Hydrogen pipeline phase change simulation method

Abstract

The present application relates to hydrogen pipeline simulation technical field, disclose a kind of hydrogen pipeline phase change simulation method, comprising: by geometric model, the hydrogen phase change physical model of hydrogen pipeline is constructed, hydrogen phase change physical model includes thermodynamic equilibrium model and wall boiling model;The property parameter model of liquid hydrogen and gaseous hydrogen is constructed;The boundary condition and initial value condition of hydrogen pipeline are constructed;According to hydrogen phase change physical model, property parameter model and boundary condition and initial value condition, when the liquid phase and steam phase of hydrogen in thermodynamic equilibrium model are in thermodynamic equilibrium, steam dryness and steam volume fraction are calculated;According to steam volume fraction, the surface heat flux of hydrogen pipeline is calculated by wall boiling model;According to surface heat flux and property parameter model, steam mass generation rate is calculated, and hydrogen pipeline phase change simulation is completed, the present application solves the technical problems that existing simulation result precision is lower, cannot accurately reflect the phase change rule in actual hydrogen pipeline.

Description

Technical Field

[0001] This invention relates to the field of hydrogen pipeline simulation technology, and discloses a phase change simulation method for hydrogen pipelines. Background Technology

[0002] Against the backdrop of the rapid development of the hydrogen energy industry, liquid hydrogen, as an efficient form of hydrogen storage and transportation, is widely used in long-distance, large-scale hydrogen transportation scenarios. However, when liquid hydrogen is transported in hydrogen pipelines, it is highly susceptible to phase transition from liquid to gas due to factors such as changes in ambient temperature, pipeline pressure fluctuations, and heat exchange at the pipeline walls. This phase transition process causes significant changes in the density, viscosity, specific heat capacity, and other physical properties of hydrogen within the pipeline, leading to problems such as increased vapor volume fraction and unstable pipeline pressure. In severe cases, this can affect the transportation efficiency of hydrogen pipelines and even pose safety hazards.

[0003] Currently, research on phase change processes in hydrogen pipelines largely relies on experimental testing. However, experimental methods have limitations such as high cost, long cycle time, and difficulty in simulating extreme operating conditions. Existing simulation methods either fail to fully consider the influence of hydrogen's unique physical properties on the phase change process or neglect the coupling effect between thermodynamic equilibrium and wall boiling, resulting in low accuracy of simulation results that cannot accurately reflect the phase change laws in actual hydrogen pipelines. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that existing simulation results have low accuracy and cannot accurately reflect the phase change law in actual hydrogen transportation pipelines, and to provide a phase change simulation method for hydrogen transportation pipelines.

[0005] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0006] A phase change simulation method for hydrogen transportation pipelines includes:

[0007] Step 1: Construct a geometric model of the hydrogen transportation pipeline using the inlet boundary, outlet boundary, and wall boundary of the pipeline;

[0008] Step 2: Construct a hydrogen phase change physical model for the hydrogen pipeline using the geometric model. The hydrogen phase change physical model includes a thermodynamic equilibrium model and a wall boiling model.

[0009] Step 3: Based on the parameter requirements of the hydrogen phase transition physics model, construct the physical property parameter models for liquid hydrogen and gaseous hydrogen;

[0010] Step 4: Construct the boundary conditions and initial conditions for the hydrogen transportation pipeline using the aforementioned geometric model;

[0011] Step 5: Based on the hydrogen phase change physical model, the physical property parameter model, and the boundary conditions and initial conditions, when the liquid phase and vapor phase of hydrogen are in thermodynamic equilibrium in the thermodynamic equilibrium model, calculate the vapor dryness and vapor volume fraction.

[0012] Step 6: Calculate the surface heat flux of the hydrogen transport pipeline using the wall boiling model based on the vapor volume fraction.

[0013] Step 7: Calculate the steam mass generation rate based on the surface heat flux and the physical property parameter model, and complete the phase change simulation of the hydrogen transportation pipeline.

[0014] As a preferred embodiment, the physical property parameter model includes fixed parameters and variable parameters;

[0015] The fixed parameters include: density, heat of formation, and molar mass;

[0016] The variable parameters include: saturation temperature, dynamic viscosity, specific heat capacity, and thermal conductivity.

