A method for analyzing hydrogen leakage and diffusion in high-pressure storage tanks

Abstract

The present invention relates to the field of gas leak detection technology, and in particular to a method for analyzing the diffusion of hydrogen leaks in high-pressure storage tanks. The method comprises constructing a physical model that accurately captures the physical properties of hydrogen and its interaction with the environment, simulating the diffusion process under different leakage scenarios. Sensors are deployed to monitor key indicator parameters in real time, ensuring the real-time and reliability of data, enabling rapid response to potential leakage events and reducing the likelihood and consequences of accidents. A mapping relationship is established between real-time monitoring data and physical model parameters, enabling dynamic adjustment of model parameters based on real-time data to optimize output results. Furthermore, quantitative assessment and risk level classification are used to generate corresponding risk warning signals, facilitating the timely identification of potential safety hazards and the implementation of necessary emergency response measures. The present invention addresses the technical problems of simulating the diffusion of hydrogen leaks in high-pressure storage tanks and conducting real-time monitoring and early warning.

Description

Technical Field

[0001] The present invention relates to the technical field of gas leakage detection, and in particular to a method for analyzing the diffusion of hydrogen leakage from a high-pressure storage tank. Background Art

[0002] Gas leak detection technology is a technical means specifically used to identify, monitor and measure accidental gas leaks. By developing and applying various advanced sensors and detection technologies, the concentration and leakage of hydrogen can be monitored in real time, and potential leakage risks can be discovered and dealt with in a timely manner.

[0003] Currently, hydrogen storage management and control still face some challenges, including the following: the complexity of gas leakage and diffusion simulation. The diffusion process after a gas leak is affected by many factors, including the physical properties of the gas, environmental conditions, and the characteristics of the leakage source, which makes accurate simulation of this process quite complicated; insufficient effective utilization of real-time monitoring data. Although modern sensor technology can monitor environmental parameters in real time, how to effectively use this data to respond to potential leakage incidents in a timely manner and optimize simulation results is still a problem that needs to be solved; insufficient risk assessment and early warning capabilities. Existing risk assessment methods may be too simple or traditional and cannot accurately reflect the true risk status of complex systems. For example, in the field of hydrogen energy, due to the characteristics of hydrogen such as low density and fast diffusion speed, traditional risk assessment methods may not be able to effectively capture the risk of leakage and diffusion, and there is a lack of timely and effective early warning response; in response to these challenges, corresponding solutions and technical means need to be adopted to improve the accuracy of hydrogen leakage and diffusion analysis. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems in the background technology and to propose a method for analyzing the leakage and diffusion of hydrogen in a high-pressure storage tank.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank, comprising:

[0007] Step 1: Build a physical model, specifically analyzing the hydrogen leakage and diffusion phenomenon, simulating the tank structure by analyzing the structural characteristics of the high-pressure storage tank, and setting leakage conditions based on different leakage scenarios;

[0008] Step 2: Based on the constructed physical model, select the numerical algorithm of the finite volume method to solve it; collect data on historical leakage events, use the historical leakage event data to verify the accuracy of the model, and perform sensitivity analysis and adjustment on the model parameters;

[0009] Step 3: Deploy sensors to monitor key indicator parameters in real time, namely wind speed, wind direction, ambient temperature, ambient humidity, and hydrogen concentration; integrate the key indicator parameters monitored in real time into the physical model as the model input conditions; establish a mapping relationship between the key indicator parameters monitored in real time and the constructed physical model parameters; and further dynamically adjust the physical model parameters to optimize the model output results;

[0010] Step 4: Obtain output results based on the physical model that integrates real-time environmental monitoring data, use statistical analysis methods to quantitatively evaluate and classify the risk levels of the physical model output results, and generate corresponding risk warning signals.

[0011] Furthermore, the analysis of hydrogen leakage and diffusion phenomena includes physical property parameters and meteorological condition parameters related to the environment in which hydrogen is located. Among them, the physical property parameters are specifically density, diffusion coefficient, thermal conductivity and flammability limit; the structural characteristics of high-pressure storage tanks are specifically material, thickness, weld strength, and safety valve setting; different leakage scenarios include small hole leakage and crack leakage.

[0012] Furthermore, the process of selecting the numerical algorithm of the finite volume method for solution includes:

[0013] For the flow process of hydrogen in the high-pressure storage tank and after leakage, a set of equations is established based on the law of conservation of mass, momentum, and energy. The specific process is as follows:

[0014] The mass conservation equation:

[0015] ,

[0016] Where, represents the density of hydrogen, Indicates time, Respectively The mass conservation equation states that the rate of change of the mass of hydrogen in a control volume with time is equal to the net mass flow of hydrogen into and out of the control volume in all directions;

[0017] Momentum conservation equation:

[0018] ,

[0019] Where, represents the internal pressure of hydrogen, The left side of the momentum conservation equation represents the dynamic viscosity of hydrogen, which reflects the friction characteristics inside the hydrogen. The rate of change of momentum with time in the direction and the convection term caused by the velocity gradient, and the right side of the momentum conservation equation represents the hydrogen pressure gradient force and viscous force;

[0020] Energy conservation equation:

[0021] ,

[0022] Where, is enthalpy; is the material derivative, and ; is the thermal conductivity, which indicates the ability of hydrogen to conduct heat; Indicates hydrogen temperature; represents the stress tensor; is an index symbol used to represent the component index of a tensor, where The value of , respectively represent the directions of the three coordinate axes; Represents viscous dissipation, which is the process of converting mechanical energy into thermal energy due to the viscosity of the fluid. is the velocity vector Quantity, Indicates the speed The rate of change in direction.

