Numerical simulation method of hybrid power generation system based on pemfc and hydrogen ammonia fusion internal combustion engine

Abstract

This invention discloses a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, relating to the field of hydrogen power generation technology. Based on the initial inlet temperature and average temperature of the internal reaction zone of the ammonia decomposer, as well as the mole fraction of each gas component in the ammonia decomposer, the fuel flow of the proton exchange membrane fuel cell and the hydrogen-ammonia fusion internal combustion engine is calculated. The exhaust temperature of the hydrogen-ammonia fusion internal combustion engine, as well as the current density and output voltage of the proton exchange membrane fuel cell, are then calculated accordingly. Based on the exhaust temperature, the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone are updated. The process is iteratively updated based on the updated inlet temperature and the average temperature of the internal reaction zone until the relative error between two adjacent calculations of the inlet temperature is less than or equal to a preset error setpoint. Then, based on the operating status data of the last iteration, the performance indicators of the hybrid power generation system are determined. This method improves the accuracy of calculating the performance indicators of the hybrid power generation system.

Description

Technical Field

[0001] This invention relates to the field of hydrogen power generation technology, and in particular to a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine. Background Technology

[0002] Hydrogen energy is a key secondary energy source for achieving renewable energy conversion at present, and energy storage and conversion systems based on hydrogen energy are gradually being established. Ammonia, as a carbon-free hydrogen energy carrier, has a volumetric energy density of approximately 11 MJ / L, exceeding that of liquid hydrogen, making it a hydrogen energy storage medium with high space utilization. However, the decomposition of hydrogen from ammonia faces high reaction barriers, requiring high heat and a relatively harsh reaction environment to release hydrogen energy, resulting in low overall energy efficiency of ammonia-based power generation or energy consumption systems. Addressing the practical problem of low energy conversion system efficiency due to the high energy demand of ammonia decomposition, the large amount of waste heat generated during hydrogen power generation has the potential to provide thermal energy for ammonia decomposition. Therefore, utilizing the waste heat from proton exchange membrane fuel cells (PEMFCs) and internal combustion engines (ICEs) to supplement the energy consumed by ammonia decomposition, and matching the different efficiency-load relationships of the two power generation systems with the required hydrogen and ammonia fuel components, is the key technological foundation for improving the performance of ammonia-based power generation systems.

[0003] Existing hybrid power generation systems combining ammonia decomposers, proton exchange membrane fuel cells, and hydrogen-ammonia fusion internal combustion engines suffer from several problems, including unclear understanding of internal subsystem phenomena, ambiguous energy efficiency calculation methods, blurred boundaries of material-energy interactions among internal components, and difficulties in analyzing system phenomena and efficiency. Iterative system development through experimental techniques is costly, and limitations in experimental technology and subsystem integration coefficients make it difficult to provide detailed distribution information guiding the optimization of energy-mass flow coupling transport. Constructing low-dimensional multi-field modeling of hybrid power generation systems, based on numerical models of the energy and mass transport characteristics of each subsystem, and achieving information transfer through the boundaries of mutually coupled subsystems, is an effective means to improve the synergistic benefits of energy and mass transport, thereby guiding the improvement of system energy efficiency. Current low-dimensional multi-field modeling methods for hybrid power generation systems are relatively lacking compared to traditional thermodynamic systems such as thermal power generation systems. Existing thermodynamic-based modeling methods fail to reflect the operating characteristics of subsystems, resulting in models that appear coupled but are actually decoupled in calculations, failing to reflect the changes in physical quantities within subsystems. Consequently, the system model cannot accurately reflect the actual operating state of the hybrid power generation system. Summary of the Invention

[0004] Therefore, it is necessary to provide a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine to address the above-mentioned technical problems. This method improves the accuracy of calculating the performance indicators of the hybrid power generation system.

[0005] The present invention adopts the following technical solution: This invention provides a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine. The hybrid power generation system includes an ammonia decomposer, a proton exchange membrane fuel cell, and a hydrogen-ammonia fusion internal combustion engine. The method includes: Based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer, calculate the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine. The exhaust temperature of the hydrogen-ammonia fusion internal combustion engine is calculated based on the pressure rise ratio, intake temperature, and initial expansion ratio of the isochoric turbocharging process. Calculate the current density and output voltage of the proton exchange membrane fuel cell based on the total mass flow rate, the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, and the operating temperature. Based on the exhaust temperature, the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone are updated by the system energy balance equation; the system energy balance equation is used to describe the effect of the waste heat from the internal combustion engine and the waste heat from the fuel cell on the vaporization and heating of liquid ammonia. Based on the updated inlet temperature and the average temperature of the internal reaction zone, the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone are iteratively updated until the relative error between two adjacent calculated inlet temperatures is less than or equal to the preset error setting value. Then, based on the operating status data of the last iteration, the performance indicators of the hybrid power generation system are determined.

[0006] Optionally, based on the initial inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone, as well as the mole fraction of each gas component in the ammonia decomposer, the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine include: The ammonia fuel conversion rate of the ammonia decomposer is calculated based on the initial inlet temperature and the average temperature of the internal reaction zone of the ammonia decomposer, as well as the mole fraction of each gas component in the ammonia decomposer. Based on the ammonia fuel conversion rate, the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and fuel mole fraction entering the hydrogen-ammonia fusion internal combustion engine are calculated using the system distribution component transfer equation. The system distribution component transfer equation is used to describe the mass flow rate and gas mole fraction from the liquid ammonia source to the hydrogen-ammonia fusion internal combustion engine and fuel cell.

[0007] Optionally, the formula for calculating the ammonia fuel conversion rate of the ammonia decomposer is: ; ; in, The ammonia fuel conversion rate of the ammonia decomposer; and These represent the inlet position of the ammonia decomposer and its length in the flow channel direction. x = L R The ammonia concentration at the location; L R This is the total length of the ammonia decomposer; This refers to the absolute pressure within the ammonia decomposer. It is the ideal gas constant; This refers to the inlet temperature of the ammonia decomposer. It is obtained by solving the governing equations for gas components along the flow direction in the ammonia decomposer; the governing equations for gas components are: ; ; in, The velocity of the gas flow in the ammonia decomposer; For the first molar concentration of each component gas ; The flow cross-sectional area of ​​the ammonia decomposer; The first in the chemical reaction of ammonia decomposition Stoichiometric coefficients of the chemical reactions of the component gases; This is the reaction rate source term, representing the amount of ammonia gas that undergoes decomposition reaction per unit time with a unit mass of catalyst. The total mass of the catalyst in the ammonia decomposer. It is the reaction rate constant; It is the activation energy of the reaction; This is the average temperature of the reaction zone inside the ammonia decomposer. This refers to the absolute pressure at which the ammonia decomposer operates; and These are the mole fractions of hydrogen and ammonia, respectively. and This is the reaction index.

[0008] Optionally, the fuel mole fraction includes the mole fractions of ammonia and hydrogen; the system distribution component transfer equations include: ; ; ; ; ; ; ; ; in, This refers to the total mass flow rate of fuel entering a proton exchange membrane fuel cell. The proportion of fuel diverted to supplement the heat of the ammonia burner; The separation efficiency of the hydrogen-ammonia separator; , , These represent the fuel proportions for the first, second, and third splits to the hydrogen-ammonia fusion internal combustion engine, respectively. The first split occurs at the ammonia source, the second split occurs after the ammonia decomposer, and the third split occurs after the hydrogen-ammonia separator. The mass flow rate of ammonia from the ammonia source into the entire system; , These are the mole fractions of ammonia and hydrogen in the fuel stream at the outlet of the ammonia decomposer, respectively. The total mass flow rate of fuel entering the hydrogen-ammonia fusion internal combustion engine; and These are the mole fractions of ammonia and hydrogen entering the hydrogen-ammonia fusion internal combustion engine, respectively. This represents the ratio of the molar mass of fuel before and after the ammonia decomposer.

[0009] Optionally, the formula for calculating the exhaust temperature is: ; in, and These are the intake and exhaust temperatures of the hydrogen-ammonia fusion internal combustion engine, respectively. is the isentropic index of the circulating working fluid, and is the ratio of the gas's isobaric specific heat capacity to its isochoric specific heat capacity; The pressure rise ratio of a hydrogen-ammonia fusion internal combustion engine; This refers to the initial expansion ratio during the isochoric turbocharging process of a hydrogen-ammonia fusion internal combustion engine.

