A method for evaluating a supercritical hydrogen state

Abstract

This invention discloses a method for assessing the supercritical state of hydrogen, relating to the field of hydrogen energy. By setting up a specific sensor array and performing conversion calculations, this invention can monitor in real time key information such as the temperature field, density field, mass field, and remaining liquid hydrogen mass during the supercritical transition process of liquid hydrogen inside a cryogenic storage tank, solving the problem of unclear supercritical transition states of liquid hydrogen within cryogenic storage tanks. It utilizes a two-dimensional axisymmetric model to geometrically model the cryogenic storage tank and obtains three-dimensional data information through angle integration, offering advantages such as fewer sensors and convenient arrangement. The proposed method for assessing the supercritical state within cryogenic storage tanks requires no complex test structure, has low hardware costs, and can achieve real-time measurement of complex states through indirect calculations, facilitating widespread application.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy, and specifically to a method for assessing the state of supercritical hydrogen. Background Technology

[0002] The applications of liquid hydrogen have gradually expanded from launch vehicles to various vehicles such as automobiles, airplanes, and ships. Because liquid hydrogen has a supercritical temperature of 33.145 K and a supercritical pressure of 1.2965 MPa, its use as fuel differs significantly from traditional hydrocarbon fuels such as kerosene and gasoline. For example, when liquid hydrogen is used as fuel in aircraft engines, its supply pressure is typically greater than 1.2965 MPa, and the temperature of the hydrogen gas used as a pressurization source is also greater than 33.145 K. Therefore, when high-pressure, high-temperature hydrogen enters a cryogenic storage tank, the liquid hydrogen in contact with it rapidly transforms from its conventional state to its supercritical state.

[0003] Supercritical state is a special state in which the properties of gas and liquid become similar above the critical temperature and critical pressure, eventually reaching a homogeneous fluid state. At this point, there is no obvious gas-liquid phase transition or gas-liquid interface inside the cryogenic storage tank, making it difficult for conventional level gauges and other measuring elements to accurately assess the hydrogen state inside the tank. Because liquid hydrogen is a highly explosive, cryogenic, and easily vaporized propellant, it presents numerous unpredictable and potentially dangerous risks, posing significant challenges to control. Therefore, supercritical transitions can trigger a series of safety issues such as overpressure, tank expansion, and explosions. Furthermore, the difficulty in assessing the remaining liquid hydrogen level inside the cryogenic storage tank can also affect the operation of subsequent equipment. Summary of the Invention

[0004] The purpose of this invention is to overcome the deficiencies in the prior art and provide a method for assessing the state of supercritical hydrogen. For cryogenic storage tanks involving the supercritical transformation of liquid hydrogen, by setting up a specific sensor array and performing transformation calculations, key information such as the temperature field, density field, mass field, and remaining liquid hydrogen mass during the supercritical transformation process of liquid hydrogen inside the cryogenic storage tank can be monitored in real time.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] In a first aspect, the present invention provides a method for assessing the state of supercritical hydrogen, as detailed below:

[0007] S1. Based on a two-dimensional axisymmetric cylindrical coordinate model, a spatial model of a cylindrical liquid hydrogen storage device involving supercritical transition is performed. Control volumes are uniformly divided along the radial and axial directions, with each control volume defined as V. i ;

[0008] S2. Install pressure sensors and arrange array-type temperature sensors in liquid hydrogen storage devices involving supercritical transitions.

[0009] S3. The liquid hydrogen storage device begins pressurization and delivery. External ambient temperature hydrogen enters the gas phase space above the liquid hydrogen storage device, and the liquid hydrogen below gradually transforms into supercritical hydrogen. The gas-liquid interface disappears, and the state assessment begins at this time.

[0010] S4. During the condition assessment process, read the pressure sensor information P and simultaneously read the array temperature sensor signal T. i Then, for each control entity, the corresponding state data (P, T) can be obtained. i By combining the spatial model of the liquid hydrogen storage device in S1, a cloud map of the hydrogen temperature distribution inside the liquid hydrogen storage device can be obtained.

