Rapid detection method for heat insulation performance of liquid hydrogen container

Abstract

The invention relates to the technical field of liquid hydrogen storage and transportation, and discloses a liquid hydrogen container heat insulation performance rapid detection method, which comprises: S1, measuring the specification of a liquid hydrogen container and the initial state parameter in the liquid hydrogen container; s2, calculating initial parameters of liquid hydrogen and hydrogen in the liquid hydrogen container; s3, the change rate of the state parameters in the liquid hydrogen container is measured, and the final state parameters in the liquid hydrogen container are monitored; s4, calculating final parameters of liquid hydrogen and hydrogen in the liquid hydrogen container; s5, calculating the evaporation mass flow rate of the gas-liquid interface of the liquid hydrogen container according to the change rate of the state parameters in the liquid hydrogen container; s6, the thermodynamic energy change rate of hydrogen and liquid hydrogen in the liquid hydrogen container is calculated; s7, calculating the total internal energy change of the liquid hydrogen container, and calculating the total heat transfer amount of the gas phase and the liquid phase of the liquid hydrogen container; and S8, comparing the total heat transfer amount of the gas phase and the liquid phase of the liquid hydrogen container with standard static evaporation rate data to obtain the heat insulation performance of the liquid hydrogen container. The detection method has the characteristics that hydrogen does not need to be discharged, and the detection precision and safety are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid hydrogen storage and transportation, and particularly to a method for rapidly detecting the adiabatic performance of a liquid hydrogen container. Background Art

[0002] With the gradual transformation of the global energy structure, hydrogen is considered an important part of future clean energy. Liquid hydrogen has a relatively high mass energy density, which enables it to store more energy and occupy less space when used as a reserve energy source. The storage temperature of liquid hydrogen is extremely low (-253 °C) and its latent heat of vaporization is small. It is necessary to carry out strict heat insulation treatment under ultra-high vacuum conditions to prevent the pressure of the liquid hydrogen container from rising due to evaporation loss. Therefore, in the design and use of liquid hydrogen containers, ensuring the adiabatic performance of the containers is crucial.

[0003] The adiabatic performance test of a liquid hydrogen container is a key link to ensure its safety and efficiency. The static evaporation rate is the most intuitive and important technical index parameter for evaluating the adiabatic performance of a liquid hydrogen container. The static evaporation rate of the liquid hydrogen container is calculated by the evaporation flow rate of hydrogen after stabilization. For liquid hydrogen media, this adiabatic performance test method has obvious defects. A large amount of hydrogen needs to be discharged during the test, resulting in certain resource waste and possibly a series of safety hazards. On the other hand, the standard GB / T18443.5-2010 (Performance Test Methods for Vacuum Insulated Cryogenic Equipment: Measurement of Static Evaporation Rate) strictly stipulates that the static evaporation rate test is not applicable to liquid hydrogen media. Currently, the evaporation rate test of most liquid hydrogen containers still relies on liquid nitrogen media. However, due to the physical property differences between liquid nitrogen and liquid hydrogen, especially the significant differences in the latent heat of evaporation of liquid nitrogen and the heat exchange characteristics between liquid nitrogen and the container wall and liquid hydrogen, there are large errors in calculating the actual adiabatic performance of liquid hydrogen containers through liquid nitrogen media. Therefore, the above problems make the adiabatic performance test of liquid hydrogen containers complex and challenging.

[0004] In summary, based on the problems existing in the existing adiabatic performance test methods for liquid hydrogen containers, there is an urgent need for a new, more efficient and safe method for detecting the adiabatic performance of liquid hydrogen containers. Summary of the Invention

[0005] In view of the above deficiencies in the prior art, the present invention provides a method for rapidly detecting the adiabatic performance of a liquid hydrogen container to solve the problems of long detection cycle, high hydrogen waste, poor measurement accuracy and large safety hazards in the existing adiabatic performance detection of liquid hydrogen containers.

