A method and system for thermodynamic analysis of a vehicle-mounted high-pressure hydrogen storage cylinder

Abstract

The application relates to a kind of vehicle-mounted high-pressure hydrogen storage bottle thermodynamic analysis method and system.The method obtains the structure,working condition and internal gas state of vehicle-mounted high-pressure hydrogen storage bottle;Based on R-K real gas state equation,hydrogen storage bottle thermodynamic model of charging and discharging process under adiabatic condition is established respectively;Based on the convective heat transfer relationship between the internal gas of vehicle-mounted high-pressure hydrogen storage bottle, bottle wall and external environment, hydrogen storage bottle thermodynamic model of charging and discharging process under convective heat transfer condition is established respectively;Based on the thermodynamic model of charging and discharging process under adiabatic condition and hydrogen storage bottle thermodynamic model of charging and discharging process under convective heat transfer condition, temperature calculation of vehicle-mounted high-pressure hydrogen storage bottle is carried out, the change rule of vehicle-mounted high-pressure hydrogen storage bottle charging and discharging process is obtained, and the thermodynamic analysis of vehicle-mounted high-pressure hydrogen storage bottle is completed.Compared with the prior art, the application has the advantages of improving the temperature analysis accuracy of vehicle-mounted high-pressure hydrogen storage bottle.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell supply technology under extreme environments, and in particular to a thermodynamic analysis method and system for on-board high-pressure hydrogen storage cylinders. Background Technology

[0002] With the global reserves of fossil fuels dwindling rapidly, the search for alternative energy sources has become increasingly urgent. Hydrogen energy, due to its high efficiency, renewability, and zero pollution, has gradually attracted widespread attention. In recent years, fuel cell power systems and fuel cell vehicles have developed rapidly, and governments worldwide have increased their investment in the research and development of hydrogen supply systems. High-pressure hydrogen storage technology has become the primary method of hydrogen storage due to its practicality, reliability, low cost, and relatively mature technology. According to safety standards, the maximum filling temperature of on-board high-pressure hydrogen storage cylinders must not exceed 85°C to prevent hydrogen leakage caused by degradation of the cylinder wall material due to heat. Considering the flammable and explosive nature of hydrogen, leakage would pose a serious safety hazard. Furthermore, under a fixed operating pressure, an increase in hydrogen temperature will reduce the hydrogen storage capacity of the storage container, thus affecting its storage capacity. During the venting process, the minimum temperature of hydrogen inside the storage cylinder must not be lower than -40°C; otherwise, it will exceed the industrial standard for hydrogen storage cylinders, causing adverse effects such as cylinder wall deformation. Therefore, in order to ensure that the on-board high-pressure hydrogen storage cylinder can be safely and quickly filled with as much hydrogen as possible during the filling and discharging cycle, and to meet the safety and driving range requirements of fuel cell vehicles, thermodynamic research on the filling and discharging cycle of the hydrogen storage cylinder is particularly necessary. In 2006, Canadian scholar CJB Dicken used the real gas equation of state under adiabatic conditions to propose a formula for calculating the temperature rise during the hydrogen filling process of the on-board hydrogen storage cylinder (Dicken CJB, Mérida W. Measured effects of filling time and initial mass on the temperature distribution within a hydrogen cylinder during refueling[J]. Journal of PowerSources, 2007, 165(1):324-336.). In 2024, Turkish scholar Muhittin Bilgili verified that the RK equation has the highest accuracy in CFD simulation. By establishing a CFD model of the rapid filling process of the vehicle hydrogen storage cylinder, the calculation results of four real gas equations of state were compared with experimental values. The results showed that the RK real gas equation of state is most consistent with the actual situation and can effectively predict the temperature change of the hydrogen storage cylinder (Bilgili M, R F. Effects of real gas equations on the fast-filling process of compressed hydrogen storage tank[J]. International Journal of Hydrogen Energy, 2024, 53: 816-828.

