Numerical simulation calculation method for release process of bromotrifluoromethane fire extinguishing agent

Abstract

The invention discloses a numerical simulation calculation method for a release process of a bromotrifluoromethane fire extinguishing agent, which belongs to the field of fire safety, and comprises the following steps of: firstly, calling a plurality of professional libraries in a sketch mode through AMESim simulation software to build a one-dimensional simulation model covering gas storage, a pipe network and a spraying system, and meticulously simulating storage and transmission of the fire extinguishing agent; selecting a reasonable mathematical model, such as a two-phase flow model and the like, by taking the sub-model mode as an element, and determining a related calculation model; then setting parameters of each element in a parameter mode according to reality, wherein the parameters comprise fire extinguishing agent and environment related parameters; finally, calculating and analyzing results in a simulation mode to obtain indexes such as release time and nozzle pressure to evaluate the functionality of the fire extinguishing system, a basis is provided for system optimization, many problems of a traditional simulation method are solved, and great significance is achieved for design optimization of the fire extinguishing system.

Description

Technical Field

[0001] The invention belongs to the field of fire safety, and particularly relates to a numerical simulation calculation method for a release process of bromotrifluoromethane fire extinguishing agent. Background Art

[0002] Bromotrifluoromethane has many advantages, such as high fire extinguishing efficiency, low toxicity and long shelf life, and is widely used in the military field. For the release process of ship fire extinguishing systems, hydraulic calculations can be performed using the requirements and methods in relevant standards and specifications, or verification can be performed using simulation experiments. However, large-scale pipe network experiments are expensive, and the measured data are also limited by the type, location, number and accuracy of sensors; hydraulic calculations cannot obtain the details of the two-phase flow of fire extinguishing agents in various parts of the pipe network. At present, most of the numerical simulation calculations of the release process of fire extinguishing agents in fire extinguishing systems use unidirectional flow or three-dimensional simulation. The former has low calculation accuracy and the latter has high calculation cost and long calculation cycle, while the current numerical simulation calculations of one-dimensional simulation of multiphase flow are rarely mentioned.

[0003] Simcenter Amesim is a modeling and simulation platform for complex systems in multidisciplinary fields. The platform contains typical model libraries such as pneumatics, hydraulics, control systems, thermal calculations, and multiphase flows. By calling the relevant components in each model library, a numerical simulation calculation model can be built to simulate actual engineering science problems. The present invention utilizes the modular modeling concept and visual user interface of the simulation platform. Through the combination of various modules and the input of relevant parameters, a gas fire extinguishing system pipeline flow model can be intuitively constructed to study the release of trifluoromonobromomethane fire extinguishing agent from the gas cylinder, the flow and spraying process of the pipeline system, and then obtain the evaluation indicators such as the release time of the fire extinguishing agent of the fire extinguishing system, the pressure at the nozzle, and the phase change process of the fire extinguishing agent, so as to judge the rationality of the design of the fire extinguishing system and provide guidance for the optimization of the fire extinguishing system. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a numerical simulation calculation method for the release process of trifluoromethyl bromo fire extinguishing agent, comprising the following steps: Step S1: Create a system and build a basic model in the sketch mode of professional simulation software.

[0005] Step S2: Select a reasonable mathematical model for the system components in the sub-model mode of the professional simulation software.

[0006] Step S3: Set the required parameters for each module component in the parameter mode of the professional simulation software.

[0007] Step S4: Perform numerical simulation calculation on the new fire extinguishing agent release process in the simulation mode of professional simulation software and analyze the simulation calculation results.

[0008] Furthermore, the step of building the system in step S1 includes: step S101: building a model of a new fire extinguishing agent fire extinguishing gas storage system with the help of a first function library, a second function library, a third function library, a fourth function library, a fifth function library and a sixth function library.

