CN115688464A - Visualization method and system for hydrogen leakage safety boundary - Google Patents
Visualization method and system for hydrogen leakage safety boundary Download PDFInfo
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Abstract
The invention relates to a method and a system for visualizing a hydrogen leakage safety boundary, and belongs to the technical field of new energy. Firstly, a hydrogen leakage experiment device and numerical simulation are utilized to carry out the same hydrogen leakage process, data fusion is carried out on the measured hydrogen concentration and the simulated hydrogen concentration to obtain fusion concentration, then points are randomly selected near the boundary of a contour curve until the point-taking position is equal to 4%, the point-taking position at the moment is marked as a standard position, the gray values of the standard position are processed when the gray values of the standard position are processed to obtain an average gray value, and finally all pixel points with the gray values being the average gray value in a hydrogen leakage gray image are marked to obtain a visible boundary with the hydrogen concentration of 4%. The invention adopts a data fusion strategy to improve the accuracy of calibrating the hydrogen leakage safety boundary contour.
Description
Technical Field
The invention relates to the technical field of new energy, in particular to a method and a system for visualizing a hydrogen leakage safety boundary.
Background
Hydrogen is a clean, efficient renewable energy source, with the advantages of no pollutant emissions and high specific heat capacity, which makes hydrogen fuel cell vehicles a significant advantage in reducing carbon emissions over traditional fuel vehicles. However, the flammable and explosive characteristics of hydrogen gas cause potential safety hazards in storage and transportation, and mixed gas in the hydrogen gas combustion concentration range can be combusted when exposed fire occurs, so that serious consequences are caused, and therefore, when hydrogen leakage occurs, the mixed gas needs to be far away from a hydrogen gas combustion concentration area to avoid safety accidents. However, due to the colorless and odorless characteristics of hydrogen, it is difficult to directly observe when hydrogen leaks, and a profile curve of the limit combustion concentration of hydrogen cannot be obtained. Therefore, when hydrogen leaks, a method for visualizing the hydrogen combustion boundary outline is needed to display the dangerous range so as to ensure the use safety of hydrogen energy and reduce the possibility of safety accidents.
The method is characterized in that a numerical simulation and gas infrared thermal imaging technology visualization method is adopted to study the hydrogen leakage and diffusion rule in documents (high-pressure under-expansion hydrogen leakage and diffusion models and experimental study), a high-temperature water vapor cloud cluster is impacted by a hydrogen jet cluster, and the initial state and the sprayed state of the water vapor cloud cluster are compared to determine the boundary profile formed by the hydrogen jet. The visualization method does not consider the influence of the mutual disturbance between the water vapor cloud cluster and the hydrogen jet on the hydrogen jet outline, only can obtain a relatively rough hydrogen jet outline, and cannot obtain an accurate and visible safety boundary outline.
The existing hydrogen leakage detection method only measures through a sensor value, but the method for measuring the hydrogen concentration by the sensor is limited by the delay characteristic of the sensor, the hydrogen concentration cannot be obtained immediately, the influence caused by the measurement error of the sensor is not considered, the measurement result is not corrected by other effective means, the obtained concentration value is only calibrated aiming at a single position, and the hydrogen leakage safety boundary outline cannot be integrally described; however, the pure numerical simulation method can only obtain the hydrogen leakage situation under ideal conditions, and it is difficult to completely simulate the hydrogen leakage concentration distribution situation after being disturbed in reality.
Disclosure of Invention
The invention aims to provide a visualization method and a visualization system for a hydrogen leakage safety boundary, which improve the accuracy of calibrating a hydrogen leakage safety boundary outline by adopting a data fusion strategy.