[0003] However, the existing thermodynamic analysis of the vehicle-mounted high-pressure hydrogen storage cylinder does not comprehensively consider the real gas state of high-pressure hydrogen and the convective heat transfer law between the cylinder wall and the external environment, especially involving the R-K real gas state equation with high precision. The existing model fails to form a systematic thermodynamic theoretical model, and the temperature variation law of the vehicle-mounted high-pressure hydrogen storage cylinder described by the existing model during the charging and discharging process is quite different from the actual test results. Therefore, how to further form a systematic thermodynamic model and improve the accuracy of the description of the temperature variation law during the charging and discharging process of the vehicle-mounted high-pressure hydrogen storage cylinder has become a problem to be solved in the field. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a vehicle-mounted high-pressure hydrogen storage cylinder thermodynamic analysis method and system, which comprehensively considers the real gas state parameter relationship of high-pressure gas and the heat transfer law between the gas, cylinder and environment, establishes a new analysis method for accurate calculation and analysis of the state parameters during the charging and discharging process of the high-pressure hydrogen storage cylinder.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] According to a first aspect of the present application, a vehicle-mounted high-pressure hydrogen storage cylinder thermodynamic analysis method is provided, comprising the following steps: S1, obtaining the structure, working condition and internal gas state of the vehicle-mounted high-pressure hydrogen storage cylinder; S2, based on the R-K real gas state equation, establishing the thermodynamic model of the hydrogen storage cylinder under adiabatic conditions during the charging and discharging process; S3, based on the convective heat transfer relationship between the internal gas of the vehicle-mounted high-pressure hydrogen storage cylinder, the cylinder wall and the external environment, establishing the thermodynamic model of the hydrogen storage cylinder under convective heat transfer conditions during the charging and discharging process; S4, based on the thermodynamic model of the hydrogen storage cylinder under adiabatic conditions during the charging and discharging process and the thermodynamic model of the hydrogen storage cylinder under convective heat transfer conditions during the charging and discharging process, carrying out temperature calculation of the vehicle-mounted high-pressure hydrogen storage cylinder, obtaining the variation law of the vehicle-mounted high-pressure hydrogen storage cylinder during the charging and discharging process, and completing the thermodynamic analysis of the vehicle-mounted high-pressure hydrogen storage cylinder.

[0007] As a preferred technical solution, the cylinder wall is divided into a heat-insulating cylinder wall and a heat-conducting cylinder wall according to different types of materials.

[0008] As a preferred technical solution, S3 specifically includes: establishing a bottle wall heat transfer model for the filling and releasing process based on the convective heat transfer relationship between the bottle wall and the gas inside the vehicle-mounted high-pressure hydrogen storage cylinder, and between the bottle wall and the surrounding environment; and establishing a hydrogen storage cylinder thermodynamic model for the filling and releasing process under convective heat transfer conditions based on the bottle wall heat transfer model and the thermodynamic model for the filling and releasing process under adiabatic conditions.

[0009] As a preferred technical solution, the thermodynamic model of the hydrogen storage bottle during the filling process under adiabatic conditions is as follows:

[0010]

[0011] In the formula, T in The temperature of the gas inside the hydrogen storage cylinder during the filling process is m. in c represents the mass of gas inside the hydrogen storage cylinder during the filling process. Vin c is the specific heat capacity of the gas at constant volume during the inflation process. V∞ T is the constant-volume specific heat capacity of the gas entering the hydrogen storage cylinder during the filling process, R is the gas constant, and T is the specific heat capacity at constant volume. ∞ The temperature of the gas entering the hydrogen storage tank during the filling process, m ∞ Let M be the mass of the gas entering the hydrogen storage tank during the filling process, V be the molar mass of the gas, a be the volume of the hydrogen storage tank, and a and b be the RK constants of hydrogen.

[0012] As a preferred technical solution, the thermodynamic model of the hydrogen storage bottle during the venting process under adiabatic conditions is as follows:

[0013]

[0014] In the formula, T out The temperature of the gas inside the hydrogen storage cylinder during the venting process is m. out c represents the mass of gas inside the hydrogen storage cylinder during the venting process. Vout This is the specific heat capacity of the gas at constant volume during the venting process.