[0010] Optionally, the current density and output voltage of the proton exchange membrane fuel cell are calculated based on the total mass flow rate of the proton exchange membrane fuel cell, the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, and the operating temperature, including: Based on the total mass flow rate and operating temperature of the proton exchange membrane fuel cell, the physical quantity distribution equation is solved to obtain the current density of the proton exchange membrane fuel cell. The voltage calculation equation is solved based on the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, the current density and the operating temperature to obtain the output voltage of the proton exchange membrane fuel cell. The equation for the distribution of physical quantities is: ; in, Length in the flow channel direction; and For the water vapor concentration and oxygen concentration of a proton exchange membrane fuel cell; This represents the current density of a proton exchange membrane fuel cell. This refers to the gas flow rate within the cathode channel of a proton exchange membrane fuel cell. It is Faraday's constant; The height of the cathode gas flow channel in a proton exchange membrane fuel cell; It is a dimensionless constant; The membrane water content of a proton exchange membrane fuel cell; This represents the leakage current density of a proton exchange membrane fuel cell. , and These are the resistance values ​​that describe the effects of membrane wetting state, gas concentration characteristics, and current distribution on the proton exchange membrane. It is the ideal gas constant; To calculate the effect of water activity, For the activity of water, , This refers to the saturation level of liquid water. This represents the water vapor concentration at gas-liquid equilibrium. , For saturation pressure, The operating temperature of a proton exchange membrane fuel cell. The calculation formula is: ; The calculation formula is: ; ; in, This represents the actual average current density of a proton exchange membrane fuel cell. This refers to the number of plates in the proton exchange membrane fuel cell stack. This represents the activation area of ​​a proton exchange membrane fuel cell; This is the stoichiometry of the cathode; This is the stoichiometric ratio of the anode; This represents the cross-sectional area of ​​the cathode flow channel in a proton exchange membrane fuel cell. This refers to the inlet concentration of oxygen in a proton exchange membrane fuel cell. This refers to the total mass flow rate of fuel entering a proton exchange membrane fuel cell. The voltage calculation equation is: ; ; ; ; ; ; ; in, This refers to the output voltage of a proton exchange membrane fuel cell. This is the reversible voltage of a proton exchange membrane fuel cell; The ohmic voltage drop of a proton exchange membrane fuel cell; This refers to the activation voltage drop of a proton exchange membrane fuel cell; The concentration overpotential of a proton exchange membrane fuel cell; and These are the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, respectively. The thickness of the proton exchange membrane; The empirical parameter for ohmic loss; and These are the reference current densities for the anode and cathode, respectively. c This is an empirical parameter for concentration loss; The limiting current density; , These are the operating pressures of the anode and cathode of a proton exchange membrane fuel cell, respectively. and These represent the relative humidity of the anode and cathode of a proton exchange membrane fuel cell, respectively.

[0011] Optionally, It is a piecewise function, specifically in the form of: ; .

[0012] Optionally, the boundary conditions of the physical quantity distribution equation include the inlet concentration of water vapor, the inlet concentration of oxygen, and the current density at the inlet location. The water vapor inlet concentration is: ; in, This represents the inlet concentration of water vapor in a proton exchange membrane fuel cell. The oxygen inlet concentration is: ; in, This refers to the inlet partial pressure of oxygen in the cathode of a proton exchange membrane fuel cell; Inlet current density of proton exchange membrane fuel cell Through actual average current density With calculation of average current density Determined by iterative updates following comparison; R m , R c and R J The specific form of the three resistors is as follows: ; in, This represents the equivalent molecular weight of a proton exchange membrane fuel cell. The density of the proton exchange membrane; The rate at which membrane water transforms into gaseous water; These are empirical parameters.

[0013] Optionally, the system energy balance equation is: ; in, , These are the average temperature and inlet temperature of the ammonia decomposer, respectively. The temperature change in the ammonia decomposer is due to the combined effects of ammonia burner reheating and internal ammonia decomposition endothermic heat absorption. ; in, The isobaric specific heat capacity of the fuel stream in the ammonia decomposer; It is the product of the combustion efficiency of the ammonia burner and the heat transfer efficiency to the ammonia decomposer; This is the absolute value of the enthalpy change during ammonia decomposition; This represents the molar mass of ammonia. This is the lower heating value of ammonia. The ammonia fuel conversion rate of the ammonia decomposer; The proportion of fuel diverted to supplement the heat of the ammonia burner; , These are the fuel ratios for the first and second splits to the hydrogen-ammonia fusion internal combustion engine, respectively. ; in, This is the vaporization temperature of liquid ammonia; The temperature of the liquid ammonia used as the ammonia source; , These are the isobaric specific heat capacities of liquid ammonia and ammonia gas, respectively. The latent heat of vaporization of liquid ammonia; , These represent the temperature rise caused by two heating processes of liquid ammonia: the cooling water of the proton exchange membrane fuel cell and the exhaust gas from the hydrogen-ammonia fusion internal combustion engine. ; ; in, , The heat exchange efficiency of proton exchange membrane fuel cell cooling water and hydrogen-ammonia fusion internal combustion engine exhaust gas to liquid ammonia are respectively. This refers to the number of plates in the proton exchange membrane fuel cell stack. This represents the activation area of ​​a proton exchange membrane fuel cell; This represents the actual average current density of a proton exchange membrane fuel cell. The specific heat capacity of the exhaust gas from a hydrogen-ammonia fusion internal combustion engine; The output voltage of a proton exchange membrane fuel cell Along the flow channel direction x The integral average; This is the reversible voltage of a proton exchange membrane fuel cell; and These are the intake and exhaust temperatures of the hydrogen-ammonia fusion internal combustion engine, respectively. The proportion of fuel diverted to supplement the heat of the ammonia burner; The separation efficiency of the hydrogen-ammonia separator; , , These represent the fuel proportions diverted to the hydrogen-ammonia fusion internal combustion engine for the 1st, 2nd, and 3rd time, respectively.

[0014] Optionally, the operating status data includes the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine, and the performance indicators include the output electric power of the hydrogen-ammonia fusion internal combustion engine; based on the operating status data of the last iteration, the performance indicators of the hybrid power generation system are determined, including: The total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine is determined based on the total mass flow rate and fuel mole fraction of the fuel entering the engine in the last iteration. The output electric power of the hydrogen-ammonia fusion internal combustion engine is determined based on the total fuel energy flowing into the engine and the actual thermal efficiency. The formula for calculating the total energy of imported fuel is: ; ; ; in, The total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine; The total mass flow rate of fuel flowing into the hydrogen-ammonia fusion internal combustion engine; and These are the lower heating values ​​of hydrogen and ammonia, respectively. and These are the mole fractions of hydrogen and ammonia, respectively. The molar mass of the fuel stream; This represents the mole fraction of nitrogen. The formula for calculating actual thermal efficiency is: ; ; in, This represents the actual thermal efficiency. This is the loss coefficient; For ideal cycle thermal efficiency; is the isentropic index of the circulating working fluid, and is the ratio of the gas's isobaric specific heat capacity to its isochoric specific heat capacity; This refers to the compression ratio of a hydrogen-ammonia fusion internal combustion engine. The pressure rise ratio of a hydrogen-ammonia fusion internal combustion engine; This refers to the initial expansion ratio during the isochoric turbocharging process of a hydrogen-ammonia fusion internal combustion engine.

[0015] This invention provides a numerical simulation device for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, comprising: The first calculation module is used to calculate the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and fuel mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer. The second calculation module is used to calculate the exhaust temperature of the hydrogen-ammonia fusion internal combustion engine based on the pressure rise ratio, intake temperature, and initial expansion ratio of the isochoric turbocharging process. The third calculation module is used to calculate the current density and output voltage of the proton exchange membrane fuel cell based on the total mass flow rate of the proton exchange membrane fuel cell, the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, and the operating temperature. The fourth calculation module is used to update the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone based on the exhaust temperature and the system energy balance equation. The system energy balance equation is used to describe the effect of the waste heat from the internal combustion engine and the waste heat from the fuel cell on the vaporization and heating of liquid ammonia. The update module is used to iteratively update the inlet temperature and the average temperature of the internal reaction zone of the ammonia decomposer based on the updated inlet temperature and the average temperature of the internal reaction zone, until the relative error between two adjacent calculated inlet temperatures is less than or equal to the preset error setting value. The determination module is used to determine the performance indicators of the hybrid power generation system based on the operating status data of the last iteration.

[0016] The present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine.

[0017] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine.

