Method and system for calculating fire envelope temperature field of large-span space structure

Abstract

The invention discloses a method and a system for calculating a fire envelope temperature field of a large-span space structure. The method comprises the following steps: reading fire scene parameters, a geometric position of a fire source area and a steel member node file; establishing a fire source plane polygon according to the geometric position of the fire source area, and calculating the horizontal projection distance and the vertical distance between each component node and the fire source and the distance between the center of the ignition source and the steel component; according to the fire scene parameters and the distance, an empirical formula library is called in parallel, and the smoke temperature time history of each steel member node is obtained; according to the smoke temperature time history, the flame geometric parameters and the component thermal parameters, the component temperature time history is iteratively calculated step by step; in all fire scenes, the highest temperature and the scene corresponding to the highest temperature are taken for each component node, and an envelope temperature field is generated; and outputting the temperature time history, the envelope temperature field and the scene extreme value to a storage medium. According to the method, the calculation precision, the calculation efficiency and the engineering operability are considered, and the overall fire-resistant safety evaluation requirement of the large-span space structure is met.

Description

Technical Field

[0001] This invention belongs to the field of building fire safety assessment technology, specifically relating to a method and system for calculating the fire envelope temperature field of large-span spatial structures. Background Technology

[0002] In large public buildings (such as airport terminals, high-speed rail stations, and stadiums), the large-span roof systems, which often use steel or aluminum alloy structures, require an assessment of the risk of mechanical performance degradation under high temperatures during the design phase.

[0003] However, the current building fire protection code uses the ISO-834 standard temperature rise curve, which treats the entire space as a uniform temperature rise and cannot reflect the non-uniform and non-steady characteristics of real fires. CFD-based FDS simulation has high accuracy, but when the number of nodes is huge, a single simulation takes several hours to several days, which is difficult to meet the iterative requirements of "multiple fire scenarios - all nodes - long time" required for design optimization. Although empirical formula methods are fast, they lack a complete solution for "arbitrary fire source location, arbitrary component location, and multiple scenarios in parallel".

[0004] Therefore, providing a method and system for calculating the fire envelope temperature field of large-span spatial structures is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method and system for calculating the fire envelope temperature field of large-span spatial structures, which takes into account the calculation accuracy, calculation efficiency and engineering operability, so as to meet the overall fire safety assessment requirements of large-span spatial structures.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for calculating the fire envelope temperature field of a large-span spatial structure includes the following steps:

[0008] S1. Read fire scene parameters, geometric location of fire source area, and steel component node files;

[0009] S2. Based on the geometric location of the fire source area, establish a plane polygon of the fire source, and calculate the horizontal projection distance, vertical distance, and distance from the center of the fire source to the steel component for each steel component node.

[0010] S3. Based on the fire scene parameters and distance, the empirical formula library is called in parallel to obtain the flue gas temperature time history at each steel component node;

[0011] S4. Based on the flue gas temperature time history, flame geometric parameters, and thermal parameters of the steel components, the temperature time history of the steel components is calculated iteratively step by step.

[0012] S5. In all fire scenarios, take the highest temperature and its corresponding scenario for each steel component node, and generate an envelope temperature field.

[0013] S6. Output the temperature time history, envelope temperature field, and scene extreme values ​​to the storage medium.

[0014] By adopting the above technical solutions, the present invention produces the following beneficial effects:

[0015] A method and system capable of performing parallel calculations on tens of thousands of nodes and dozens of fire scenarios at once, and directly outputting the envelope temperature and its corresponding scenario, can be used for rapid fire resistance assessment of large-span spatial structures.

[0016] Furthermore, step S1 includes:

[0017] S11. Read the fire scene parameter table to obtain the fire source power, building area and fire duration for each scene;

[0018] S12. Parse the geometric node data of the fire source area, supporting the definition of a single point or a polygonal fire source area with more than or equal to 3 points;

[0019] S13. Load the steel component node file, including node number, spatial coordinates, section shape factor, section correction factor and section type.

[0020] Furthermore, step S2 includes:

[0021] S21. Construct the fire source planar polygon: Convert the input vertices into a two-dimensional planar polygon;

[0022] S22. Calculate the horizontal projection distance: Use the ray method to determine the node position. The distance to the internal point is 0, and the distance to the nearest edge is calculated for the external point.

[0023] S23. Calculate the vertical height difference: Δh = |node z-coordinate - fire source reference height|;

[0024] S24. Calculate the distance from the center of the ignition source to the steel component: Where hf is the height of the fire source and Δx is the horizontal projection distance.