[0015] As a preferred technical solution, the heat transfer model of the bottle wall during the inflation process is as follows:

[0016]

[0017] In the formula, T w_in A represents the average temperature of the hydrogen storage cylinder wall during the filling process. in Let m be the surface area of ​​the inner wall of the hydrogen storage cylinder. w c is the total mass of the hydrogen storage cylinder wall. w_in q represents the average specific heat capacity of the hydrogen storage cylinder wall during the filling process, c is the correlation coefficient with the hydrogen storage cylinder parameters, and q represents the average specific heat capacity of the hydrogen storage cylinder wall during the filling process. m_in d represents the mass flow rate of hydrogen during the filling process. in c is the diameter of the hydrogen storage cylinder interface during the filling process. p_inLet λ be the specific heat capacity of hydrogen at constant pressure during the filling process, λ be the thermal conductivity of hydrogen, and SOC be the specific heat capacity of hydrogen at constant pressure. in The state of hydrogen gas inside the hydrogen storage cylinder during the filling process, L is the characteristic length of the hydrogen storage cylinder, and D is the hydrogen gas state inside the cylinder. in Let a be the inner diameter of the hydrogen storage cylinder. n And n are constants related to the flow state, g is the acceleration due to gravity, and β in β is the coefficient of volume expansion of hydrogen during the filling process. e ΔT is the coefficient of volumetric expansion of air during the inflation process, and ΔT is the temperature difference between the gas and the bottle wall. e v is the temperature difference between the air and the bottle wall. in v is the kinematic viscosity of hydrogen during the filling process. e The kinematic viscosity of air during the inflation process, μ in The dynamic viscosity of hydrogen during the filling process, μ e c represents the aerodynamic viscosity during the inflation process. p_e A is the specific heat capacity of air at constant pressure during the inflation process. out T is the surface area of ​​the outer wall of the hydrogen storage cylinder. e D represents the ambient temperature. out This refers to the outer diameter of the hydrogen storage cylinder.

[0018] As a preferred technical solution, the thermodynamic model of the hydrogen storage bottle during the gas filling process under convective heat transfer conditions is as follows:

[0019]

[0020] In the formula, q in The mass flow rate of hydrogen being filled into the storage cylinder during the filling process.

[0021] As a preferred technical solution, the heat transfer model of the bottle wall during the venting process is as follows:

[0022]

[0023] In the formula, T w_out c is the average temperature of the hydrogen storage cylinder wall during the venting process. w_out c is the average specific heat capacity of the hydrogen storage cylinder wall during the venting process. p_out β is the isobaric specific heat capacity of hydrogen during the gas release process. out v is the coefficient of volume expansion of hydrogen gas during the venting process; out Let μ be the kinematic viscosity of hydrogen during the outgassing process. out The kinetic viscosity of hydrogen during the venting process.

[0024] As a preferred technical solution, the thermodynamic model of the hydrogen storage bottle for the gas release process under convective heat transfer conditions is as follows:

[0025]

[0026] In the formula, q outMass flow rate of the gaseous hydrogen out of the hydrogen storage cylinder during the discharge process.