[0011] S5. Based on the current state data (P, T) of each controller... i Obtain the corresponding density information ρ i By combining the spatial model of the liquid hydrogen storage device in S1, the hydrogen density distribution cloud map inside the liquid hydrogen storage device is obtained.

[0012] S6, based on volume V i and density information ρ i The mass m of each control volume is obtained through transformation calculation. i =V i ×ρ i By combining the spatial model of the liquid hydrogen storage device in S1, a cloud map of hydrogen mass distribution inside the liquid hydrogen storage device is obtained.

[0013] S7. Integrate and sum the mass of the two-dimensional control volume to obtain the total mass of hydrogen inside the liquid hydrogen storage device. Where n is the total number of control entities, m i Let θ be the mass of each control volume, and θ be the azimuth angle in the two-dimensional cylindrical coordinate integral.

[0014] Preferably, in S1, spatial modeling is performed in two dimensions only along the radial direction of the liquid hydrogen storage device.

[0015] Preferably, the array-type temperature sensor is a liquid hydrogen temperature sensor, and at least one sub-temperature sensor is provided at each control unit.

[0016] Preferably, the density information ρ in S5 i The data is obtained through calculations using a hydrogen-based physical property data model or by calling the Refprop software.

[0017] Preferably, the supercritical hydrogen state assessment method is implemented based on a supercritical hydrogen state assessment system;

[0018] The supercritical hydrogen state assessment system includes a cylindrical liquid hydrogen storage device, a hydrogen pressurization pipeline, a high-pressure hydrogen cylinder, a high-pressure hydrogen valve, a liquid hydrogen supply pipeline, a liquid hydrogen shut-off valve, a discharge pipeline, a discharge shut-off valve, an array of temperature sensors, signal lines, a pressure sensor, and a controller. The upper gas phase region of the cylindrical liquid hydrogen storage device is externally connected to the hydrogen pressurization pipeline and the discharge pipeline, which are respectively equipped with a high-pressure hydrogen valve and a discharge shut-off valve. The cylindrical liquid hydrogen storage device is connected to the high-pressure hydrogen cylinder via the hydrogen pressurization pipeline. The lower liquid phase region of the cylindrical liquid hydrogen storage device is externally connected to the liquid hydrogen supply pipeline, which is equipped with a liquid hydrogen shut-off valve. The cylindrical liquid hydrogen storage device internally houses an array of temperature sensors and pressure sensors, which are connected to the external controller via signal lines.

[0019] It should be noted that, provided there are no conflicts between the technical features in the above preferred methods,

[0020] All can be combined without restriction.

[0021] The outstanding and beneficial technical effects of this invention compared to existing technologies are as follows: By setting up a specific sensor array and performing conversion calculations, key information such as the temperature field, density field, mass field, and remaining liquid hydrogen mass during the supercritical transition process of liquid hydrogen inside a cryogenic storage tank can be monitored in real time, solving the problem of the difficulty in clearly understanding the supercritical transition state of liquid hydrogen inside a cryogenic storage tank; a two-dimensional axisymmetric model is used to geometrically model the cryogenic storage tank, and three-dimensional data information is obtained through angle integration, which has advantages such as fewer sensors and convenient arrangement; the proposed method for evaluating the supercritical state inside a cryogenic storage tank does not require a complex test structure, has low hardware costs, and can achieve real-time measurement of complex states only through indirect calculations, which is conducive to widespread application.

[0022] The following will further explain the concept, specific structure and technical effects of the present invention with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. Attached Figure Description

[0023] Figure 1 This is a flowchart of a method for assessing the state of supercritical hydrogen.

[0024] Figure 2 This is a schematic diagram of a supercritical hydrogen state assessment system.