[0023] Furthermore, the process of collecting data on historical leakage incidents, using the historical leakage incident data to verify the accuracy of the model, and conducting sensitivity analysis and adjustment of model parameters includes:

[0024] Set the data of historical hydrogen leakage events to include leakage events, each of which includes leakage scenarios, environmental conditions, and leakage consequences;

[0025] Using error indicators Evaluate model accuracy:

[0026] ,

[0027] Where, Indicates the The actual observed hydrogen concentration value, Indicates the corresponding hydrogen concentration value obtained by model simulation, Indicates the leak event index, Indicates the number of leakage events;

[0028] Based on error index As a result, the sensitivity analysis of model parameters was carried out: by changing the value of each parameter one by one, observing the changes in simulation results, calculating the change rate of error indicators caused by parameter changes, and screening sensitive parameters;

[0029] Use optimization algorithms to adjust the sensitive parameters of the model:

[0030] Using the gradient descent method, the error index As the objective function of optimization, it is recorded as ;

[0031] The goal is to find a set of parameter values ​​such that the objective function Minimize; among them, represents the vector containing all sensitive parameters to be adjusted;

[0032] Calculate the objective function with respect to the sensitive parameter vector Gradient , the sensitive parameter update formula is:

[0033] ,

[0034] Where, represents the updated sensitive parameters, Represents the learning rate, which controls the step size of each sensitive parameter update;

[0035] By continuously iteratively updating the sensitive parameters until the error index converges to the preset range, the new parameters obtained at this time are the optimized model parameters.

[0036] Furthermore, the process of deploying sensors to monitor key indicator parameters in real time includes:

[0037] In a certain area centered on the leakage source, multiple meteorological sensors are arranged in a grid or radial pattern, and the position coordinates of the meteorological sensors are defined as ;in, is the location coordinate index of the meteorological sensor, and , Indicates the number of meteorological sensors;

[0038] The meteorological sensor measures wind speed, wind direction, ambient temperature and ambient humidity in real time, and marks the wind speed, wind direction, ambient temperature and ambient humidity measured by the meteorological sensor in real time to obtain the wind speed ,wind direction , ambient temperature and ambient humidity ;

[0039] Hydrogen concentration sensors are arranged at different heights and distances around the leak source, and the position coordinates of the hydrogen concentration sensors are set as ;in, is the location coordinate index of the hydrogen concentration sensor, and , Indicates the number of hydrogen concentration sensors;

[0040] The hydrogen concentration sensor measures the hydrogen concentration at the location in real time, marks the hydrogen concentration measured by the hydrogen concentration sensor in real time, and obtains the hydrogen concentration .

[0041] Furthermore, the process of integrating the key indicator parameters monitored in real time into the physical model as the input conditions of the model includes:

[0042] The key indicator parameters monitored by the sensors in real time are incorporated into the physical model as input conditions for the model operation, as follows:

[0043] Step F1, integration of wind speed and direction:

[0044] For the entire leakage area, the wind speed and wind direction data measured by various meteorological sensors are integrated, and the weighted average method is used to determine the effective wind speed input into the model. and effective wind direction ; Among them, the calculation formula for effective wind speed is:

[0045] ,

[0046] Where, is the weight coefficient, and When determining the weight coefficient, it is necessary to consider the distance between the sensor and the leak source. and the importance of sensor location on hydrogen diffusion;

[0047] Convert the wind direction angle into a vector form in Cartesian coordinate system:

[0048] ,

[0049] Where, represents the wind direction vector;

[0050] The resultant wind direction vector for:

[0051] ;

[0052] Convert the resultant wind direction vector back to angle form to get the effective wind direction :

[0053] ,

[0054] Where, Represents the inverse tangent function, which is used to calculate the angle value corresponding to the synthetic wind direction vector. Respectively Directional component of the wind vector;

[0055] Step F2: Integration of temperature and humidity:

[0056] Calculate effective temperature using weighted average method and effective humidity :

[0057] ,

[0058] ;

[0059] Step F3, integration of hydrogen concentration:

[0060] In order to obtain the overall hydrogen concentration distribution trend of the leakage area, the data of each hydrogen concentration sensor is interpolated: the leakage area is divided into multiple grid cells, and the center position of each grid cell is , calculate the hydrogen concentration at that location by distance-weighted inverse interpolation ;

[0061] Set the distance from the center of the grid cell Recent The hydrogen concentration sensor number is , which are located at the center of the grid cell The distances are ,but:

[0062] ,

[0063] Where, Indicates the hydrogen concentration sensor index, and .

[0064] Furthermore, a mapping relationship is established between the key indicator parameters monitored in real time and the constructed physical model parameters. The process of further dynamically adjusting the physical model parameters includes:

[0065] Establish a mapping relationship between wind speed, wind direction and meteorological condition parameters:

[0066] Set the convection velocity vector in the model ;

[0067] The effective wind speed and effective wind direction Mapping into the model, we get:

[0068] ,

[0069] Where, They represent the convection velocity vector in the model. Directional component;

[0070] Establish a mapping relationship between temperature and physical characteristic parameters;

[0071] Establish a mapping relationship between humidity and physical characteristic parameters;

[0072] The hydrogen concentration distribution output by the model is defined as , and the actual hydrogen concentration distribution obtained by interpolation of hydrogen concentration sensor data Make a comparison;

[0073] Establishing the error function :

[0074] ,

[0075] Where, represents the total volume of the leakage area, Indicates a small change in total volume;

[0076] According to the error function, an adaptive adjustment strategy is used to dynamically adjust the model parameters.