[0027] According to a second aspect of the present application, a thermodynamic analysis system for a vehicle-mounted high-pressure hydrogen storage cylinder is provided, which is used to implement the thermodynamic analysis method, and comprises: a data acquisition module for acquiring the structure, working condition and internal gas state of the vehicle-mounted high-pressure hydrogen storage cylinder; a hydrogen storage cylinder thermodynamic model construction module under adiabatic condition for establishing hydrogen storage cylinder thermodynamic models under adiabatic conditions for the charging and discharging processes respectively based on a R-K real gas state equation; a hydrogen storage cylinder thermodynamic model construction module under convective heat transfer condition for establishing hydrogen storage cylinder thermodynamic models under convective heat transfer conditions for the charging and discharging processes respectively based on the convective heat transfer relationship among the internal gas of the vehicle-mounted high-pressure hydrogen storage cylinder, the cylinder wall and the external environment; and a vehicle-mounted high-pressure hydrogen storage cylinder thermodynamic analysis module for carrying out temperature calculation of the vehicle-mounted high-pressure hydrogen storage cylinder based on the hydrogen storage cylinder thermodynamic models under adiabatic conditions for the charging and discharging processes and the hydrogen storage cylinder thermodynamic models under convective heat transfer conditions for the charging and discharging processes, obtaining the variation law of the vehicle-mounted high-pressure hydrogen storage cylinder during the charging and discharging processes, and completing the thermodynamic analysis of the vehicle-mounted high-pressure hydrogen storage cylinder.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The thermodynamic analysis method for a vehicle-mounted high-pressure hydrogen storage cylinder provided by the present application considers the high-pressure environment of the internal gas of the vehicle-mounted high-pressure hydrogen storage cylinder, uses the real gas R-K equation to describe the state of the internal gas of the vehicle-mounted high-pressure hydrogen storage cylinder, and sequentially establishes the thermodynamic mathematical models of the vehicle-mounted high-pressure hydrogen storage cylinder under adiabatic conditions and under convective heat transfer conditions, thereby forming a more systematic and comprehensive thermodynamic model of the vehicle-mounted high-pressure hydrogen storage cylinder, which can effectively improve the temperature analysis accuracy of the vehicle-mounted high-pressure hydrogen storage cylinder.

[0030] 2. The method provided by the present application considers the convective heat transfer among the internal gas of the vehicle-mounted high-pressure hydrogen storage cylinder, the cylinder wall and the surrounding environment, respectively describes the heat transfer process of the vehicle-mounted high-pressure hydrogen storage cylinder from the charging and discharging states, and on the basis of establishing the thermodynamic model under adiabatic conditions for the hydrogen storage cylinder with good heat insulation effect, also constructs the cylinder wall heat transfer model for the charging and discharging processes of the hydrogen storage cylinder with good heat conduction performance, and further establishes the complete thermodynamic mathematical model of the vehicle-mounted high-pressure hydrogen storage cylinder under convective heat transfer conditions, thereby providing theoretical and technical support for the thermodynamic analysis of various types of vehicle-mounted high-pressure hydrogen storage cylinders.

[0031] 3. The thermodynamic analysis method provided by the present application is used for the vehicle-mounted high-pressure hydrogen storage cylinder of the fuel supply of the vehicle power device, and aims to optimize the thermodynamic analysis in the fuel supply arrangement design of the vehicle power device, and the application of the method is helpful to ensure the efficient, safe and reliable operation of the hydrogen fuel supply system. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1A flow chart of a modeling process of a thermodynamic model of a vehicle-mounted high-pressure hydrogen storage cylinder in an embodiment of the present application;

[0033] Figure 2 A structural schematic diagram of a vehicle-mounted high-pressure hydrogen storage cylinder in an embodiment of the present application;

[0034] Figure 3 A temperature variation law (charging / gas discharging) of a vehicle-mounted high-pressure hydrogen storage system under a convection heat exchange condition in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present application, and gives a detailed implementation manner and specific operation process, but the protection scope of the present application is not limited to the following embodiments.

[0036] EMBODIMENT

[0037] The present embodiment provides a thermodynamic analysis method of a vehicle-mounted high-pressure hydrogen storage cylinder, which comprises the following steps:

[0038] Step S1, obtaining a structure, working condition and internal gas state of the vehicle-mounted high-pressure hydrogen storage cylinder;

[0039] Step S2, respectively establishing thermodynamic models of the hydrogen storage cylinder in the charging and discharging processes under an adiabatic condition based on a R-K real gas state equation;

[0040] Step S3, respectively establishing thermodynamic models of the hydrogen storage cylinder in the charging and discharging processes under a convection heat exchange condition based on a convection heat exchange relationship among the internal gas of the vehicle-mounted high-pressure hydrogen storage cylinder, the cylinder wall and the external environment;

[0041] Step S4, carrying out temperature calculation of the vehicle-mounted high-pressure hydrogen storage cylinder based on the thermodynamic models of the charging and discharging processes under the adiabatic condition and the thermodynamic models of the charging and discharging processes under the convection heat exchange condition, obtaining a variation law of the charging and discharging processes of the vehicle-mounted high-pressure hydrogen storage cylinder, and completing the thermodynamic analysis of the vehicle-mounted high-pressure hydrogen storage cylinder.