[0006] To achieve the above invention object, the technical solution adopted by the present invention is: a method for rapidly detecting the adiabatic performance of a liquid hydrogen container, comprising the following steps:

[0007] S1, measuring the specifications of the liquid hydrogen container and the initial state parameters inside the liquid hydrogen container;

[0008] S2. Calculate the initial parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container;

[0009] S3. Measure the change rate of the state parameters in the liquid hydrogen container and monitor the final state parameters in the liquid hydrogen container;

[0010] S4. Calculate the final parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container based on the final state parameters;

[0011] S5. Calculate the evaporation mass flow rate of the liquid-vapor interface in the liquid hydrogen container according to the change rate of the state parameters in the liquid hydrogen container;

[0012] S6. Calculate the change rate of the thermodynamic energy of the hydrogen gas and liquid hydrogen in the liquid hydrogen container based on the change rate of the state parameters in the liquid hydrogen container, the final state parameters in the liquid hydrogen container, and the evaporation mass flow rate of the interface;

[0013] S7. Calculate the total internal energy change of the liquid hydrogen container based on the initial state parameters, final state parameters, initial parameters, and final parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container. Calculate the total heat transfer of the gas phase and liquid phase of the liquid hydrogen container based on the evaporation mass flow rate of the interface and the change rate of the thermodynamic energy of the hydrogen gas and liquid hydrogen;

[0014] S8. Compare the total heat transfer of the gas phase and liquid phase of the liquid hydrogen container with the standard static evaporation rate data to obtain the adiabatic performance of the liquid hydrogen container.

[0015] Furthermore, for the above rapid detection method of the adiabatic performance of the liquid hydrogen container, in S1, the specifications of the liquid hydrogen container include the geometric volume V g , the effective volume V e , and the structural dimensions; the initial state parameters include the pressure P1 of the liquid hydrogen container, the liquid level height h1, the temperature T L1 of the liquid hydrogen, and the temperature T V1 of the hydrogen gas.

[0016] Furthermore, for the above rapid detection method of the adiabatic performance of the liquid hydrogen container, in S2, the initial parameters of the liquid hydrogen include the liquid hydrogen volume V L1 , the liquid hydrogen density ρ V1 , the liquid hydrogen mass m L1 ; the initial parameters of the hydrogen gas include the hydrogen gas volume V g1 , the hydrogen gas density ρ g1 , and the hydrogen gas mass m g1 .

[0017] Furthermore, for the above rapid detection method of the adiabatic performance of the liquid hydrogen container, in S3, the change rate of the state parameters in the liquid hydrogen container includes the pressure change rate dP / dt, the hydrogen gas temperature change rate dT g / dt, and the liquid hydrogen temperature change rate dT L / dt; the pressure change rate is obtained by dividing the change in pressure over at least 12 hours by the time; the hydrogen temperature change rate is obtained by dividing the change in hydrogen temperature over at least 12 hours by the time; the liquid hydrogen temperature change rate is obtained by dividing the change in liquid hydrogen temperature over at least 12 hours by the time.

[0018] Furthermore, in the above rapid detection method for the heat insulation performance of the liquid hydrogen container, the final state parameters in S4 include the pressure P2, liquid level height h2, and temperature T of the liquid hydrogen at the end, L2 and the temperature T of the hydrogen. V2 The final parameters of the liquid hydrogen include the liquid hydrogen volume V L2 and the liquid hydrogen mass m. L2 The final parameters of the hydrogen include the hydrogen volume V g2 and the hydrogen mass m. g2 .

[0019] Furthermore, in the above rapid detection method for the heat insulation performance of the liquid hydrogen container, the evaporation mass flow rate of the gas-liquid interface of the liquid hydrogen container in S5 is dm / dt, where where Q Lb , Q Vb are the interface heat transfer amounts from the liquid hydrogen to the hydrogen and from the hydrogen to the liquid hydrogen respectively, and γ(T s ) is the latent heat of vaporization at the temperature of T s .

[0020] Furthermore, in the above rapid detection method for the heat insulation performance of the liquid hydrogen container, the change rate of the internal energy of the hydrogen in S6 the change rate of the internal energy of the liquid hydrogen where Q V , Q L are the heat transfer amounts of the gas phase and liquid phase of the liquid hydrogen container respectively, and h V (T s ), h L (T s ) are the enthalpy values of the hydrogen and liquid hydrogen at the temperature of T s respectively.

[0021] Furthermore, in the above rapid detection method for the heat insulation performance of the liquid hydrogen container, the total internal energy change in S7 is dU. According to the law of conservation of energy, dU = dU L + dU V . Combining with the change laws of the internal energy in steps 6 and 7, the heat transfer amounts Q V , Q L of the gas phase and liquid phase of the liquid hydrogen container are calculated; the total heat transfer amount Q of the gas phase and liquid phase of the liquid hydrogen container = Q V + Q L .