[0077] Furthermore, based on the output of the physical model integrated with real-time environmental monitoring data, the process of quantitatively evaluating and classifying the risk levels of the output of the physical model using statistical analysis methods to generate corresponding risk warning signals includes:

[0078] Obtain output based on a physical model that integrates real-time environmental monitoring data , i.e. the predicted hydrogen concentration distribution;

[0079] Determine hydrogen leakage areas based on predicted hydrogen concentration distribution ;

[0080] Set hydrogen concentration thresholds for different risk levels: is the high risk concentration threshold, is the medium risk concentration threshold; among them, ;

[0081] For hydrogen leak areas , calculate the average hydrogen concentration in the area :Assume that in the area Memory Monitoring points, obtain the hydrogen concentration of each monitoring point (in represents the monitoring point index, and ),but ;

[0082] The average hydrogen concentration calculated based on , for hydrogen leakage areas Perform risk level classification and obtain risk assessment results: If , then the hydrogen leakage area is determined to be a high-risk area and a high-risk warning signal is generated; if , then the hydrogen leakage area is judged as a medium-risk area and a medium-risk warning signal is generated; if , then the hydrogen leakage area is determined to be a low-risk area and a low-risk warning signal is generated;

[0083] Based on the risk assessment results, emergency response measures are taken, while changes in hydrogen concentration are continuously monitored and emergency response strategies are adjusted.

[0084] Compared with the existing technology, the advantages of the method for analyzing hydrogen leakage and diffusion in high-pressure storage tanks provided by the present invention are:

[0085] 1. This invention constructs a physical model by analyzing the hydrogen leakage and diffusion phenomenon and the structural characteristics of the high-pressure storage tank. This model is closer to reality and provides a solid theoretical foundation for subsequent numerical simulation and risk assessment. The finite volume method can accurately simulate the flow process of hydrogen in the high-pressure storage tank and after leakage, obtaining more specific and precise physical quantity distribution and change patterns. By collecting data from historical leakage events to verify the model's accuracy, the reliability of the model under different working conditions and environmental conditions can be ensured. By performing sensitivity analysis and adjustment on the model parameters, the model performance can be optimized, providing a solid foundation for subsequent real-time analysis and risk assessment.

[0086] 2. The present invention can promptly detect and respond to hydrogen leaks by real-time monitoring of key indicator parameters such as wind speed, wind direction, ambient temperature, ambient humidity, and hydrogen concentration. By integrating real-time monitoring data into the physical model as the model's input, the model can reflect the current actual environmental conditions and improve the accuracy of the simulation. By establishing a mapping relationship between the key indicator parameters monitored in real time and the constructed physical model parameters, the model parameters can be further dynamically adjusted to optimize the model output results.

[0087] 3. The present invention uses statistical analysis methods to quantitatively evaluate the output results of the physical model and classify the risk levels, which can generate corresponding risk warning signals, provide a scientific basis for decision makers, and take emergency response measures based on the risk warning signals, such as evacuating personnel and cutting off power supply, which can effectively reduce the losses caused by hydrogen leakage incidents.

[0088] In summary, the present invention forms a complete high-pressure storage tank hydrogen leakage and diffusion analysis system through accurate simulation, real-time monitoring, dynamic adjustment and optimization, as well as risk assessment and early warning of hydrogen leakage and diffusion phenomena, comprehensively improving the safety management level and emergency response capabilities of industrial enterprises, providing strong protection for industrial safety, and ensuring the normal implementation of a subsequent high-pressure storage tank hydrogen leakage and diffusion analysis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 This is a flow chart of a method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank proposed by the present invention. DETAILED DESCRIPTION

[0090] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0091] Reference Figure 1 , a method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank, comprising:

[0092] Step 1: Construct a physical model, specifically analyzing the hydrogen leakage and diffusion phenomenon, namely the physical property parameters and meteorological condition parameters related to the hydrogen environment. By analyzing the structural characteristics of the high-pressure storage tank, the tank structure is simulated, and leakage conditions are set according to different leakage scenarios. Among them, the physical property parameters are density, diffusion coefficient, thermal conductivity, and flammability limit. The structural characteristics of the high-pressure storage tank are material, thickness, weld strength, and safety valve setting. Different leakage scenarios include small hole leakage and crack leakage.

[0093] Step 2: Based on the constructed physical model, select the numerical algorithm of the finite volume method for solution. The purpose of selecting the numerical algorithm of the finite volume method for solution is to numerically simulate the physical phenomena in the model, thereby obtaining a more specific and accurate distribution and variation pattern of physical quantities; collect data from historical leakage events, use the historical leakage event data to verify the accuracy of the model, and perform sensitivity analysis and adjustment of the model parameters;

[0094] Step 3: Deploy sensors to monitor key indicator parameters in real time, namely wind speed, wind direction, ambient temperature, ambient humidity, and hydrogen concentration; integrate the key indicator parameters monitored in real time into the physical model as the model input conditions; establish a mapping relationship between the key indicator parameters monitored in real time and the constructed physical model parameters; and further dynamically adjust the physical model parameters to optimize the model output results;

[0095] Step 4: Obtain output results based on the physical model that integrates real-time environmental monitoring data, use statistical analysis methods to quantitatively evaluate and classify the risk levels of the physical model output results, and generate corresponding risk warning signals.

[0096] See also Figure 1The present invention provides a method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank. In step 1, the hydrogen leakage and diffusion phenomenon is analyzed, the tank structure is simulated by analyzing the structural characteristics of the high-pressure storage tank, and leakage conditions are set in combination with different leakage scenarios. The steps of constructing a physical model include:

[0097] Step 101: Analyze the physical characteristic parameters:

[0098] Step B1: For hydrogen density,

[0099] ,

[0100] Where, represents the density of hydrogen, represents the internal pressure of hydrogen, represents the molar mass of hydrogen, Refers to the ideal gas constant and hydrogen temperature The product of represents the thermodynamic state of hydrogen; it is understandable that the density of hydrogen is important for understanding its settling or rising trend after leakage;

[0101] Step B2: For the diffusion coefficient,

[0102] ,

[0103] Where, represents the diffusion coefficient, represents the diffusion coefficient under reference conditions, Indicates the current hydrogen temperature. represents the hydrogen reference temperature, Indicates the current internal pressure of hydrogen, Indicates the internal reference pressure of hydrogen, It represents the temperature dependence coefficient. It can be understood that the diffusion coefficient reflects the diffusion ability of hydrogen molecules in the medium, which is related to factors such as the size of hydrogen molecules and the properties of the medium.