[0009] Step S102: Complete the construction of the new fire extinguishing agent fire extinguishing pipe network system model by calling the second function library, the fifth function library and the sixth function library. The pipe network system model components are composed of a first heat exchange tube with special resistance and capacitance characteristics, a first heat capacity element and a first control element. The first heat exchange tube can handle complex flow, phase change and heat exchange conditions, accurately calculate the pressure and density state parameters, and thus accurately obtain the multi-phase or single-phase pressure loss. The first heat capacity element is used to accurately calculate the heat exchange between the pipeline and the fire extinguishing agent and the environment. At the same time, considering that the special structure in the pipe network system is inevitable, the influence on the flow of the fire extinguishing agent is simulated through a specific component combination.

[0010] Step S103: Complete the construction of the new fire extinguishing agent fire extinguishing spraying system model by calling the second function library, the fifth function library and the sixth function library.

[0011] Furthermore, in the gas storage system model, the gas cylinder is mainly composed of five elements, namely the first element, the second element, the third element, the fourth element and the fifth element; the first element is used as a container for storing a certain driving gas to simulate the storage condition of the driving gas; the second element is used as a pneumatic driving structure to promote the movement of the driving gas; the fifth element is used as a storage container for a new type of fire extinguishing agent and is responsible for storing the fire extinguishing agent; the fourth element is used as a driving structure for the spraying of the fire extinguishing agent and controls the spraying of the fire extinguishing agent; the third element is used as an element to simulate the special interface in the liquid storage bottle. Although its mass is small, it plays a key role in the model. By reasonably setting its parameters, such as setting the mass to a minimum value and setting its active height according to actual conditions to reflect the storage height of the fire extinguishing agent in the gas cylinder, specific parameters are set to simulate the accelerated release process in the later stage of the driving gas spraying to accurately simulate the change in the release rate of the fire extinguishing agent.

[0012] Furthermore, the step of selecting a mathematical model in step S2 includes step S201: Since the release process of the new fire extinguishing agent is accompanied by special physical changes, the numerical simulation calculation model uses a special multiphase flow calculation model, which needs to comprehensively consider the actual special phase proportion and the actual flow velocity of different phases, as well as the friction between each phase and the pipeline wall and the mutual friction between the phases.

[0013] Step S202: The numerical simulation calculation model pipeline system selects an adaptive friction factor calculation model, which can accurately calculate the friction coefficient based on the specific surface characteristics of the pipeline, the flow characteristics of the fluid and the physical property factors, thereby accurately calculating the pressure loss in the pipeline.

[0014] Step S203: The nozzle resistance coefficient of the numerical simulation calculation model is obtained by combining the calculation model and professional simulation software based on the resistance coefficient relationship measured by a large number of experiments.

[0015] Furthermore, step S3 of setting component parameters includes: step 301: completing parameter setting of the fire extinguishing agent storage system according to the characteristics and filling conditions of the fire extinguishing agent in the actual system design; the first component and the fifth component input are the volumes of the driving gas and the new fire extinguishing agent in the gas storage system.

[0016] Step 302: Complete the parameter setting of the fire extinguishing agent pipe network system according to the pipe network layout, properties and nozzle models of the fire extinguishing system.

[0017] Step S303: Complete the setting of simulation system environment parameters according to actual environment characteristics.

[0018] Furthermore, the simulation calculation step of step S4 includes: step S401: setting the simulation time and step length in the simulation calculation setting according to actual conditions.

[0019] Step S402: perform numerical simulation calculations and extract simulation results; during the calculation process, the model will calculate the state parameters of the fire extinguishing agent at each time and each position according to the set parameters and mathematical model, including pressure, temperature, speed, and special phase ratio.

[0020] Step S403: Analyze the simulation results, extract the data of the release time of the fire extinguishing agent, the pressure at the fire extinguishing agent nozzle, and the change of the special phase ratio in the pipeline, and perform a functional evaluation on the new fire extinguishing agent fire extinguishing system.