[0025] Furthermore, step S3 includes:

[0026] S31. Parallel invocation of multi-model empirical formula library, including Li Guoqiang-Du Yong model, Zhang Guowei-Zhu Guoqing model and Xue Suduo-Liang Jin model;

[0027] S32. Calculate the flue gas temperature time history data for each steel component node.

[0028] Furthermore, step S4 includes:

[0029] S41. Based on Zhang Guowei's model of temperature rise in high-rise steel components exposed to fire, establish the heat transfer equation:

[0030]

[0031] Where: ΔT s F represents the temperature rise of the steel component within the time interval Δt; s ρ is the external surface area of ​​a steel component per unit length. s C is the density of the steel component. s Specific heat of steel components; V s ε is the volume of a steel member per unit length; s σ is the correction factor; σ0 is the Boltzmann constant, taken as 5.67 × 10⁻⁶. -8 W / (m 2 ·K 4 );a g T represents the flue gas absorption rate. g Let T be the temperature of the flue gas at time t. s Let be the temperature of the steel component at time t; D is the equivalent diameter of the fire source.

[0032] S42. The heating process of the steel component is analyzed using an iterative method, and the calculation formula is as follows:

[0033] T s j+1 =T s j +ΔtT s

[0034] In the formula: T s j+1 T represents the temperature of the steel component at step j+1. s j Let be the temperature of the steel component in step j.

[0035] Furthermore, step S5 includes:

[0036] S51, Envelope Field Construction Algorithm: For each steel component node, traverse all fire scenarios and record the highest temperature and corresponding scenario;

[0037] S52. Generate a temperature statistics matrix table, which includes the highest temperature, envelope temperature, and fire scenario corresponding to each steel component node in each scenario.

[0038] S53. Identify the steel component node with the highest global temperature and its corresponding scenario.

[0039] Furthermore, step S6 includes:

[0040] S61. Employs dynamic block storage technology to automatically split the output file when the number of nodes exceeds a threshold;

[0041] S62, Output temperature time history data table, including time column and temperature data of each node;

[0042] S63. Output scene extreme value data, including the highest temperature of each scene and the global highest temperature node information.

[0043] A computational system for implementing the above-described method for calculating the fire envelope temperature field of large-span spatial structures includes:

[0044] The information input module is used to read fire scene parameters, the geometric location of the fire source area, and steel component node files;

[0045] The geometric analysis module is used to create a plane polygon of the fire source based on the geometric location of the fire source area, and to calculate the horizontal projection distance, vertical distance and the distance from the center of the fire source to the steel component of each steel component node.

[0046] The flue gas temperature calculation module is used to call the empirical formula library in parallel based on fire scene parameters and distance to obtain the flue gas temperature time history at each steel component node.

[0047] The component temperature rise calculation module is used to iteratively calculate the temperature time history of the steel component based on the flue gas temperature time history, flame geometric parameters, and thermal parameters of the steel component.

[0048] The envelope temperature statistics module is used to take the highest temperature and its corresponding scenario for each steel component node in all fire scenarios and generate an envelope temperature field.

[0049] The results output module is used to output the temperature time history, envelope temperature field and scene extreme values ​​to the storage medium. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0051] Figure 1 A flowchart of a method for calculating the envelope temperature field of a fire in a large-span spatial structure, provided by the present invention;

[0052] Figure 2 This is a schematic diagram of the envelope temperature field of a building roof steel component obtained using the fire envelope temperature field calculation method and system of the present invention for a large-span spatial structure. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] like Figure 1-2 As shown in the figure, this invention discloses a method for calculating the fire envelope temperature field of a large-span spatial structure, including the following steps:

[0055] S1. Read fire scene parameters, geometric location of fire source area, and steel component node files;

[0056] S2. Based on the geometric location of the fire source area, establish a plane polygon of the fire source, and calculate the horizontal projection distance, vertical distance, and distance from the center of the fire source to the steel component for each steel component node.

[0057] S3. Based on the fire scene parameters and distance, the empirical formula library is called in parallel to obtain the flue gas temperature time history at each steel component node;

[0058] S4. Based on the flue gas temperature time history, flame geometric parameters, and thermal parameters of the steel components, the temperature time history of the steel components is calculated iteratively step by step.

[0059] S5. In all fire scenarios, take the highest temperature and its corresponding scenario for each steel component node, and generate an envelope temperature field.

[0060] S6. Output the temperature time history, envelope temperature field, and scene extreme values ​​to the storage medium.

[0061] This invention provides a method and system for performing parallel calculations on tens of thousands of nodes and dozens of fire scenarios at once, and directly outputting the envelope temperature and its corresponding scenario, which can be used for rapid fire resistance assessment of large-span spatial structures.

