Building flood disaster treatment method and system based on free surface simulation

Abstract

The present invention discloses a method and system for treating building waterlogging disasters based on free surface simulation, belonging to the technical field of flood disaster prevention. In the existing waterlogging disaster treatment solutions, there is no disclosure on how to predict waterlogging disasters inside buildings and how to treat waterlogging disasters inside buildings, which affects the normal use or operation of buildings. The method for treating building waterlogging disasters based on free surface simulation of the present invention constructs a building object generation model, a building flow field simulation model, an indoor water level calculation model, and a door opening and closing control model, and combines computational fluid dynamics and free surface algorithms to perform simulation calculations on the waterlogging situation inside the building, which can accurately represent the interaction between the geometric structure of the building and the hydrodynamic characteristics, so as to comprehensively understand the water flow situation under the waterlogging accident inside the building, and thus can timely treat the waterlogging disasters inside the building to ensure the normal use or operation of the building.

Description

Technical Field

[0001] The invention relates to a method and system for handling building flood disasters based on free surface simulation, and belongs to the technical field of flood disaster prevention. Background Art

[0002] The Chinese patent application (publication number: CN117079418A) provides an urban waterlogging disaster forecasting, warning and emergency rescue system and method thereof, including: information input module, geographic information processing module, urban rainfall convergence calculation module, urban waterlogging inundation calculation module, disaster analysis module, warning information release and feedback module, disaster relief material management and rescue team communication and coordination module. The above invention can calculate the scope of urban waterlogging inundation and release warning information, command the evacuation of disaster victims, and supplement and dispatch disaster relief materials and disaster relief personnel.

[0003] However, the above scheme mainly involves early warning of flood disasters at the urban interface, i.e. around buildings. It does not disclose how to predict flood disasters inside buildings and how to deal with flood disasters inside buildings. If the flooding situation inside buildings cannot be understood and dealt with in a timely manner, there will be many safety hazards and affect the normal use or operation of the buildings.

[0004] Furthermore, since electrical systems and various mechanical equipment are usually installed inside buildings, especially in some factories, radioactive materials or chemical raw materials may be stored. If a flood disaster occurs and cannot be effectively handled, it will cause huge economic losses and may pose a threat to the surrounding environment and personnel health.

[0005] The information disclosed in this Background Art is only for understanding the background of the inventive concept and therefore it may include information that does not constitute the prior art. Summary of the invention

[0006] In response to the above problem or one of the above problems, an object of the present invention is to provide a method and system for handling building flooding disasters based on free surface simulation, which uses computational fluid dynamics and free surface algorithms to simulate and calculate the flooding situation inside the building, and based on the indoor water level change data, sets the door opening and closing data in the building to achieve the handling of building flooding disasters. Therefore, the building's geometric structure, fluid mechanics characteristics and the interaction of multiple influencing factors can be accurately characterized, so that the water flow situation under the flooding accident inside the building can be fully understood, potential safety hazards can be discovered in time, and building flooding disasters can be accurately predicted, so that the flooding disaster inside the building can be handled in time to ensure that the building can be used or operated normally.

[0007] In response to the above problem or one of the above problems, the second object of the present invention is to provide a method and system for handling building flooding disasters based on free surface simulation, which can effectively prevent floods from damaging the electrical system and mechanical equipment inside the building, prevent waterlogging disasters from causing huge economic losses to the building, and ensure that factory materials do not pose a threat to the surrounding environment and personnel health.

[0008] To achieve one of the above purposes, the first technical solution of the present invention is:

[0009] The method for dealing with building flooding disaster based on free surface simulation includes the following steps:

[0010] Step 1, generating a model of a pre-built building object and generating building simulation grid information according to relevant structural data of the building;

[0011] Step 2: Using the pre-built building flow field simulation model, according to computational fluid dynamics and the water inflow of the building, the building simulation grid information is processed to determine the flow field density and flow field velocity of the building;

[0012] Step 3: Use the pre-built indoor water level calculation model, based on the free surface algorithm, and according to the flow field density and flow field velocity, to simulate the flooding situation inside the building and obtain the indoor water level change data;

[0013] Step 4: According to the pre-built door opening and closing control model and based on the indoor water level change data, the door opening and closing data in the building is set to handle the building flooding disaster.

[0014] The present invention constructs a building object generation model, a building flow field simulation model, an indoor water level calculation model, and a door opening and closing control model, and combines computational fluid dynamics and a free surface algorithm to simulate and calculate the flooding situation inside the building, and based on the indoor water level change data, sets the door opening and closing data in the building to achieve the handling of building flooding disasters. Therefore, the geometric structure of the building, the fluid mechanics characteristics and the interaction of multiple influencing factors can be accurately characterized, so that the water flow situation under the flooding accident inside the building can be fully understood, potential safety hazards can be discovered in time, and the building flooding disaster can be accurately predicted, so that the flooding disaster inside the building can be handled in time to ensure that the building can be used or operated normally.

[0015] Furthermore, the present invention can be applied to prevent flooding disasters in certain factories, which can effectively avoid damage to the electrical system and mechanical equipment inside the building. In particular, for certain factories storing radioactive materials or chemical raw materials, the present invention can predict and control factory flooding disasters, avoid huge economic losses caused by floods to the factory, and ensure that factory materials will not pose a threat to the surrounding environment and personnel health.