In order to achieve the purpose, the invention provides the following scheme:
a hydrogen leakage safety boundary visualization method comprises the following steps:
building a hydrogen leakage experimental device;
carrying out abstract modeling on the hydrogen leakage experimental device, simulating a hydrogen leakage process, obtaining a simulated concentration field when hydrogen leakage diffusion reaches a steady state, and determining a profile curve of which the hydrogen concentration is equal to 4% in the simulated concentration field;
carrying out a hydrogen leakage experiment by using the hydrogen leakage schlieren experiment device, obtaining a hydrogen leakage gray level image after the hydrogen leakage diffusion reaches a stable state, randomly taking points on the boundary of the contour curve, and measuring the hydrogen concentration at the point taking position;
carrying out data fusion on the hydrogen concentration measured at the sampling point position and the hydrogen concentration at the sampling point position in the simulated concentration field to obtain the fusion concentration at the sampling point position;
if the fusion concentration of the point taking position is not equal to 4%, adjusting the point taking position until the fusion concentration of the point taking position is equal to 4%, and recording the point taking position at the moment as a standard position;
finding a gray value corresponding to the calibration position in the hydrogen leakage gray image and carrying out time-sharing processing to obtain an average gray value;
marking and connecting all pixel points with the gray values equal to the average gray value in the hydrogen leakage gray image to obtain a visible lower boundary profile curve of the hydrogen combustion limit.
Optionally, the hydrogen leakage experimental apparatus includes: a hydrogen gas cylinder;
the hydrogen cylinder is used for simulating hydrogen leakage in a mode of injecting the hydrogen cylinder into air at a fixed mass flow.
Optionally, the abstract modeling is performed on the hydrogen leakage experimental apparatus, the hydrogen leakage process is simulated, a simulated concentration field when the hydrogen leakage diffusion reaches a steady state is obtained, and a profile curve with a hydrogen concentration equal to 4% is determined in the simulated concentration field, which specifically includes:
modeling a hydrogen leakage experimental device by adopting finite element analysis software, and simulating a hydrogen leakage process according to preset temperature, air pressure conditions and mass flow to obtain a simulated concentration field when hydrogen leakage diffusion reaches a steady state;
establishing a plane rectangular coordinate system by taking the center of a nozzle of the hydrogen cylinder as an original point, taking the axial spraying direction of a spray pipe of the hydrogen cylinder as the positive direction of an x axis and taking the radial upward direction of the spray pipe of the hydrogen cylinder as the positive direction of a y axis;
and representing the simulated concentration field in a plane rectangular coordinate system, setting the hydrogen concentration display minimum threshold value to be 4%, and obtaining a hydrogen gas combustion limit boundary profile curve with 4% as a lower limit as a profile curve with the hydrogen concentration equal to 4%.
Optionally, the data fusion is performed on the hydrogen concentration measured at the sampling point position and the hydrogen concentration at the sampling point position in the simulated concentration field, so as to obtain the fusion concentration at the sampling point position, which specifically includes:
calculating the variance of the hydrogen concentration simulation result according to the simulation concentration field;
measuring the hydrogen concentration of each point in the developed hydrogen leakage experiment, and calculating the variance of the hydrogen concentration measurement result;
determining a reliability weight of the simulation result and a reliability weight of the measurement result according to the variance of the hydrogen concentration simulation result and the variance of the hydrogen concentration measurement result;
according to the hydrogen concentration C of the sampling point position in the simulated concentration field 1 Hydrogen concentration C measured at the point-taking position 2 Reliability weight W of simulation result 1 And the confidence weight W of the measurement result 2 Using the formula C 3 ＝W 1 *C 1 +W 2 *C 2 Calculating the point-taking positionConfluent concentration C 3 。
Optionally, the determining the reliability weight of the simulation result and the reliability weight of the measurement result according to the variance of the hydrogen concentration simulation result and the variance of the hydrogen concentration measurement result specifically includes:
on the premise that the hydrogen concentration simulation result and the hydrogen concentration measurement result are subjected to normal distribution, the variance calculation formula for determining the fusion concentration is
In the formula (I), the compound is shown in the specification,
is the variance of the fusion concentration and is,
is the variance of the results of the hydrogen concentration simulation,
variance as a hydrogen concentration measurement;
the variance calculation formula of the fusion concentration is derived to obtain a calculation formula of a credibility weight of a simulation result, wherein the calculation formula is
When the variance of the fusion concentration takes the minimum value, the calculation formula for determining the reliability weight of the measurement result is
And determining the reliability weight of the simulation result by using a calculation formula of the reliability weight of the simulation result according to the variance of the hydrogen concentration simulation result and the variance of the hydrogen concentration measurement result, and determining the reliability weight of the measurement result by using a calculation formula of the reliability weight of the measurement result.