[0018] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects: In this invention, the initial inlet temperature, internal average temperature, and mole fraction of gas components of the ammonia decomposer are used as a basis to directly correlate the generation and distribution of subsequent fuels. Then, based on the total mass flow rate and mole fraction of fuel in the hydrogen-ammonia fusion internal combustion engine fuel, combined with operating parameters such as pressure rise ratio and inlet temperature, the output power and exhaust temperature are accurately calculated. Furthermore, based on the total mass flow rate of the proton exchange membrane fuel cell, the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, and the operating temperature, the current density and output voltage of the proton exchange membrane fuel cell are calculated. Finally, based on the exhaust temperature, the system energy balance equation used to describe the effect of waste heat from the internal combustion engine and fuel cell on the vaporization and heating of liquid ammonia is used to calculate the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone at the next iteration. Through the above calculations, a dynamic closed loop is achieved. This mechanism avoids the simplification error of treating energy flow as a "unidirectional linear process" and is closer to the complex characteristics of the interaction between "energy-matter-temperature" in the actual system. The iteration is repeated until the absolute value of the difference between two adjacent inlet temperatures is less than the set value (i.e., the system reaches a thermally stable state). At this point, the simulation calculation results are closer to the actual steady-state operating conditions. It effectively eliminates errors caused by isolated calculations and static assumptions, thus enabling accurate calculation of the performance indicators of fuel cells and internal combustion engines. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 A schematic flowchart of a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine provided by the present invention; Figure 2A schematic diagram of a hybrid power generation system provided by the present invention; Figure 3 A flowchart for calculating the distribution equation of physical quantities is provided for this invention; Figure 4 A schematic diagram of the numerical simulation method for another hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine provided by the present invention. Figure 5 The first step of the multi-field model establishment method for the proton exchange membrane fuel cell and hydrogen-based internal combustion engine hybrid power generation system provided by the present invention is the fuel cell model verification polarization curve. Figure 6 The verification curves of ammonia conversion rate at different ammonia decomposition temperatures in the third step of the multi-field model establishment method for the proton exchange membrane fuel cell and hydrogen-based internal combustion engine hybrid power generation system provided by the present invention. Figure 7 The third step of the multi-field model establishment method for the proton exchange membrane fuel cell and hydrogen-based internal combustion engine hybrid power generation system provided by the present invention is the ammonia conversion rate verification curve of the ammonia decomposer at different ammonia volume space velocities. Figure 8 The curves showing the variation of ammonia conversion rate of the ammonia decomposer in the hybrid power generation system under different ammonia mass flow rates are provided by the multi-field model establishment method of the proton exchange membrane fuel cell and hydrogen-based internal combustion engine hybrid power generation system provided by the present invention. Figure 9 The output power variation curves of the internal combustion engine, fuel cell and total system in the hybrid power generation system under different ammonia mass flow rates are provided by the multi-field model establishment method of the proton exchange membrane fuel cell and hydrogen-based internal combustion engine hybrid power generation system provided by the present invention. Figure 10 The curves showing the variation of energy efficiency of the internal combustion engine, fuel cell, and overall system in the hybrid power generation system under different ammonia mass flow rates, based on the multi-field model establishment method of the proton exchange membrane fuel cell and hydrogen-based internal combustion engine hybrid power generation system provided by the present invention. Figure 11 A schematic diagram of a computer device for implementing a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, provided by the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] This invention addresses the problem that existing system models often differ significantly from actual systems, failing to reflect the changing characteristics of physical quantities within subsystems. By constructing subsystem models of an ammonia decomposer, a proton exchange membrane fuel cell, and a hydrogen-ammonia fusion internal combustion engine, and establishing data interaction boundaries between subsystems, this method forms the energy and mass flow transfer function of the hybrid power generation system. Under different system operating parameters, this method enables numerical calculation and characteristic analysis of the output characteristics and internal distribution patterns of the hybrid power generation system.

[0023] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, as described in this invention. The method specifically includes the following steps: S101, based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer, calculate the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine.

[0025] In one embodiment, such as Figure 2 As shown, Figure 2 This is a schematic diagram of a hybrid power generation system, which includes an ammonia decomposer, a proton exchange membrane fuel cell, a hydrogen-ammonia fusion internal combustion engine, heat exchanger 1, heat exchanger 2, an ammonia burner, and a hydrogen-ammonia separator. Liquid ammonia is vaporized into ammonia gas through heat exchangers 1 and 2, then converted into hydrogen and nitrogen gas through the ammonia decomposer, and finally purified into pure hydrogen gas through the hydrogen-ammonia separator. The ammonia burner generates heat energy by burning ammonia gas and transfers heat to the ammonia gas in the ammonia decomposer through the heat exchange structure, providing the heat energy required for the ammonia decomposition reaction. The pure hydrogen gas is utilized in two parts: one part enters the hydrogen-ammonia fusion internal combustion engine together with the ammonia gas to generate electricity, and the other part enters the fuel cell to generate electricity. The electrical energy generated by the hydrogen-ammonia fusion internal combustion engine and the fuel cell jointly supplies the electrical load, and the generated heat energy is recovered through heat exchangers 1 and 2 to heat the liquid ammonia and ammonia gas, reducing the fuel consumption of the ammonia burner.

[0026] Before performing numerical analysis on the hybrid power generation system, initial state data of the system can be obtained first. For example, initial state data includes the initial inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone, the mass flow rate of liquid ammonia at the system inlet, the proportions of each flow split, input operating and structural parameters, etc.

[0027] In one embodiment, the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and fuel mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine are calculated based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer. This includes: calculating the ammonia fuel conversion rate of the ammonia decomposer based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer; and calculating the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and fuel mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine using a system-allocated component transfer equation based on the ammonia fuel conversion rate. The system-allocated component transfer equation describes the mass flow rate and gas mole fraction from the liquid ammonia source to the hydrogen-ammonia fusion internal combustion engine and the proton exchange membrane fuel cell.

[0028] Specifically, a computational model for an ammonia decomposer is constructed. This model is used to calculate the relationship between the conversion rate of ammonia gas into hydrogen and nitrogen gas after catalytic reaction and the structure and operating parameters of the reactor.

[0029] The ammonia decomposer calculation model includes the formula for calculating the ammonia fuel conversion rate of the ammonia decomposer; the formula for calculating the ammonia fuel conversion rate of the ammonia decomposer is: (1); (2); in, The ammonia fuel conversion rate of the ammonia decomposer; and These represent the inlet position of the ammonia decomposer and its length in the flow channel direction. x = L R The ammonia concentration at the location; This is the total length of the ammonia decomposer; This refers to the absolute pressure within the ammonia decomposer. It is the ideal gas constant; This refers to the inlet temperature of the ammonia decomposer. It is obtained by solving the governing equations for gas components along the flow direction in the ammonia decomposer; the governing equations for gas components are: (3); (4); in, The velocity of the gas flow in the ammonia decomposer; For the first molar concentration of each component gas ; The flow cross-sectional area of ​​the ammonia decomposer; The first in the chemical reaction of ammonia decomposition Stoichiometric coefficients of the chemical reactions of the component gases; This is the reaction rate source term, representing the amount of ammonia gas that undergoes decomposition reaction per unit time with a unit mass of catalyst. The total mass of the catalyst in the ammonia decomposer. It is the reaction rate constant; It is the activation energy of the reaction; This is the average temperature of the reaction zone inside the ammonia decomposer. This refers to the absolute pressure at which the ammonia decomposer operates; and These are the mole fractions of hydrogen and ammonia, respectively. and The reaction index represents the influence of component characteristics on the reaction process.

[0030] The fuel mole fraction includes the mole fractions of ammonia and hydrogen; the system distribution component transfer equations include: the calculation formulas for the total mass flow rate of fuel entering the proton exchange membrane fuel cell, the calculation formulas for the total mass flow rate of fuel entering the hydrogen-ammonia fusion internal combustion engine, and the calculation formulas for the mole fractions of ammonia and hydrogen entering the hydrogen-ammonia fusion internal combustion engine.

[0031] The formula for calculating the total mass flow rate of fuel entering a proton exchange membrane fuel cell, based on material balance, is as follows: (5); (6); (7); (8); in, This refers to the total mass flow rate of fuel entering a proton exchange membrane fuel cell. The proportion of fuel diverted to supplement the heat of the ammonia burner; The separation efficiency of the hydrogen-ammonia separator; , , These represent the fuel proportions for the first, second, and third splits to the hydrogen-ammonia fusion internal combustion engine, respectively. The first split occurs at the ammonia source, the second split occurs after the ammonia decomposer, and the third split occurs after the hydrogen-ammonia separator. The mass flow rate of ammonia from the ammonia source into the entire system; , Here, represents the mole fractions of ammonia and hydrogen in the fuel stream at the outlet of the ammonia decomposer, respectively. The hydrogen-ammonia separator is considered sufficient to separate the inlet hydrogen and ammonia; therefore, the separation efficiency of the hydrogen-ammonia separator is... As shown in formula (6).

[0032] The formula for calculating the total mass flow rate of fuel entering a hydrogen-ammonia fusion internal combustion engine is as follows: (9); in, The total mass flow rate of fuel entering the hydrogen-ammonia fusion internal combustion engine.

[0033] The formulas for calculating the mole fractions of ammonia and hydrogen entering a hydrogen-ammonia fusion internal combustion engine are as follows: (10); (11); (12); in; and These are the mole fractions of ammonia and hydrogen entering the hydrogen-ammonia fusion internal combustion engine, respectively. This represents the ratio of the molar mass of fuel before and after the ammonia decomposer.