[0104] Step B3: For thermal conductivity, use Fourier's law to describe heat conduction:

[0105] ,

[0106] Where, is the heat flux density, is the thermal conductivity, is the hydrogen temperature gradient; it is understandable that the thermal conductivity of hydrogen affects its heat transfer during the leakage and diffusion process, thereby affecting its state change;

[0107] Step B4: For the flammability limit, the flammability limit of hydrogen in air is ;in, It is an empirical range, such as the lower flammable limit of hydrogen in air , upper flammable limit If the hydrogen concentration is within this range, combustion or explosion may occur when encountering a fire source;

[0108] Step 102: Analyze the meteorological condition parameters and use the formula to reflect the meteorological conditions:

[0109] ,

[0110] Where, Indicates meteorological condition parameters, Represent wind speed and wind direction respectively. are all constants, Control wind speed Meteorological condition parameters The impact of Control direction Meteorological condition parameters The impact of Used to adjust for periodic changes in wind direction, is the direction offset, which is used to adjust the sensitivity of the formula to wind direction;

[0111] Step 103: For the strength analysis of the high-pressure storage tank material, assume that the internal pressure of the high-pressure storage tank is , according to Laplace's formula:

[0112] ,

[0113] Where, represents the stress of the high-pressure tank wall, represents the radius of the high-pressure storage tank, Represents the wall thickness of the high-pressure storage tank; it is understandable that by analyzing the Laplace formula, the structural stability of the tank under different pressures can be evaluated, thereby determining possible leakage points;

[0114] Step 104: For the weld strength analysis of the high-pressure storage tank, assume that the shear force borne by the weld is The cross-sectional area of ​​the weld is , then the shear stress of the weld is:

[0115] ,

[0116] Where, Indicates the shear stress of the weld;

[0117] when When the allowable shear stress of the weld material is exceeded, cracks may appear in the weld, leading to leakage;

[0118] Step 105: Use pilot operated safety valve for setting: The pilot operated safety valve consists of a main valve and a pilot valve. Spring rate of pilot valve , and the main valve piston area The opening pressure is expressed as:

[0119] ,

[0120] Where, Indicates the set pressure of the safety valve. Represents the displacement of the pilot valve core; it is understandable that this formula can be used to determine the reasonable setting parameters of the safety valve and the impact of the safety valve opening on the leakage situation;

[0121] Step 106: For small hole leakage, calculate the small hole leakage flow rate using the formula:

[0122] ,

[0123] Where, Indicates the leakage flow of the small hole, represents the flow coefficient of the small hole, represents the area of ​​the small hole, , is the internal pressure of the high-pressure storage tank. The external pressure on the high-pressure storage tank. represents the density of hydrogen;

[0124] Step 107: For crack leakage, calculate the crack leakage flow rate using the formula:

[0125] ,

[0126] Where, Indicates the crack leakage flow rate, represents the discharge coefficient of the crack, represents the crack width, Indicates the crack length.

[0127] See also Figure 1 The present invention provides a method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank. In step 2, the numerical algorithm of the finite volume method is selected for solving the problem based on the constructed physical model; data of historical leakage events are collected, the accuracy of the model is verified using the historical leakage event data, and sensitivity analysis and adjustment of the model parameters are performed, including the following steps:

[0128] Step 201: For the flow process of hydrogen in the high-pressure storage tank and after leakage, a set of equations is established based on the law of conservation of mass, the law of conservation of momentum, and the law of conservation of energy. The specific process is as follows:

[0129] The mass conservation equation:

[0130] ,

[0131] Where, represents the density of hydrogen, Indicates time, Respectively The mass conservation equation states that the rate of change of the mass of hydrogen in a control volume with time is equal to the net mass flow of hydrogen into and out of the control volume in all directions;

[0132] Momentum conservation equation:

[0133] ,

[0134] Where, represents the internal pressure of hydrogen, The left side of the momentum conservation equation represents the dynamic viscosity of hydrogen, which reflects the friction characteristics inside the hydrogen. The rate of change of momentum with time in the direction and the convection term caused by the velocity gradient, and the right side of the momentum conservation equation represents the hydrogen pressure gradient force and viscous force;

[0135] Energy conservation equation:

[0136] ,

[0137] Where, Enthalpy is a thermodynamic state function that combines internal energy and flow work. During the leakage and diffusion process of hydrogen, heat exchange occurs with the surrounding environment. Enthalpy can be directly related to heat transfer. When hydrogen exchanges heat with the outside world, the change in enthalpy directly reflects the impact of this energy exchange on the overall energy state of hydrogen, which helps to accurately describe the energy changes of hydrogen under different conditions (such as different temperatures, pressures and flow states) in the energy conservation equation. is the material derivative, and ; is the thermal conductivity, which indicates the ability of hydrogen to conduct heat; Indicates hydrogen temperature; represents the stress tensor, which is a second-order tensor with nine components corresponding to stresses in different directions (e.g., Indicates Normal stress in the direction, Indicates shear stress in the direction); is an index symbol used to represent the component index of a tensor, where The value of , respectively represent the directions of the three coordinate axes; Represents viscous dissipation, which is the process of converting mechanical energy into thermal energy due to the viscosity of the fluid. is the velocity vector Quantity, Indicates the speed The rate of change in direction, when When taking different values, this term will correspond to viscous dissipation in different directions;

[0138] Step 202: Set the data of historical hydrogen leakage events to include leakage events, each of which includes leakage scenarios, environmental conditions, and leakage consequences;