[0062] Specifically, step S1 includes:

[0063] S11. Read the fire scene parameter table to obtain the fire source power, building area and fire duration for each scene;

[0064] S12. Parse the geometric node data of the fire source area, supporting the definition of a single point or a polygonal fire source area with more than or equal to 3 points;

[0065] S13. Load the steel component node file, including node number, spatial coordinates (x,y,z), section shape factor, section correction factor, and section type.

[0066] Specifically, step S2 includes:

[0067] S21. Construct the fire source planar polygon: Convert the input vertices into a two-dimensional planar polygon;

[0068] S22. Calculate the horizontal projection distance: Use the ray method to determine the node position. The distance to the internal point is 0, and the distance to the nearest edge is calculated for the external point.

[0069] S23. Calculate the vertical height difference: Δh = |node z-coordinate - fire source reference height|;

[0070] S24. Calculate the distance from the center of the ignition source to the steel component: Where h f Δx represents the height of the fire source, and Δx represents the horizontal projection distance.

[0071] Specifically, step S3 includes:

[0072] S31. Parallel invocation of multi-model empirical formula library, including Li Guoqiang-Du Yong model, Zhang Guowei-Zhu Guoqing model and Xue Suduo-Liang Jin model;

[0073] S32. Calculate the flue gas temperature time history data for each steel component node.

[0074] Specifically, step S4 includes:

[0075] S41. Based on Zhang Guowei's model of temperature rise in high-rise steel components exposed to fire, establish the heat transfer equation:

[0076]

[0077] Where: ΔT s F represents the temperature rise of the steel component within the time interval Δt; s ρ is the external surface area of ​​a steel component per unit length. s C is the density of the steel component. s Specific heat of steel components; V s ε is the volume of a steel member per unit length; s σ is the correction factor; σ0 is the Boltzmann constant, taken as 5.67 × 10⁻⁶. -8 W / (m 2 ·K 4 );a g T represents the flue gas absorption rate. g Let T be the temperature of the flue gas at time t. s Let be the temperature of the steel component at time t; D is the equivalent diameter of the fire source.

[0078] S42. The heating process of the steel component is analyzed using an iterative method, and the calculation formula is as follows:

[0079] T s j+1 =T s j+ΔtT s

[0080] In the formula: T s j+1 T represents the temperature of the steel component at step j+1. s j Let be the temperature of the steel component in step j.

[0081] Specifically, step S5 includes:

[0082] S51, Envelope Field Construction Algorithm: For each steel component node, traverse all fire scenarios and record the highest temperature and corresponding scenario;

[0083] S52. Generate a temperature statistics matrix table, which includes the highest temperature, envelope temperature, and fire scenario corresponding to each steel component node in each scenario.

[0084] S53. Identify the steel component node with the highest global temperature and its corresponding scenario.

[0085] Specifically, step S6 includes:

[0086] S61. Employs dynamic block storage technology to automatically split the output file when the number of nodes exceeds a threshold;

[0087] S62, Output temperature time history data table, including time column and temperature data of each node;

[0088] S63. Output scene extreme value data, including the highest temperature of each scene and the global highest temperature node information.

[0089] This invention also discloses a computational system for implementing the above-described method for calculating the envelope temperature field of a fire in a large-span spatial structure, comprising:

[0090] The information input module is used to read fire scene parameters, the geometric location of the fire source area, and steel component node files;

[0091] The geometric analysis module is used to create a plane polygon of the fire source based on the geometric location of the fire source area, and to calculate the horizontal projection distance, vertical distance and the distance from the center of the fire source to the steel component of each steel component node.

[0092] The flue gas temperature calculation module is used to call the empirical formula library in parallel based on fire scene parameters and distance to obtain the flue gas temperature time history at each steel component node.

[0093] The component temperature rise calculation module is used to iteratively calculate the temperature time history of the steel component based on the flue gas temperature time history, flame geometric parameters, and thermal parameters of the steel component.

[0094] The envelope temperature statistics module is used to take the highest temperature and its corresponding scenario for each steel component node in all fire scenarios and generate an envelope temperature field.

[0095] The results output module is used to output the temperature time history, envelope temperature field and scene extreme values ​​to the storage medium.

[0096] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0097] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating the envelope temperature field of a fire in a large-span spatial structure, characterized in that, Includes the following steps: S1. Read fire scene parameters, geometric location of fire source area, and steel component node files; S2. Based on the geometric location of the fire source area, establish a plane polygon of the fire source, and calculate the horizontal projection distance, vertical distance, and distance from the center of the fire source to the steel component for each steel component node. S3. Based on the fire scene parameters and distance, the empirical formula library is called in parallel to obtain the flue gas temperature time history at each steel component node; S4. Based on the flue gas temperature time history, flame geometric parameters, and thermal parameters of the steel components, the temperature time history of the steel components is calculated iteratively step by step. S5. In all fire scenarios, take the highest temperature and its corresponding scenario for each steel component node, and generate an envelope temperature field. S6. Output the temperature time history, envelope temperature field, and scene extreme values ​​to the storage medium.