[0021] Furthermore, the model of the new fire extinguishing agent fire extinguishing gas storage system is built by calling the first function library, the second function library, the third function library, the fourth function library, the fifth function library and the sixth function library; the first function library provides basic functional elements and models related to storage and driving, which are used to simulate the basic characteristics of the fire extinguishing agent during storage and driving; the second function library is used for simulating special flow phenomena, and can accurately handle the interaction and changes of special phases; the third function library is used to simulate the part related to the driving gas; the fourth function library provides elements for simulating special structures; the fifth function library is used for simulation of control signals and calculations related to special flow characteristics; the sixth function library is used to process calculations related to heat exchange, reflecting the various state changes of the new fire extinguishing agent in the gas storage system.

[0022] Furthermore, a simulation model is established, parameter settings are completed, and simulation calculations are performed; from the simulation results, the fire extinguishing agent release time, pressure at the nozzle, and functional evaluation indicators of the special phase ratio fire extinguishing system of the fire extinguishing system are directly read out, and then the functional evaluation of the fire extinguishing system is performed; by comparing and analyzing these indicators with the design requirements, it is determined whether the fire extinguishing system meets the standards in terms of fire extinguishing agent release speed, injection effect, and system stability; if the fire extinguishing agent release time does not meet the requirements, it is necessary to check the parts of the model related to the storage and release of the fire extinguishing agent; if the pressure at the nozzle does not meet the standards, it is necessary to review the nozzle configuration and related parameters, and the driving pressure setting; if the special phase ratio in the pipeline changes abnormally, consider the pipe network system design and fire extinguishing agent characteristics.

[0023] Compared with the prior art, the present invention has the following beneficial effects: the present invention is applicable to the numerical simulation research and functional verification of trifluoromonobromomethane fire extinguishing system. By building a model according to the actual design scheme, selecting the mathematical model, setting parameters according to the working conditions, simulating calculations and analyzing the results, and comparing the accuracy of the model with the actual scale experiment, the function of the fire extinguishing system is effectively evaluated and optimization suggestions are put forward. The problems of low precision, long time consumption, and difficulty in parameter adjustment of traditional numerical simulation methods are solved, which strongly supports the optimization of the fire extinguishing system and is of great significance to its design optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the overall process of simulation calculation of the present invention.

[0025] Figure 2 A schematic flow chart for building a model for the present invention.

[0026] Figure 3 Flow chart of exemplary steps for selecting a mathematical model for the present invention.

[0027] Figure 4 Flow chart of exemplary steps for setting parameters for the present invention.

[0028] Figure 5 A flowchart of exemplary steps for simulation calculations of the present invention. DETAILED DESCRIPTION

[0029] Example: Based on the AMESim simulation platform, this example develops a numerical simulation calculation method for the release process of trifluoromonobromomethane fire extinguishing agent in one-dimensional two-phase flow. Figure 1 As shown, the following steps are included: Step S1: Create a system and build a basic model in the sketch mode of professional simulation software.

[0030] Step S2: Select a reasonable mathematical model for the system components in the sub-model mode of the professional simulation software.

[0031] Step S3: Set the required parameters for each module component in the parameter mode of the professional simulation software.

[0032] Step S4: Perform numerical simulation calculation on the new fire extinguishing agent release process in the simulation mode of professional simulation software and analyze the simulation calculation results.

[0033] like Figure 2 As shown in the figure, the steps of creating a system and building a basic model in this embodiment include: Step S101: Complete the construction of a new fire extinguishing agent fire extinguishing gas storage system model with the help of the first function library, the second function library, the third function library, the fourth function library, the fifth function library and the sixth function library.

[0034] Step S102: Complete the construction of the new fire extinguishing agent fire extinguishing pipe network system model by calling the second function library, the fifth function library and the sixth function library. The pipe network system model components are composed of a first heat exchange tube with special resistance and capacitance characteristics, a first heat capacity element and a first control element. The first heat exchange tube can handle complex flow, phase change and heat exchange conditions, accurately calculate the pressure and density state parameters, and thus accurately obtain the multi-phase or single-phase pressure loss. The first heat capacity element is used to accurately calculate the heat exchange between the pipeline and the fire extinguishing agent and the environment. At the same time, considering that the special structure in the pipe network system is inevitable, the influence on the flow of the fire extinguishing agent is simulated through a specific component combination.