[0034] In one embodiment, since the ammonia decomposer requires the concentration of each gas component at the inlet as a definite solution condition, and since the inlet is pure ammonia, the concentrations of hydrogen and nitrogen components are 0. The ammonia concentration is related to the inlet pressure of the ammonia decomposer. (13); in, The concentration of imported ammonia gas. This is the absolute pressure in the ammonia decomposer.

[0035] S102, calculate the exhaust temperature of the hydrogen-ammonia fusion internal combustion engine based on the pressure rise ratio, intake temperature, and initial expansion ratio of the isochoric turbocharging process.

[0036] First, a calculation model for the output of a hydrogen-ammonia fusion internal combustion engine is constructed. This model is used to calculate the output electric power and exhaust temperature of the hydrogen-ammonia fusion internal combustion engine.

[0037] Specifically, the total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine is determined based on the total mass flow rate and mole fraction of the fuel entering the engine; the output electric power of the engine is determined based on the total fuel energy flowing into the engine and the actual thermal efficiency.

[0038] The total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine is determined by the composition of the inlet fuel gas and the calorific value of each component. Since the combustible fuel composition in the hybrid power generation system consists only of hydrogen and ammonia, the formula for calculating the total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine is as follows: (14); (15); in, The total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine; The total mass flow rate of fuel flowing into the hydrogen-ammonia fusion internal combustion engine; and These are the lower heating values ​​of hydrogen and ammonia, respectively. and These are the mole fractions of hydrogen and ammonia, respectively. The molar mass of the fuel stream, expressed in g / mol; This represents the mole fraction of nitrogen gas.

[0039] The fuel stream flowing into the hydrogen-ammonia fusion internal combustion engine consists of three main components: hydrogen, ammonia, and nitrogen. The mole fraction relationship of the three gases is as follows: (16).

[0040] The actual thermal efficiency is obtained by multiplying the loss coefficient by the ideal cycle thermal efficiency. The formula for calculating the actual thermal efficiency is: (17); in, This represents the actual thermal efficiency. This is the loss coefficient; For ideal cycle thermal efficiency.

[0041] The ideal cycle thermal efficiency is calculated using the thermodynamic thermal efficiency of a hybrid cycle consisting of two isentropic processes, one isochoric decompression process, and one composite process of isochoric pressurization followed by isobaric expansion. (18); in, is the isentropic exponent of the circulating working fluid, is the ratio of the gas's isobaric specific heat capacity to its isochoric specific heat capacity, and is a physical property parameter of the gas; This refers to the compression ratio of a hydrogen-ammonia fusion internal combustion engine. The pressure rise ratio of a hydrogen-ammonia fusion internal combustion engine; This refers to the initial expansion ratio during the isochoric turbocharging process of a hydrogen-ammonia fusion internal combustion engine.

[0042] The exhaust temperature of a hydrogen-ammonia fusion internal combustion engine is calculated from the gas state before the final isochoric pressure reduction process. The formula for calculating the exhaust temperature of a hydrogen-ammonia fusion internal combustion engine is: (19); in, and These are the intake and exhaust temperatures of the hydrogen-ammonia fusion internal combustion engine, respectively, with the intake temperature being the system's input condition.

[0043] S103. Calculate the current density and output voltage of the proton exchange membrane fuel cell based on the total mass flow rate of the proton exchange membrane fuel cell, the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, and the operating temperature.

[0044] The steady-state control equations for proton exchange membrane fuel cells are constructed, including equations for the distribution of physical quantities and equations for voltage calculation.

[0045] In one embodiment, calculating the current density and output voltage of a proton exchange membrane fuel cell based on the total mass flow rate of the proton exchange membrane fuel cell, the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, and the operating temperature includes: solving the physical quantity distribution equation based on the total mass flow rate and operating temperature of the proton exchange membrane fuel cell to obtain the current density of the proton exchange membrane fuel cell; and solving the voltage calculation equation based on the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, the current density, and the operating temperature to obtain the output voltage of the proton exchange membrane fuel cell.

[0046] The equations for the distribution of physical quantities include the equations for the distribution of water vapor concentration, the equations for the distribution of oxygen concentration, and the equations for the distribution of electric current. The equations for the distribution of physical quantities are as follows: (20); in, Length in the flow channel direction; and For the water vapor concentration and oxygen concentration of a proton exchange membrane fuel cell; This represents the current density of a proton exchange membrane fuel cell. This refers to the gas flow rate within the cathode channel of a proton exchange membrane fuel cell. is the Faraday constant, usually taken as 96500 C / mol; The height of the cathode gas flow channel in a proton exchange membrane fuel cell can be 10. -3 m; It is a dimensionless constant, usually taken as 0.628; The membrane water content of a proton exchange membrane fuel cell; The leakage current density of a proton exchange membrane fuel cell can be 0.01 A cm⁻¹. -2 ; , and These are the resistance values ​​that describe the effects of membrane wetting state, gas concentration characteristics, and current distribution on the proton exchange membrane. The ideal gas constant is typically taken as 8.314 J / (K·mol); To calculate the effect of water activity, The activity of water is related to the water vapor concentration and the saturation of liquid water. , This refers to the saturation level of liquid water. This represents the water vapor concentration at gas-liquid equilibrium. , For saturation pressure, This refers to the operating temperature of the proton exchange membrane fuel cell, expressed in K. 333.15 K and 343.15 K can be selected. The calculation formula is: (twenty one); Gas flow rate in cathode channel Compared with the stoichiometry of the anode and cathode, and the actual average current density related, The calculation formula is: (twenty two); in, This represents the actual average current density of a proton exchange membrane fuel cell. This refers to the number of plates in the proton exchange membrane fuel cell stack. This represents the activation area of ​​a proton exchange membrane fuel cell; This is the stoichiometry of the cathode; This represents the cross-sectional area of ​​the cathode flow channel in a proton exchange membrane fuel cell. This represents the inlet concentration of oxygen in a proton exchange membrane fuel cell.

[0047] Actual average current density Calculated using the hydrogen mass flow rate entering the proton exchange membrane fuel cell and the anode stoichiometry: (twenty three); in, For the stoichiometry of the anode, This refers to the total mass flow rate of fuel entering a proton exchange membrane fuel cell.

[0048] The voltage calculation equation is used to calculate the output voltage of a proton exchange membrane fuel cell under steady-state operating conditions. The output voltage is the reversible voltage minus the ohmic voltage drop, activation voltage drop, and concentration overpotential. The voltage calculation equation is as follows: (twenty four); (25); (26); (27); (28); in, This refers to the output voltage of a proton exchange membrane fuel cell. This is the reversible voltage of a proton exchange membrane fuel cell; The ohmic voltage drop of a proton exchange membrane fuel cell; This refers to the activation voltage drop of a proton exchange membrane fuel cell; The concentration overpotential of a proton exchange membrane fuel cell; and These are the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, respectively, in atm; The thickness of the proton exchange membrane can be 5 × 10⁻⁶. -5 m; The ohmic loss empirical parameter is used to calculate the conductivity effect of membrane water content, and 5.0 can be selected. and These are the reference current densities for the anode and cathode, respectively, and can be selected as 0.1 and 3 × 10⁻⁶. -6 A cm -2 ; c This is an empirical parameter for concentration loss; For the limiting current density, 2.4 A cm⁻¹ can be selected. -2 .

[0049] , It is related to the operating pressure of the anode and cathode, and the calculation formula is: (29); (30); in, , These are the operating pressures of the anode and cathode of a proton exchange membrane fuel cell, respectively. and These represent the relative humidity of the anode and cathode of a proton exchange membrane fuel cell, respectively.

[0050] It is a piecewise function, specifically in the form of: (31); Where sech(·) is the hyperbolic secant function, and its specific relationship with the exponential function is as follows: (32); in, e It is a natural constant, with a value of approximately 2.718281828459045.

[0051] In one embodiment, the physical quantity distribution equation of a proton exchange membrane fuel cell needs to establish initial conditions for the water vapor inlet concentration, oxygen inlet concentration, and inlet current density.

[0052] The water vapor inlet concentration is related to the relative humidity of the cathode. The formula for calculating the water vapor inlet concentration is: (33); in, This represents the inlet concentration of water vapor in a proton exchange membrane fuel cell. Operating temperature of proton exchange membrane fuel cells The saturation pressure at that time.

[0053] Oxygen inlet concentration The formula for calculating the oxygen inlet concentration, which is related to the cathode pressure, is as follows: (34); in, This represents the inlet partial pressure of oxygen in the cathode of a proton exchange membrane fuel cell.

[0054] Inlet current density of proton exchange membrane fuel cell Through actual average current density With calculation of average current density The average current density determined by comparison and iterative updates The calculated value is obtained by integrating and averaging the current density distribution obtained from the physical quantity distribution equation of the proton exchange membrane fuel cell.