A hydrogen leak safety boundary visualization system, comprising:
the experimental device building module is used for building a hydrogen leakage experimental device;
the hydrogen leakage simulation module is used for carrying out abstract modeling on the hydrogen leakage experimental device, simulating a hydrogen leakage process, obtaining a simulated concentration field when hydrogen leakage diffusion reaches a steady state, and determining a profile curve of which the hydrogen concentration is equal to 4% in the simulated concentration field;
the hydrogen leakage experiment development module is used for developing a hydrogen leakage experiment by using the hydrogen leakage experiment device, obtaining a hydrogen leakage gray image by using a schlieren method after the hydrogen leakage diffusion reaches a stable state, randomly taking points on the boundary of the contour curve, and measuring the hydrogen concentration at the point taking position;
the fusion module is used for carrying out data fusion on the hydrogen concentration measured at the point taking position and the hydrogen concentration at the point taking position in the simulated concentration field to obtain the fusion concentration at the point taking position;
the calibration position recording module is used for adjusting the point taking position if the fusion concentration of the point taking position is not equal to 4% until the fusion concentration of the point taking position is equal to 4% and recording the point taking position at the moment as a calibration position;
the time average processing module is used for finding the gray value corresponding to the calibration position in the hydrogen leakage gray image and carrying out time average processing to obtain an average gray value;
and the connecting module is used for marking and connecting all pixel points with the gray values equal to the average gray value in the hydrogen leakage gray image to obtain a visible boundary profile curve under the hydrogen combustion limit.
An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the hydrogen leakage safety boundary visualization method as described above when executing the computer program.
A computer-readable storage medium having stored thereon a computer program which, when executed, implements a hydrogen leakage safety boundary visualization method as previously described.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention discloses a hydrogen leakage safety boundary visualization method and a hydrogen leakage safety boundary visualization system, wherein a hydrogen leakage experiment device and numerical simulation are utilized to carry out the same hydrogen leakage process, data fusion is carried out on the measured hydrogen concentration and the simulated hydrogen concentration to obtain the fusion concentration, then points are randomly selected on the boundary of a contour curve and fine adjustment is carried out near the point-taking position until the point-taking position is equal to 4%, the point-taking position at the moment is marked as a marking position, the gray value of the marking position is processed when time is taken to obtain an average gray value, and finally all pixel points with the gray value as the average gray value in a hydrogen leakage gray image are marked to obtain a visible boundary with the hydrogen concentration of 4%. The invention adopts a data fusion strategy to improve the accuracy of calibrating the hydrogen leakage safety boundary contour.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a flowchart of a method for visualizing a hydrogen leakage safety boundary according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a hydrogen leakage safety boundary visualization method provided by an embodiment of the invention;
FIG. 3 is a diagram illustrating numerical simulation results provided by an embodiment of the present invention;
FIG. 4 is a schematic diagram of gray scale value calibration provided by an embodiment of the present invention;
fig. 5 is a schematic view of a hydrogen leakage safe concentration profile provided by an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The invention aims to provide a visualization method and a visualization system for a hydrogen leakage safety boundary, which improve the accuracy of calibrating a hydrogen leakage safety boundary outline by adopting a data fusion strategy.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Aiming at the hydrogen leakage working condition, the invention aims to comprehensively utilize numerical simulation information, sensor information and gray value information, obtain an image gray value corresponding to 4% of hydrogen concentration based on a data fusion strategy, calibrate the outline of the integral hydrogen combustible boundary after time-averaging processing of the gray value, and finally obtain a real-time hydrogen leakage gray image with combustible boundary marks.
The hydrogen leakage safety boundary visualization method provided by the embodiment of the invention, as shown in fig. 1 and 2, comprises the following steps:
and S1, building a hydrogen leakage experimental device.