[0025] Figure 3 This is a top view of a two-dimensional axisymmetric cylindrical coordinate model of a cylindrical liquid hydrogen storage device;

[0026] Figure 2In the middle: 1. Cylindrical liquid hydrogen storage device; 2. Hydrogen pressurization pipeline; 3. High-pressure hydrogen cylinder; 4. High-pressure hydrogen valve; 5. Liquid hydrogen supply pipeline; 6. Liquid hydrogen shut-off valve; 7. Discharge pipeline; 8. Discharge shut-off valve; 9. Array-type temperature sensor; 10. Signal line; 11. Pressure sensor; 12. Controller. Detailed Implementation

[0027] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0028] like Figure 1 As shown, this invention provides a method for assessing the state of supercritical hydrogen, which mainly includes the following steps:

[0029] S1. Based on a two-dimensional axisymmetric cylindrical coordinate model, a spatial model of a cylindrical liquid hydrogen storage device involving supercritical transition is performed. Control volumes are uniformly divided along the radial and axial directions, with each control volume defined as V. i ,like Figure 3 As shown.

[0030] As a preferred embodiment of the present invention, spatial modeling can be performed in two dimensions only along the radial direction of the liquid hydrogen storage device, but more control volumes should be divided as much as possible to improve the accuracy of data such as temperature field, density field, and mass field.

[0031] S2. Install pressure sensors and arrange array-type temperature sensors in (cylindrical) liquid hydrogen storage devices involving supercritical transitions.

[0032] In a preferred embodiment of the present invention, the array-type temperature sensor comprises multiple sub-temperature sensors. To achieve better data measurement, at least one sub-temperature sensor should be provided at each control unit. The array-type temperature sensor should employ a liquid hydrogen temperature sensor to further improve measurement accuracy.

[0033] S3. The liquid hydrogen storage device begins pressurization and delivery. External ambient temperature hydrogen enters the gas phase space above the liquid hydrogen storage device, and the liquid hydrogen below gradually transforms into supercritical hydrogen. The gas-liquid interface disappears, and the state assessment begins at this time.

[0034] S4. During the condition assessment process, read the pressure sensor information P, and simultaneously read the array temperature sensor signal (the corresponding temperature signal is denoted as T). i Then, for each control entity, the corresponding state data (P, T) can be obtained. i By combining the spatial model of the liquid hydrogen storage device in S1, a cloud map of the hydrogen temperature distribution inside the liquid hydrogen storage device can be obtained.

[0035] S5. Based on the current state data (P, T) of each controller... i Obtain the corresponding density information ρ i By combining the spatial model of the liquid hydrogen storage device in S1, a cloud map of the hydrogen density distribution inside the liquid hydrogen storage device is obtained.

[0036] As a preferred embodiment of the present invention, density information ρ i It can be calculated directly from the basic hydrogen property data formula, or the data can be obtained by calling software such as Refprop.

[0037] S6, based on volume V i and density information ρ i The mass m of each control volume is obtained through transformation calculation. i =V i ×ρ i By combining the spatial model of the liquid hydrogen storage device in S1, a cloud map of the hydrogen mass distribution inside the liquid hydrogen storage device is obtained.

[0038] S7. Integrate and sum the mass of the two-dimensional control volume to obtain the total mass of hydrogen inside the liquid hydrogen storage device. Where n is the total number of control entities, m i Let θ be the mass of each control volume, and θ be the azimuth angle in the two-dimensional cylindrical coordinate integral.

[0039] As a preferred embodiment of the present invention, before the method is actually applied, the model of the cylindrical liquid hydrogen storage device, as well as the calculation formula and drawing code of the information distribution cloud map, should be stored in the controller in advance to facilitate the real-time display of the above data.

[0040] As a preferred embodiment of the present invention, the supercritical hydrogen state assessment method of the present invention is implemented based on a supercritical hydrogen state assessment system. For example... Figure 2 As shown, the supercritical hydrogen state assessment system includes a cylindrical liquid hydrogen storage device 1, a hydrogen pressurization pipeline 2, a high-pressure hydrogen cylinder 3, a high-pressure hydrogen valve 4, a liquid hydrogen supply pipeline 5, a liquid hydrogen shut-off valve 6, a discharge pipeline 7, a discharge shut-off valve 8, an array of temperature sensors 9, a signal line 10, a pressure sensor 11, and a controller 12.

