used to adjust the carbon dioxide inlet pressure to meet the requirements of the heat transfer test. The fifth, sixth, and seventh temperature sensors 24e, 24f, and 24g, and the fifth, sixth, and seventh pressure sensors 25e, 25f, and 25g are used to measure the temperature and pressure changes of the carbon dioxide at the inlet and outlet of the heat transfer test section.

[0038] The water circuit consists of a cooling tower 19, a water pump 20, a first water flow meter 21, a second water flow meter 22, a sixth flow regulating valve 23g, a seventh flow regulating valve 23h, an eighth temperature sensor 24h, a ninth temperature sensor 24i, a tenth temperature sensor 24j, an eleventh temperature sensor 24k, an eighth pressure sensor 25h, a ninth pressure sensor 25i, a tenth pressure sensor 25j, and an eleventh pressure sensor 25k. The cooling tower 19 is used for water storage and heat dissipation; the water pump 20 is used to overcome the resistance of the circulation loop and establish water circulation; the sixth and seventh flow regulating valves 23g and 23h work together to achieve precise control of water flow by adjusting the flow distribution of each branch; the eighth, ninth, tenth, and eleventh temperature sensors 24h, 24i, 24j, and 24k are used to measure the temperature and pressure changes of the water at the inlet and outlet of the heat transfer test section.

[0039] The heat transfer test section is the core component, including molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18. All three elements adopt a partitioned heat exchange form. Different heat exchanger types can be selected according to the medium characteristics and test purpose, such as shell and tube type, plate and fin type, sleeve type, plate type, microchannel type, and composite type.

[0040] Data acquisition and storage module: The data acquisition system connects the temperature measuring points, pressure measuring points, and flow meters in the loop, as well as the temperature control system in the heating and temperature control module. It collects data such as temperature, pressure, flow rate, and heating power in real time during the test. The sampling frequency can be set according to requirements (e.g., 1 time / second). The collected data is transmitted to the data storage unit for subsequent flow and heat transfer coefficient calculation and analysis.

[0041] refer to Figure 1 The thermal hydraulic testing method for molten salt-carbon dioxide-water described in this invention includes the following steps: 1) Preheating preparation stage: Start the main heat tracing device 3 and the pipeline heat tracing device 26 to heat the molten salt and the molten salt circuit pipeline. After the molten salt in the molten salt storage tank 1 is completely melted, start the molten salt pump 2 to establish the molten salt circulation; start the carbon dioxide compressor 15 to establish the carbon dioxide circulation; start the water pump 20 to establish the water circulation.

[0042] 2) Adjustment Test Stage: By adjusting the opening of the first flow regulating valve 23a, the second flow regulating valve 23b, and the third flow regulating valve 23c, the molten salt flow rate through the molten salt-water heat transfer test element 6 and the molten salt-carbon dioxide heat transfer test element 11 are adjusted to the test target values ​​respectively; the heating power is adjusted by the temperature controllers of the first molten salt heating temperature control module 4 and the second molten salt heating temperature control module 9, so that the molten salt inlet temperature of the molten salt-water heat transfer test element 6 and the molten salt-carbon dioxide heat transfer test element 11 reaches the test target value respectively; by adjusting the opening of the fourth flow regulating valve 23d and the fifth flow regulating valve 23e, the carbon dioxide flow rate through the molten salt-carbon dioxide heat transfer test element 11 and the carbon dioxide-water heat transfer test element 18 is adjusted to the test target value; the pressure regulating valve 23f is adjusted to adjust the flow rate of the molten salt-carbon dioxide heat transfer test element 11... The carbon dioxide inlet pressure is controlled at the target pressure; the heating power is adjusted by the temperature controller of the carbon dioxide heating and temperature control module 17, and the carbon dioxide inlet temperature of the molten salt-carbon dioxide heat transfer test element 11 reaches the target value; by adjusting the opening of the sixth flow regulating valve 23g and the seventh flow regulating valve 23h, the water flow rates through the molten salt-water heat transfer test element 6 and the carbon dioxide-water heat transfer test element 18 are adjusted to the test target values ​​respectively; the data acquisition system continuously monitors the flow rate, temperature, and pressure data of molten salt, carbon dioxide, and water at the inlet and outlet of the molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18, as well as the heating power data of the heating module. After all parameters stabilize (e.g., 5-10 minutes), data is recorded and saved to complete a steady-state measurement cycle (e.g., 5-30 minutes). After one operating condition measurement is completed, the flow rate, pressure, temperature, and other parameters are adjusted, and the above steps are repeated to perform variable operating condition tests.