[0016] As the preferred technical measures:

[0017] Step 1: Generate a model of a pre-built building object and generate building simulation grid information based on the relevant structural data of the building as follows:

[0018] Obtain relevant structural data of buildings;

[0019] Perform geometric pre-processing on the building-related structural data to obtain three-dimensional geometric objects;

[0020] Considering the structural characteristics of stairs, holes and doors, the three-dimensional geometric objects are structured meshed using the block partitioning method to obtain the building simulation mesh information.

[0021] As the preferred technical measures:

[0022] Step 2: Using the pre-built building flow field simulation model, according to computational fluid dynamics and the water inflow of the building, the building simulation grid information is processed to determine the flow field density and flow field velocity of the building as follows:

[0023] Obtain initial pressure data and water inflow to the building;

[0024] According to the initial pressure data and water inflow, dynamic simulation is performed on the building simulation grid information based on computational fluid dynamics to obtain the discrete distribution of the fluid flow field inside the building on the entire computational domain to simulate the fluid flow process inside the building under flooding accidents;

[0025] According to the discrete distribution of the fluid flow field, the velocity field of the building is obtained;

[0026] Replace the velocity term in the momentum conservation equation with the building velocity field, and extract the pressure term separately as the unknown pressure field to construct the pressure Poisson equation;

[0027] Solve the pressure Poisson equation to obtain the pressure field of the building;

[0028] The building pressure field is used to correct the building velocity field, and the pressure field and velocity field inside the building are obtained by iterative calculation based on the mass conservation equation;

[0029] According to the pressure field and velocity field inside the building, the flow field density and flow field velocity of the building are determined.

[0030] As the preferred technical measures:

[0031] According to the initial pressure data and water inflow, the dynamic simulation of the building simulation grid information is performed based on computational fluid dynamics to obtain the discrete distribution of the fluid flow field inside the building on the entire calculation domain as follows:

[0032] According to the structural characteristic information inside the building, the flow information of the fluid when flowing through the internal structure of the building is obtained;

[0033] The structural feature information includes at least hole location information and stair location information;

[0034] Based on the bypass information, initial pressure data and water inflow, the turbulent kinetic energy equation and dissipation rate equation are constructed;

[0035] Based on the turbulent kinetic energy equation and the dissipation rate equation, and combined with computational fluid dynamics, the dynamic simulation of the building simulation grid information is carried out to obtain the discrete distribution of the fluid flow field inside the building in the entire computational domain.

[0036] As the preferred technical measures:

[0037] Step 3: Use the pre-built indoor water level calculation model, based on the free surface algorithm, and simulate the flooding situation inside the building according to the flow field density and flow field velocity. The method for obtaining the indoor water level change data is as follows:

[0038] Setting boundary conditions according to the internal structure of the building, wherein the boundary conditions include closed area boundary conditions, wall boundary conditions and flow inlet boundary conditions;

[0039] The closed area boundary conditions include door structure information and pipe structure information, the wall boundary conditions include staircase structure information, building internal wall position information and ground position information, and the flow inlet boundary conditions are pipe breach structure data;

[0040] Based on the free surface algorithm, and according to the boundary conditions and gravity, the fluid cavitation fraction continuity equation is constructed;

[0041] According to the flow field density and flow field velocity, the fluid cavitation fraction continuity equation is solved to obtain the cavitation fraction distribution inside the building to simulate the flooding of the building;

[0042] According to the cavitation share distribution, the indoor water level change data is determined.

[0043] As the preferred technical measures:

[0044] According to the cavitation share distribution, the indoor water level change data is determined, which includes the following:

[0045] Obtaining structural information of one or more rooms in a building;

[0046] The room structure information includes room size data and room location data;

[0047] According to the room size data, set one or more virtual measurement points;

[0048] According to the room position data, the coordinate value of the virtual measuring point is obtained;

[0049] Substitute the coordinate value of the virtual measuring point into the cavitation share distribution to obtain the cavitation share of the virtual measuring point;

[0050] Based on the cavitation share of the virtual measuring point, the indoor water level change data is determined. The specific method is as follows:

[0051] When a single virtual measuring point is set in a room structure, if the cavitation share at the virtual measuring point is less than the cavitation threshold, the water level at the virtual measuring point is lower than the water level threshold; if the cavitation share is greater than or equal to the cavitation threshold, it indicates that the water level at the virtual measuring point is higher than the water level threshold; the water level threshold is the water level position corresponding to the cavitation threshold;

[0052] When multiple virtual measuring points are set for a room structure, the cavitation share of each virtual measuring point is judged. If the cavitation share of all virtual measuring points is greater than or equal to the cavitation threshold, it indicates that the room water level is higher than the water level threshold; if the cavitation share of any virtual measuring point is less than the cavitation threshold, it indicates that the room water level has not completely reached the water level threshold.

[0053] As the preferred technical measures:

[0054] Step 4: According to the pre-built door opening and closing control model and based on the indoor water level change data, the method for setting the door opening and closing data in the building is as follows:

[0055] According to the door structure information in the building, a porous medium body group is established;

[0056] By using the porous medium group, the momentum conservation equation and the mass conservation equation are modified to obtain new momentum conservation equation and new mass conservation equation;

[0057] Based on the new momentum conservation equation and the new mass conservation equation, a porous media model is constructed to simulate the flow behavior of fluids passing through porous materials.

[0058] According to the porous media model, the indoor water level change data is processed to obtain the water level information of each door structure;

[0059] According to the water level information of the gate structure, the unit is automatically converted based on the flow domain to obtain the porosity of each gate structure, and the porosity value is 0 or 1;

[0060] According to the porosity, the opening and closing state of each door structure is determined to realize the conversion between the closed area and the circulation area in the building, which includes the following contents:

[0061] When the porosity is zero, the fluid cannot flow and the door is closed;

[0062] When the porosity is 1, the fluid can flow and the door is open;

[0063] Based on the opening and closing status of each door structure, the door opening and closing data in the building is determined.