[0042] The vehicle-mounted high-pressure hydrogen storage cylinder is used for storing high-pressure hydrogen gas and serves as a fuel supply source of a hydrogen fuel cell power device to supply fuel for a vehicle fuel system.

[0043] It can be understood that the present embodiment does not limit the type and structure of the vehicle-mounted high-pressure hydrogen storage cylinder, and the present method can be applied to analyze the required vehicle-mounted high-pressure hydrogen storage cylinder. In order to facilitate the description, a certain type of vehicle-mounted high-pressure hydrogen storage cylinder shown in FIG. 1 is used to describe the scheme of the present embodiment. Figure 1

[0044] As shown in FIG. 1, the vehicle-mounted high-pressure hydrogen storage cylinder comprises a cylinder body 1, a cylinder head 2 and a cylinder neck 3. Figure 2 ​As shown, the thermodynamic analysis system of the on-board high-pressure hydrogen storage cylinder is composed of three parts: ① stored high-pressure hydrogen gas (gas); ② inner liner and carbon fiber reinforced composite material layer (cylinder wall); and ③ external environment (environment). Among them, d represents the interface diameter of the hydrogen storage cylinder, L represents the total length of the hydrogen storage cylinder, D in represents the inner diameter of the hydrogen storage cylinder, and D out represents the outer diameter of the hydrogen storage cylinder. The internal gas temperature of the on-board high-pressure hydrogen storage cylinder must be between -40°C and 85°C, and the hydrogenation time needs to be controlled within 3 minutes.

[0045] As shown in Figure 1 , the on-board high-pressure hydrogen storage cylinder has two working conditions of charging and discharging. In the charging condition, hydrogen is continuously charged into the cylinder, and the internal hydrogen is compressed to produce a corresponding temperature rise; in the discharging condition, hydrogen is continuously discharged from the cylinder, and the internal hydrogen expands to produce a corresponding temperature drop. According to the different materials of the on-board high-pressure hydrogen storage cylinder, during the charging or discharging process, some types of hydrogen storage cylinders have good thermal insulation effect, and the gas in the cylinder cannot exchange heat with the outside world in time, and is in adiabatic condition; the hydrogen gas in the hydrogen storage cylinder generates heat, which is conducted to the cylinder wall through the inner liner and the composite material layer, and then dissipated to the external environment of the cylinder in the form of natural convection.

[0046] At the same time, during the charging and discharging process of the on-board high-pressure hydrogen storage cylinder, there is a strong jet flow of internal hydrogen, with a large amplitude of pressure and density change, which needs to be described by the R-K real gas state equation. Based on the real gas state equation, the thermodynamic mathematical model of the charging process of the on-board high-pressure hydrogen storage cylinder under adiabatic condition can be described as:

[0047]

[0048] In the formula, T in is the temperature of the gas in the hydrogen storage cylinder during the charging process, m in is the mass of the gas in the hydrogen storage cylinder during the charging process, c Vin is the specific heat capacity at constant volume of the gas during the charging process, c V∞ is the specific heat capacity at constant volume of the gas entering the hydrogen storage cylinder during the charging process, R is the gas constant, T ∞ is the temperature of the gas entering the hydrogen storage cylinder during the charging process, m ∞ is the mass of the gas entering the hydrogen storage cylinder during the charging process, M is the molar mass of the gas, V is the volume of the hydrogen storage cylinder, and a and b are the R-K constants of hydrogen.

[0049] The thermodynamic mathematical model of the discharging process of the on-board high-pressure hydrogen storage cylinder under adiabatic condition can be described as:

[0050]

[0051] In the formula, T out is the temperature of the gas in the hydrogen storage cylinder during the discharging process, m outThe gas mass in the hydrogen storage cylinder during the gassing process; c Vout The specific heat capacity of the gas during the gassing process.