[0055] R m , R c and R J The specific form of the three resistors is as follows: (35); (36); (37); in, The equivalent molecular weight of a proton exchange membrane fuel cell is expressed in kg / mol, representing the number of reaction sites per unit weight. The density of the proton exchange membrane; The rate at which water in the membrane state transforms into water vapor, expressed in seconds (s). -1 ; The thickness of the proton exchange membrane; This is an empirical parameter, with a value of 0.6278.

[0056] In one embodiment, such as Figure 3 As shown, Figure 3 This is a flowchart for calculating the physical quantity distribution equation, including the calculation of the current density at the inlet location. j inThe inlet current density and the physical quantity distribution equations of the proton exchange membrane fuel cell model are calculated using a bisection iterative method. The specific steps are as follows: S301, input fuel cell operating parameters, structural parameters and model calculation parameters.

[0057] S302, Calculate the actual average current density j ave,real .

[0058] S303, according to j ave, real Calculate the upper limit of the inlet current density j ave, max and lower limit j ave, min .

[0059] Specifically, based on the given actual average current density j ave，real By determining the upper and lower limits of the inlet current density calculated using the bisection method, the lower limit can be taken as 90% of the actual average current density, and the upper limit can be taken as 1.5 to 3 times the actual average current density. The higher the upper limit, the more difficult the convergence becomes. However, if the inlet current density is too small, it may lead to failure to achieve convergence. The average of the upper and lower limits is used as the initial inlet current density. j in,0 .

[0060] S304, establish discrete units along the flow path of the proton exchange membrane fuel cell (total number of units is N).

[0061] S305, Calculate the current inlet current density j in,0 , j in,0 = ( j ave , max + j ave , min ) / 2.

[0062] S306, Fourth-order Runge-Kutta method for calculating the... i +1 discrete unit physical quantity distribution values, until i =N.

[0063] Specifically, based on the input operating parameters and empirical parameters, combined with the boundary conditions, the physical quantity distribution equation of the proton exchange membrane fuel cell model is solved to obtain the current density distribution along the flow channel under the current density setting at the current inlet position.

[0064] S307, calculate the average current density of each discrete unit to obtain the calculated average current density. jave, cal .

[0065] Specifically, the integral average of the current density of each discrete unit is calculated to obtain the calculated average current density under the current density setting at the current initial inlet position. j ave，cal .

[0066] S308, Judgment |j ave, cal −j ave,real | <Error setting value.

[0067] Specifically, calculate the average current density. j ave，cal and actual average current density j ave，real If the absolute value of the relative error is less than the set error value, the solution is terminated and step S310 is executed; otherwise, step S309 is executed.

[0068] S309, Comparison of calculated average current density j ave，cal and actual average current density j ave，real If calculating the average current density j ave，cal Less than the actual average current density j ave，real The current inlet current density is then used as the lower limit of the inlet current density, and vice versa.

[0069] Update the upper limit of imported current density j ave , max and lower limit j ave , min Then, return to step S305 to calculate the average of the upper and lower limits of the inlet position current density as the inlet position current density to be selected for the next iteration. j in,i+1 .

[0070] S310 stores discrete unit physical quantity data.

[0071] S104, based on the exhaust temperature, updates the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone through the system energy balance equation; the system energy balance equation is used to describe the effect of the waste heat from the internal combustion engine and the waste heat from the fuel cell on the vaporization and heating of liquid ammonia.

[0072] The system energy balance equation is used to calculate the inlet temperature of the ammonia decomposer during the next iteration. and the average temperature of the internal reaction zone .

[0073] The system energy balance equation is: (38); in, , These are the average temperature and inlet temperature of the reaction zone inside the ammonia decomposer, respectively. The temperature change in the ammonia decomposer is due to the combined effects of ammonia burner reheating and internal ammonia decomposition endothermic heat absorption. The average temperature of the internal reaction zone of the ammonia decomposer after three main heat exchange processes: cooling water from the proton exchange membrane fuel cell, exhaust gas from the hydrogen-ammonia fusion internal combustion engine, and ammonia combustor.

[0074] Constructed through energy balance , The calculation formula is: (39); in, This is the isobaric specific heat capacity of the fuel stream in the ammonia decomposer, expressed in J / (kg·K). It is the product of the combustion efficiency of the ammonia burner and the heat transfer efficiency to the ammonia decomposer; This is the absolute value of the enthalpy change of ammonia decomposition, usually taken as 46.2 kJ / mol; This is the molar mass of ammonia, usually taken as 17 g / mol; This is the lower heating value of ammonia. The ammonia fuel conversion rate of the ammonia decomposer; The proportion of fuel diverted to supplement the heat of the ammonia burner; , These represent the fuel ratios for the first and second diversions to the hydrogen-ammonia fusion internal combustion engine, respectively.

[0075] The inlet temperature of the ammonia decomposer is determined by the energy balance of the two heat exchange processes involving the fuel cell cooling water and the exhaust gas from the hydrogen-ammonia fusion internal combustion engine. The calculations assume that the waste heat from the proton exchange membrane fuel cell cooling water and the heat from the hydrogen-ammonia fusion internal combustion engine exhaust gas are sufficient to vaporize the liquid ammonia in the fuel stream passing through the ammonia decomposer. Therefore, the inlet temperature of the ammonia decomposer is... The calculation formula is: (40); in, This is the vaporization temperature of liquid ammonia; The temperature of the liquid ammonia used as the ammonia source; , These are the isobaric specific heat capacities of liquid ammonia and ammonia gas, respectively. The latent heat of vaporization of liquid ammonia; , These represent the temperature rise caused by the proton exchange membrane fuel cell cooling water and the liquid ammonia produced by heating the liquid ammonia twice, respectively, using hydrogen-ammonia fusion internal combustion engine exhaust gas.

[0076] and The calculation formulas are as follows: (41); (42); in, , The heat exchange efficiency of proton exchange membrane fuel cell cooling water and hydrogen-ammonia fusion internal combustion engine exhaust gas to liquid ammonia are respectively. This refers to the number of plates in the proton exchange membrane fuel cell stack. This represents the activation area of ​​a proton exchange membrane fuel cell; This represents the actual average current density of a proton exchange membrane fuel cell. The specific heat capacity of the exhaust gas from a hydrogen-ammonia fusion internal combustion engine; The output voltage of a proton exchange membrane fuel cell Along the flow channel direction x The integral average; This is the reversible voltage of a proton exchange membrane fuel cell; and These are the intake and exhaust temperatures of the hydrogen-ammonia fusion internal combustion engine, respectively. The proportion of fuel diverted to supplement the heat of the ammonia burner; The separation efficiency of the hydrogen-ammonia separator; , , These represent the fuel proportions diverted to the hydrogen-ammonia fusion internal combustion engine for the 1st, 2nd, and 3rd time, respectively.

[0077] S105, based on the updated inlet temperature and the average temperature of the internal reaction zone, continue to iteratively update the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone until the relative error between two adjacent calculated inlet temperatures is less than or equal to the preset error setting value. Based on the operating status data of the last iteration, determine the performance indicators of the hybrid power generation system.

[0078] Operating status data refers to data that can be calculated during the iteration process, including but not limited to the current density and output voltage of the proton exchange membrane fuel cell, the total mass flow rate of fuel entering the proton exchange membrane fuel cell, and the total mass flow rate and fuel mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine; performance indicators include the output power and energy efficiency of the proton exchange membrane fuel cell and the hydrogen-ammonia fusion internal combustion engine, as well as the output power and energy efficiency of the hybrid power generation system.

[0079] Among these, the actual average current density of the proton exchange membrane fuel cell in the last iteration is obtained. and the integral average value of the output voltage Among them, the actual average current density and the integral average value of the output voltage These are for the current density distribution respectively j and output voltage distribution V Obtained by integral averaging; based on and Calculate the output power of a proton exchange membrane fuel cell. The output power of a proton exchange membrane fuel cell The calculation formula is: (43).

[0080] Based on the output power of the proton exchange membrane fuel cell Total mass flow rate of fuel entering a proton exchange membrane fuel cell and the lower heating value of hydrogen Calculate the energy efficiency of a proton exchange membrane fuel cell. The formula for calculating the energy efficiency of a proton exchange membrane fuel cell is: (44).

[0081] Based on the operating status data from the last iteration, the performance indicators of the hybrid power generation system are determined, including: determining the total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine based on the total mass flow rate and fuel mole fraction of fuel entering the engine from the last iteration. Based on the total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine and actual thermal efficiency Determine the output electrical power of the hydrogen-ammonia fusion internal combustion engine The calculation formula is: (45).

[0082] The actual thermal efficiency obtained in the last iteration This refers to the energy efficiency of a hydrogen-ammonia fusion internal combustion engine. ,Right now .

[0083] The sum of the output power of the proton exchange membrane fuel cell and the output power of the hydrogen-ammonia fusion internal combustion engine is the system output power of the hybrid power generation system. The calculation formula is: (46).

[0084] Based on the system output power and the ammonia mass flow rate into the entire system from the ammonia source. The lower heating value of ammonia The system energy efficiency of the hybrid power generation system was calculated. The calculation formula is: (47).