[0043] 3) Data processing stage: Calculate the heat release Q of the working fluid on the high-temperature side of molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 according to the law of conservation of energy. H Heat absorption Q of the working fluid on the low-temperature side L When the deviation between the two does not exceed 5%, calculate the heat transfer Q of the test element: Q = 0.5(Q H +Q L ) Q H = m H (H Hin -H Hout ) Q L = m L (H Lout -H Lin ) Where, m H m L The mass flow rates of the working fluids on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 are measured by the first molten salt flow meter 8, the second molten salt flow meter 13, the carbon dioxide flow meter 16, the first water flow meter 21, and the second water flow meter 22, respectively; H Hin H Hout These are the inlet and outlet enthalpies of the working fluid on the high-temperature side, H. Lin H Lout These are the inlet and outlet enthalpy values ​​of the working fluid on the low-temperature side, respectively. The enthalpy values ​​are obtained from the physical property parameter tables of molten salt, carbon dioxide, and water based on the measured temperature and pressure.

[0044] The overall heat transfer coefficient U of molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 is calculated based on the heat transfer equation. U = Q / A / T LM Where A is the heat transfer area of ​​the heat transfer test element; T LM This represents the logarithmic heat transfer temperature difference of the heat transfer test element.

[0045] The flow resistance coefficients f of the working fluids on the high-temperature and low-temperature sides of molten salt-water heat transfer test elements 6, molten salt-carbon dioxide heat transfer test elements 11, and carbon dioxide-water heat transfer test elements 18 are calculated based on the fluid internal flow resistance formula. H f L :

[0046]

[0047] in, p H , p L The pressure differences between the inlet and outlet of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 are respectively obtained by subtracting the inlet and outlet pressure values; ρ H ρ L The working fluid densities on the high-temperature and low-temperature sides of molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 are respectively obtained from the medium property parameter table based on temperature and pressure; u H u L The flow rates of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 are respectively obtained by dividing the mass flow rate by the density and then by the flow cross-sectional area; D H D L These are the equivalent diameters of the high-temperature and low-temperature side channels in molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18, respectively; L H L L The lengths of the high-temperature and low-temperature side channels in molten salt-water heat transfer test element 6, molten salt-carbon dioxide heat transfer test element 11, and carbon dioxide-water heat transfer test element 18 are respectively.

[0048] Example 1 Molten salt flows through the shell side, while carbon dioxide flows through the tube side. The molten salt releases heat, while the carbon dioxide absorbs heat. The molten salt is a mixed salt of lithium fluoride, sodium fluoride, and potassium fluoride, with an inlet temperature of 700℃ and a flow rate of 1.2 kg / s. The carbon dioxide is in a supercritical state, with an inlet temperature of 50℃, an inlet pressure of 25 MPa, and a flow rate of 0.6 kg / s.

[0049] Start the main heat tracing unit 3 of the molten salt storage tank 1 to heat the molten salt from room temperature to 500℃ and hold it at that temperature for 20 minutes (ensuring the molten salt is completely melted and the temperature is uniform). Start the molten salt pump 2 to fill the molten salt pipeline and ensure a stable flow. Adjust the opening of the first flow regulating valve 23a, the second flow regulating valve 23b, and the third flow regulating valve 23c to stabilize the molten salt-carbon dioxide heat transfer test element 11 at a flow rate of 1.2 kg / s. Start the carbon dioxide compressor 15 and adjust the opening of the fourth flow regulating valve 23d and the fifth flow regulating valve 23e to stabilize the carbon dioxide-carbon dioxide heat transfer test element 11 at a flow rate of 0.6 kg / s. Adjust the second molten salt heating and temperature control module 9 to stabilize the molten salt inlet temperature of the molten salt-carbon dioxide heat transfer test element 11 at 700℃; adjust the carbon dioxide heating and temperature control module 17 to stabilize the carbon dioxide inlet temperature of the molten salt-carbon dioxide heat transfer test element 11 at 50℃; use the pressure regulating valve 23f to adjust the carbon dioxide inlet pressure of the molten salt-carbon dioxide heat transfer test element 11 to 25MPa; after all parameters (temperature, pressure, flow rate) have stabilized for 10 minutes, start recording and storing data, with a data acquisition cycle of 10 minutes and an acquisition frequency of 1Hz.