[0064] As the preferred technical measures:

[0065] According to the water level information of the gate structure, the method of automatically converting the unit based on the flow domain to obtain the porosity of each gate structure is as follows:

[0066] Set several virtual measuring points behind the door structure of each room, and obtain the coordinates of each virtual measuring point;

[0067] According to the coordinates of the virtual measuring points and the water level information of the door structure, the water level information of each virtual measuring point is obtained;

[0068] Based on the water level information of each virtual measuring point, the porosity of each door structure is obtained, which includes the following:

[0069] When a single virtual measuring point is set in the door structure, the water level of the virtual measuring point is judged. If the water level of the virtual measuring point is lower than the set height, the porosity of the door structure is 0, that is, the door remains closed at this time; if the water level of the virtual measuring point is higher than the set height, the flow domain automatic conversion unit will modify the porosity of the door structure to 1, and the door structure at this time will be transformed from a closed domain to a flow domain, that is, the door will be changed from a closed state to an open state at this time;

[0070] When multiple virtual measuring points are set for the door structure, the water level of each virtual measuring point is judged one by one. If the water level of all virtual measuring points is higher than the set height, the flow domain automatic conversion unit will change the porosity of the door structure from 0 to 1, and the door will open; if the water level of any virtual measuring point does not completely reach the set height, the porosity of the door structure will continue to be 0.

[0071] To achieve one of the above purposes, the second technical solution of the present invention is:

[0072] The method for dealing with building flooding disasters based on free surface simulation includes the following contents:

[0073] Generate building simulation grid information based on relevant structural data of the building;

[0074] According to computational fluid dynamics, the building simulation grid information is processed to determine the flow field velocity of the building;

[0075] Based on the flow field velocity and free surface algorithm, the building is simulated and the cavitation fraction is output;

[0076] Based on the cavitation share, the water level change of the building is calculated;

[0077] Determine the porosity of door structures in buildings based on water level changes;

[0078] The opening and closing of the door structure are determined based on the porosity.

[0079] To achieve one of the above purposes, the third technical solution of the present invention is:

[0080] Building flood disaster treatment system based on free surface simulation, which includes:

[0081] one or more processors;

[0082] A storage device for storing one or more programs;

[0083] When the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned method for handling building flooding disasters based on free surface simulation.

[0084] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0085] The present invention utilizes computational fluid dynamics and a free surface algorithm to simulate and calculate the flooding situation inside a building, and based on the indoor water level change data, sets the door opening and closing data in the building to achieve the handling of building flooding disasters. Therefore, the geometric structure of the building, the fluid mechanics characteristics, and the interaction of multiple influencing factors can be accurately characterized, so that the water flow situation under flooding accidents inside the building can be fully understood, potential safety hazards can be discovered in time, and building flooding disasters can be accurately predicted, and then the flooding disasters inside the building can be handled in time to ensure that the building can be used or operated normally.

[0086] Furthermore, the present invention can be applied to deal with flood disasters in some factories, which can effectively prevent the damage of floods to the electrical system and mechanical equipment inside the building. In particular, for some factories storing radioactive substances or chemical raw materials, the present invention can effectively deal with factory flood disasters, avoid huge economic losses caused by floods to the factories, and ensure that factory materials will not pose a threat to the surrounding environment and personnel health. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 A schematic diagram of a flow chart of a method for handling building flooding disasters according to the present invention;

[0088] Figure 2A schematic diagram for generating a geometric simulation object of a nuclear power plant by applying the method for handling building flooding disasters of the present invention;

[0089] Figure 3 A schematic diagram of obtaining building simulation grid information by applying the building flood disaster treatment method of the present invention;

[0090] Figure 4 A schematic diagram of a flooding situation before a door is opened according to an embodiment of the present invention;

[0091] Figure 5 A schematic diagram of a flooding situation after a door is opened according to an embodiment of the present invention. DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0093] On the contrary, the present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the following detailed description of the present invention. Those skilled in the art can fully understand the present invention without the description of these details.

[0094] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0095] like Figure 1 As shown, the first specific embodiment of the method for dealing with building flooding disasters of the present invention is as follows:

[0096] The method for dealing with building flooding disaster based on free surface simulation includes the following steps:

[0097] Step 1, generating a model of a pre-built building object and generating building simulation grid information according to relevant structural data of the building;

[0098] Step 2: Using the pre-built building flow field simulation model, according to computational fluid dynamics and the water inflow of the building, the building simulation grid information is processed to determine the flow field density and flow field velocity of the building;

[0099] Step 3: Use the pre-built indoor water level calculation model, based on the free surface algorithm, and according to the flow field density and flow field velocity, to simulate the flooding situation inside the building and obtain the indoor water level change data;

[0100] Step 4: According to the pre-built door opening and closing control model and based on the indoor water level change data, the door opening and closing data in the building is set to handle the building flooding disaster.

[0101] In this embodiment, the building is a factory or a plant or a community or an office building or a park or a residential building.

[0102] A second specific embodiment of the method for dealing with building flooding disasters of the present invention:

[0103] The building flood disaster treatment method based on free surface simulation predicts and controls the flood disaster inside the building by constructing a building flow field simulation model, an indoor water level calculation model, a porous media model, and an automatic flow domain conversion unit.