[0022] Furthermore, in the above method for rapidly detecting the adiabatic performance of a liquid hydrogen container, the initial state parameters inside the liquid hydrogen container, the final state parameters inside the liquid hydrogen container, the initial parameters of liquid hydrogen and hydrogen gas, and the final parameters of liquid hydrogen and hydrogen gas are all measured by a rapid adiabatic performance detection system for the liquid hydrogen container; the rapid adiabatic performance detection system for the liquid hydrogen container includes a liquid hydrogen container and a liquid level gauge, a pressure sensor, a temperature sensor, a safety valve, and a measurement and control system arranged inside the liquid hydrogen container. The liquid level gauge is placed in the liquid hydrogen container and monitors the liquid level of liquid hydrogen in real time. The pressure sensor monitors the pressure change inside the liquid hydrogen container. The temperature sensor monitors the temperature changes of liquid hydrogen and hydrogen gas. The safety valve prevents the liquid hydrogen container from overpressurizing.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) The method for rapidly detecting the adiabatic performance of the liquid hydrogen container of the present invention does not need to measure the evaporation flow rate of hydrogen gas, only measures the pressure and temperature changes of the liquid hydrogen container, avoids the measurement deviation of the evaporation rate caused by environmental temperature, zero drift of the flow meter, calibration working conditions, and measurement errors, and at the same time prevents hydrogen gas emission waste and potential safety hazards.

[0025] (2) The test medium of the liquid hydrogen container of the present invention is liquid hydrogen and does not rely on liquid nitrogen medium. This method can eliminate the errors caused by the difference in the physical properties of the medium and has higher accuracy and repeatability.

[0026] (3) The detection method of the present invention is not only applicable to the factory inspection of liquid hydrogen containers, but also can be widely applied to the daily maintenance and safety inspection of liquid hydrogen containers. Users can judge whether there are problems such as adiabatic performance attenuation or vacuum failure of the container by regularly or real-time monitoring the pressure rise rate inside the liquid hydrogen container, and then take corresponding measures to ensure the safety and reliability of the use of the liquid hydrogen container.

[0027] (4) The method for rapidly detecting the adiabatic performance of the liquid hydrogen container of the present invention has the advantages of simplicity, rapidity, and low cost. It can significantly improve the efficiency and accuracy of the adiabatic performance detection of the liquid hydrogen container, and can also provide a scientific basis for the maintenance and management of the liquid hydrogen container. This technology is expected to become the standard method for liquid hydrogen container detection and provide strong support for the safe use and popularization of liquid hydrogen. Description of the Drawings

[0028] Figure 1 It is a flowchart of a specific embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of a specific embodiment of the present invention;

[0030] Figure 3 It is a reference diagram of the actual physical property parameters of the liquid hydrogen medium in a specific embodiment of the present invention;

[0031] Figure 4Data comparison chart of the evaporation rate of the liquid hydrogen container in the specific embodiment of the present invention;

[0032] Figure 5 Actual change diagram of the state parameters inside the liquid hydrogen container in Specific Embodiment 1 of the present invention;

[0033] Figure 6 Actual change diagram of the state parameters inside the liquid hydrogen container in Specific Embodiment 2 of the present invention. Specific Embodiments

[0034] The following describes the specific embodiments of the present invention to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0035] Embodiment 1

[0036] As Figure 1 shown, this embodiment provides a method for quickly detecting the heat insulation performance of a liquid hydrogen container. First, identify the specifications of the liquid hydrogen cylinder, mainly record the geometric volume, effective volume, and structural dimensions of the container, etc., to provide basic parameters for the quick detection of the heat insulation performance of the liquid hydrogen container. Secondly, identify the initial state parameters inside the liquid hydrogen container, and calculate parameters such as the liquid hydrogen volume, hydrogen volume, liquid hydrogen density, hydrogen density, liquid hydrogen mass, and hydrogen mass inside the initial liquid hydrogen container. Then measure the pressure rise rate and temperature change rate inside the liquid hydrogen container for a period of time, and at the same time record the state parameters such as the pressure, liquid level height, and temperatures of the liquid hydrogen and hydrogen in the liquid hydrogen container at the end of the pressure rise. According to the law of conservation of mass, calculate the liquid hydrogen volume, hydrogen volume, liquid hydrogen mass, hydrogen mass, etc. inside the liquid hydrogen container at the end.