[0050] The molten salt inlet temperature is 700℃, the outlet temperature is 580℃, and the heat release is 288kW (molten salt specific heat capacity 2kJ / kg / K); the CO2 inlet temperature is 50℃, the outlet temperature is 350℃, and the heat absorption is 293kW. The energy conservation error is 1.7% (meets the test accuracy requirements); the calculated overall heat transfer coefficient of molten salt-carbon dioxide in the shell-and-tube heat transfer test element 11 is 650W / (m²). K); The pressure loss on the molten salt side is 800 Pa, and the pressure loss on the CO2 side is 4 kPa.

[0051] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0052] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0053] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A thermo-hydraulic testing device for molten salt-carbon dioxide-water, characterized in that, Includes molten salt storage tank (1), carbon dioxide storage tank (14) and cooling tower (19); The molten salt storage tank (1) is equipped with a main heat tracing device (3). The outlet of the molten salt storage tank (1) is divided into three paths after passing through the molten salt pump (2). The first path is connected to the inlet of the molten salt pump (2) via the first flow regulating valve (23a). The second path is connected to the inlet of the molten salt storage tank (1) via the third flow regulating valve (23c), the second molten salt heating and temperature control module (9), and the molten salt-carbon dioxide heat transfer test element (11). The third path is connected to the inlet of the molten salt storage tank (1) via the second flow regulating valve (23b), the first molten salt heating and temperature control module (4), and the molten salt-water heat transfer test element (6). The outlet of the carbon dioxide storage tank (14) is divided into two paths after passing through the carbon dioxide compressor (15) and the fifth flow regulating valve (23e). One path is connected to the inlet of the carbon dioxide compressor (15) through the fourth flow regulating valve (23d), and the other path is connected to the inlet of the carbon dioxide storage tank (14) through the pressure regulating valve (23f), the carbon dioxide heating and temperature control module (17), the carbon dioxide side of the molten salt-carbon dioxide heat transfer test element (11) and the carbon dioxide side of the carbon dioxide-water heat transfer test element (18). The outlet of the cooling tower (19) is divided into three paths after passing through the water pump (20). The first path is connected to the inlet of the water pump (20) via the sixth flow regulating valve (23g). The second path is connected to the inlet of the cooling tower (19) via the water side of the molten salt-water heat transfer test element (6). The third path is connected to the inlet of the cooling tower (19) via the water side of the seventh flow regulating valve (23h) and the carbon dioxide-water heat transfer test element (18).

2. The molten salt-carbon dioxide-water thermo-hydraulic testing device according to claim 1, characterized in that, The outlet of the molten salt storage tank (1) is divided into three paths after passing through the molten salt pump (2). The first path is connected to the inlet of the molten salt pump (2) via the first flow regulating valve (23a). The second path passes through the third flow regulating valve (23c), the second molten salt heating and temperature control module (9), the third molten salt stirrer (10), the third temperature sensor (24c), the third pressure sensor (25c), the molten salt side of the molten salt-carbon dioxide heat transfer test element (11), the fourth molten salt stirrer (12), the fourth temperature sensor (24d), and the fourth pressure sensor. (25d) The second molten salt flow meter (13) is connected to the inlet of the molten salt storage tank (1). The third path is connected to the inlet of the molten salt storage tank (1) via the second flow regulating valve (23b), the first molten salt heating and temperature control module (4), the first molten salt stirrer (5), the first temperature sensor (24a), the second pressure sensor (25b), the molten salt-water heat transfer test element (6), the second molten salt stirrer (7), the second temperature sensor (24b), the second pressure sensor (25b), and the first molten salt flow meter (8).

3. The molten salt-carbon dioxide-water thermo-hydraulic testing device according to claim 2, characterized in that, The outlet of the carbon dioxide storage tank (14) is divided into two paths after passing through the carbon dioxide compressor (15) and the fifth flow regulating valve (23e). One path is connected to the inlet of the carbon dioxide compressor (15) via the fourth flow regulating valve (23d). The other path is connected to the inlet of the carbon dioxide storage tank (14) via the carbon dioxide flow meter (16), the pressure regulating valve (23f), the carbon dioxide heating and temperature control module (17), the fifth temperature sensor (24e), the fifth pressure sensor (25e), the carbon dioxide side of the molten salt-carbon dioxide heat transfer test element (11), the sixth temperature sensor (24f), the sixth pressure sensor (25f), the carbon dioxide side of the carbon dioxide-water heat transfer test element (18), the seventh pressure sensor (25g), and the seventh temperature sensor (24g).

