The use of PyroSim for creation of the input FDS geometry for cinema fire simulation LUKAS VALASEK Slovak Academy of Sciences/Institute of Informatics Dubravska cesta 9, 845 07 Bratislava SLOVAK REPUBLIC [email protected]Abstract: - PyroSim is a graphical user interface developed for FDS. It is intended for efficient creation of the input FDS representation of buildings with complex geometry. In this paper, the use of PyroSim for creating a typical cinema with sloping floor and curved ceiling is described and simulation of a simple cinema fire scenario is illustrated. Key-Words: - computer simulation, cinema fire, FDS, graphical user interface, PyroSim 1 Introduction Several advanced simulation systems capable to simulate and visualize fire in complex environments under variable conditions, such as for instance Fluent, SMARTFIRE, CFX, FDS, have been developed. Fire Dynamics Simulator (FDS) [4, 5] is a computational fluid dynamics system developed by NIST (National Institute of Standards and Technology), USA. It numerically solves a form of Navier-Stokes equations for low-speed, fire induced flows with emphasis on transport of smoke and heat from fire, and includes numerous physical and chemical processes associated with fire and smoke spread. FDS covers modelling of low-speed thermal flows and combustion of pyrolysis products, heat radiation and convective transfer of heat between gases and solid surfaces, pyrolysis, flames and smoke spread, sprinklers activation, heat and smoke detectors, and suppression. All objects in the space in which the fire is to be simulated must respect the space division onto orthogonal 3D computational meshes composed of cells. Creating the input geometry for FDS simulations is a complicated, labourious and time-consuming process especially for complex models with several complicated components. Nowadays, several advanced graphical user interfaces (GUI) are available. PyroSim [6] is a GUI developed by Thunderhead Engineering Consultants, Inc., USA in order to facilitate preparation of inputs for FDS simulations. The main functions of PyroSim cover an interactive creation of complex models (the use of ground plans, creation of multiple repetitious objects, curved walls, stairways, etc.), import of existing input FDS files, PyroSim files and CAD files (see also [8]). PyroSim enables importing a ground plan, saving it as a background image and displaying it in its 2D or 3D View modes. The background image scale can be modified to correspond to the computational mesh chosen for intended FDS simulation. This feature greatly facilitates the creation of geometry of complicated models. In the 2D View mode, there are several useful tools for creating the basic elements and their combinations (obstructions, holes, vents, wall holes, blocks, block holes, rooms, particle clouds), which represent the input FDS geometry of objects appearing in buildings. The current PyroSim version (PyroSim 2011) includes FDS (version 5.5.3) and allows to run FDS simulations. In the literature, several papers related to FDS simulations of fire in structures with a critical concentration of people (such as a theatre, supermarket, room, car, tunnel, car park and office) have appeared. However, only few papers were devoted to the use of PyroSim in such buildings (e.g., theatre fire and compartment fire [3, 9]). Utilizing our experience with the use of FDS for simulation of car fire and tunnel fires [2, 10, 11], we used FDS for several preliminary studies on cinema fire simulation [1, 7]. In this paper, we demonstrate creating the input FDS geometry of a chosen cinema by PyroSim for cinema fire simulation. The paper has the following structure. In Section 2, 3D model of a typical cinema with sloping floor and curved ceiling is introduced. Section 3 describes in detail creating the input FDS geometry of this cinema using PyroSim. In Section 4, a simple scenario of fire in the cinema is illustrated. Section 5 summarizes the main results of the paper. Recent Advances in Systems Science and Mathematical Modelling ISBN: 978-1-61804-141-8 304
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The use of PyroSim for creation of the input FDS geometry
for cinema fire simulation
LUKAS VALASEK
Slovak Academy of Sciences/Institute of Informatics