[0085] The inlet temperature and the average temperature of the internal reaction zone updated in the current iteration are used as the inlet temperature and the average temperature of the internal reaction zone for the next iteration. Steps S102-S105 are then executed to continue updating the inlet temperature and the average temperature of the internal reaction zone of the ammonia decomposer until the relative error between the inlet temperatures calculated in two adjacent iterations is less than or equal to the preset error setpoint. This "dynamic convergence" process eliminates the errors caused by the initial assumptions, ensuring that the final output power and efficiency are stable values ​​after the system reaches energy balance, rather than instantaneous or deviating from steady-state results.

[0086] The formula for calculating the relative error is as follows: (48); in, For the first Second and third The relative error between the inlet temperatures calculated in each iteration. For the first The inlet temperature calculated in the next iteration. For the first The inlet temperature calculated in the next iteration, with a preset error setpoint. Generally, the value is less than 10. -3 .

[0087] It should be noted that the operating state of the hybrid power generation system refers to the state of the hybrid power generation system under equilibrium.

[0088] In one embodiment, after the proton exchange membrane fuel cell and ammonia decomposer are discretized into units along the flow direction, the distribution of physical quantities along the flow direction is calculated using the fourth-order Runge-Kutta method based on the model boundary conditions; based on the fourth-order Runge-Kutta method, according to the... i Derivation of physical quantities of discrete unit i The formula for calculating the physical quantities of +1 discrete unit is: (49); (50); Among them, the dependent variable Y It can represent current or concentration, subscript i Indicates the first i Each discrete unit, in the ammonia decomposer calculation model i The components they refer to are different; x Δ represents the position in the direction of flow.x The length of the discrete unit; G The (·) function is the function for calculating the first derivative of the dependent variable.

[0089] Solving the system model of the hybrid power generation system involves coupled calculations of heat and ammonia conversion rate. The system model calculation is completed by iteratively solving the equations for the proton exchange membrane fuel cell, the hydrogen-ammonia fusion internal combustion engine, the ammonia decomposer, the system component transfer, and the system energy balance. The output power and energy efficiency of the proton exchange membrane fuel cell and the hydrogen-ammonia fusion internal combustion engine, the outlet ammonia conversion rate of the ammonia decomposer, and the output power and energy efficiency of the system are output.

[0090] In one embodiment, the values ​​of the parameters of the present invention can be as shown in Table 1.

[0091] Table 1 Parameter Values In one specific embodiment, the present invention also provides a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, such as... Figure 4 As shown, this embodiment uses an iterative method based on the inlet temperature of the ammonia decomposer to calculate the operating status of the hybrid power generation system. The specific steps are as follows: S401, obtain system operating parameters, structural parameters and model calculation parameters.

[0092] Specifically, the system inlet liquid ammonia mass flow rate and the proportions of each flow split are set, operating and structural parameters are input, and the ammonia decomposer inlet temperature is initialized. .

[0093] S402, Solve the ammonia decomposer calculation model to obtain the conversion rate of fuel at the ammonia decomposer outlet.

[0094] S403 solves the system distribution component transfer equation to obtain the hydrogen flow rate of the proton exchange membrane fuel cell, the total mass flow rate of the hydrogen-ammonia fusion internal combustion engine, and the mole fraction of the components.

[0095] S404, solve the calculation model of the hydrogen-ammonia fusion internal combustion engine to obtain the output electric power and exhaust gas temperature of the hydrogen-ammonia fusion internal combustion engine; S405, solve the physical quantity distribution equation of the proton exchange membrane fuel cell model, and obtain the current density and gas concentration distribution along the flow channel through iterative calculation.

[0096] S406, Solve the fuel cell model voltage calculation equation to calculate the fuel cell output voltage.

[0097] Specifically, the voltage calculation equation of the proton exchange membrane fuel cell model is calculated to obtain the output voltage of the proton exchange membrane fuel cell along the flow channel direction, and the integral average value of the voltage of each discrete unit is calculated to obtain the output voltage of the proton exchange membrane fuel cell model.

[0098] S407, solve the system energy balance equation to obtain the inlet temperature of the ammonia decomposer in the next iteration.

[0099] S408, calculate the residual temperature at the inlet of the ammonia decomposer between two iterations.

[0100] S409, Determine if the temperature residual is less than the set value.

[0101] If the temperature residual is less than the set value, the solution ends and step S411 is executed; otherwise, step S410 is executed.

[0102] S410, take the ammonia decomposer inlet temperature calculated in S407 for the next iteration as the new inlet temperature of the ammonia decomposer.

[0103] To improve convergence speed, the inlet temperature of the ammonia decomposer is updated using either over-relaxation or sub-relaxation, and the calculation is then performed again in S402.

[0104] S411 processes and stores computational data.

[0105] The hybrid power generation system comprises an ammonia decomposer, a proton exchange membrane fuel cell, a hydrogen-ammonia fusion internal combustion engine, and multiple stages of heat exchange processes. This invention constructs the main equations describing the material conversion and energy transfer within the system, including the steady-state control equations for the proton exchange membrane fuel cell, the output calculation model for the hydrogen-ammonia fusion internal combustion engine, the calculation model for the ammonia decomposer, the system component transfer equations, and the system energy balance equations. Boundary conditions are established for the ammonia decomposer and proton exchange membrane fuel cell models based on the main equations, ensuring that the main equation system can obtain boundary value results through boundary conditions and numerical calculation methods. Based on the main equation system and boundary conditions, a system model solution strategy is developed that iterates through the ammonia decomposer inlet temperature and solves the system model using temperature residuals. This achieves relatively high computational efficiency and stability in obtaining the output power and energy efficiency of components and the overall system in the hybrid power generation system. This invention can provide guidance for system performance simulation analysis and system structure optimization of hybrid power generation systems.

[0106] This invention constructs a low-dimensional multi-field numerical model of a hybrid power generation system, comprehensively considering the key multi-field coupling characteristics within the proton exchange membrane fuel cell, the hydrogen-ammonia fusion internal combustion engine, and the ammonia decomposer, as well as the correlation between heat and material conversion within the hybrid power generation system comprised of these three components. The low-dimensional multi-field numerical model of the hybrid power generation system uses one-dimensional convection equations to describe the distribution characteristics of key physical quantities such as gas concentration in the proton exchange membrane fuel cell and the ammonia decomposer. It can account for the influence of operating conditions on the power output of the fuel cell and the conversion rate of the ammonia decomposer, overcoming the problem of sub-model outputs relying on fitting experimental data under multiple operating conditions in thermodynamic system models. It is suitable for the system characteristics of hybrid power generation systems where subsystems are closely interacting and mutually influencing each other's operating conditions. For the numerical solution of this model, this invention further proposes a method for solving the electrical and thermal energy outputs of the sub-models, and also proposes an iterative solution method and process for the hybrid power generation system with mutually coupled sub-models. This invention can provide guidance for solving the problems of insufficient understanding of internal material and energy transfer characteristics and difficulties in analyzing system phenomena and efficiency during the performance optimization and improvement of hybrid power generation systems.

[0107] In one embodiment, the method provided by the present invention can be verified. Figure 5 This document presents the verification polarization curves for the fuel cell model corresponding to the steady-state control equation of the proton exchange membrane fuel cell provided in this invention. The operating conditions for this example are: relative humidity of 0.8 at both the anode and cathode, anode operating pressure of 0.25 MPa, and anode-cathode stoichiometry ratios of 1.5 and 2.5, respectively. Three sets of verification conditions were performed using different operating temperatures and cathode operating pressures: 333 K, cathode pressure 2.0 atm; 343 K, cathode pressure 2.0 atm; and 343 K, cathode pressure 2.2 atm. The results show good agreement between the experimental data and the model calculation data, demonstrating the reliability of the proton exchange membrane fuel cell model.

[0108] To further understand the present invention, Figure 6 and Figure 7 The conversion rate curve is used to verify the ammonia decomposer calculation model provided by this invention. The reactor used for verification is a typical packed bed membrane reactor, and the catalyst type is Al2O3 doped with 0.5% Ru by mass. Figure 6 The ammonia volume hourly space velocity is 488 h⁻¹. -1 A comparison chart of model calculation values ​​and experimental data when the ammonia decomposer temperature is in the range of 720 K ~ 820 K; Figure 7 When the ammonia decomposer temperature is 763.15 K, the ammonia volume hourly space velocity is 250–650 h⁻¹. -1 A comparison graph showing the numerical values ​​calculated by the model and the experimental data within the specified range. The results indicate that the experimental data and the calculated data agree well, demonstrating the reliability of the ammonia decomposer model.