[0139] Step 203: Using error indicators Evaluate model accuracy:

[0140] ,

[0141] Where, Indicates the The actual observed hydrogen concentration value, Indicates the corresponding hydrogen concentration value obtained by model simulation, Indicates the leak event index, Indicates the number of leakage events; understandably, the error index It measures the average size of the error between the simulated value and the actual value and is more sensitive to larger errors;

[0142] Step 204: Based on the error index As a result, the sensitivity analysis of model parameters was conducted to determine the model parameters that have a greater impact on the simulation results: by changing the value of each parameter one by one, observing the changes in the simulation results, calculating the rate of change of the error index caused by the parameter change, and screening out sensitive parameters. Among them, the model parameters include physical property parameters (density, diffusion coefficient, thermal conductivity and flammability limit) and meteorological condition parameters. Sensitive parameters (i.e. parameters with higher sensitivity) have a significant impact on the model results and are the key adjustment objects; for example, for the diffusion coefficient in the physical property parameters , calculate when the diffusion coefficient changes When the error index The amount of change , then the sensitivity of the diffusion coefficient :

[0143] ;

[0144] Step 205: Use optimization algorithms to adjust the sensitive parameters of the model:

[0145] Using the gradient descent method, the error index As the objective function of optimization, it is recorded as ;

[0146] The goal is to find a set of parameter values ​​such that the objective function Minimize; among them, represents the vector containing all sensitive parameters to be adjusted;

[0147] Calculate the objective function with respect to the sensitive parameter vector Gradient , the sensitive parameter update formula is:

[0148] ,

[0149] Where, represents the updated sensitive parameters, Represents the learning rate, which controls the step size of each sensitive parameter update;

[0150] By continuously iteratively updating sensitive parameters until the error index converges to the preset range, the new parameters obtained at this time are the optimized model parameters, which can improve the accuracy of the model's simulation of the hydrogen leakage and diffusion process; it is understandable that through the historical data collection and model verification process, it can be ensured that the constructed physical model has high accuracy and reliability under different working conditions and environmental conditions, providing a solid foundation for subsequent real-time analysis and risk assessment.

[0151] See also Figure 1 The present invention provides a method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank. In step three, sensors are deployed to monitor key indicator parameters in real time, and the key indicator parameters monitored in real time are integrated into a physical model as input conditions of the model; a mapping relationship is established between the key indicator parameters monitored in real time and the constructed physical model parameters; and the physical model parameters are further dynamically adjusted to optimize the output results of the model. The steps include:

[0152] Step 301: Based on the topography of the leak site and the possible diffusion range of hydrogen, multiple meteorological sensors are arranged in a grid or radial pattern within a certain area centered on the leak source, and the position coordinates of the meteorological sensors are defined as ;in, is the location coordinate index of the meteorological sensor, and , Indicates the number of meteorological sensors;

[0153] Step 302: The meteorological sensor measures the wind speed, wind direction, ambient temperature and ambient humidity in real time, and marks the wind speed, wind direction, ambient temperature and ambient humidity measured by the meteorological sensor in real time to obtain the wind speed. ,wind direction , ambient temperature and ambient humidity ;

[0154] Step 303: hydrogen concentration sensors are arranged at different heights and distances around the leak source, focusing on areas where hydrogen may spread to, areas near sensitive facilities, etc., and the position coordinates of the hydrogen concentration sensors are set as ;in, is the location coordinate index of the hydrogen concentration sensor, and , Indicates the number of hydrogen concentration sensors;

[0155] Step 304: The hydrogen concentration sensor measures the hydrogen concentration at the location in real time, and marks the hydrogen concentration measured by the hydrogen concentration sensor in real time to obtain the hydrogen concentration. ;

[0156] Step 305: Incorporate key indicator parameters monitored by the sensor in real time into the physical model (key indicator parameters include wind speed, wind direction, ambient temperature, ambient humidity, and hydrogen concentration) as input conditions for model operation so that the model can reflect the current actual environmental conditions. The details are as follows:

[0157] Step F1, integration of wind speed and direction:

[0158] For the entire leakage area, the wind speed and wind direction data measured by various meteorological sensors are integrated, and the weighted average method is used to determine the effective wind speed input into the model. and effective wind direction ; Among them, the calculation formula for effective wind speed is:

[0159] ,

[0160] Where, is the weight coefficient, and When determining the weight coefficient, it is necessary to consider the distance between the sensor and the leak source. and the importance of sensor location on hydrogen diffusion;

[0161] Convert the wind direction angle into a vector form in Cartesian coordinate system:

[0162] ,

[0163] Where, represents the wind direction vector;

[0164] The resultant wind direction vector for:

[0165] ;

[0166] Convert the resultant wind direction vector back to angle form to get the effective wind direction :

[0167] ,

[0168] Where, Represents the inverse tangent function, which is used to calculate the angle value corresponding to the synthetic wind direction vector. Respectively Directional component of the wind vector;

[0169] Step F2: Integration of temperature and humidity:

[0170] Calculate effective temperature using weighted average method and effective humidity :

[0171] ,

[0172] ;

[0173] Step F3, integration of hydrogen concentration:

[0174] In order to obtain the overall hydrogen concentration distribution trend of the leakage area, the data of each hydrogen concentration sensor is interpolated: the leakage area is divided into multiple grid cells, and the center position of each grid cell is , calculate the hydrogen concentration at that location by distance-weighted inverse interpolation ;

[0175] Set the distance from the center of the grid cell Recent The hydrogen concentration sensor number is ( Indicates the number of hydrogen concentration sensors, and ), which are located at the center of the grid cell The distances are ,but:

[0176] ,

[0177] Where, Indicates the hydrogen concentration sensor index, and ;

[0178] Step 306: Establish a mapping relationship between wind speed, wind direction and meteorological condition parameters:

[0179] In physical models, meteorological conditions usually affect the convective transport of hydrogen. The convective velocity vector in the model is set to ;

[0180] The effective wind speed and effective wind direction Mapping into the model, we get:

[0181] ,

[0182] Where, They represent the convection velocity vector in the model. The directional component is used for the subsequent calculation of the convective transport of hydrogen in the model;

[0183] Step 307: Establish a mapping relationship between temperature and physical characteristic parameters:

[0184] Diffusion coefficient The relationship with temperature is expressed as:

[0185] ,

[0186] Where, Indicates standard temperature The diffusion coefficient under is an index related to gas properties;

[0187] Step 308: Establish a mapping relationship between humidity and physical characteristic parameters:

[0188] Humidity affects some physical properties of hydrogen and air mixtures, such as thermal conductivity; assuming that humidity and thermal conductivity There is a linear relationship between:

[0189] ,

[0190] Where, Indicates standard humidity Thermal conductivity under A coefficient that represents the effect of humidity on thermal conductivity;

[0191] Step 309: Define the hydrogen concentration distribution output by the model as , and the actual hydrogen concentration distribution obtained by interpolation of hydrogen concentration sensor data Make a comparison;

[0192] Step 310: Establish an error function :

[0193] ,

[0194] Where, represents the total volume of the leakage area, Indicates a small change in total volume;

[0195] Step 311: Adopt an adaptive adjustment strategy to dynamically adjust the model parameters according to the error function:

[0196] For the diffusion coefficient , if the error function If it is large, it means that the diffusion process of the model is not simulated accurately. Adjust the diffusion coefficient according to the following formula:

[0197] ,

[0198] Where, represents the diffusion coefficient after adaptive adjustment; Indicates the adjustment step factor to ensure the stability and convergence of the adjustment process; is the partial derivative of the error function with respect to the diffusion coefficient;

[0199] For dynamic adjustment of flammable limits: mark the initial lower flammable limit and upper flammable limit as and ;Based on the effective temperature in real-time monitoring data and effective humidity , use the formula for dynamic adjustment:

[0200] ,

[0201] ,

[0202] Where, Respectively represent the dynamically adjusted lower flammable limit and upper flammable limit, Respectively represent the temperature and humidity factors affecting the lower flammable limit, They represent the temperature and humidity influencing factors of the upper flammable limit respectively; it can be understood that the flammable limit is affected by environmental factors such as temperature and humidity, that is, the effective temperature and effective humidity in the real-time monitoring data will change the flammable limit of hydrogen.

[0203] See also Figure 1 The present invention provides a method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank. In step 4, the steps of obtaining output results based on a physical model integrating real-time environmental monitoring data, quantitatively evaluating the output results of the physical model and classifying the risk levels using statistical analysis methods, and generating corresponding risk warning signals include:

[0204] Step 401: Obtain output results based on the physical model integrating real-time environmental monitoring data , i.e. the predicted hydrogen concentration distribution;

[0205] Step 402: Determine the hydrogen leakage area based on the predicted hydrogen concentration distribution ;

[0206] Step 403: Set hydrogen concentration thresholds for different risk levels: is a high-risk concentration threshold (for example, a certain proportion of the lower explosion limit concentration of hydrogen, assuming it is 50% of the lower explosion limit concentration, which can be adjusted according to actual conditions), is the medium risk concentration threshold; among them, ;

[0207] Step 404: For hydrogen leakage area , calculate the average hydrogen concentration in the area :Assume that in the area Memory Monitoring points, obtain the hydrogen concentration of each monitoring point (in represents the monitoring point index, and ),but ;

[0208] Step 405: calculate the average hydrogen concentration , for hydrogen leakage areas Perform risk level classification and obtain risk assessment results: If , then the hydrogen leakage area is determined to be a high-risk area and a high-risk warning signal is generated. The high-risk warning signal indicates that in this area, hydrogen leakage may cause explosions, serious casualties and property losses and other serious consequences; if , then the hydrogen leakage area is judged as a medium-risk area and a medium-risk warning signal is generated. The medium-risk warning signal indicates that although the hydrogen concentration has not yet reached the level that is extremely likely to cause an explosion, it may cause certain damage to personnel health and equipment; if , then the hydrogen leakage area is determined to be a low-risk area and a low-risk warning signal is generated. The low-risk warning signal indicates that the hydrogen leakage in this area currently has little impact on personnel, property and the environment, but continuous monitoring is still required to prevent the situation from worsening;

[0209] Step 406: Based on the risk assessment results, emergency response measures are taken, while continuously monitoring changes in hydrogen concentration and adjusting the emergency response strategy, including: for high-risk warning signals, emergency measures need to be taken immediately, such as evacuating personnel and cutting off power; for medium-risk warning signals, monitoring needs to be strengthened and preventive measures such as increased ventilation need to be taken.

[0210] In the embodiment of the present invention, by conducting a detailed analysis of hydrogen properties (such as density, diffusion coefficient, thermal conductivity, flammability limit) and meteorological condition parameters of the environment (such as wind speed and wind direction), it is possible to have a more comprehensive understanding of the behavior of hydrogen after leakage. By analyzing the structural characteristics of the high-pressure storage tank (such as material, thickness, weld strength, safety valve setting) and performing tank structure simulation, it is possible to predict leakage under different leakage scenarios (such as small hole leakage, crack leakage), providing a basis for risk assessment. Based on the law of conservation of mass, the law of conservation of momentum, and the law of conservation of energy, a set of equations is established to accurately describe the flow process of hydrogen in the high-pressure storage tank and after leakage. By collecting data from historical leakage events to verify the accuracy of the model and performing sensitivity analysis and adjustment of the model parameters, the model can be further optimized to improve the simulation results. The reliability of the results is improved by deploying sensors to monitor key indicator parameters such as wind speed, wind direction, ambient temperature, ambient humidity, and hydrogen concentration in real time. In this way, field data can be obtained in real time to provide accurate input conditions for the model. By integrating the key indicator parameters monitored in real time into the physical model as the input conditions of the model, the model can be made closer to the actual environmental conditions and the accuracy of the simulation can be improved. By establishing a mapping relationship between the key indicator parameters monitored in real time and the constructed physical model parameters and dynamically adjusting the physical model parameters, the model can be further optimized so that it can maintain a high accuracy under different working conditions and environmental conditions. By using statistical analysis methods to quantitatively evaluate the output results of the physical model and classify the risk levels, corresponding risk warning signals can be generated to provide decision support for emergency response. In summary, the examples of the present invention involve decision-making on data processing, comprehensive analysis, and intelligent adjustment, solving the technical problems of simulation and real-time monitoring and warning of hydrogen leakage and diffusion in high-pressure storage tanks. In actual situations, more data and contextual information may be required to make specific decisions and optimization plans.

