The article deals with the modeling of accidents at the storage sites of ammable and combustible liquids. The frequencies of initiating events used in the calculations, possible scenarios for the development of accidents, are given. The software for calculating the parameters of damaging factors in the case of re of straits and ignition with the formation of a reball in case of accidents on objects with ammable and combustible liquids using the NET Framework was developed. To visualize the accident, Unity 3D developed an application illustrating the depressurization of a tank, with a combustible substance with the formation of a hole in the side wall of the tank through which the ow occurs, followed by spreading and ignition of the combustible liquid. In this case, the individual risk is calculated and its value is indicated in the image.
On the territory of the Stavropol region there are more than 300 re and explosion hazard facilities that can be a source of danger to the population, surrounding objects, the natural environment. Therefore, the modeling of emergency situations in re hazardous areas, both at the design stage and in emergency situations, is an urgent social and economic problem.
From the data given in Table 2 it can be seen that scenarios related to res in the spill of oil products and the combustion of a cloud of a fuel-air mixture in the de agration regime have the highest frequency of realization.
As is known, modeling and supporting decision-making in emergency situations includes the following main
stages [
In the case of air defense accidents, as a rule, a complex of damaging factors operates, of which three main ones are necessary:
Destructive impact (during explosions) { destruction of technological blocks, buildings of structures; Contamination of the ground layer of the atmosphere by combustion products { poisoning of people and pollution of the environment;
Thermal e ects on people { burns, overheating and on surrounding objects, damage to buildings, cars etc. 3
We have developed software that will allow us to quickly calculate the parameters of accidents involving ammable and combustible liquids.
The software consists of two parts. The rst part of the software package makes it possible to calculate the amount of thermal radiation in case of a re in the strait at di erent distances from the source, the amount of thermal radiation in the occurrence of the reball and the time of its existence.
The second part allows spatial representation of the dynamics and consequences of a strait re from a single object containing fuel.
The rst part of the program is created using the NET Framework. NET Frame-work is a software platform released by Microsoft in 2002. It is actually an operating system inside the operating system. The basis of the platform is the Common Language Runtime (CLR) virtual machine, capable of performing both normal desktop applications and web applications. A distinctive feature of the NET Framework is the ability to execute programs written in di erent programming languages. It is believed that the platform NET Framework was the response of Microsoft to the highly ac-claimed Java platform of Sun Microsystems (now owned by Oracle), also based on a virtual machine. Although NET is a proprietary technology from Microsoft and Microsoft Windows, there are independent projects (primarily Mono and Portable NET) that allow you to run NET programs on many other operating systems.
The program for the NET Framework, written in any supported programming language, is rst translated by the compiler into a single, easy-to-understand, Common Intermediate Language (CIL) for the person (formerly called Microsoft Intermediate Language, MSIL). The compiler then translates the CIL code into an object bytecode (in NET terms, assembly is obtained, English assembly), and the bytecode is either executed by the CLR virtual machine, or translated by the utility NGen.exe into executable code for the speci c target processor. The use of a virtual machine is preferable, as it saves developers from having to take care of the hardware features. In the case of using a CLR virtual machine, the built-in JIT compiler on-the- y (just in time) compiles the intermediate byte-code into the machine codes of the desired processor. Modern technology of dynamic compilation allows achieving a high level of performance. The CLR virtual machine also takes care of basic security, memory management and exception systems, saving the developer from part of the work.
Using the software platform NET Framework, we have developed a program that allows the following: to calculate the parameters of damaging factors in the re of spills of ammable and combustible liquids; to calculate the consequences of the formation of a reball.
After downloading the program, the user must select the scenario for the failure of the calculation of the parameters to be carried out. To do this, there are two function buttons in the upper part of the window. Two types of scenarios for the "Flammable and combustible liquids strait" and "Fire Ball" crashes are shown on the top of the window.
After selecting the alarm scenario, the user must enter the alarm parameters and set the value of the heat radiation to which the calculation will be made. In the eld of the accident parameters it is necessary to set the area of the strait and the type of fuel involved in the accident.