[0109] To further understand the present invention, the present invention is aimed at Figure 2 In a specific calculation example of the system shown, the relevant structural parameters are: the height of the proton exchange membrane fuel cell cathode gas flow channel is selected as 10. -3 m, the total cross-sectional area of ​​the cathode flow channel is selected as 200mm. 2 The activation area is taken as 450 cm². 2 The thickness of the proton exchange membrane was chosen to be 5 × 10⁻⁶. -5 m, with membrane density taken as 1980 kg / m³ 3 The equivalent molecular weight of the proton exchange membrane fuel cell was selected as 1.1 kg / mol; the single-tube flow cross-sectional area of ​​the ammonia decomposer was 5.94 cm². 2 The total mass of the catalyst in the decomposer is 3000 g, and the total length is 1.93 m.

[0110] The relevant operating parameters are as follows: the proton exchange membrane fuel cell operating temperature is selected as 343.15 K, the anode and cathode operating pressures are 0.25 MPa and 0.22 MPa respectively, the anode and cathode stoichiometric ratios are 1.5 and 2.5 respectively, and the relative humidity of the inlet gas for both the anode and cathode is 0.8; the compression ratio of the hydrogen-ammonia fusion internal combustion engine is selected as 21, the pressure rise ratio as 1.20, the initial expansion ratio as 1.80, and the inlet temperature as 320 K; the absolute pressure of the ammonia decomposer is 0.45 MPa; the operating pressure of the hybrid power generation system is 0.45 MPa, the ammonia source temperature is 266.15 K, the liquid ammonia mass flow rate is 20 ~ 220 g / s, and the split ratio is: burner split ratio ζ B = 0.35, and the fuel proportions for the first, second, and third diversions to the hydrogen-ammonia fusion internal combustion engine are 0.3, 0.2, and 0.1, respectively.

[0111] Based on the structure and operating parameters in the above specific embodiments, the method proposed in this invention performs step-by-step calculations. Figure 8 The above embodiments show the variation curves of ammonia conversion rate of the ammonia decomposer under different inlet ammonia flow rates. Figure 9 The graph shows the output power variation of the proton exchange membrane fuel cell, the hydrogen-ammonia fusion internal combustion engine, and the overall system under different inlet ammonia flow rates. Figure 10 The graph shows the energy efficiency variations of the proton exchange membrane fuel cell, the hydrogen-ammonia fusion internal combustion engine, and the overall system under different inlet ammonia flow rates.

[0112] This method effectively enables low-dimensional and efficient numerical simulation of hybrid power generation systems with multi-stage heat exchange and multiple power generation modes using ammonia as the source, improving the computational efficiency of complex systems under single operating conditions. This method can provide guidance for system performance simulation analysis and system structure optimization of hybrid power generation systems.

[0113] When applying the numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine provided by this invention, it is not necessary to consider... Figure 1 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this invention does not impose any restrictions on it.

[0114] The above describes a numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding numerical simulation device for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, the device comprising: The first calculation module is used to calculate the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and fuel mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer. The second calculation module is used to calculate the output electric power of the hydrogen-ammonia fusion internal combustion engine based on the total mass flow rate and fuel mole fraction of the fuel entering the hydrogen-ammonia fusion internal combustion engine, and to calculate the exhaust temperature of the hydrogen-ammonia fusion internal combustion engine based on the pressure rise ratio, intake temperature and initial expansion ratio of the isochoric turbocharging process. The third calculation module is used to calculate the output voltage of the proton exchange membrane fuel cell based on the total mass flow rate of the proton exchange membrane fuel cell, the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, and the operating temperature. The fourth calculation module is used to update the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone based on the exhaust temperature and the system energy balance equation. The system energy balance equation is used to describe the effect of the waste heat from the internal combustion engine and the waste heat from the fuel cell on the vaporization and heating of liquid ammonia. The update module is used to iteratively update the inlet temperature and the average temperature of the internal reaction zone of the ammonia decomposer based on the updated inlet temperature and the average temperature of the internal reaction zone, until the relative error between two adjacent calculated inlet temperatures is less than or equal to the preset error setting value. The determination module is used to determine the performance indicators of the hybrid power generation system based on the operating status data of the last iteration.

[0115] Specific limitations regarding the numerical simulation apparatus for the hybrid power generation system based on PEMFC and a hydrogen-ammonia fusion internal combustion engine can be found in the limitations of the numerical simulation method for the hybrid power generation system based on PEMFC and a hydrogen-ammonia fusion internal combustion engine mentioned above, and will not be repeated here. Each module in the aforementioned numerical simulation apparatus for the hybrid power generation system based on PEMFC and a hydrogen-ammonia fusion internal combustion engine can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the operations corresponding to each module.

[0116] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1 A numerical simulation method is provided for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine.

[0117] The present invention also provides Figure 11 The schematic diagram of the computer device shown is as follows: Figure 11 As shown, at the hardware level, this computer device includes a processor, internal bus, network interface, memory, and non-volatile memory, and may also include other hardware required for business operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then executes it to achieve the above. Figure 1 A numerical simulation method is provided for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine.

[0118] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A numerical simulation method for a hybrid power generation system based on a PEMFC and a hydrogen-ammonia fusion internal combustion engine, characterized in that, The hybrid power generation system includes an ammonia decomposer, a proton exchange membrane fuel cell, and a hydrogen-ammonia fusion internal combustion engine, and the method includes: Based on the initial inlet temperature of the ammonia decomposer, the average temperature of the internal reaction zone, and the mole fraction of each gas component in the ammonia decomposer, calculate the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine. The exhaust temperature of the hydrogen-ammonia fusion internal combustion engine is calculated based on the pressure rise ratio, intake temperature, and initial expansion ratio of the isochoric turbocharging process. Calculate the current density and output voltage of the proton exchange membrane fuel cell based on the total mass flow rate of the fuel, the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, and the operating temperature. Based on the exhaust temperature, the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone are updated by the system energy balance equation; the system energy balance equation is used to describe the effect of the waste heat from the internal combustion engine and the waste heat from the fuel cell on the vaporization and heating of liquid ammonia. Based on the updated inlet temperature and the average temperature of the internal reaction zone, the inlet temperature of the ammonia decomposer and the average temperature of the internal reaction zone are iteratively updated until the relative error between two adjacent calculated inlet temperatures is less than or equal to the preset error setting value. Based on the operating status data of the last iteration, the performance indicators of the hybrid power generation system are determined.

2. The method according to claim 1, characterized in that, Based on the initial inlet temperature and average temperature of the internal reaction zone of the ammonia decomposer, and the mole fraction of each gas component in the ammonia decomposer, calculate the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine, including: The ammonia fuel conversion rate of the ammonia decomposer is calculated based on the initial inlet temperature and the average temperature of the internal reaction zone of the ammonia decomposer, as well as the mole fraction of each gas component in the ammonia decomposer. Based on the ammonia fuel conversion rate, the total mass flow rate of fuel entering the proton exchange membrane fuel cell and the total mass flow rate and fuel mole fraction entering the hydrogen-ammonia fusion internal combustion engine are calculated using the system distribution component transfer equation. The system distribution component transfer equation is used to describe the mass flow rate and gas mole fraction from the liquid ammonia source to the hydrogen-ammonia fusion internal combustion engine and fuel cell.

3. The method according to claim 2, characterized in that, The formula for calculating the ammonia fuel conversion rate of an ammonia decomposer is: ； ； in, The ammonia fuel conversion rate of the ammonia decomposer; and These represent the inlet position of the ammonia decomposer and its length in the flow channel direction. x = L R The ammonia concentration at the location; This is the total length of the ammonia decomposer; This refers to the absolute pressure within the ammonia decomposer. It is the ideal gas constant; This refers to the inlet temperature of the ammonia decomposer. It is obtained by solving the governing equations for gas components along the flow direction in the ammonia decomposer; the governing equations for gas components are: ； ； in, The velocity of the gas flow in the ammonia decomposer; For the first molar concentration of each component gas ; The cross-sectional area of ​​the ammonia decomposer; The first in the chemical reaction of ammonia decomposition Stoichiometric coefficients of the chemical reactions of the component gases; This is the reaction rate source term, representing the amount of ammonia gas that undergoes decomposition reaction per unit time with a unit mass of catalyst. The total mass of the catalyst in the ammonia decomposer. The reaction rate constant; It is the activation energy of the reaction; This is the average temperature of the reaction zone inside the ammonia decomposer. This refers to the absolute pressure at which the ammonia decomposer operates; and These are the mole fractions of hydrogen and ammonia, respectively. and This is the reaction index.