[0104] The building flow field simulation model and the indoor water level calculation model are used to simulate the flow of fluid under flooding conditions inside the building; the porous medium model, together with the automatic flow domain conversion unit, can read the water level of the virtual measuring point in real time and change the state of the door according to the water level of the virtual measuring point. When the water level is higher than a certain height, the state of the door structure is changed from a closed domain to a flow domain.

[0105] In this embodiment, the building flow field simulation model obtains the discrete distribution of the flow field of the fluid flow in a continuous area by numerically solving the basic equations of fluid calculation, thereby approximately simulating the complex fluid flow conditions inside the building under a flooding accident, which includes the following contents:

[0106] The basic equations of fluid calculation mainly include the mass conservation equation, energy conservation equation and momentum conservation equation.

[0107] The mass conservation equation is calculated as follows:

[0108]

[0109] The energy conservation equation is calculated as follows:

[0110]

[0111]

[0112] The momentum conservation equation is given by:

[0113]

[0114]

[0115] In the formula, is the flow field density inside the building; t represents time; Represents the velocity vector of the flow field inside the building, which contains velocity components in three directions; i represents a direction identifier of the coordinate axis in the flow field (i=1 represents the x direction, i=2 represents the y direction, and i=3 represents the z direction), which is used to describe the components of physical quantities such as velocity and pressure in this direction; represents the velocity component in the i direction; is the spatial coordinate in the i direction; is the component of gravity acceleration in the i direction; P is the flow field pressure inside the building; represents the constant pressure specific heat capacity of the fluid; T represents the temperature; and are the viscosity and heat transfer coefficient of the fluid respectively; is the divergence operator, which represents the divergence of the vector field; is the gradient operator, which represents the spatial rate of change of the scalar field.

[0116] For the flow process inside the building, this embodiment mainly focuses on the behavior of water as a fluid. Water has extremely low compressibility under normal temperature and pressure conditions, and its density remains almost unchanged, so the fluid is set to an incompressible fluid. In addition, incompressible fluids can also simplify fluid mechanics equations, reduce the complexity and uncertainty in the calculation process, and help simulate the flooding process more efficiently. Therefore, the density of the fluid inside the building is a constant and is set before the calculation begins.

[0117] Calculating the velocity and pressure field of the flow field based on the momentum conservation equation is a complex process. The momentum conservation equation essentially describes the equilibrium relationship between the velocity change and pressure of each fluid element in the building calculation domain. In order to solve the momentum conservation equation, it is necessary to consider the mass conservation equation at the same time, which is simplified in incompressible fluids as:

[0118]

[0119] That is, the divergence of the fluid velocity field is 0.

[0120] Since the momentum conservation equation is nonlinear and contains coupling terms of velocity and pressure, it is very difficult to solve it directly. Therefore, this embodiment uses an iterative method to gradually approach the true solution. In the iterative process, a new velocity field is first solved based on the known velocity and pressure fields. After the velocity field is updated, the mass conservation will be destroyed. It is necessary to correct the velocity field by updating the pressure field to ensure mass conservation. In order to update the pressure field, it is necessary to solve a Poisson equation for pressure, and its calculation formula is as follows:

[0121]

[0122] in, It indicates the change in pressure, which is caused by the velocity gradient. Indicates the density of the fluid; and represents the velocity component, and Represent the components of the velocity field in the i and j directions, respectively. Usually, i and j can represent the x, y or z directions; and is the spatial coordinate. Specifically, and Represent the spatial coordinates in the i and j directions respectively.

[0123] The Poisson equation above is obtained by replacing the velocity term in the momentum equation with a known velocity field and extracting the pressure term separately. Solving the pressure Poisson equation can obtain a new pressure field. Then, the velocity field is corrected using the new pressure field to ensure that the velocity satisfies the continuity equation. This iterative process is repeated until the velocity and pressure converge, and finally the velocity field and pressure field inside the building are obtained.

[0124] For computational fluid dynamics simulation, the convergence of velocity and pressure means that during the iteration process, the changes in the velocity field and pressure field reach a preset accuracy threshold, which involves the velocity field convergence standard and the pressure field convergence standard.

[0125] The velocity field convergence criteria specifically include the following:

[0126] During the iteration process, the change of each component of the velocity field (that is, the difference between the current iteration and the previous iteration) is less than the preset threshold. For example, the velocity change of a component satisfies the following conditions:

[0127]

[0128] in, and are the velocity fields of the nth and n+1th iterations respectively, is the accuracy threshold for the velocity field to converge.

[0129] The pressure field convergence criteria specifically include the following:

[0130] During the iteration process, the change in the pressure field (i.e., the difference between the current iteration and the previous iteration) is less than the preset threshold. For example, the change in the pressure field meets the following conditions:

[0131]

[0132] in, and are the velocity fields of the nth and n+1th iterations respectively, is the accuracy threshold for the velocity field to converge.

[0133] Usually, the choice of convergence criteria is based on the accuracy requirements of the problem and the limitations of computing resources. If the velocity and pressure fields are less than these preset thresholds in several consecutive iterations, then the velocity and pressure fields can be considered to have converged and the iteration process can be terminated. In other words, the convergence criterion refers to the quantitative requirements for the changes in the velocity and pressure fields to ensure that the solution stabilizes within a certain accuracy range.

[0134] In this embodiment, the indoor water level calculation model is a method for dealing with multiphase flow problems in fluid mechanics, which can track the phase interface in the gas-liquid two-phase flow and accurately capture the water level changes during the flooding process. The model is based on the description of the fluid volume fraction and can effectively simulate the movement, interaction and interface shape of different phases (such as bubbles, droplets, etc.).