[0211] In addition, the formulas involved in the above are all calculated by removing the dimensions and taking their numerical values. They are a formula that is closest to the actual situation obtained by collecting a large amount of data and performing software simulation. The proportional coefficients in the formulas and the various preset thresholds in the analysis process are set by technical personnel in this field according to actual conditions or obtained by simulating a large amount of data; the size of the proportional coefficient is to quantify each parameter to obtain a specific numerical value, which is convenient for subsequent comparison. The size of the proportional coefficient depends on the amount of sample data and the corresponding processing coefficients initially set by technical personnel in this field for each group of sample data; as long as it does not affect the proportional relationship between the parameters and the quantized values.

[0212] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences from other embodiments. In particular, the device embodiments are described in a relatively simple manner because they are based on the method embodiments. For relevant parts, refer to the partial description of the method embodiments.

[0213] For the convenience of description, the above device is described as being divided into various units according to their functions. Of course, when implementing this application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0214] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0215] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0216] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0217] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0218] Secondly: The drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures may refer to conventional designs. The same embodiment and different embodiments of the present invention may be combined with each other without conflict.

[0219] Finally: The above description is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the protection scope of the present invention.

Claims

1. A method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank, characterized by: Step 1: Construct a physical model to analyze the hydrogen leakage and diffusion phenomenon. The tank structure is simulated by analyzing the structural characteristics of the high-pressure storage tank, and leakage conditions are set based on different leakage scenarios. The analysis of hydrogen leakage and diffusion phenomena includes physical property parameters and meteorological condition parameters related to the hydrogen environment. Physical property parameters include density, diffusion coefficient, thermal conductivity, and flammability limit. The structural characteristics of the high-pressure storage tank include material, thickness, weld strength, and safety valve setting. Different leakage scenarios include small hole leakage and crack leakage. Step 2: Based on the constructed physical model, select the finite volume method numerical algorithm for solution; collect data from historical leakage events, use this data to verify the accuracy of the model, and perform sensitivity analysis and adjustment on the model parameters; when selecting the finite volume method numerical algorithm for solution, establish a set of equations based on the laws of conservation of mass, conservation of momentum, and conservation of energy for the flow process of hydrogen in the high-pressure storage tank and after the leak; Step 3: Deploy sensors to monitor key indicator parameters in real time, including wind speed, wind direction, ambient temperature, ambient humidity, and hydrogen concentration; integrate the key indicator parameters monitored in real time into the physical model as the model's input conditions; establish a mapping relationship between the key indicator parameters monitored in real time and the constructed physical model parameters; and further dynamically adjust the physical model parameters to optimize the model's output results. The process of deploying sensors to monitor key indicator parameters in real time includes: In a certain area centered on the leakage source, multiple meteorological sensors are arranged in a grid or radial pattern, and the position coordinates of the meteorological sensors are defined as ;in, is the location coordinate index of the meteorological sensor, and , Indicates the number of meteorological sensors; The meteorological sensor measures wind speed, wind direction, ambient temperature and ambient humidity in real time, and marks the wind speed, wind direction, ambient temperature and ambient humidity measured by the meteorological sensor in real time to obtain the wind speed ,wind direction , ambient temperature and ambient humidity ; Hydrogen concentration sensors are arranged at different heights and distances around the leak source, and the position coordinates of the hydrogen concentration sensors are set as ;in, is the location coordinate index of the hydrogen concentration sensor, and , Indicates the number of hydrogen concentration sensors; The hydrogen concentration sensor measures the hydrogen concentration at the location in real time, marks the hydrogen concentration measured by the hydrogen concentration sensor in real time, and obtains the hydrogen concentration ; Step 4: Obtain output results based on the physical model that integrates real-time environmental monitoring data, use statistical analysis methods to quantitatively evaluate and classify the risk levels of the physical model output results, and generate corresponding risk warning signals.

2. A method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank according to claim 1, characterized in that: In step 2, for the flow process of hydrogen in the high-pressure storage tank and after leakage, the process of establishing a set of equations based on the law of conservation of mass, the law of conservation of momentum, and the law of conservation of energy includes: The mass conservation equation: ， Where, represents the density of hydrogen, Indicates time, Respectively The mass conservation equation states that the rate of change of the mass of hydrogen in a control volume with time is equal to the net mass flow of hydrogen into and out of the control volume in all directions; Momentum conservation equation: ， Where, represents the internal pressure of hydrogen, The left side of the momentum conservation equation represents the dynamic viscosity of hydrogen, which reflects the friction characteristics inside the hydrogen. The rate of change of momentum with time in the direction and the convection term caused by the velocity gradient, and the right side of the momentum conservation equation represents the hydrogen pressure gradient force and viscous force; Energy conservation equation: ， Where, is enthalpy; is the material derivative, and ; is the thermal conductivity, which indicates the ability of hydrogen to conduct heat; Indicates hydrogen temperature; represents the stress tensor; is an index symbol used to represent the component index of a tensor, where The value of , respectively represent the directions of the three coordinate axes; Represents viscous dissipation, which is the process of converting mechanical energy into thermal energy due to the viscosity of the fluid. is the velocity vector Quantity, Indicates the speed The rate of change in direction.