4. The method according to claim 3, characterized in that, The fuel mole fraction includes the mole fractions of ammonia and hydrogen; the system distribution component transfer equations include: ； ； ； ； ； ； ； ； in, The total mass flow rate of fuel entering a proton exchange membrane fuel cell; The proportion of fuel diverted to supplement the heat of the ammonia burner; The separation efficiency of the hydrogen-ammonia separator; , , These represent the fuel proportions for the first, second, and third splits to the hydrogen-ammonia fusion internal combustion engine, respectively. The first split occurs at the ammonia source, the second split occurs after the ammonia decomposer, and the third split occurs after the hydrogen-ammonia separator. The mass flow rate of ammonia entering the entire system from the ammonia source; , These are the mole fractions of ammonia and hydrogen in the fuel stream at the outlet of the ammonia decomposer, respectively. The total mass flow rate of fuel entering the hydrogen-ammonia fusion internal combustion engine; and These are the mole fractions of ammonia and hydrogen entering the hydrogen-ammonia fusion internal combustion engine, respectively. This represents the ratio of the molar mass of fuel before and after the ammonia decomposer.

5. The method according to claim 1, characterized in that, The formula for calculating exhaust temperature is: ； in, and These are the intake and exhaust temperatures of the hydrogen-ammonia fusion internal combustion engine, respectively. is the isentropic index of the circulating working fluid, and is the ratio of the gas's isobaric specific heat capacity to its isochoric specific heat capacity; The pressure rise ratio of a hydrogen-ammonia fusion internal combustion engine; This refers to the initial expansion ratio during the isochoric turbocharging process of a hydrogen-ammonia fusion internal combustion engine.

6. The method according to claim 1, characterized in that, Based on the total mass flow rate of the fuel in a proton exchange membrane fuel cell, the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, and the operating temperature, calculate the current density and output voltage of the proton exchange membrane fuel cell, including: Based on the total mass flow rate of the fuel in the proton exchange membrane fuel cell and the operating temperature, the physical quantity distribution equation is solved to obtain the current density of the proton exchange membrane fuel cell. The voltage calculation equation is solved based on the inlet partial pressure of hydrogen in the anode and oxygen in the cathode, the current density and the operating temperature to obtain the output voltage of the proton exchange membrane fuel cell. The equation for the distribution of physical quantities is: ； in, Length in the flow channel direction; and For the water vapor concentration and oxygen concentration of a proton exchange membrane fuel cell; This represents the current density of a proton exchange membrane fuel cell. This refers to the gas flow rate within the cathode channel of a proton exchange membrane fuel cell. It is Faraday's constant; The height of the cathode gas flow channel in a proton exchange membrane fuel cell; It is a dimensionless constant; The membrane water content of a proton exchange membrane fuel cell; This represents the leakage current density of a proton exchange membrane fuel cell. , and These are the resistance values ​​that describe the effects of membrane wetting state, gas concentration characteristics, and current distribution on the proton exchange membrane. It is the ideal gas constant; To calculate the effect of water activity, For the activity of water, , This refers to the saturation level of liquid water. This represents the water vapor concentration at gas-liquid equilibrium. , For saturation pressure, The operating temperature of a proton exchange membrane fuel cell. The calculation formula is: ； The calculation formula is: ； ； in, This represents the actual average current density of a proton exchange membrane fuel cell. This refers to the number of plates in the proton exchange membrane fuel cell stack. This represents the activation area of ​​the proton exchange membrane fuel cell; This is the stoichiometry of the cathode; This is the stoichiometric ratio of the anode; This represents the cross-sectional area of ​​the cathode flow channel in a proton exchange membrane fuel cell. This refers to the inlet concentration of oxygen in a proton exchange membrane fuel cell. The total mass flow rate of fuel entering a proton exchange membrane fuel cell; The voltage calculation equation is: ； ； ； ； ； ； ； in, This refers to the output voltage of a proton exchange membrane fuel cell. This is the reversible voltage of a proton exchange membrane fuel cell; The ohmic voltage drop of a proton exchange membrane fuel cell; This refers to the activation voltage drop of a proton exchange membrane fuel cell; The concentration overpotential of a proton exchange membrane fuel cell; and These are the inlet partial pressures of hydrogen in the anode and oxygen in the cathode, respectively. The thickness of the proton exchange membrane; The empirical parameter for ohmic loss; and These are the reference current densities for the anode and cathode, respectively. c This is an empirical parameter for concentration loss; The limiting current density; , These are the operating pressures of the anode and cathode of a proton exchange membrane fuel cell, respectively. and These represent the relative humidity of the anode and cathode of a proton exchange membrane fuel cell, respectively.

7. The method according to claim 6, characterized in that, It is a piecewise function, specifically in the form of: ； 。 8. The method according to claim 7, characterized in that, The boundary conditions for the physical quantity distribution equation include the inlet concentration of water vapor, the inlet concentration of oxygen, and the current density at the inlet location. The water vapor inlet concentration is: ； in, This represents the inlet concentration of water vapor in a proton exchange membrane fuel cell. The oxygen inlet concentration is: ； in, This refers to the inlet partial pressure of oxygen in the cathode of a proton exchange membrane fuel cell; Inlet current density of proton exchange membrane fuel cell Through actual average current density With calculation of average current density Determined by iterative updates following comparison; R m , R c and R J The specific form of the three resistors is as follows: ； in, This represents the equivalent molecular weight of a proton exchange membrane fuel cell. The density of the proton exchange membrane; The rate at which membrane water transforms into gaseous water; These are empirical parameters.

9. The method according to claim 1, characterized in that, The system energy balance equation is: ； in, , These are the average temperature and inlet temperature of the ammonia decomposer, respectively. The temperature change in the ammonia decomposer is due to the combined effects of ammonia burner reheating and internal ammonia decomposition endothermic heat absorption. ； in, The isobaric specific heat capacity of the fuel stream in the ammonia decomposer; It is the product of the combustion efficiency of the ammonia burner and the heat transfer efficiency to the ammonia decomposer; This is the absolute value of the enthalpy change during ammonia decomposition; This represents the molar mass of ammonia. This is the lower heating value of ammonia. The ammonia fuel conversion rate of the ammonia decomposer; The proportion of fuel diverted to supplement the heat of the ammonia burner; , These are the fuel ratios for the first and second splits to the hydrogen-ammonia fusion internal combustion engine, respectively. ； in, This is the vaporization temperature of liquid ammonia; The temperature of the liquid ammonia used as the ammonia source; , These are the isobaric specific heat capacities of liquid ammonia and ammonia gas, respectively. The latent heat of vaporization of liquid ammonia; , These represent the temperature rise caused by two heating processes of liquid ammonia: the cooling water of the proton exchange membrane fuel cell and the exhaust gas from the hydrogen-ammonia fusion internal combustion engine. ； ； in, , The heat exchange efficiency of proton exchange membrane fuel cell cooling water and hydrogen-ammonia fusion internal combustion engine exhaust gas to liquid ammonia are respectively. This refers to the number of plates in the proton exchange membrane fuel cell stack. This represents the activation area of ​​the proton exchange membrane fuel cell; This represents the actual average current density of a proton exchange membrane fuel cell. The specific heat capacity of the exhaust gas from a hydrogen-ammonia fusion internal combustion engine; The output voltage of a proton exchange membrane fuel cell Along the flow channel direction x The integral average; This is the reversible voltage of a proton exchange membrane fuel cell; and These are the intake and exhaust temperatures of the hydrogen-ammonia fusion internal combustion engine, respectively. The proportion of fuel diverted to supplement the heat of the ammonia burner; The separation efficiency of the hydrogen-ammonia separator; , , These represent the fuel proportions diverted to the hydrogen-ammonia fusion internal combustion engine for the 1st, 2nd, and 3rd time, respectively.

10. The method according to claim 1, characterized in that, Operating status data includes the total mass flow rate and mole fraction of fuel entering the hydrogen-ammonia fusion internal combustion engine, and performance indicators include the output electrical power of the hydrogen-ammonia fusion internal combustion engine; based on the operating status data from the last iteration, the performance indicators of the hybrid power generation system are determined, including: The total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine is determined based on the total mass flow rate and fuel mole fraction of the fuel entering the engine in the last iteration. The output electric power of the hydrogen-ammonia fusion internal combustion engine is determined based on the total fuel energy flowing into the engine and the actual thermal efficiency. The formula for calculating the total energy of imported fuel is: ； ； ； in, The total fuel energy flowing into the hydrogen-ammonia fusion internal combustion engine; The total mass flow rate of fuel flowing into the hydrogen-ammonia fusion internal combustion engine; and These are the lower heating values ​​of hydrogen and ammonia, respectively. and These are the mole fractions of hydrogen and ammonia, respectively. The molar mass of the fuel stream; This represents the mole fraction of nitrogen. The formula for calculating actual thermal efficiency is: ； ； in, This represents the actual thermal efficiency. This is the loss coefficient; For ideal cycle thermal efficiency; is the isentropic index of the circulating working fluid, and is the ratio of the gas's isobaric specific heat capacity to its isochoric specific heat capacity; This refers to the compression ratio of a hydrogen-ammonia fusion internal combustion engine. The pressure rise ratio of a hydrogen-ammonia fusion internal combustion engine; This refers to the initial expansion ratio during the isochoric turbocharging process of a hydrogen-ammonia fusion internal combustion engine.

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