[0035] Step S103: Complete the construction of the new fire extinguishing agent fire extinguishing spraying system model by calling the second function library, the fifth function library and the sixth function library.

[0036] In the gas storage system model, the gas cylinder is mainly composed of five elements, namely the first element, the second element, the third element, the fourth element and the fifth element; the first element is a container for storing a certain driving gas and simulates the storage condition of the driving gas; the second element is a pneumatic driving structure that drives the driving gas to move; the fifth element is a storage container for a new type of fire extinguishing agent and is responsible for storing the fire extinguishing agent; the fourth element is a driving structure for the ejection of the fire extinguishing agent and controls the ejection of the fire extinguishing agent; the third element is an element that simulates the special interface in the liquid storage bottle. Although its mass is small, it plays a key role in the model. By reasonably setting its parameters, such as setting the mass to a minimum value and setting its active height according to actual conditions to reflect the storage height of the fire extinguishing agent in the gas cylinder, specific parameters are set to simulate the accelerated release process in the later stage of the ejection of the driving gas to accurately simulate the change in the release rate of the fire extinguishing agent.

[0037] like Figure 3As shown, exemplary steps for selecting a reasonable mathematical model for this embodiment include: step S201: Since the release process of the new fire extinguishing agent is accompanied by special physical changes, the numerical simulation calculation model uses a special multiphase flow calculation model, which needs to comprehensively consider the actual special phase proportion and the actual flow velocity of different phases, as well as the friction between each phase and the pipeline wall and the mutual friction between the phases.

[0038] Step S202: The numerical simulation calculation model pipeline system selects an adaptive friction factor calculation model, which can accurately calculate the friction coefficient based on the specific surface characteristics of the pipeline, the flow characteristics of the fluid and the physical property factors, thereby accurately calculating the pressure loss in the pipeline.

[0039] Step S203: The nozzle resistance coefficient of the numerical simulation calculation model is obtained by combining the calculation model and professional simulation software based on the resistance coefficient relationship measured by a large number of experiments.

[0040] like Figure 4 As shown, exemplary steps for setting parameters in this embodiment include: Step 301: According to the characteristics and filling conditions of the fire extinguishing agent in the actual system design, complete the parameter setting of the fire extinguishing agent storage system; the first element and the fifth element input are the volumes of the driving gas and the new fire extinguishing agent in the gas storage system.

[0041] Step 302: Complete the parameter setting of the fire extinguishing agent pipe network system according to the pipe network layout, properties and nozzle models of the fire extinguishing system.

[0042] Step S303: Complete the setting of simulation system environment parameters according to actual environment characteristics.

[0043] like Figure 5 As shown, exemplary steps of performing simulation calculations in this embodiment are shown, which include: Step S401: Set the simulation duration and step size in the simulation calculation settings according to actual conditions.

[0044] Step S402: perform numerical simulation calculations and extract simulation results: During the calculation process, the model will calculate the state parameters of the fire extinguishing agent at each time and each position according to the set parameters and mathematical model, including pressure, temperature, speed, and special phase ratio.

[0045] Step S403: Analyze the simulation results, extract the data of the release time of the fire extinguishing agent, the pressure at the fire extinguishing agent nozzle, and the change of the special phase ratio in the pipeline, and perform a functional evaluation on the new fire extinguishing agent fire extinguishing system.

[0046] The model of the new fire extinguishing agent fire extinguishing gas storage system is built by calling the first function library, the second function library, the third function library, the fourth function library, the fifth function library and the sixth function library; the first function library provides basic functional elements and models related to storage and driving, which are used to simulate the basic characteristics of the fire extinguishing agent during storage and driving; the second function library is used for simulating special flow phenomena, and can accurately handle the interaction and changes of special phases; the third function library is used to simulate the part related to the driving gas; the fourth function library provides elements for simulating special structures; the fifth function library is used for simulation of control signals and calculations related to special flow characteristics; the sixth function library is used to process calculations related to heat exchange, reflecting the various state changes of the new fire extinguishing agent in the gas storage system.