[0135] The core idea of ​​the indoor water level calculation model is to divide the calculation domain inside the building into several tiny units. Each unit has a volume fraction to represent the proportion of different fluids, that is, the cavitation fraction. At the interface, the volume fractions of these units will change to simulate the movement and deformation of the interface between water and air, that is, the change of water level. Specifically, if two fluids exist in a unit at the same time, their volume fractions should be a value between 0 and 1, where 0 means that there is no fluid in the unit, 1 means that the unit is completely filled with the fluid, and a value between 0 and 1 indicates that there is a fluid interface in the unit.

[0136] When using the indoor water level calculation model, the key parameter of cavitation fraction needs to be introduced. At this time, the new two-phase fluid property, namely the flow field density and the viscosity of the fluid The expression is as follows:

[0137]

[0138]

[0139] in, is the cavitation fraction, which indicates the proportion of the liquid phase in a unit volume, and its value range is 0 to 1; and are the densities of the gas phase and the liquid phase, respectively. The specific values ​​are as follows:

[0140]

[0141]

[0142] in, It means kilogram per cubic meter, which is the unit of density; and are the dynamic viscosities of the gas phase and liquid phase, respectively, and their specific values ​​are as follows:

[0143]

[0144]

[0145] in, Pascal Second is the unit of dynamic viscosity of a fluid and is used to indicate the resistance to flow of a fluid.

[0146] when When , it means that the unit is all gas phase; when When , it means that the unit is full of liquid phase; when When , it indicates that there is a phase interface in the unit, that is, gas-liquid coexist.

[0147] In this embodiment, the formula of the mass conservation equation is as follows:

[0148]

[0149] The equation shows that the cavitation fraction changes with time, and the velocity field of the fluid affects the change of the cavitation fraction. The indoor water level calculation model tracks the phase interface by solving the above equation, which is the continuity equation of the fluid cavitation fraction. The computational domain in the building is discretized into several tiny units by meshing. In each computational unit, the sum of the volume fractions of all phases is 1, and each phase shares the same set of momentum equations and energy equations.

[0150] The interior of the building contains complex structures such as doors, holes and stairs. After flooding, when the fluid flows through such structures, complex flow phenomena will occur, and the turbulence intensity will increase sharply, so it is necessary to introduce a turbulence model. The turbulence model of this embodiment is composed of turbulent kinetic energy Equations and dissipation rates The equations together.

[0151] Turbulent kinetic energy The calculation formula of the equation is as follows:

[0152]

[0153] Dissipation rate The calculation formula of the equation is as follows:

[0154]

[0155] in, Indicates fluid density, unit ; represents turbulent kinetic energy, unit ; Indicates time, unit ; Represents the average velocity component, unit ; Represents spatial coordinates, unit: m; Indicates dynamic viscosity, unit ; represents turbulent viscosity, unit ; Prandtl number, which represents the kinetic energy of turbulence (dimensionless); Prandtl number, which represents the turbulent dissipation rate (dimensionless); It represents the generation term of turbulent kinetic energy, and its unit is ; represents the turbulent dissipation rate, in units of ; and represents the model constant (dimensionless); The source term for the dissipation rate, in units of ; Indicates kinematic viscosity, unit .

[0156] A third specific embodiment of the method for dealing with building flooding disasters of the present invention:

[0157] The building flood disaster treatment method based on free surface simulation can simulate the flow of fluid under flooding conditions inside the building, such as the distribution of physical quantities such as velocity and cavitation fraction, which helps to accurately grasp the flooding conditions of the fluid inside the building. It specifically includes the following steps:

[0158] Step 1: Generate a model using building objects. According to the relevant structural data of the building, construct a three-dimensional geometric object. Considering the complexity of the structure of stairs, holes and doors, use the block partitioning method to perform structured meshing on the geometric object to obtain the building simulation mesh information. This method obtains a high-quality mesh model with an appropriate quantity, which can greatly reduce the calculation cost and improve the calculation accuracy.

[0159] Step 2: Transmit the building simulation grid information to the building flow field simulation model, and select a suitable turbulence model, such as turbulent kinetic energy and dissipation rate calculation model.

[0160] Step 3, set boundary conditions according to the internal structure of the building, that is, set doors and pipes as closed areas, set stairs, internal walls and floors of the building as wall boundary conditions, and set pipe breaks as flow inlet boundary conditions; at the same time, call the indoor water level calculation model and add gravity.

[0161] Step 4: The indoor water level calculation model selects an appropriate time step and number of calculation cores for simulation and solution. The specific process is as follows:

[0162] First, the momentum conservation equation is numerically iterated to obtain the velocity field inside the building; the cavitation fraction inside each calculation unit is obtained by solving the continuity equation of the fluid cavitation fraction. Distribution. The continuity equation is expressed as follows:

[0163]

[0164] when When , the computing unit is full of air; when When the computational unit is full of water, the share threshold is usually set to 0.5 during the flooding process inside the building, so the water level threshold is defined as water level position.

[0165] Step 5: Visualize the cavitation fraction of the entire flow field obtained by simulation by means of a post-processing model. The dynamic change of the cavitation fraction is the dynamic change of the water level.

[0166] In this embodiment, in the simulation of flooding inside a building, the door structure is set as a porous medium body group, and a porous medium model is constructed. The model is used to modify the state of the door structure. It is a simplified model for simulating the flow behavior of fluids passing through porous materials. In the porous medium model, the momentum equation and mass simulation need to be modified. The new momentum equation expression is as follows:

[0167]

[0168] The new mass equation is expressed as follows:

[0169]

[0170] In the formula, is the porosity, ranging from 0 to 1. When , the fluid cannot flow and the door is closed; when When the fluid can flow, the door is in the open state.