[0017] In a preferred embodiment, the saturation temperature of the liquid hydrogen is related to its saturation pressure as follows:

[0018] ;

[0019] Where T is the saturation temperature of liquid hydrogen and P is the saturation pressure of liquid hydrogen;

[0020] The functional relationship between the saturation temperature and saturation pressure of the gaseous hydrogen is as follows:

[0021] ;

[0022] Where T1 is the saturation temperature of gaseous hydrogen, and P1 is the saturation pressure of gaseous hydrogen.

[0023] In a preferred embodiment, the dynamic viscosity of the liquid hydrogen is related to the saturation temperature as follows:

[0024] ;

[0025] Where u1 is the dynamic viscosity of liquid hydrogen;

[0026] The dynamic viscosity of gaseous hydrogen as a function of saturation temperature is as follows:

[0027] ;

[0028] Where u2 is the dynamic viscosity of gaseous hydrogen.

[0029] As a preferred embodiment, the functional relationship between the specific heat capacity of the liquid hydrogen and the saturation temperature is as follows:

[0030] ;

[0031] Where Cp1 is the specific heat capacity of liquid hydrogen;

[0032] The functional relationship between the specific heat capacity of gaseous hydrogen and the saturation temperature is as follows:

[0033] ;

[0034] Where Cp2 is the specific heat capacity of gaseous hydrogen.

[0035] As a preferred embodiment, the functional relationship between the thermal conductivity of the liquid hydrogen and the saturation temperature is as follows:

[0036] ;

[0037] Where λ1 is the thermal conductivity of liquid hydrogen;

[0038] The functional relationship between the thermal conductivity of gaseous hydrogen and the saturation temperature is as follows:

[0039] ;

[0040] Where λ2 is the thermal conductivity of gaseous hydrogen.

[0041] In a preferred embodiment, the inlet boundary is set with inlet temperature and inlet velocity, the outlet boundary is set with outlet pressure, and the wall boundary is set with heat flux parameters.

[0042] As a preferred embodiment, the formula for calculating the steam dryness is:

[0043] ;

[0044] Where Y is the steam dryness, h m The enthalpy of a mixture of liquid and gaseous hydrogen, h ls h is the enthalpy of a liquid at saturation temperature. vs Enthalpy of vapor at saturation temperature;

[0045] The formula for calculating the volume fraction of steam is as follows:

[0046] ;

[0047] Among them, a v ρ is the volume fraction of steam. vs ρ is the density of steam at saturation temperature. ls This is the density of the liquid at saturation temperature.

[0048] As a preferred embodiment, the formula for calculating the surface heat flux of the hydrogen transport pipeline is as follows:

[0049] ;

[0050] Where, q bw Let u1 be the surface heat flux, u1 be the dynamic viscosity of liquid hydrogen, and h be the surface heat flux. lat Let be the latent heat of phase transition of hydrogen, and g be the acceleration due to gravity. The density of liquid hydrogen in the liquid phase. Let C be the gaseous density of hydrogen, σ be the surface tension coefficient at the liquid-gas interface, and C be the density of hydrogen in the gas phase. p1 T is the specific heat capacity of liquid hydrogen. W T is the wall temperature. sat C is the saturation temperature of liquid hydrogen. qw This is an empirical coefficient representing the variation of liquid hydrogen with the liquid surface composition. The liquid phase Prandtl number of liquid hydrogen. is the Prandtl number exponent for liquid hydrogen.

[0051] In a preferred embodiment, the calculation of the steam mass generation rate includes:

[0052] Step 7.1: Obtain the surface heat flux q bw Wall temperature T W The saturation temperature T of liquid hydrogen sat The model constants C for steam dryness Y and the magnitude of boiling heat flux that creates bubbles. ew The latent heat of liquid phase of gaseous hydrogen, h lat ;

[0053] Step 7.2: If T is satisfied W <T sat or q bw If any one of the three conditions ≤0 or Y≥1 is met, then the steam mass generation rate m is set. ew =0;

[0054] Step 7.3: If T is not satisfied W <T sat or q bw If any one of the three conditions ≤0 or Y≥1 is met, the steam mass generation rate is calculated using the following formula:

[0055] ;

[0056] Where, m ew C represents the steam mass generation rate. ew To create a model constant for the magnitude of the boiling heat flux of the bubbles, h lat This is the latent heat of phase transition of hydrogen.

[0057] Compared with the prior art, the beneficial effects of this invention are:

[0058] First, this method comprehensively considers the energy balance and wall heat exchange effect in the hydrogen phase transition process by constructing a coupled physical model of thermodynamic equilibrium model and wall boiling model. At the same time, the physical property parameter model distinguishes between fixed parameters and variable parameters, and obtains the functional relationship of variable parameters based on experimental data, which ensures the accuracy of physical property parameters and thus improves the accuracy of simulation results.