[0037] The principle of the method for quickly detecting the heat insulation performance of the liquid hydrogen container of the present invention can be referred to Figure 2 , a liquid level gauge, a pressure sensor, and a temperature sensor are arranged inside the liquid hydrogen container. The liquid level gauge is placed in the liquid hydrogen container and monitors the liquid level of the liquid hydrogen in real time. The pressure sensor monitors the pressure change inside the liquid hydrogen container, and the temperature sensor monitors the temperature changes of the liquid hydrogen and hydrogen. According to the monitored pressure rise rate and temperature change rate, and referring to Figure 3 the variation laws of temperature, density, specific heat, and latent heat of vaporization with pressure in the actual physical properties of hydrogen, calculate the mass transfer rate dm / dt at the gas-liquid interface of the liquid hydrogen container. Calculate the change rate of the thermodynamic energy of hydrogen and liquid hydrogen inside the container according to the law of conservation of energy dU = dU L + dU V , where Q V, Q L are the heat transfer of gas phase and liquid phase of liquid hydrogen container, h V (T s ),h L (T s ) are T s The enthalpy of hydrogen gas and liquid hydrogen at the temperature. Combining the above equations, the total heat leakage of the gas phase and liquid phase of the liquid hydrogen container can be calculated as Q = Q V +Q L . You can refer to Figure 4 By comparing the evaporation rate data of the liquid hydrogen container, the thermal insulation performance of the liquid hydrogen container can be directly obtained.

[0038] refer to Figure 5 In this embodiment, the geometric volume of the liquid hydrogen container is 1m 3 , the initial liquid level height is 546mm, the pressure is 0.2MPa, and the gas phase and liquid phase temperatures are 24.2K and 23K respectively. Close all the discharge valves of the liquid hydrogen container, measure the pressure change, temperature change and liquid level change of the liquid hydrogen container for 20h, and at the end, the liquid level of the liquid hydrogen container is 601mm, the pressure is 0.6MPa, and the gas phase and liquid phase temperatures are 28.3K and 29.1K respectively.

[0039] Due to the increase in liquid hydrogen saturation pressure and temperature, the density of liquid hydrogen decreases, causing the liquid level to rise by 55mm. According to the formula The heat transfer of liquid hydrogen gas phase and liquid phase is calculated to be 3.2W and 8.1W respectively, which can be referred to Figure 4 Comparison of evaporation rate data shows that the evaporation rate of the liquid hydrogen container is 4.3% / d.

[0040] Example 2

[0041] refer to Figure 6 , the geometric volume of the liquid hydrogen container is 1m 3 , the initial liquid level height is 232mm, the pressure is 0.1MPa, and the gas phase and liquid phase temperatures are 20.5K and 22.2K respectively. Close all the discharge valves of the liquid hydrogen container, measure the pressure change, temperature change, and liquid level change of the liquid hydrogen container for 32 hours, and at the end, the liquid level of the liquid hydrogen container is 193mm, the pressure is 0.6MPa, and the gas phase and liquid phase temperatures are 31.9K and 28.6K respectively. Due to the small amount of liquid hydrogen initially filled, the gas phase space is large, and the evaporation of liquid hydrogen causes the liquid level to drop by 39mm. According to the formula The heat transfer of liquid hydrogen gas phase and liquid phase is calculated to be 1.5W and 1.9W respectively, so we can refer to Figure 4 Comparison of evaporation rate data shows that the evaporation rate of the liquid hydrogen container is 4.2% / d.

[0042] For the above two embodiments, for two different initial states of the same liquid hydrogen cylinder, according to a rapid detection method for the adiabatic performance of a liquid hydrogen container provided by the present invention, the evaporation rate error of the liquid hydrogen container is calculated to be 2.3%. The results show that the detection method provided by the present invention has high accuracy and is not limited by the initial state of the liquid hydrogen container. This technology is expected to become a standard method for the detection of liquid hydrogen containers, providing strong support for the safe use and popularization of liquid hydrogen.

[0043] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

[0044] It should be noted that in this article, terms such as "including", "comprising", or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such a process or method.

Claims

1. A method for rapid detection of thermal insulation performance of a liquid hydrogen container, characterized in that: The following steps are involved: S1, measuring the specifications of the liquid hydrogen container and the initial state parameters in the liquid hydrogen container; S2, calculate the initial parameters of liquid hydrogen and hydrogen gas in the liquid hydrogen container; S3, measuring the rate of change of state parameters in the liquid hydrogen container, and monitoring the final state parameters in the liquid hydrogen container; S4, calculating the final parameters of the liquid hydrogen and hydrogen gas in the liquid hydrogen container according to the final state parameters; S5, calculating the evaporation mass flow rate of the gas-liquid interface of the liquid hydrogen container according to the change rate of the state parameters in the liquid hydrogen container; S6, calculating the thermodynamic energy change rate of hydrogen gas and liquid hydrogen in the liquid hydrogen container according to the change rate of the state parameter in the liquid hydrogen container, the final state parameter in the liquid hydrogen container and the interface evaporation mass flow rate; S7, calculating the total internal energy change of the liquid hydrogen container according to the initial state parameters, the final state parameters, the initial parameters of the liquid hydrogen and the hydrogen gas, and the final parameters, and calculating the total heat transfer of the gas phase and the liquid phase of the liquid hydrogen container according to the interface evaporation mass flow rate and the thermodynamic energy change rate of the hydrogen gas and the liquid hydrogen; S8, the insulation performance of the liquid hydrogen container is obtained by comparing the total heat transfer of the gas phase and liquid phase of the liquid hydrogen container with the standard static evaporation rate data.

2. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 1, characterized in that: The liquid hydrogen container specifications in S1 include the geometric volume V of the liquid hydrogen container g 、Effective volume V e and structural dimensions; the initial state parameters include the liquid hydrogen container pressure P1, liquid level height h1, liquid hydrogen temperature T L1 and the temperature of hydrogen T V1 .

3. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 2, characterized in that: The initial parameters of the liquid hydrogen in S2 include the liquid hydrogen volume V L1 , liquid hydrogen density ρ V1 、Liquid hydrogen mass m L1 ; The initial parameters of the hydrogen include the hydrogen volume V g1 , hydrogen density ρ g1 and hydrogen mass m g1 .

4. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 3, characterized in that: The change rates of the state parameters in the liquid hydrogen container in S3 include the pressure change rate dP / dt, the hydrogen temperature change rate dT g / dt and liquid hydrogen temperature change rate dT L / dt; the pressure change rate is obtained by measuring the change in pressure within at least 12 hours and dividing it by time; the hydrogen temperature change rate is obtained by measuring the change in hydrogen temperature within at least 12 hours and dividing it by time; the liquid hydrogen temperature change rate is obtained by measuring the change in liquid hydrogen temperature within at least 12 hours and dividing it by time.

5. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 4, characterized in that: The final state parameters in S4 include the final state parameters of the liquid hydrogen container pressure P2, liquid level height h2, liquid hydrogen temperature T L2 and the temperature of hydrogen T V2 The final parameters of the liquid hydrogen include the liquid hydrogen volume V L2 and the mass of liquid hydrogen m L2 ; The final parameters of hydrogen include the hydrogen volume V g2 and hydrogen mass m g2 .

6. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 5, characterized in that: The evaporation mass flow rate of the gas-liquid interface of the liquid hydrogen container in S5 is dm / dt, where Where Q Lb , Q Vb The heat transfer from liquid hydrogen to hydrogen and from hydrogen to liquid hydrogen, γ(T s ) is T s latent heat of vaporization at temperature.

7. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 6, characterized in that: The thermodynamic energy change rate of hydrogen in S6 Thermodynamic energy change rate of liquid hydrogen Where Q V , Q L are the heat transfer of gas phase and liquid phase of liquid hydrogen container, h V (T s ),h L (T s ) are T s Enthalpy of hydrogen gas and liquid hydrogen at temperature.

8. The method for rapid detection of thermal insulation performance of liquid hydrogen container according to claim 7, characterized in that: The total internal energy change in S7 is dU According to the law of conservation of energy, dU = dU L +dU V , combined with the change law of internal energy in steps 6 and 7, the heat transfer Q of the gas phase and liquid phase of the liquid hydrogen container is calculated V , Q L ; The total heat transfer of gas phase and liquid phase of liquid hydrogen container Q = Q V +Q L .

9. The method for rapid detection of thermal insulation performance of a liquid hydrogen container according to any one of claims 1 to 8, characterized in that: The initial state parameters in the liquid hydrogen container, the final state parameters in the liquid hydrogen container, the initial parameters of liquid hydrogen and hydrogen, and the final parameters of liquid hydrogen and hydrogen are all measured by a rapid detection system for thermal insulation performance of a liquid hydrogen container; the rapid detection system for thermal insulation performance of a liquid hydrogen container comprises a liquid hydrogen container and a liquid level gauge, a pressure sensor, a temperature sensor, a safety valve and a measurement and control system arranged in the liquid hydrogen container, the liquid level gauge is placed in the liquid hydrogen container and monitors the liquid level of liquid hydrogen in real time, the pressure sensor monitors the pressure change in the liquid hydrogen container, the temperature sensor monitors the temperature change of liquid hydrogen and hydrogen, and the safety valve prevents the liquid hydrogen container from being over-pressurized.

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