A hydrogen leakage experiment device is built by utilizing the schlieren method principle, the experiment simulates hydrogen leakage in a mode that a high-pressure hydrogen cylinder sprays into air at a fixed mass flow, and meanwhile, a leakage process is shot by utilizing a high-speed camera.
And S2, carrying out abstract modeling on the hydrogen leakage experimental device, simulating a hydrogen leakage process, obtaining a simulated concentration field when hydrogen leakage diffusion reaches a steady state, and determining a profile curve of which the hydrogen concentration is equal to 4% in the simulated concentration field.
And (3) carrying out abstract modeling on the experimental device in the first step in finite element software, setting the same temperature and pressure conditions as those in the experimental device, calculating and solving after setting the mass flow of hydrogen outflow, finally obtaining the distribution of the concentration field when the hydrogen diffusion reaches a steady state, and defining a profile curve f (x) of which the hydrogen concentration is equal to 4% in the concentration field.
The credibility of the numerical simulation can be calculated according to the variance of the numerical simulation resultMetric value W 1 。
Illustratively, the specific process of step S2 is:
during modeling, the left boundary is set as an incident boundary and divided into an upper section and a lower section which are respectively set as an air inlet and a hydrogen inlet, the rest boundaries are set as pressure outlets for simulating the process of hydrogen leaking into the air, numerical simulation calculation is carried out on the model to obtain the concentration field distribution under steady state diffusion, calculation is carried out again after grids are encrypted until the number of the grids does not obviously influence the calculation result any more, and the independence of the grids is verified to obtain the concentration field when the hydrogen leakage reaches the steady state;
establishing a plane rectangular coordinate system by taking the center of the nozzle as an original point, the axial spraying direction of the spray pipe as the positive direction of an x axis and the radial upward direction of the spray pipe as the positive direction of a y axis;
setting the minimum threshold of concentration display to be 4%, obtaining a hydrogen combustion limit boundary contour with 4% as a lower limit, obtaining a boundary contour function y = f (x) according to a contour curve, wherein x is an abscissa of each point on the contour in a rectangular plane coordinate system, y is an ordinate of each point on the contour in the rectangular plane coordinate system, and f is a mapping relation between the abscissa and the ordinate of each point on the contour, and assuming that a numerical simulation result obeys normal distribution, calculating a reliability weight W of the numerical simulation result according to a variance of the numerical simulation result 1 。
And S3, carrying out a hydrogen leakage experiment by using a hydrogen leakage experiment device, obtaining a hydrogen leakage gray image after the hydrogen leakage diffusion reaches a stable state, randomly taking points on the boundary of the contour curve, and measuring the hydrogen concentration at the point taking position.
Developing a hydrogen leakage experiment, obtaining a hydrogen leakage gray level image by using a schlieren method, randomly sampling and measuring a leakage curve on the f (x) curve obtained in the step S2 by using a hydrogen sensor, and respectively obtaining simulated concentration C from the simulated concentration field in the step S2 1 Obtaining the measured concentration C from the sensor measurement reading 2 。
And S4, carrying out data fusion on the hydrogen concentration measured at the sampling point position and the hydrogen concentration at the sampling point position in the simulated concentration field to obtain the fusion concentration at the sampling point position.
Definition of fusion concentration C 3 ＝W 1 *C 1 +W 2 *C 2 The meaning of the fusion concentration is that the numerical simulation result and the sensor measurement result are comprehensively utilized, and the fusion concentration is closer to the actual concentration value after being combined and added according to the credibility weights respectively, so that the fusion concentration is considered to be closer to the actual concentration value compared with the simulated concentration and the measured concentration.