[0047] Establish a simulation model, complete parameter settings, and perform simulation calculations; directly read out the fire extinguishing agent release time, pressure at the nozzle, and functional evaluation indicators of the special phase ratio fire extinguishing system from the simulation results, and then perform a functional evaluation of the fire extinguishing system; by comparing and analyzing these indicators with the design requirements, determine whether the fire extinguishing system meets the standards in terms of fire extinguishing agent release speed, injection effect, and system stability; if the fire extinguishing agent release time does not meet the requirements, it is necessary to check the parts of the model related to the storage and release of the fire extinguishing agent; if the pressure at the nozzle does not meet the standards, it is necessary to review the nozzle configuration and related parameters, and the driving pressure setting; if the special phase ratio in the pipeline changes abnormally, consider the pipe network system design and fire extinguishing agent characteristics.

[0048] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A numerical simulation calculation method for the release process of trifluoromethyl bromofire extinguishing agent, characterized in that: The following steps are involved: Step S1: Create a system and build a basic model in the sketch mode of professional simulation software; Step S2: Selecting a reasonable mathematical model for the system components in the sub-model mode of the professional simulation software; Step S3: setting the required parameters for each module component in the parameter mode of the professional simulation software; Step S4: Perform numerical simulation calculation on the new fire extinguishing agent release process in the simulation mode of professional simulation software and analyze the simulation calculation results.

2. The numerical simulation calculation method for the release process of a trifluoromethyl bromofire extinguishing agent according to claim 1, characterized in that: Steps for setting up the S1 system include: Step S101: Building a new fire extinguishing agent fire extinguishing gas storage system model with the help of the first function library, the second function library, the third function library, the fourth function library, the fifth function library and the sixth function library; Step S102: The model of the new fire extinguishing agent fire extinguishing pipe network system is built by calling the second function library, the fifth function library and the sixth function library; the pipe network system model element is composed of a first heat exchange tube with special resistance and capacitance characteristics, a first heat capacity element and a first control element. The first heat exchange tube can handle complex flow, phase change and heat exchange conditions, accurately calculate the pressure and density state parameters, and thus accurately obtain the multi-phase or single-phase pressure loss. The first heat capacity element is used to accurately calculate the heat exchange between the pipeline and the fire extinguishing agent and the environment. At the same time, considering that the special structure in the pipe network system is inevitable, the influence of the special structure on the flow of the fire extinguishing agent is simulated through a specific component combination; Step S103: Complete the construction of the new fire extinguishing agent fire extinguishing spraying system model by calling the second function library, the fifth function library and the sixth function library.

3. The numerical simulation calculation method of a trifluoromethyl bromofire extinguishing agent release process according to claim 2, characterized in that: In the gas storage system model, the gas storage cylinder is mainly composed of five components, namely, the first component, the second component, the third component, the fourth component and the fifth component; the first component is used as a container for storing a certain driving gas to simulate the storage condition of the driving gas; the second component is used as a pneumatic driving structure to drive the driving gas to move; The fifth element is a storage container for the new type of fire extinguishing agent and is responsible for storing the fire extinguishing agent; the fourth element is a driving structure for the discharge of the fire extinguishing agent and controls the discharge of the fire extinguishing agent; the third element is a component that simulates the special interface in the liquid storage bottle. Although its mass is small, it plays a key role in the model. By reasonably setting its parameters, such as setting the mass to a minimum value and setting its active height according to actual conditions to reflect the storage height of the fire extinguishing agent in the gas cylinder, and setting specific parameters to simulate the accelerated release process in the later stage of the driving gas discharge, the change in the release rate of the fire extinguishing agent can be accurately simulated.