[0171] Furthermore, before simulation calculation, initial conditions should be set, which include the following:

[0172] Before the flooding accident, there is no water in the entire building, so the initial cavitation fraction of the entire computational domain is set to 1, that is, the entire computational domain is filled with air. Then, in the simulation of the internal flooding of the building, the door structure is set as a porous medium body group, and its porosity is set to When set to 0, the door structure in the initial state does not allow fluid to flow, that is, the door is in a closed state.

[0173] In this embodiment, the circulation domain automatic conversion unit is a timely drainage program in case of flooding inside the building. Its principle is to read the water level of the virtual measuring point in real time, judge the water level, and realize the conversion between the closed domain and the circulation domain. The specific steps are as follows:

[0174] Step 1: Set up several virtual measuring points in each room. The measuring points are set behind the door structure at a height of 0.5m. Then, according to the coordinates of the measuring points, perform flooding simulation inside the building and output the cavitation fraction on the virtual measuring points. data.

[0175] Step 2, write the coordinates of the measuring point in the flow domain automatic conversion unit, and read the cavitation fraction data of the measuring point.

[0176] Step 3: Calculate the cavitation fraction of the measuring point Make a judgment, which includes the following:

[0177] 1) When a single measuring point is set in the room, if the cavitation fraction at the measuring point , then the water level at the measuring point is lower than a certain height, and the porosity of the gate structure group Continue to be 0, that is, the door remains closed at this time; if , it means that the water level at the measuring point is higher than a certain height, and the flow domain automatic conversion unit will convert the porosity of the gate structure group Modified to 1, the door structure is changed from a closed domain to a flow domain, that is, the door changes from a closed state to an open state.

[0178] 2) When multiple measuring points are set in a room, the cavitation share of each measuring point needs to be measured. If the cavitation fraction of all measuring points , it means that the water level behind the gate is higher than a certain height, and the flow domain automatic conversion unit will convert the porosity of the gate structure group Change from 0 to 1, then the gate is open; if there is a cavitation share at any measuring point , indicating that the water level behind the door has not completely reached a specific height, and the porosity of the door structure group Will continue to be 0.

[0179] In this embodiment, the simulation results can display the water level changes inside the building, especially the water level changes in key areas (such as equipment rooms, control rooms, etc.). As the water level gradually rises, the degree of flooding in different areas can be seen. During the simulation process, the door is automatically opened according to the set water level to drain the accumulated water. At the same time, the simulation results can show the correlation between the water flow and the door state, as well as the changes in fluid flow after the door is opened. By simulating the expansion of water flow inside the building, it is possible to accurately show which areas are flooded, especially whether the core equipment of the building is flooded, and whether there is a potential risk of equipment damage.

[0180] At the same time, set the water level critical value of key areas, such as the waterproof elevation (specific height) of the equipment room, control room and other areas, which is generally higher than the water level judgment standard for automatic door opening, that is, higher than 0.5m. If the water level exceeds this specific height, it means there is a risk of flooding disaster, which may cause damage to the facility or shutdown.

[0181] Therefore, through the above-mentioned simulation models and the automatic flow domain conversion unit, the dynamic simulation of flooding inside the building can be completed, and the automatic opening of doors during the flooding process can be realized, so as to better predict and control flooding disasters.

[0182] A specific embodiment of applying the building flood disaster treatment method of the present invention to simulate flooding in a nuclear power plant:

[0183] The building flood disaster treatment method of the present invention is applied to simulate and analyze the internal flooding process of a two-story room in a nuclear power plant, which includes the following steps:

[0184] Step 1: Create a nuclear power plant room geometry simulation object containing stairs, holes and doors. The process is as follows:

[0185] According to the design drawings of the two-story room of the nuclear power plant, a geometric simulation object of the nuclear power plant room including stairs, holes and doors is established. Figure 2 , and then the geometric simulation object is divided into blocks to reduce the number of units of the geometric simulation object. At the same time, according to the nuclear power plant room drawings, the leakage location is clear, and the leakage flow is In order to ensure the mass conservation of the two fluids, gas and liquid, in the computational domain, the upper surface of the room is set as the pressure outlet, and the internal boundary of the room is set as the wall boundary.

[0186] Step 2: According to the geometric simulation object, set the calculation grid size, perform structured grid division on the geometric simulation object established in step 1, and generate the building simulation grid information. Figure 3 After the geometric object block processing in step 1, the quality of the mesh model is guaranteed while the number of mesh units can be reduced, greatly improving the calculation efficiency.

[0187] Step 3: Read the water level of the measuring point through the automatic conversion unit of the flow domain, which includes the following:

[0188] Use the custom function to write the automatic conversion unit of the circulation domain, obtain the water level of the measuring point according to the virtual measuring point position (behind the door), and set the water level height required to open the door. The general water level threshold is set to 0.5m.

[0189] Step 4: After the water level reading of the measuring point is completed in step 3, the circulation domain automatic conversion unit will judge the water level of the measuring point. When the water level of the measuring point is lower than 0.5m, the door structure remains in the closed domain unchanged, that is, the door is in a closed state at this time; when the water level of the measuring point is higher than 0.5m, the door structure is modified to the circulation domain state, that is, the door is in an open state at this time.