During the selection of the necessary accident parameters, the program immediately performs all calculations and presents the results of the calculation in the form of a graph and a table.
In the upper right corner of the program window there are functional buttons for generating the report as a word processor le and printing the report. They allow you to get a printed version of the calculations made by the program.
User interface of the program for input of initial data are presented in Fig. 1.
The results of calculations for the "Fireball" scenario are shown in the Fig. 2. An example of printing the results of the calculation for printing is shown in the Fig. 3. The second part of the program includes a graphical representation of the accident at a re and explosion hazard site. Taking into account the numerous numbers of scenarios for the development of accidents at re and explosion hazard sites and the di culty of creating a three-dimensional model for each of these scenarios, we chose the accident scenario that is most relevant at the time. It includes the depressurization of the tank, with combustible material, as a result of the formation of an opening in the side wall of the container through which the ow occurs, followed by spreading and ignition of the combustible liquid.
The implementation of the three-dimensional image and the execution of calculations is formed on the basis of Unity 3D - it is a multi-platform tool for developing three-dimensional applications, including a powerful engine (Unity Engine) for developing 3D applications and games, as well as an integrated development editor.
Unity Engine includes a highly optimized 3D graphics engine for both DirectX and OpenGL. It allows you to create animated 3D objects, particle systems, advanced lighting and shadows. Unity Engine supports delayed rendering technology (Rendering is a term in computer graphics that indicates the process of obtaining an image on a model using a computer program.). Unity provides a visual creation of a particle system, through which it is possible to create rain, sparks, dust poles, ames, explosions and other e ects.
It is possible to combine 3D real-time graphics with streaming audio and video.
Unity supports a wide range of platforms to run the created project. 3D applications created with Unity work on Windows, MacOS, Wii, iPhone, iPod, iPad, Android, Play Station 3, XBox 360, and also through the Unity web player (connects to a browser on Windows or Mac OS as a plug-in).
Due to a large set of mathematical, trigonometric and other functions contained in the .NET libraries, the software implementation of the mathematical model of the application is greatly simpli ed. The rich functionality of the .NET libraries, together with the powerful 3D engine Unity, allows you to create simulation models of real processes and phenomena and visualize them in the form of three-dimensional inter-active applications. In accordance with the results of calculations performed in the software implementation of the mathematical model, a set of parameters characterizing the simulated phenomenon is obtained, with the help of which it is possible to control the visual display of three-dimensional objects.
The calculation is carried out in the same manner as the rst part of the program [
After downloading the program, the user must specify: { type of fuel involved in the accident; { the lling of the tank with fuel; { hole height; { diameter of the hole; { the required value of the intensity of thermal radiation.
After entering the necessary parameters, the user starts the simulation process and the program performs the necessary calculations. As a result of the calculation, we obtain a three-dimensional image of the accident with the designation of safe and dangerous zones of thermal radiation and re risk.
The data entry window is shown in the Fig. 4.
During the work, an analysis of the causes and scenarios for the development of emergency situations at oil product storage facilities was carried out.
Two programs have been developed. One is designed to calculate the consequences of emergency situations associated with the formation of a re in the strait and the reball, and the second is designed to visualize the dynamics of an emergency situation associated with the formation of a strait re. To perform calculations, the NET Framework and the Unity Engine are used. These developments will be useful for a wide range of specialists involved in providing security. [1] TNO Green Book, Methods for the determination of possible damage to people and objects resulting from release of hazardous materials, CPR16E. Prepared for the Committee for the Prevention of Disasters, SDU. Netherlands, Hague, 1992. [2] TNO Yellow Book, Methods for the calculation of the physical e ects due to releases of hazardous materials, CPR-14E. Prepared for the Committee for the Prevention of Disasters. Netherlands, Hague, 1997. [3] TNO Yellow Book, Methods for the calculation of the physical e ects due to releases of hazardous materials, CPR-14E. Prepared for the Committee for the Prevention of Disasters. Netherlands, Hague, 2005. [4] TNO Purple Book, Guidelines for quantitative risk assessment, CPR18E. Prepared for the Committee for the Prevention of Disasters, SDU. Netherlands, Hague, 2005.