[0041] Specifically, the cylindrical liquid hydrogen storage device 1 includes an upper gas phase zone and a lower liquid phase zone. The upper gas phase zone is connected to a hydrogen pressurization pipeline 2 and a discharge pipeline 7. The hydrogen pressurization pipeline 2 and the discharge pipeline 7 are respectively equipped with a high-pressure hydrogen valve 4 and a discharge shut-off valve 8. The cylindrical liquid hydrogen storage device 1 is connected to a high-pressure hydrogen cylinder 3 via the hydrogen pressurization pipeline 2, which transports the pressurized hydrogen from the high-pressure hydrogen cylinder 3 to the gas pillow space (i.e., the upper gas phase zone) of the cylindrical liquid hydrogen storage device 1. The discharge pipeline 7 discharges the vaporized liquid hydrogen to the outside. The lower liquid phase zone of the cylindrical liquid hydrogen storage device 1 is connected to a liquid hydrogen supply pipeline 5, which is equipped with a liquid hydrogen shut-off valve 6. The liquid hydrogen supply pipeline 5 can transport the pressurized liquid hydrogen from the cylindrical liquid hydrogen storage device 1 to subsequent hydrogen power equipment. The cylindrical liquid hydrogen storage device 1 is equipped with an array of temperature sensors 9 and pressure sensors 11 to measure the temperature and pressure values ​​inside the cylindrical liquid hydrogen storage device 1. The array of temperature sensors 9 and pressure sensors 11 are respectively connected to an external controller 12 via signal lines 10 to realize real-time processing of measurement data.

[0042] Example

[0043] Based on the aforementioned supercritical hydrogen state assessment system, this embodiment provides a supercritical hydrogen state assessment method, namely, the operating principle of the supercritical hydrogen state assessment system, as follows:

[0044] Assume all shut-off valves are in the closed state.

[0045] (1) Based on a two-dimensional axisymmetric cylindrical coordinate model, a spatial model of the cylindrical liquid hydrogen storage device 1 is constructed. The control volumes are uniformly divided along the radial and axial directions, and the volumes corresponding to each control volume are V1, V2, V3, V4, V5, V6, V7, V8, and V9 (all uniformly set as V). i The geometric model is then stored in the controller 12.

[0046] (2) Open the high-pressure hydrogen valve 4. High-temperature and high-pressure hydrogen (temperature and pressure greater than 33.145K and 1.2965MPa respectively) from the high-pressure hydrogen cylinder 3 enters the gas pillow space of the cylindrical liquid hydrogen storage device 1 through the hydrogen pressurization pipeline 2. If the pressure is too high, open the discharge shut-off valve 8 to reduce the pressure. Open the liquid hydrogen shut-off valve 6. The liquid hydrogen at the bottom of the cylindrical liquid hydrogen storage device 1 is supplied through the liquid hydrogen supply pipeline 5. At this time, the liquid hydrogen at the top of the cylindrical liquid hydrogen storage device 1 begins to undergo supercritical transformation from top to bottom. At this time, the gas-liquid interface disappears.

[0047] (3) The controller 12 reads the data from the array temperature sensor 9 and the pressure sensor 11 through the signal line 10, so that each controller can obtain the corresponding status data (P, T). iBy combining the spatial model of the liquid hydrogen storage device, a cloud map of the hydrogen temperature distribution inside the liquid hydrogen storage device can be obtained.

[0048] (4) Based on the hydrogen-based physical property data model, based on the current state data (P, T) i Obtain the corresponding density information ρ i By combining the spatial model of the liquid hydrogen storage device, a cloud map of the hydrogen density distribution inside the liquid hydrogen storage device can be obtained.

[0049] (5) Based on the corresponding volume V mentioned above i and the obtained density information ρ i The mass m of each control volume is obtained through transformation calculation. i =V i ×ρ i By combining the spatial model of the liquid hydrogen storage device, a cloud map of the hydrogen mass distribution inside the liquid hydrogen storage device can be obtained.