[0052] When the thermal conductivity of the material of the on-board high-pressure hydrogen storage cylinder is good, the hydrogen storage cylinder exchanges heat with the external environment during the gassing or degassing process. The heat exchange process of the cylinder wall during the gassing process can be described as:

[0053]

[0054] In the formula, T w_in The average temperature of the hydrogen storage cylinder wall during the gassing process; A in The surface area of the inner wall of the hydrogen storage cylinder; m w The total mass of the hydrogen storage cylinder wall; c w_in The average specific heat capacity of the hydrogen storage cylinder wall during the gassing process; c is a coefficient related to the parameters of the hydrogen storage cylinder; q m_in The mass flow rate of hydrogen during the gassing process; d in The interface diameter of the hydrogen storage cylinder during the gassing process; c p_in The specific heat capacity of hydrogen at constant pressure during the gassing process; λ is the thermal conductivity of hydrogen; SOC in The state of hydrogen in the hydrogen storage cylinder during the gassing process; L is the characteristic length of the hydrogen storage cylinder; D in The inner diameter of the hydrogen storage cylinder; a n And n are constants related to the flow state; g is the acceleration of gravity; β in The volume expansion coefficient of hydrogen during the gassing process; β e The volume expansion coefficient of air during the gassing process; ΔT is the temperature difference between the gas and the cylinder wall; ΔT e The temperature difference between air and the cylinder wall; v in The kinematic viscosity of hydrogen during the gassing process; v e The kinematic viscosity of air during the gassing process; μ in The dynamic viscosity of hydrogen during the gassing process; μ e The dynamic viscosity of air during the gassing process; c p_e The specific heat capacity of air at constant pressure during the gassing process; A out The surface area of the outer wall of the hydrogen storage cylinder; T e The ambient temperature; D out The outer diameter of the hydrogen storage cylinder.

[0055] The heat exchange process of the cylinder wall during the degassing process can be described as:

[0056]

[0057] In the formula, T w_out The average temperature of the hydrogen storage cylinder wall during the degassing process, c w_cut The average specific heat capacity of the hydrogen storage cylinder wall during the degassing process, c p_outβ is the specific heat capacity at constant pressure of hydrogen during the discharge process out v is the volume expansion coefficient of hydrogen during the discharge process out μ is the kinematic viscosity of hydrogen during the discharge process out is the dynamic viscosity of hydrogen during the discharge process.

[0058] The thermodynamic mathematical model of the charging process can be described as:

[0059]

[0060] q is the mass flow rate of hydrogen into the hydrogen storage cylinder during the charging process. in

[0061] The thermodynamic mathematical model of the discharge process can be described as:

[0062]

[0063] q is the mass flow rate of hydrogen out of the hydrogen storage cylinder during the discharge process. out

[0064] To carry out temperature calculation of the on-board high-pressure hydrogen storage cylinder, a Matlab / SIMULINK calculation platform for thermodynamic analysis of the on-board high-pressure hydrogen storage cylinder is built based on the above mathematical model of the on-board high-pressure hydrogen storage cylinder, and the simulation step, solver, simulation accuracy, etc. are set for calculation. The temperature variation law of the on-board high-pressure hydrogen storage system during the charging and discharging processes under the condition of convective heat transfer is studied, as shown in FIG. 1. Figure 3 According to the established thermodynamic mathematical model, the temperature variation law of the real gas in the on-board hydrogen storage cylinder under the condition of convective heat transfer in a high-pressure environment can be analyzed, which provides theoretical and technical support for thermodynamic analysis of various types of on-board high-pressure hydrogen storage cylinders, and helps to ensure efficient, safe and reliable operation of the hydrogen fuel supply system of the vehicle power device.