Step S4 specifically includes the following processes:
the image of hydrogen leakage is shot by utilizing the schlieren method, and the fusion concentration C at the random sampling point is defined 3 ＝W 1 *C 1 +W 2 *C 2 In which C is 3 The calculated fused concentration value for this point, W 1 To simulate the concentration C 1 Confidence weight of, W 2 To measure the concentration C 2 Confidence weight of, W 1 And W 2 It should satisfy: w 1 +W 2 ＝1。
The specific determination method of the reliability weight comprises the following steps: assuming that the numerical simulation result and the sensor measurement result both obey normal distribution, namely:
wherein N represents a normal distribution, μ 1 、
Respectively is simulated concentration C 1 Mean and variance of (d), mu 2 、
Respectively is a measured concentration C 2 Mean and variance of, then C 3 The variance of (d) can be expressed as:
equality of simultaneous pairs of two sides w 1 The derivation shows that:
C 3 the variance of (c) has a minimum value, and it can be considered that the uncertainty of the fusion concentration at this time is minimum, and at this time:
and S5, if the fusion concentration of the point taking position is not equal to 4%, adjusting the point taking position until the fusion concentration of the point taking position is equal to 4%, and recording the point taking position at the moment as a standard position.
Adjusting the point-taking position until the fusion concentration C 3 Equal to 4%, and the position at that time is recorded as the nominal position P (x, y).
And S6, finding the gray value corresponding to the calibration position in the hydrogen leakage gray image and performing time-sharing processing to obtain an average gray value.
Finding out the gray value corresponding to the P (x, y) point position in the gray image through the hydrogen leakage gray image, and performing time-averaging processing on the gray value to obtain an average gray value V 1 Establishing an average gray value V 1 Calibration relationship with 4% hydrogen concentration.
And S7, marking and connecting all pixel points with the gray values equal to the average gray value in the hydrogen leakage gray image to obtain a visible hydrogen combustion limit lower boundary contour curve.
In a grayscale image, all grayscale values are V 1 The pixel points have one-to-one correspondence with 4 percent of hydrogen concentration, and all gray values are V 1 The pixel points are marked to obtain a visible outline curve, and the visible outline curve can be used for safety early warning.
The invention provides a hydrogen gas release deviceA safety exposure boundary visualization method, wherein a hydrogen leakage experimental device is built by utilizing the schlieren method principle; modeling and calculating the experimental device in the first step in finite element software to obtain the distribution of the hydrogen concentration field when the hydrogen leakage diffusion reaches a steady state, defining the profile curve of the hydrogen concentration in the concentration field equal to 4% as f (x), and calculating the reliability weight W of numerical simulation according to the variance of the numerical simulation result 1 The method is used for representing the credibility of the numerical simulation result; developing a hydrogen leakage experiment, obtaining a hydrogen leakage gray level image by a schlieren method, randomly taking a point on the obtained f (x) curve by using a hydrogen sensor for measurement, and defining the concentration value of the point at a corresponding point in a simulated concentration field obtained by numerical simulation calculation as simulated concentration C 1 Recording the concentration obtained by actually taking point measurement as the measured concentration C 2 Obtaining the reliability weight W of the sensor measurement through the variance calculation of the sensor measurement 2 For characterizing the degree of confidence of the sensor measurements, by formula C 3 ＝W 1 *C 1 +W 2 *C 2 Calculating the fusion concentration C at the position of the actual measurement point 3 The value of (3) can be considered as that the real concentration value of the point-taking position is closer to the concentration obtained by numerical simulation at the position and the concentration measured by the sensor are respectively multiplied by respective credibility weights to be added, namely, the fusion concentration C 3 (ii) a Finely adjusting the sampling position of the sensor to the position C 3 Equal to 4%, the point-taking position at this time is taken as a calibration position P (x, y); the gray values of the P (x, y) positions are processed to obtain the gray value V 1 Let all gray values in the gray map be V 1 Marking the point positions to obtain a visible boundary of 4% hydrogen concentration.
Setting the mass flow of air at 0.006kg/s and the mass flow of hydrogen inlet at 6.29 × 10 in environment with 293K temperature and 1 standard atmospheric pressure -5 kg/s is a specific condition to illustrate the hydrogen leakage safety margin visualization method.
Using Fluent software to solve, using a second-order windward difference format for convection terms in a momentum and energy equation, obtaining a hydrogen concentration field when hydrogen leakage reaches a steady state, setting a minimum display threshold of hydrogen concentration to be 4%, distributing the obtained concentration field as shown in figure 3, establishing a plane rectangular coordinate system by taking an outlet central point as an original point, recording a curve outline of the hydrogen concentration at the outermost side to be 4% as f (x), calculating the variance of a numerical simulation result, and calculating the reliability weight of the simulation result according to the variance.