[0059] Second, the boundary conditions and initial conditions in the method are closely aligned with the actual operating conditions of hydrogen pipelines. They can be flexibly adjusted according to different pipeline structures, medium parameters and environmental conditions. This method is applicable to phase change simulation of hydrogen pipelines under various specifications and operating conditions, providing direct guidance for engineering practice.

[0060] Third, compared with traditional experimental methods, this simulation method does not require the construction of complex experimental equipment. It can quickly complete phase transition simulation under multiple operating conditions through computers, which greatly shortens the research cycle and reduces R&D costs.

[0061] Fourth, simulation can predict the changes in key parameters such as steam dryness and steam volume fraction in hydrogen pipelines in advance, and promptly identify safety risks such as pressure fluctuations and flow instability caused by phase change. This provides an important basis for the safe design, operation and maintenance optimization and fault early warning of hydrogen pipelines, and ensures the safe and reliable operation of hydrogen energy transmission systems. Attached Figure Description

[0062] Figure 1 This is a flowchart of the hydrogen pipeline phase change simulation method of the present invention.

[0063] Figure 2 This is a schematic diagram of the geometric model of the hydrogen transportation pipeline of the present invention. Detailed Implementation

[0064] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings. However, it should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention are within the scope of the present invention.

[0065] refer to Figure 1 , 2 This invention provides a phase change simulation method for hydrogen transportation pipelines.

[0066] Includes the following steps:

[0067] Step 1: Construct the geometric model of the hydrogen transportation pipeline

[0068] The geometric model of the hydrogen pipeline forms the basic framework for simulation calculations. Its construction must be based on the actual structural characteristics of the hydrogen pipeline, focusing on three key components: the inlet boundary, the outlet boundary, and the wall boundary (see reference). Figure 2 ):

[0069] Inlet boundary: The location of the hydrogen inlet corresponding to the hydrogen pipeline needs to be accurately simulated to ensure that it is consistent with the actual pipeline inlet structure;

[0070] Outlet boundary: The hydrogen outlet location corresponding to the hydrogen pipeline also needs to be restored, including the cross-sectional dimensions, shape, and connection relationship with downstream equipment at the outlet.

[0071] Wall boundary: This includes the pipe wall portion of the hydrogen transport pipeline. It is necessary to accurately describe the thickness of the pipe wall, the material distribution (if it is a multi-layered structure), and the spatial extension trajectory, and fully present the three-dimensional geometry of the pipeline.

[0072] By precisely defining the aforementioned boundaries, a geometric model that closely matches the geometric characteristics of the actual hydrogen pipeline is constructed using 3D modeling software (such as ANSYS Design Modeler, SolidWorks, etc.), laying the foundation for the subsequent construction of physical models and simulation calculations.

[0073] Step 2: Construct a physical model of hydrogen phase change for the hydrogen transportation pipeline.

[0074] The hydrogen phase transition physical model is used to describe the physical process of liquid hydrogen transforming into gaseous hydrogen in hydrogen transportation pipelines. This model consists of two parts: a thermodynamic equilibrium model and a wall boiling model.

[0075] Thermodynamic equilibrium model: This model assumes that during the phase transition, the liquid phase (liquid hydrogen) and vapor phase (gaseous hydrogen) of hydrogen are always in thermodynamic equilibrium, meaning that the temperature and pressure of the two phases remain equal and the phase equilibrium conditions are satisfied. This model is the core basis for calculating parameters such as steam dryness fraction and steam volume fraction, and it reflects the energy and matter balance relationship during the phase transition.

[0076] Wall boiling model: This model focuses on the boiling phenomenon caused by heat exchange between the wall of a hydrogen pipeline and the hydrogen medium. When the pipe wall temperature is higher than the saturation temperature of liquid hydrogen, the liquid hydrogen near the wall will boil and generate bubbles. This model quantifies the heat flux transfer between the wall and the hydrogen medium by describing the generation, growth, and detachment of bubbles, and is a key model for calculating surface heat flux.

[0077] Step 3: Construct property parameter models for liquid hydrogen and gaseous hydrogen

[0078] Physical property parameter models are used to provide the physical property parameters required during the hydrogen phase transition process. Based on whether the parameters change with operating conditions, they are divided into two categories: fixed parameters and variable parameters.