[0065] ​​Further, the embodiment also provides a vehicle-mounted high-pressure hydrogen storage bottle thermodynamic analysis system for realizing each step of the foregoing thermodynamic analysis method, including a data acquisition module, an adiabatic condition hydrogen storage bottle thermodynamic model construction module, a convection heat exchange condition hydrogen storage bottle thermodynamic model construction module, and a vehicle-mounted high-pressure hydrogen storage bottle thermodynamic analysis module. The data acquisition module is used to acquire the structure, working condition and internal gas state of the vehicle-mounted high-pressure hydrogen storage bottle. The adiabatic condition hydrogen storage bottle thermodynamic model construction module is used to establish the hydrogen storage bottle thermodynamic model of the charging and discharging processes under adiabatic condition based on the R-K real gas state equation. The convection heat exchange condition hydrogen storage bottle thermodynamic model construction module is used to establish the hydrogen storage bottle thermodynamic model of the charging and discharging processes under convection heat exchange condition based on the convection heat exchange relationship among the internal gas of the vehicle-mounted high-pressure hydrogen storage bottle, the bottle wall and the external environment. The vehicle-mounted high-pressure hydrogen storage bottle thermodynamic analysis module is used to carry out temperature calculation of the vehicle-mounted high-pressure hydrogen storage bottle based on the thermodynamic model of the charging and discharging processes under adiabatic condition and the hydrogen storage bottle thermodynamic model of the charging and discharging processes under convection heat exchange condition, to obtain the change rule of the charging and discharging processes of the vehicle-mounted high-pressure hydrogen storage bottle, and to complete the thermodynamic analysis of the vehicle-mounted high-pressure hydrogen storage bottle. The specific execution process and method steps are consistent, and will not be described here again.

[0066] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations without creative work based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art according to the concept of the present application shall be within the protection scope determined by the claims.

Claims

1. A thermodynamic analysis method for an on-board high-pressure hydrogen storage cylinder, characterized in that, Includes the following steps: S1, obtain the structure, operating conditions and internal gas state of the on-board high-pressure hydrogen storage cylinder; S2, Based on the RK real gas equation of state, thermodynamic models of the hydrogen storage bottle for the filling and venting processes under adiabatic conditions are established respectively; among them, the thermodynamic model of the hydrogen storage bottle for the filling process under adiabatic conditions is as follows: In the formula, The temperature of the gas inside the hydrogen storage cylinder during the filling process. The mass of the gas inside the hydrogen storage cylinder during the filling process. This refers to the specific heat capacity of the gas at constant volume during the inflation process. This refers to the specific heat capacity at constant volume of the gas entering the hydrogen storage cylinder during the filling process. The gas constant is The temperature at which the gas enters the hydrogen storage tank during the filling process. The mass of the gas entering the hydrogen storage tank during the filling process. For gas molar mass, This refers to the volume of the hydrogen storage cylinder. and RK constant for hydrogen; The thermodynamic model of the hydrogen storage bottle during the venting process under adiabatic conditions is as follows: In the formula, The temperature of the gas inside the hydrogen storage bottle during the venting process. This refers to the mass of gas inside the hydrogen storage cylinder during the venting process. This refers to the specific heat capacity of the gas at constant volume during the venting process. S3, based on the convective heat transfer relationship between the internal gas, the cylinder wall, and the external environment of the on-board high-pressure hydrogen storage cylinder, establishes thermodynamic models of the hydrogen storage cylinder during the filling and releasing processes under convective heat transfer conditions; S3 specifically includes: Based on the convective heat transfer relationships between the cylinder wall and the internal gas of the on-board high-pressure hydrogen storage cylinder, and between the cylinder wall and the surrounding environment, a cylinder wall heat transfer model is established for the filling and degassing processes; wherein, the cylinder wall heat transfer model for the filling process is as follows: In the formula, The average temperature of the hydrogen storage cylinder wall during the filling process. The surface area of ​​the inner wall of the hydrogen storage cylinder. This represents the total mass of the hydrogen storage cylinder wall. The average specific heat capacity of the hydrogen storage cylinder wall during the filling process. The correlation coefficient with the parameters of the hydrogen storage cylinder, This refers to the mass flow rate of hydrogen during the filling process. The diameter of the hydrogen storage cylinder inlet during the filling process. The isobaric specific heat capacity of hydrogen during the filling process. The thermal conductivity of hydrogen gas. This refers to the state of hydrogen gas inside the hydrogen storage cylinder during the filling process. The characteristic length of the hydrogen storage cylinder The inner diameter of the hydrogen storage cylinder and It is a constant related to the flow state. It is the acceleration due to gravity. This represents the volume expansion coefficient of hydrogen during the filling process. This is the coefficient of volumetric expansion of air during the inflation process. The temperature difference between the gas and the bottle wall. The temperature difference between the air and the bottle wall. The viscosity of hydrogen gas during the filling process is given by its kinematic viscosity. The viscosity of air during the inflation process. The dynamic viscosity of hydrogen during the filling process. The aerodynamic viscosity during the inflation process. This refers to the specific heat capacity of air at constant pressure during the inflation process. The surface area of ​​the outer wall of the hydrogen storage cylinder. For ambient temperature, The outer diameter of the hydrogen storage cylinder; The heat transfer model of the bottle wall during the venting process is as follows: In the formula, This represents the average temperature of the hydrogen storage cylinder wall during the venting process. This refers to the average specific heat capacity of the hydrogen storage cylinder wall during the venting process. This refers to the isobaric specific heat capacity of hydrogen during the gas release process. The coefficient of volume expansion of hydrogen gas during the venting process; The viscosity of hydrogen gas during the venting process is given by its kinematic viscosity. The dynamic viscosity of hydrogen during the venting process; Based on the aforementioned bottle wall heat transfer model and the thermodynamic model of the filling and releasing process under adiabatic conditions, a thermodynamic model of the hydrogen storage bottle for the filling and releasing processes under convective heat transfer conditions is established; wherein, the thermodynamic model of the hydrogen storage bottle for the filling process under convective heat transfer conditions is as follows: In the formula, The mass flow rate of hydrogen storage cylinders filled during the filling process; The thermodynamic model of the hydrogen storage bottle for the gas release process under convective heat transfer conditions is as follows: In the formula, This refers to the mass flow rate of hydrogen exiting the storage tank during the venting process. S4. Based on the thermodynamic model of the filling and degassing process under the adiabatic conditions and the thermodynamic model of the hydrogen storage cylinder under the convective heat transfer conditions, the temperature of the vehicle-mounted high-pressure hydrogen storage cylinder is calculated to obtain the change law of the filling and degassing process of the vehicle-mounted high-pressure hydrogen storage cylinder, and the thermodynamic analysis of the vehicle-mounted high-pressure hydrogen storage cylinder is completed.