After the simulated concentration field is obtained, the hydrogen leakage experiment is carried out under the same working condition and the same hydrogen mass flow is controlled, a high-speed camera is used for shooting the hydrogen leakage process after the hydrogen leakage reaches a stable state, a hydrogen concentration sensor is used for randomly taking points on f (x) for measurement, and the concentration value of the points in the simulated concentration field is recorded as the simulated concentration C 1 The concentration value actually measured by the sensor is the measured concentration C 2 Calculating the reliability weight of the measured value of the hydrogen concentration sensor according to the variance of the hydrogen concentration sensor, and then obtaining the fusion concentration C of the point 3 Is the simulated concentration C of the point 1 And measuring the concentration C 2 Respectively multiplying the values by the respective credibility weights, and then adding and combining the values to finally obtain a concentration value. If the concentration value is not equal to 4%, fine-tuning is performed at the original sampling position until C 3 And when the current sampling position is equal to 4%, defining the sampling position at the moment as a standard position, and recording the horizontal and vertical coordinate values of the point in the established coordinate system. According to the coordinates, finding out corresponding pixel points in the gray image, and performing time-sharing processing on gray values at the pixel points to obtain gray values V 1 Thereby establishing a gray value V 1 And 4% of the minimum combustion concentration of hydrogen, as shown in fig. 4.
Establishing a raised grey value V 1 After the correspondence relationship with 4%, all gray values in the gray image are set as V 1 The pixel points are labeled to obtain a visible lower boundary profile curve of the combustion limit, and the visible lower boundary profile curve can be used for safety early warning as shown in fig. 5.
The invention provides a visualization method for a hydrogen leakage safety boundary, which has the following beneficial effects:
1. according to the invention, a data fusion strategy is adopted in the visualization problem of the hydrogen leakage safety boundary for the first time, the numerical simulation result and the sensor measurement result are comprehensively utilized, the defects that the numerical simulation is difficult to completely simulate the real situation and the delay of the sensor measuring the gas concentration are overcome, the accuracy of calibrating the hydrogen leakage safety boundary outline is improved, and the result is credible;
2. the method firstly relates the concentration value with the gray value in the schlieren method, theoretically can reconstruct the outline of any concentration value, is applied to the field of hydrogen safety early warning, can visualize the safety boundary when hydrogen leakage occurs, and provides direct reference for preventing danger;
3. the method can be suitable for various working condition occasions, is not limited to hydrogen leakage occasions, and can be used for visually displaying the corresponding concentration profile as long as the calibration corresponding relation between the gray value and the concentration is obtained;
4. compared with the traditional visualization method, the hydrogen leakage safety boundary visualization method based on data fusion has the advantages that the accuracy is high, real-time display can be realized, the cost is reduced, the using method is simplified and the utilization possibility is improved compared with the Laser-induced fluorescence (LIF) technology.
The embodiment of the invention also provides a hydrogen leakage safety boundary visualization system, which comprises:
the experimental device building module is used for building a hydrogen leakage experimental device;
the hydrogen leakage simulation module is used for carrying out abstract modeling on the hydrogen leakage experiment device, simulating a hydrogen leakage process, obtaining a simulated concentration field when hydrogen leakage diffusion reaches a steady state, and determining a profile curve of which the hydrogen concentration is equal to 4% in the simulated concentration field;
the hydrogen leakage experiment development module is used for developing a hydrogen leakage experiment by using the hydrogen leakage experiment device, acquiring a hydrogen leakage gray image after the hydrogen leakage diffusion reaches a stable state, randomly taking points on the boundary of the contour curve, and measuring the hydrogen concentration at the point taking position;
the fusion module is used for carrying out data fusion on the hydrogen concentration measured at the sampling point position and the hydrogen concentration at the sampling point position in the simulated concentration field to obtain the fusion concentration at the sampling point position;
the calibration position recording module is used for adjusting the point taking position if the fusion concentration of the point taking position is not equal to 4% until the fusion concentration of the point taking position is equal to 4% and recording the point taking position at the moment as a calibration position;
the time average processing module is used for finding the gray value corresponding to the calibration position in the hydrogen leakage gray image and carrying out time average processing to obtain an average gray value;
and the connecting module is used for marking and connecting all pixel points with the gray values equal to the average gray value in the hydrogen leakage gray image to obtain a visible boundary profile curve under the hydrogen combustion limit.