3. The method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank according to claim 1, wherein: In step 2, the process of collecting data on historical leakage events, using the data to verify the accuracy of the model, and performing sensitivity analysis and adjustment on the model parameters includes: Set the data of historical hydrogen leakage events to include leakage events, each of which includes leakage scenarios, environmental conditions, and leakage consequences; Using error indicators Evaluate model accuracy: ， Where, Indicates the The actual observed hydrogen concentration value, Indicates the corresponding hydrogen concentration value obtained by model simulation, Indicates the leak event index, Indicates the number of leakage events; Based on error index As a result, the sensitivity analysis of model parameters was carried out: by changing the value of each parameter one by one, observing the changes in simulation results, calculating the change rate of error indicators caused by parameter changes, and screening sensitive parameters; Use optimization algorithms to adjust the sensitive parameters of the model: Using the gradient descent method, the error index As the objective function of optimization, it is recorded as ; The goal is to find a set of parameter values ​​such that the objective function Minimize; among them, represents the vector containing all sensitive parameters to be adjusted; Calculate the objective function with respect to the sensitive parameter vector Gradient , the sensitive parameter update formula is: ， Where, represents the updated sensitive parameters, Represents the learning rate, which controls the step size of each sensitive parameter update; By continuously iteratively updating the sensitive parameters until the error index converges to the preset range, the new parameters obtained at this time are the optimized model parameters.

4. The method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank according to claim 1, wherein: In step 3, the process of integrating the key indicator parameters monitored in real time into the physical model as the input conditions of the model includes: The steps to incorporate the key indicator parameters monitored by the sensor in real time into the physical model as the input conditions for the model operation are as follows: Step F1, integration of wind speed and direction: For the entire leakage area, the wind speed and wind direction data measured by various meteorological sensors are integrated, and the weighted average method is used to determine the effective wind speed input into the model. and effective wind direction ; Among them, the calculation formula for effective wind speed is: ， Where, is the weight coefficient, and When determining the weight coefficient, it is necessary to consider the distance between the sensor and the leak source. and the importance of sensor location on hydrogen diffusion; is the wind speed; Convert the wind direction angle into a vector form in Cartesian coordinate system: ， Where, represents the wind direction vector; For wind direction; The resultant wind direction vector for: ； Convert the resultant wind direction vector back to angle form to get the effective wind direction : ， Where, Represents the inverse tangent function, which is used to calculate the angle value corresponding to the synthetic wind direction vector. Respectively Directional component of the wind vector; Step F2: Integration of temperature and humidity: Calculate effective temperature using weighted average method and effective humidity : ， , where is the ambient temperature, is the ambient humidity; Step F3, integration of hydrogen concentration: In order to obtain the overall hydrogen concentration distribution trend of the leakage area, the data of each hydrogen concentration sensor is interpolated: the leakage area is divided into multiple grid cells, and the center position of each grid cell is , calculate the hydrogen concentration at that location by distance-weighted inverse interpolation ; Set the distance from the center of the grid cell Recent The hydrogen concentration sensor number is , which are located at the center of the grid cell The distances are ,but: ， Where, Indicates the hydrogen concentration sensor index, and .

5. A method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank according to claim 4, characterized in that: In step 3, a mapping relationship is established between the key indicator parameters monitored in real time and the constructed physical model parameters. The process of further dynamically adjusting the physical model parameters includes: Establish a mapping relationship between wind speed, wind direction and meteorological condition parameters: Set the convection velocity vector in the model ; The effective wind speed and effective wind direction Mapping into the model, we get: ， Where, They represent the convection velocity vector in the model. Directional component; Establish a mapping relationship between temperature and physical characteristic parameters; Establish a mapping relationship between humidity and physical characteristic parameters; The hydrogen concentration distribution output by the model is defined as , and the actual hydrogen concentration distribution obtained by interpolation of hydrogen concentration sensor data Make a comparison; Establishing the error function : ， Where, represents the total volume of the leakage area, Indicates a small change in total volume; According to the error function, an adaptive adjustment strategy is used to dynamically adjust the model parameters.

6. A method for analyzing hydrogen leakage and diffusion in a high-pressure storage tank according to claim 5, characterized in that: In step 4, the process of obtaining output results based on the physical model integrating real-time environmental monitoring data, quantitatively evaluating and classifying the risk levels of the physical model output results using statistical analysis methods, and generating corresponding risk warning signals includes: Obtain output based on a physical model that integrates real-time environmental monitoring data , i.e. the predicted hydrogen concentration distribution; Determine hydrogen leakage areas based on predicted hydrogen concentration distribution ; Set hydrogen concentration thresholds for different risk levels: is the high risk concentration threshold, is the medium risk concentration threshold; among them, ; For hydrogen leak areas , calculate the average hydrogen concentration in the area :Assume that in the area Memory Monitoring points, obtain the hydrogen concentration of each monitoring point ,but ;in, represents the monitoring point index, and ; The average hydrogen concentration calculated based on , for hydrogen leakage areas Perform risk level classification and obtain risk assessment results: If , then the hydrogen leakage area is determined to be a high-risk area and a high-risk warning signal is generated; if , then the hydrogen leakage area is judged as a medium-risk area and a medium-risk warning signal is generated; if , then the hydrogen leakage area is determined to be a low-risk area and a low-risk warning signal is generated; Based on the risk assessment results, emergency response measures are taken, while changes in hydrogen concentration are continuously monitored and emergency response strategies are adjusted.

Images