4. The numerical simulation calculation method for the release process of a trifluoromethyl bromofire extinguishing agent according to claim 1, characterized in that: The step of selecting a mathematical model in step S2 includes: Step S201: Since the release process of the new fire extinguishing agent is accompanied by special physical changes, the numerical simulation calculation model uses a special multiphase flow calculation model, which needs to comprehensively consider the real special phase proportion and the actual flow velocity of different phases, as well as the friction between each phase and the pipe wall and the mutual friction between the phases; Step S202: The numerical simulation calculation model pipeline system selects an adaptive friction factor calculation model, which accurately calculates the friction coefficient based on the specific surface characteristics of the pipeline, the flow characteristics of the fluid and the physical property factors, thereby accurately calculating the pressure loss in the pipeline; Step S203: The resistance coefficient of the nozzle of the numerical simulation calculation model is obtained by combining the calculation model and professional simulation software based on the resistance coefficient relationship measured in the experiment.

5. The numerical simulation calculation method for the release process of a trifluoromethyl bromofire extinguishing agent according to claim 1, characterized in that: Step S3: setting component parameters includes: Step 301: according to the characteristics and filling conditions of the fire extinguishing agent in the actual system design, the parameters of the fire extinguishing agent storage system are set; the first element and the fifth element are input as the volumes of the driving gas and the new fire extinguishing agent in the gas storage system; Step 302: Complete the parameter setting of the fire extinguishing agent pipe network system according to the pipe network layout, properties and nozzle model of the fire extinguishing system; Step S303: Complete the setting of simulation system environment parameters according to actual environment characteristics.

6. The numerical simulation calculation method for the release process of trifluoromethyl bromoform fire extinguishing agent according to claim 1, characterized in that: The steps of simulation calculation in step S4 include: Step S401: setting the simulation duration and step size in the simulation calculation settings according to the actual situation; Step S402: perform numerical simulation calculations and extract simulation results; during the calculation process, the model will calculate the state parameters of the fire extinguishing agent at each time and each position according to the set parameters and mathematical model, including pressure, temperature, speed, and special phase ratio; Step S403: Analyze the simulation results, extract the data of the release time of the fire extinguishing agent, the pressure at the fire extinguishing agent nozzle, and the change of the special phase ratio in the pipeline, and perform a functional evaluation on the new fire extinguishing agent fire extinguishing system.

7. The numerical simulation calculation method for the release process of a trifluoromethyl bromofire extinguishing agent according to claim 1, characterized in that: The model of the new fire extinguishing agent fire extinguishing gas storage system is built by calling the first function library, the second function library, the third function library, the fourth function library, the fifth function library and the sixth function library; the first function library provides basic functional elements and models related to storage and driving, which are used to simulate the basic characteristics of the fire extinguishing agent during storage and driving; the second function library is used for simulating special flow phenomena, and can accurately handle the interaction and changes of special phases; the third function library is used to simulate the part related to the driving gas; the fourth function library provides elements for simulating special structures; the fifth function library is used for simulation of control signals and calculations related to special flow characteristics; the sixth function library is used to process calculations related to heat exchange, reflecting the various state changes of the new fire extinguishing agent in the gas storage system.

8. The numerical simulation calculation method for the release process of a trifluoromethyl bromofire extinguishing agent according to claim 1, characterized in that: Establish a simulation model, complete parameter settings, and perform simulation calculations; directly read out the fire extinguishing agent release time, pressure at the nozzle, and functional evaluation indicators of the special phase ratio fire extinguishing system from the simulation results, and then perform a functional evaluation of the fire extinguishing system; by comparing and analyzing these indicators with the design requirements, determine whether the fire extinguishing system meets the standards in terms of fire extinguishing agent release speed, injection effect, and system stability; if the fire extinguishing agent release time does not meet the requirements, it is necessary to check the parts of the model related to the storage and release of the fire extinguishing agent; if the pressure at the nozzle does not meet the standards, it is necessary to review the nozzle configuration and related parameters, and the driving pressure setting; if the special phase ratio in the pipeline changes abnormally, consider the pipe network system design and fire extinguishing agent characteristics.

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