The hydrogen leakage safety boundary visualization system provided by the embodiment of the invention is similar to the hydrogen leakage safety boundary visualization method of the embodiment in working principle and beneficial effect, so detailed description is omitted here, and specific contents can be referred to the introduction of the method embodiment.
The invention also provides an electronic device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the hydrogen leakage safety boundary visualization method.
Further, the computer program stored in the memory described above may be stored in a computer-readable storage medium when it is implemented in the form of a software functional unit and sold or used as a separate product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: u disk, removable hard disk, read only memory, random access memory, magnetic or optical disk, etc. for storing program codes.
Further, the present invention also provides a computer readable storage medium, on which a computer program is stored, which when executed, implements the hydrogen leakage safety boundary visualization method as described above.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the foregoing, the description is not to be taken in a limiting sense.
Claims (8)
1. A hydrogen leakage safety boundary visualization method is characterized by comprising the following steps:
building a hydrogen leakage experimental device;
carrying out abstract modeling on the hydrogen leakage experimental device, simulating a hydrogen leakage process, obtaining a simulated concentration field when hydrogen leakage diffusion reaches a steady state, and determining a profile curve of which the hydrogen concentration is equal to 4% in the simulated concentration field;
carrying out a hydrogen leakage experiment by using the hydrogen leakage experiment device, acquiring a hydrogen leakage gray image after hydrogen leakage diffusion reaches a stable state, randomly taking points on the boundary of the contour curve, and measuring the hydrogen concentration at the point taking position;
carrying out data fusion on the hydrogen concentration measured at the sampling point position and the hydrogen concentration at the sampling point position in the simulated concentration field to obtain the fusion concentration at the sampling point position;
if the fusion concentration of the point taking position is not equal to 4%, adjusting the point taking position until the fusion concentration of the point taking position is equal to 4%, and recording the point taking position at the moment as a standard position;
finding a gray value corresponding to the calibration position in the hydrogen leakage gray image and performing time-sharing processing to obtain an average gray value;
marking and connecting all pixel points with the gray values equal to the average gray value in the hydrogen leakage gray image to obtain a visible lower boundary profile curve of the hydrogen combustion limit.
2. The visualization method for the safety boundary of hydrogen leakage according to claim 1, wherein the hydrogen leakage experimental device comprises: a hydrogen gas cylinder;
the hydrogen cylinder is used for simulating hydrogen leakage in a mode of injecting the hydrogen cylinder into air at a fixed mass flow.
3. The visualization method for the safety boundary of hydrogen leakage according to claim 2, wherein the abstract modeling is performed on the hydrogen leakage experimental apparatus, the hydrogen leakage process is simulated, a simulated concentration field when the hydrogen leakage diffusion reaches a steady state is obtained, and a profile curve with the hydrogen concentration equal to 4% is determined in the simulated concentration field, which specifically comprises:
modeling a hydrogen leakage experimental device by adopting finite element analysis software, and simulating a hydrogen leakage process according to preset temperature, air pressure conditions and mass flow to obtain a simulated concentration field when hydrogen leakage diffusion reaches a steady state;
establishing a plane rectangular coordinate system by taking the center of a nozzle of the hydrogen cylinder as an original point, taking the axial spraying direction of a spray pipe of the hydrogen cylinder as the positive direction of an x axis and taking the radial upward direction of the spray pipe of the hydrogen cylinder as the positive direction of a y axis;
and representing the simulated concentration field in a plane rectangular coordinate system, setting the hydrogen concentration display minimum threshold value to be 4%, and obtaining a hydrogen gas combustion limit boundary profile curve with 4% as a lower limit as a profile curve with the hydrogen concentration equal to 4%.