[0050] (6) By integrating and summing the mass of the two-dimensional control volume, the total mass of hydrogen inside the liquid hydrogen storage device can be obtained.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method of evaluating a supercritical hydrogen state, characterized by, Specifically as follows: S1, based on the two-dimensional axisymmetric cylindrical coordinate model, the cylindrical liquid hydrogen storage device involving supercritical transformation is spatially modeled, and the control bodies are evenly divided along the radial and axial directions in turn, and the volume corresponding to each control body is set as V i ; S2. Install pressure sensors and arrange array-type temperature sensors in liquid hydrogen storage devices involving supercritical transitions. S3. The liquid hydrogen storage device begins pressurization and delivery. External ambient temperature hydrogen enters the gas phase space above the liquid hydrogen storage device, and the liquid hydrogen below gradually transforms into supercritical hydrogen. The gas-liquid interface disappears, and the state assessment begins at this time. S4, in the state evaluation process, reading pressure sensor information P, while reading array temperature sensor signal T i , then for each control body can obtain the corresponding state data (P, T i ); combined with the space model of the liquid hydrogen storage device in S1, the hydrogen temperature distribution cloud picture inside the liquid hydrogen storage device can be obtained; S5. Based on the current state data (P, T) of each controller... i Obtain the corresponding density information ρ i By combining the spatial model of the liquid hydrogen storage device in S1, the hydrogen density distribution cloud map inside the liquid hydrogen storage device is obtained. S6、According to the volume V i And the density information p i , through the conversion calculation, the mass m of each control body is obtained i = V i * p i , combined with the space model of the liquid hydrogen storage device in S1, the hydrogen mass distribution cloud picture inside the liquid hydrogen storage device is obtained; S7, integrate and sum the quality of the two-dimensional control bodies to obtain the total mass of hydrogen inside the liquid hydrogen storage device wherein n is the total number of control bodies, m i is the mass of each control body, and θ is the azimuth angle in the two-dimensional cylindrical coordinate integration.

2. The method of claim 1, wherein, In S1, spatial modeling is a two-dimensional modeling performed only along the radial direction of the liquid hydrogen storage device.

3. The method of claim 1, wherein, The array-type temperature sensor is a liquid hydrogen temperature sensor, and each control unit has at least one sub-temperature sensor.

4. The method of claim 1, wherein, The density information p in S5 i Calculated by hydrogen base property data model or obtained by calling Refprop software.

5. The method of claim 1, wherein, The supercritical hydrogen state assessment method is implemented based on a supercritical hydrogen state assessment system. The supercritical hydrogen state assessment system includes a cylindrical liquid hydrogen storage device (1), a hydrogen pressurization pipeline (2), a high-pressure hydrogen cylinder (3), a high-pressure hydrogen valve (4), a liquid hydrogen supply pipeline (5), a liquid hydrogen shut-off valve (6), an exhaust pipeline (7), an exhaust shut-off valve (8), an array-type temperature sensor (9), a signal line (10), a pressure sensor (11), and a controller (12). The upper gas phase zone of the cylindrical liquid hydrogen storage device (1) is connected to a hydrogen pressurization pipeline (2) and an exhaust pipeline (7). The hydrogen pressurization pipeline (2) and the exhaust pipeline (7) are respectively equipped with… A high-pressure hydrogen valve (4) and a discharge shut-off valve (8) are provided. The cylindrical liquid hydrogen storage device (1) is connected to the high-pressure hydrogen cylinder (3) through a hydrogen pressurization pipeline (2). A liquid hydrogen supply pipeline (5) is connected to the liquid phase zone at the bottom of the cylindrical liquid hydrogen storage device (1). A liquid hydrogen shut-off valve (6) is provided on the liquid hydrogen supply pipeline (5). An array-type temperature sensor (9) and a pressure sensor (11) are provided inside the cylindrical liquid hydrogen storage device (1). The array-type temperature sensor (9) and the pressure sensor (11) are connected to an external controller (12) through signal lines (10).

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