4. The molten salt-carbon dioxide-water thermo-hydraulic testing device according to claim 3, characterized in that, The outlet of the cooling tower (19) is divided into three paths after passing through the water pump (20). The first path is connected to the inlet of the water pump (20) via the sixth flow regulating valve (23g). The second path is connected to the inlet of the cooling tower (19) via the first water flow meter (21), the eighth temperature sensor (24h), the eighth pressure sensor (25h), the water side of the molten salt-water heat transfer test element (6), the ninth temperature sensor (24i), and the ninth pressure sensor (25i). The third path is connected to the inlet of the cooling tower (19) via the seventh flow regulating valve (23h), the second water flow meter (22), the tenth temperature sensor (24j), the tenth pressure sensor (25j), the water side of the carbon dioxide-water heat transfer test element (18), the eleventh temperature sensor (24k), and the eleventh pressure sensor (25k).

5. A thermo-hydraulic testing method for molten salt-carbon dioxide-water, characterized in that, The thermal-hydraulic testing apparatus based on the molten salt-carbon dioxide-water according to claim 4 includes the following steps: Preheating preparation stage; Adjustment to the testing phase; Data processing stage.

6. The thermal hydraulic testing method for molten salt-carbon dioxide-water according to claim 5, characterized in that, During the data processing stage, the heat release Q of the working fluid on the high-temperature side of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18) was calculated according to the law of conservation of energy. H Heat absorption Q of the working fluid on the low-temperature side L When the deviation between the two does not exceed 5%, the heat transfer Q of the test element is calculated. The total heat transfer coefficient U of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18) is calculated according to the heat transfer equation. The flow resistance coefficients f of the working fluids on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element (6), molten salt-carbon dioxide heat transfer test element (11), and carbon dioxide-water heat transfer test element (18) are calculated based on the fluid internal flow resistance formula. H f L .

7. The thermal hydraulic testing method for molten salt-carbon dioxide-water according to claim 5, characterized in that, The heat release Q of the working fluid on the high-temperature side of the molten salt-water heat transfer test element (6), molten salt-carbon dioxide heat transfer test element (11), and carbon dioxide-water heat transfer test element (18) H Heat absorption Q of the working fluid on the low-temperature side L for: Q H = m H (H Hin -H Hout ) Q L = m L (H Lout -H Lin ) Where, m H m L The mass flow rates of the working fluids on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18) are respectively; H Hin H Hout These are the inlet and outlet enthalpies of the working fluid on the high-temperature side, respectively; H Lin H Lout These are the inlet and outlet enthalpies of the working fluid on the low-temperature side, respectively.

8. The thermal hydraulic testing method for molten salt-carbon dioxide-water according to claim 7, characterized in that, The heat transfer Q of the test element is: Q = 0.5(Q H +Q L )。 9. The thermal hydraulic testing method for molten salt-carbon dioxide-water according to claim 5, characterized in that, The overall heat transfer coefficient U of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18) is: U = Q / A / T LM Where A is the heat transfer area of ​​the heat transfer test element; T LM This represents the logarithmic heat transfer temperature difference of the heat transfer test element.

10. The thermal hydraulic testing method for molten salt-carbon dioxide-water according to claim 5, characterized in that, The flow resistance coefficient f of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element (6), molten salt-carbon dioxide heat transfer test element (11), and carbon dioxide-water heat transfer test element (18) H f L : in, p H , p L The pressure difference between the inlet and outlet of the working fluid on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18) are respectively; ρ H ρ L The working fluid densities on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18), respectively; u H u L The working fluid flow rates on the high-temperature and low-temperature sides of the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18), respectively; D H D L The equivalent diameters of the high-temperature and low-temperature side channels in the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18), respectively; L H L L The lengths of the high-temperature and low-temperature side channels in the molten salt-water heat transfer test element (6), the molten salt-carbon dioxide heat transfer test element (11), and the carbon dioxide-water heat transfer test element (18) are respectively.

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