4. The visualization method for the safety boundary of hydrogen leakage according to claim 1, wherein the data fusion is performed on the hydrogen concentration measured at the sampling point position and the hydrogen concentration at the sampling point position in the simulated concentration field to obtain the fusion concentration at the sampling point position, and specifically comprises:
calculating the variance of the hydrogen concentration simulation result according to the simulation concentration field;
measuring the hydrogen concentration of each point in the developed hydrogen leakage experiment, and calculating the variance of the hydrogen concentration measurement result;
determining a reliability weight of the simulation result and a reliability weight of the measurement result according to the variance of the hydrogen concentration simulation result and the variance of the hydrogen concentration measurement result;
according to the hydrogen concentration C of the sampling point position in the simulated concentration field 1 Hydrogen concentration C measured at the sampling point 2 And the reliability weight W of the simulation result 1 And the confidence weight W of the measurement result 2 Using the formula C 3 ＝W 1 *C 1 +W 2 *C 2 Calculating the fusion concentration C of the point-taking position 3 。
5. The visualization method for the safety margin of hydrogen leakage according to claim 4, wherein the determining the reliability weight of the simulation result and the reliability weight of the measurement result according to the variance of the hydrogen concentration simulation result and the variance of the hydrogen concentration measurement result specifically comprises:
on the premise that the hydrogen concentration simulation result and the hydrogen concentration measurement result are in normal distribution, the variance calculation formula for determining the fusion concentration is
In the formula (I), the compound is shown in the specification,
is the variance of the fusion concentration and is,
is the variance of the results of the hydrogen concentration simulation,
variance as a hydrogen concentration measurement;
calculating the derivation of the variance calculation formula of the fusion concentration to obtain the confidence weight of the simulation resultThe formula is
When the variance of the fusion concentration takes the minimum value, the calculation formula for determining the reliability weight of the measurement result is
And determining the reliability weight of the simulation result by using a calculation formula of the reliability weight of the simulation result according to the variance of the hydrogen concentration simulation result and the variance of the hydrogen concentration measurement result, and determining the reliability weight of the measurement result by using a calculation formula of the reliability weight of the measurement result.
6. A hydrogen leak safety margin visualization system, comprising:
the experimental device building module is used for building a hydrogen leakage experimental device;
the hydrogen leakage simulation module is used for carrying out abstract modeling on the hydrogen leakage experimental device, simulating a hydrogen leakage process, obtaining a simulated concentration field when hydrogen leakage diffusion reaches a steady state, and determining a profile curve of which the hydrogen concentration is equal to 4% in the simulated concentration field;
the hydrogen leakage experiment development module is used for developing a hydrogen leakage experiment by using the hydrogen leakage experiment device, acquiring a hydrogen leakage gray image after the hydrogen leakage diffusion reaches a stable state, randomly taking points on the boundary of the contour curve, and measuring the hydrogen concentration at the point taking position;
the fusion module is used for carrying out data fusion on the hydrogen concentration measured at the point taking position and the hydrogen concentration at the point taking position in the simulated concentration field to obtain the fusion concentration at the point taking position;
the calibration position recording module is used for adjusting the point taking position if the fusion concentration of the point taking position is not equal to 4% until the fusion concentration of the point taking position is equal to 4% and recording the point taking position at the moment as a calibration position;
the time average processing module is used for finding the gray value corresponding to the calibration position in the hydrogen leakage gray image and carrying out time average processing to obtain an average gray value;
and the connecting module is used for marking and connecting all pixel points with the gray values equal to the average gray value in the hydrogen leakage gray image to obtain a visible boundary profile curve under the hydrogen combustion limit.
7. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the hydrogen leak safety boundary visualization method according to any one of claims 1 to 5 when executing the computer program.
8. A computer-readable storage medium, characterized in that a computer program is stored thereon, which when executed implements the hydrogen leakage safety margin visualization method according to any one of claims 1 to 5.
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| CN116309505B (en) * | 2023-03-28 | 2024-04-05 | 北京理工大学 | Visual image calibration system, method and detection method for hydrogen concentration |
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