2. The thermodynamic analysis method for on-board high-pressure hydrogen storage cylinders according to claim 1, characterized in that, The bottle walls are classified into heat-insulating bottle walls and heat-conducting bottle walls based on different types of materials.

3. A vehicle-mounted high-pressure hydrogen storage cylinder thermodynamic analysis system, characterized in that, The system is used to implement the thermodynamic analysis method as described in any one of claims 1-2, comprising: The data acquisition module is used to acquire information about the structure, operating conditions, and internal gas state of the on-board high-pressure hydrogen storage cylinder. The module for constructing thermodynamic models of hydrogen storage cylinders under adiabatic conditions is used to establish thermodynamic models of hydrogen storage cylinders for the filling and venting processes under adiabatic conditions based on the RK real gas equation of state. A module for constructing thermodynamic models of hydrogen storage cylinders under convective heat transfer conditions is used to establish thermodynamic models of hydrogen storage cylinders during the filling and releasing processes under convective heat transfer conditions, based on the convective heat transfer relationship between the internal gas, cylinder wall, and external environment of the on-board high-pressure hydrogen storage cylinder; and The on-board high-pressure hydrogen storage cylinder thermodynamic analysis module is used to perform temperature calculations on the on-board high-pressure hydrogen storage cylinder based on the thermodynamic models of the filling and releasing processes under the adiabatic conditions and the thermodynamic models of the hydrogen storage cylinder under the convective heat transfer conditions, to obtain the change law of the filling and releasing processes of the on-board high-pressure hydrogen storage cylinder, and to complete the thermodynamic analysis of the on-board high-pressure hydrogen storage cylinder.

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