[0079] 3.1 Fixed parameters

[0080] The fixed parameters do not change with the operating conditions of the hydrogen pipeline, such as temperature and pressure. Specifically, these include:

[0081] Density (ρ): The inherent density values ​​of liquid hydrogen and gaseous hydrogen under standard conditions, which can be obtained from experimental data or authoritative physical property handbooks;

[0082] Heat of formation (Q): The inherent heat required for hydrogen to change from the liquid phase to the gas phase, which is a constant.

[0083] Molar mass (M): The molar mass of hydrogen is a constant, with a value of 2.016 g / mol.

[0084] 3.2 Variable Parameters

[0085] The variable parameters vary with the operating conditions of the hydrogen pipeline, such as saturation temperature and saturation pressure, and their functional relationship is as follows:

[0086] ①Saturation temperature

[0087] The functional relationship between the saturation temperature and saturation pressure of the liquid hydrogen is as follows:

[0088] ;

[0089] Where T is the saturation temperature of liquid hydrogen and P is the saturation pressure of liquid hydrogen;

[0090] The functional relationship between the saturation temperature and saturation pressure of the gaseous hydrogen is as follows:

[0091] ;

[0092] Where T1 is the saturation temperature of gaseous hydrogen, and P1 is the saturation pressure of gaseous hydrogen.

[0093] ② Dynamic viscosity

[0094] The dynamic viscosity of the liquid hydrogen as a function of the saturation temperature is as follows:

[0095] ;

[0096] Where u1 is the dynamic viscosity of liquid hydrogen;

[0097] The dynamic viscosity of gaseous hydrogen as a function of saturation temperature is as follows:

[0098] ;

[0099] Where u2 is the dynamic viscosity of gaseous hydrogen.

[0100] ③Specific heat capacity

[0101] The functional relationship between the specific heat capacity of liquid hydrogen and the saturation temperature is as follows:

[0102] ;

[0103] Where Cp1 is the specific heat capacity of liquid hydrogen;

[0104] The functional relationship between the specific heat capacity of gaseous hydrogen and the saturation temperature is as follows:

[0105] ;

[0106] Where Cp2 is the specific heat capacity of gaseous hydrogen.

[0107] ④ Thermal conductivity

[0108] The functional relationship between the thermal conductivity of liquid hydrogen and the saturation temperature is as follows:

[0109] ;

[0110] Where λ1 is the thermal conductivity of liquid hydrogen;

[0111] The functional relationship between the thermal conductivity of gaseous hydrogen and the saturation temperature is as follows:

[0112] ;

[0113] Where λ2 is the thermal conductivity of gaseous hydrogen.

[0114] Step 4: Construct the boundary conditions and initial conditions for the hydrogen transportation pipeline.

[0115] Boundary conditions and initial conditions are prerequisites for simulation calculations and must be set according to the actual operating conditions of the hydrogen pipeline:

[0116] Inlet boundary: Set the inlet temperature and inlet velocity. The inlet temperature is usually determined based on the storage temperature of liquid hydrogen, while the inlet velocity is calculated by combining the design flow rate and inlet cross-sectional area of ​​the hydrogen transmission pipeline;

[0117] Export boundary: Set the export pressure. The export pressure needs to be referenced to the downstream pressure demand of the hydrogen pipeline or the system design pressure to ensure consistency with the actual operating pressure;

[0118] Wall boundary: Set heat flux parameters. Wall heat flux parameters need to take into account factors such as ambient temperature and pipe insulation measures, and can be obtained through experimental testing or heat transfer theory calculations;

[0119] Initial conditions: Set the temperature, pressure, velocity, and phase distribution of hydrogen in the pipeline at the initial moment of the simulation. It is usually assumed that the pipeline is filled with liquid hydrogen at the initial moment, and the temperature and pressure are uniformly distributed, and the velocity is zero (or the initial flow velocity).

[0120] Step 5: Calculate steam dryness and steam volume fraction

[0121] In the thermodynamic equilibrium model, when the liquid and vapor phases of hydrogen are in thermodynamic equilibrium, the vapor dryness fraction and vapor volume fraction are calculated by combining the hydrogen phase change physical model constructed in step 2, the physical property parameter model in step 3, and the boundary and initial conditions in step 4.