[0190] Step 5: Perform computational fluid dynamics (CFD) simulation calculations on the flooding inside the nuclear power plant, which includes the following:

[0191] The grid information required for simulation calculation is obtained in step 2, and the writing of the automatic conversion unit of the flow domain is completed in steps 3 and 4; the settings required for CFD calculation are determined in step 1, including the boundary conditions, source terms and simulation domains of the internal flooding calculation of the nuclear power plant, and then the input file of the CFD calculation is generated. Then, the CFD simulation module is used to perform transient numerical simulation calculation. The numerical simulation adopts the pressure and velocity coupling equation solving algorithm to obtain dynamic flow field data and realize the simulation calculation of the internal flooding process of the nuclear power plant.

[0192] Step 6: Based on the dynamic flow field data, demonstrate the flooding process inside the nuclear power plant. Figure 4 is the flow field state before the door is opened, Figure 5 is the flow field state after the door is opened, Figure 4 and Figure 5 The dark red color in the figure represents the cavitation share. Therefore, it can be seen that the present invention can accurately predict flooding disasters under the conditions of complex internal structures of nuclear power plants, can fully understand the water flow conditions under flooding accidents inside nuclear power plants, promptly discover potential safety hazards, and can achieve timely control of flooding disasters, thereby effectively avoiding damage to internal equipment of nuclear power plants and economic losses caused by flooding accidents.

[0193] An embodiment of a device applying the method of the present invention:

[0194] An electronic device comprising:

[0195] one or more processors;

[0196] A storage device for storing one or more programs;

[0197] When the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned method for handling building flooding disasters based on free surface simulation.

[0198] A computer medium embodiment using the method of the present invention:

[0199] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned method for handling building flooding disasters based on free surface simulation.

[0200] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, and computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, optical storage, etc.) containing computer-usable program codes.

[0201] The present application is described by flowcharts or / and block diagrams of the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each process or / and block in the flowchart or / and block diagram and the combination of the processes or / and blocks in the flowchart or / and block diagram 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 generate 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 flowchart or / and block diagram. Figure 1 Process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0202] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 Process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0203] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 Process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0204] The model in this application is an object that objectively describes the morphological structure with the help of physical or virtual representation. The object is not equal to the object and is not limited to physical and virtual. It can be a data processing function, software program, processing mode, usage method, operation method, workflow, application process, electronic hardware, circuit module, processing system, system imitation or simulation object.

[0205] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field can still modify or replace the specific implementation methods of the present invention with equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for dealing with building flooding disasters based on free surface simulation, characterized in that: The following steps are involved: Step 1, generating a model of a pre-built building object and generating building simulation grid information according to relevant structural data of the building; Step 2: Using the pre-built building flow field simulation model, according to computational fluid dynamics and the water inflow of the building, the building simulation grid information is processed to determine the flow field density and flow field velocity of the building; Step 3: Use the pre-built indoor water level calculation model, based on the free surface algorithm, and according to the flow field density and flow field velocity, to simulate the flooding situation inside the building and obtain the indoor water level change data; the method is as follows: Setting boundary conditions according to the internal structure of the building, wherein the boundary conditions include closed area boundary conditions, wall boundary conditions and flow inlet boundary conditions; The closed area boundary conditions include door structure information and pipe structure information, the wall boundary conditions include staircase structure information, building internal wall position information and ground position information, and the flow inlet boundary conditions are pipe breach structure data; Based on the free surface algorithm, and according to the boundary conditions and gravity, the fluid cavitation fraction continuity equation is constructed; According to the flow field density and flow field velocity, the fluid cavitation fraction continuity equation is solved to obtain the cavitation fraction distribution inside the building to simulate the flooding of the building; Determine the indoor water level change data based on the cavitation share distribution; Step 4: According to the pre-built door opening and closing control model and based on the indoor water level change data, the door opening and closing data in the building is set to handle the building flooding disaster.

2. The method for dealing with building flooding disasters based on free surface simulation according to claim 1, characterized in that: Step 1: Generate a model of a pre-built building object and generate building simulation grid information based on the relevant structural data of the building as follows: Obtain relevant structural data of buildings; Perform geometric pre-processing on the building-related structural data to obtain three-dimensional geometric objects; Considering the structural characteristics of stairs, holes and doors, the three-dimensional geometric objects are structured meshed using the block partitioning method to obtain the building simulation mesh information.

3. The method for dealing with building flooding disasters based on free surface simulation according to claim 1, characterized in that: Step 2: Using the pre-built building flow field simulation model, according to computational fluid dynamics and the water inflow of the building, the building simulation grid information is processed to determine the flow field density and flow field velocity of the building as follows: Obtain initial pressure data and water inflow to the building; According to the initial pressure data and water inflow, dynamic simulation is performed on the building simulation grid information based on computational fluid dynamics to obtain the discrete distribution of the fluid flow field inside the building on the entire computational domain to simulate the fluid flow process inside the building under flooding accidents; According to the discrete distribution of the fluid flow field, the velocity field of the building is obtained; Replace the velocity term in the momentum conservation equation with the building velocity field, and extract the pressure term separately as the unknown pressure field to construct the pressure Poisson equation; Solve the pressure Poisson equation to obtain the pressure field of the building; The building pressure field is used to correct the building velocity field, and the pressure field and velocity field inside the building are obtained by iterative calculation based on the mass conservation equation; According to the pressure field and velocity field inside the building, the flow field density and flow field velocity of the building are determined.