2. The method for calculating the fire envelope temperature field of a large-span spatial structure according to claim 1, characterized in that, Step S1 includes: S11. Read the fire scene parameter table to obtain the fire source power, building area and fire duration for each scene; S12. Parse the geometric node data of the fire source area, supporting the definition of a single point or a polygonal fire source area with more than or equal to 3 points; S13. Load the steel component node file, including node number, spatial coordinates, section shape factor, section correction factor and section type.

3. The method for calculating the fire envelope temperature field of a large-span spatial structure according to claim 1, characterized in that, Step S2 includes: S21. Construct the fire source planar polygon: Convert the input vertices into a two-dimensional planar polygon; S22. Calculate the horizontal projection distance: Use the ray method to determine the node position. The distance to the internal point is 0, and the distance to the nearest edge is calculated for the external point. S23. Calculate the vertical height difference: Δh = |node z-coordinate - fire source reference height|; S24. Calculate the distance from the center of the ignition source to the steel component: Where h f Δx represents the height of the fire source, and Δx represents the horizontal projection distance.

4. The method for calculating the fire envelope temperature field of a large-span spatial structure according to claim 1, characterized in that, Step S3 includes: S31. Parallel invocation of multi-model empirical formula library, including Li Guoqiang-Du Yong model, Zhang Guowei-Zhu Guoqing model and Xue Suduo-Liang Jin model; S32. Calculate the flue gas temperature time history data for each steel component node.

5. The method for calculating the fire envelope temperature field of a large-span spatial structure according to claim 1, characterized in that, Step S4 includes: S41. Based on Zhang Guowei's model of temperature rise in steel components exposed to fire in tall spaces, establish the heat transfer equation: Where: ΔT s F represents the temperature rise of the steel component within the time interval Δt; s ρ is the external surface area of ​​a steel component per unit length. s C is the density of the steel component. s Specific heat of steel components; V s ε is the volume of a steel member per unit length; s σ is the correction factor; σ0 is the Boltzmann constant, taken as 5.67 × 10⁻⁶. -8 W / (m 2 ·K 4 );a g T represents the flue gas absorption rate. g Let T be the temperature of the flue gas at time t. s Let be the temperature of the steel component at time t; D is the equivalent diameter of the fire source. S42. The heating process of the steel component is analyzed using an iterative method, and the calculation formula is as follows: In the formula: T s j+1 The temperature of the steel component at step j+1; T s j Let be the temperature of the steel component in step j.

6. The method for calculating the fire envelope temperature field of a large-span spatial structure according to claim 1, characterized in that, Step S5 includes: S51, Envelope Field Construction Algorithm: For each steel component node, traverse all fire scenarios and record the highest temperature and corresponding scenario; S52. Generate a temperature statistics matrix table, which includes the highest temperature, envelope temperature, and fire scenario corresponding to each steel component node in each scenario. S53. Identify the steel component node with the highest global temperature and its corresponding scenario.

7. The method for calculating the fire envelope temperature field of a large-span spatial structure according to claim 1, characterized in that, Step S6 includes: S61. Employs dynamic block storage technology to automatically split the output file when the number of nodes exceeds a threshold; S62, Output temperature time history data table, including time column and temperature data of each node; S63. Output scene extreme value data, including the highest temperature of each scene and the global highest temperature node information.

8. A computational system for implementing the fire envelope temperature field calculation method for large-span spatial structures as described in any one of claims 1-7, characterized in that, include: The information input module is used to read fire scene parameters, the geometric location of the fire source area, and steel component node files; The geometric analysis module is used to create a plane polygon of the fire source based on the geometric location of the fire source area, and to calculate the horizontal projection distance, vertical distance and the distance from the center of the fire source to the steel component of each steel component node. The flue gas temperature calculation module is used to call the empirical formula library in parallel based on fire scene parameters and distance to obtain the flue gas temperature time history at each steel component node. The component temperature rise calculation module is used to iteratively calculate the temperature time history of the steel component based on the flue gas temperature time history, flame geometric parameters, and thermal parameters of the steel component. The envelope temperature statistics module is used to take the highest temperature and its corresponding scenario for each steel component node in all fire scenarios and generate an envelope temperature field. The results output module is used to output the temperature time history, envelope temperature field and scene extreme values ​​to the storage medium.

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