[0122] The formula for calculating the steam dryness is as follows:

[0123] ;

[0124] Where Y is the steam dryness, h m The enthalpy of a mixture of liquid and gaseous hydrogen, h ls h is the enthalpy of a liquid at saturation temperature. vs Enthalpy of vapor at saturation temperature;

[0125] The formula for calculating the volume fraction of steam is as follows:

[0126] ;

[0127] Among them, a v ρ is the volume fraction of steam. vs ρ is the density of steam at saturation temperature. ls This is the density of the liquid at saturation temperature.

[0128] Step 6: Calculate the surface heat flux of the hydrogen transport pipeline.

[0129] Based on the vapor volume fraction calculated in step 5, and combined with the wall boiling model, the surface heat flux of the hydrogen transport pipeline is calculated. Surface heat flux is a key parameter describing the intensity of heat exchange between the wall and the hydrogen medium.

[0130] The formula for calculating the surface heat flux of the hydrogen transport pipeline is as follows:

[0131] ;

[0132] Where, q bw Let u1 be the surface heat flux, u1 be the dynamic viscosity of liquid hydrogen, and h be the surface heat flux. lat Let be the latent heat of phase transition of hydrogen, and g be the acceleration due to gravity. The density of liquid hydrogen in the liquid phase. Let C be the gaseous density of hydrogen, σ be the surface tension coefficient at the liquid-gas interface, and C be the density of hydrogen in the gas phase. p1 T is the specific heat capacity of liquid hydrogen. W T is the wall temperature. sat C is the saturation temperature of liquid hydrogen. qw This is an empirical coefficient representing the variation of liquid hydrogen with the liquid surface composition. The liquid phase Prandtl number of liquid hydrogen. is the Prandtl number exponent for liquid hydrogen.

[0133] Step 7: Calculate the steam mass generation rate and complete the simulation.

[0134] Steam mass generation rate is a core indicator for measuring the hydrogen phase change rate. The calculation process consists of the following three steps:

[0135] ① Obtain the surface heat flux q bw Wall temperature T W The saturation temperature T of liquid hydrogen sat The model constants C for steam dryness Y and the magnitude of boiling heat flux that creates bubbles. ew The latent heat of liquid phase of gaseous hydrogen, h lat ;

[0136] ② If any of the following three conditions are met, it indicates that no significant phase change has occurred in the hydrogen transport pipeline at this time, and the steam mass generation rate m is set. ew =0;

[0137] (1) Wall temperature T W <Saturation temperature T of liquid hydrogen sat (The wall temperature is insufficient to induce boiling).

[0138] (2) Surface heat flux q bw ≤0 (no heat is transferred from the wall to the hydrogen medium);

[0139] (3) Steam dryness Y≥1 (hydrogen in the pipeline has completely turned into gaseous state, and there is no liquid phase that can change phase).

[0140] ③ If T is not satisfied W <T sat or q bw If any one of the three conditions ≤0 or Y≥1 is met, it indicates that a phase transition process from liquid hydrogen to gaseous hydrogen exists within the pipeline. The steam mass generation rate is then calculated using the following formula:

[0141] ;

[0142] Where, m ew C represents the steam mass generation rate. ew To create model constants for the magnitude of the boiling heat flux of bubbles (determined based on fitting experimental data), h lat This is the latent heat of phase transition of hydrogen.

[0143] Through the above steps, the simulation calculation of the phase change process of the hydrogen transportation pipeline is completed, and key parameters such as steam dryness, steam volume fraction, surface heat flux and steam mass generation rate at different times and locations can be output, providing data support for the performance analysis of the hydrogen transportation pipeline.