4. The method for dealing with building flooding disasters based on free surface simulation according to claim 3, characterized in that: According to the initial pressure data and water inflow, the dynamic simulation of the building simulation grid information is performed based on computational fluid dynamics to obtain the discrete distribution of the fluid flow field inside the building on the entire calculation domain as follows: According to the structural characteristic information inside the building, the flow information of the fluid when flowing through the internal structure of the building is obtained; The structural feature information includes at least hole location information and stair location information; Based on the bypass information, initial pressure data and water inflow, the turbulent kinetic energy equation and dissipation rate equation are constructed; Based on the turbulent kinetic energy equation and the dissipation rate equation, and combined with computational fluid dynamics, the dynamic simulation of the building simulation grid information is carried out to obtain the discrete distribution of the fluid flow field inside the building in the entire computational domain.

5. The method for dealing with building flooding disasters based on free surface simulation according to claim 1, characterized in that: According to the cavitation share distribution, the indoor water level change data is determined, which includes the following: Obtaining structural information of one or more rooms in a building; The room structure information includes room size data and room location data; According to the room size data, set one or more virtual measurement points; According to the room position data, the coordinate value of the virtual measuring point is obtained; Substitute the coordinate value of the virtual measuring point into the cavitation share distribution to obtain the cavitation share of the virtual measuring point; Based on the cavitation share of the virtual measuring point, the indoor water level change data is determined. The specific method is as follows: When a single virtual measuring point is set in a room structure, if the cavitation share at the virtual measuring point is less than the cavitation threshold, the water level at the virtual measuring point is lower than the water level threshold; if the cavitation share is greater than or equal to the cavitation threshold, it indicates that the water level at the virtual measuring point is higher than the water level threshold; the water level threshold is the water level position corresponding to the cavitation threshold; When multiple virtual measuring points are set for a room structure, the cavitation share of each virtual measuring point is judged. If the cavitation share of all virtual measuring points is greater than or equal to the cavitation threshold, it indicates that the room water level is higher than the water level threshold; if the cavitation share of any virtual measuring point is less than the cavitation threshold, it indicates that the room water level has not completely reached the water level threshold.

6. The method for dealing with building flooding disasters based on free surface simulation according to claim 1, characterized in that: Step 4: According to the pre-built door opening and closing control model and based on the indoor water level change data, the method for setting the door opening and closing data in the building is as follows: According to the door structure information in the building, a porous medium body group is established; By using the porous medium group, the momentum conservation equation and the mass conservation equation are modified to obtain new momentum conservation equation and new mass conservation equation; Based on the new momentum conservation equation and the new mass conservation equation, a porous media model is constructed to simulate the flow behavior of fluids passing through porous materials. According to the porous media model, the indoor water level change data is processed to obtain the water level information of each door structure; According to the water level information of the gate structure, the unit is automatically converted based on the flow domain to obtain the porosity of each gate structure, and the porosity value is 0 or 1; According to the porosity, the opening and closing state of each door structure is determined to realize the conversion between the closed area and the circulation area in the building, which includes the following contents: When the porosity is zero, the fluid cannot flow and the door is closed; When the porosity is 1, the fluid can flow and the door is open; Based on the opening and closing status of each door structure, the door opening and closing data in the building is determined.

7. The method for dealing with building flooding disasters based on free surface simulation according to claim 6, characterized in that: According to the water level information of the gate structure, the method of automatically converting the unit based on the flow domain to obtain the porosity of each gate structure is as follows: Set several virtual measuring points behind the door structure of each room, and obtain the coordinates of each virtual measuring point; According to the coordinates of the virtual measuring points and the water level information of the door structure, the water level information of each virtual measuring point is obtained; Based on the water level information of each virtual measuring point, the porosity of each door structure is obtained, which includes the following: When a single virtual measuring point is set in the door structure, the water level of the virtual measuring point is judged. If the water level of the virtual measuring point is lower than the set height, the porosity of the door structure is 0, that is, the door remains closed at this time; if the water level of the virtual measuring point is higher than the set height, the flow domain automatic conversion unit will modify the porosity of the door structure to 1, and the door structure at this time will be transformed from a closed domain to a flow domain, that is, the door will be changed from a closed state to an open state at this time; When multiple virtual measuring points are set for the door structure, the water level of each virtual measuring point is judged one by one. If the water level of all virtual measuring points is higher than the set height, the flow domain automatic conversion unit will change the porosity of the door structure from 0 to 1, and the door will open; if the water level of any virtual measuring point does not completely reach the set height, the porosity of the door structure will continue to be 0.

8. A method for dealing with building flooding disasters based on free surface simulation, characterized in that: Includes the following: Generate building simulation grid information based on relevant structural data of the building; According to computational fluid dynamics, the building simulation grid information is processed to determine the flow field velocity of the building; Based on the flow field velocity and the free surface algorithm, the fluid simulation of the building is performed to output the cavitation fraction; the method is as follows: Setting boundary conditions according to the internal structure of the building, wherein the boundary conditions include closed area boundary conditions, wall boundary conditions and flow inlet boundary conditions; The closed area boundary conditions include door structure information and pipe structure information, the wall boundary conditions include staircase structure information, building internal wall position information and ground position information, and the flow inlet boundary conditions are pipe breach structure data; Based on the free surface algorithm, and according to the boundary conditions and gravity, the fluid cavitation fraction continuity equation is constructed; According to the flow field density and flow field velocity, the fluid cavitation fraction continuity equation is solved to obtain the cavitation fraction distribution inside the building to simulate the flooding of the building; Based on the cavitation share, the water level change of the building is calculated; Determine the porosity of door structures in buildings based on water level changes; The opening and closing of the door structure are determined based on the porosity.

9. Building flood disaster treatment system based on free surface simulation, characterized by: It includes: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the building flood disaster handling method based on free surface simulation as described in any one of claims 1-8.

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