[0144] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for simulating phase transition in a hydrogen pipeline, characterized in that, The application relates to a hydrogen pipeline phase change simulation method, which comprises the following steps: Step 1: constructing a geometric model of the hydrogen pipeline through an inlet boundary, an outlet boundary and a wall boundary of the hydrogen pipeline; Step 2: constructing a hydrogen phase change physical model of the hydrogen pipeline through the geometric model, wherein the hydrogen phase change physical model comprises a thermodynamic equilibrium model and a wall boiling model; Step 3: constructing a physical property parameter model of liquid hydrogen and gaseous hydrogen through parameter requirements of the hydrogen phase change physical model; Step 4: constructing boundary conditions and initial value conditions of the hydrogen pipeline through the geometric model; Step 5: when liquid phase and vapor phase of hydrogen are in thermodynamic equilibrium in the thermodynamic equilibrium model, calculating a steam dryness and a steam volume fraction according to the hydrogen phase change physical model, the physical property parameter model and the boundary conditions and initial value conditions; the calculation formula of the steam dryness is as follows: wherein, x is the steam dryness, h is the enthalpy, and hfg is the latent heat of vaporization; the calculation formula of the steam volume fraction is as follows: wherein, x is the steam dryness, and h is the enthalpy; ； where Y is the steam dryness, h m is the enthalpy of the liquid and gaseous hydrogen mixture, h ls is the enthalpy of the liquid at saturation temperature, h vs is the enthalpy of the vapor at saturation temperature; Step 7: calculating a steam mass generation rate according to the surface heat flux and the physical property parameter model, and completing the hydrogen pipeline phase change simulation; the calculation of the steam mass generation rate comprises the following steps: ； where a v is the vapor volume fraction, p vs is the density of the vapor at the saturation temperature, p ls is the density of the liquid at the saturation temperature; Step 6: Calculate the surface heat flux of the hydrogen feed pipe by the wall boiling model according to the vapor volume fraction where q bw is the surface heat flux, u1 is the dynamic viscosity of liquid hydrogen, h lat is the latent heat of hydrogen, g is the gravitational acceleration, is the liquid phase density of liquid hydrogen, is the gas phase density of gaseous hydrogen, σ is the surface tension coefficient of the liquid-gas interface, C p1 is the specific heat capacity of liquid hydrogen, T W is the wall temperature, T sat is the saturation temperature of liquid hydrogen, C qw is the empirical coefficient of liquid hydrogen with the liquid surface combination change, is the liquid Prandtl number of liquid hydrogen, is the Prandtl number index of liquid hydrogen; In step 3, the physical property parameter model comprises fixed parameters and variable parameters; Step 7.1: Obtain surface heat flux q bw , wall temperature T W , saturation temperature of liquid hydrogen T sat , vapor quality Y, model constant C of the size of the boiling heat flux that creates bubbles ew , liquid phase latent heat of gaseous hydrogen h lat ; Step 7.2: If three of the conditions T W <T sat or q bw ≤0 or Y≥1 are met, then set the steam mass generation rate m ew =0; Step 7.3: If three of the conditions T W <T sat or q bw ≤0 or Y≥1 are not met, then calculate the steam mass generation rate, which is given by: ； where m ew is the vapor mass generation rate, C ew is a model constant for the size of the boiling heat flux that creates bubbles, h lat is the latent heat of phase change of hydrogen.

2. The method of claim 1, wherein, The fixed parameters comprise density, heat of formation and molar mass; The variable parameters comprise saturation temperature, dynamic viscosity, specific heat capacity and thermal conductivity. In step 3, the functional relationship between the saturation temperature and the saturation pressure of the liquid hydrogen is as follows: wherein, T is the saturation temperature of the liquid hydrogen, and P is the saturation pressure of the liquid hydrogen; 3. The method of claim 2, wherein, The functional relationship between the saturation temperature and the saturation pressure of the gaseous hydrogen is as follows: wherein, T1 is the saturation temperature of the gaseous hydrogen, and P1 is the saturation pressure of the gaseous hydrogen. ； In step 3, the functional relationship between the dynamic viscosity and the saturation temperature of the liquid hydrogen is as follows: wherein, u1 is the dynamic viscosity of the liquid hydrogen; The functional relationship between the dynamic viscosity and the saturation temperature of the gaseous hydrogen is as follows: wherein, u2 is the dynamic viscosity of the gaseous hydrogen. ； In step 3, the functional relationship between the specific heat capacity and the saturation temperature of the liquid hydrogen is as follows: wherein, Cp1 is the specific heat capacity of the liquid hydrogen; 4. The method of claim 3, wherein, The functional relationship between the specific heat capacity and the saturation temperature of the gaseous hydrogen is as follows: wherein, Cp2 is the specific heat capacity of the gaseous hydrogen. ； In step 3, the functional relationship between the thermal conductivity and the saturation temperature of the liquid hydrogen is as follows: wherein, lambda1 is the thermal conductivity of the liquid hydrogen; The functional relationship between the thermal conductivity and the saturation temperature of the gaseous hydrogen is as follows: wherein, lambda2 is the thermal conductivity of the gaseous hydrogen. ； In step 4, the inlet boundary is provided with an inlet temperature and an inlet velocity, the outlet boundary is provided with an outlet pressure, and the wall boundary is provided with a heat flow parameter.

5. The method of claim 4, wherein, ​ ； ​ ​ ； ​ 6. The method of claim 5, wherein, ​ ； ​ ​ ； ​ 7. The method of claim 6, wherein, ​

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