Parallel Computation of Smoke Movement During a Car Park Fire

In this paper the use of Fire Dynamics Simulator (FDS) for parallel computer simulation of the smoke movement during a fire of two passenger cars in an underground car park is investigated. The simulations were executed on a high-performance computer cluster. A specific problem of FDS parallel computation using Message-Passing Interface (MPI) is a separate solution of governing equations on computational subdomains causing a loss of accuracy. Therefore, the impact of parallelisation on simulation accuracy in the case of using a greater number of computational cores of the computer cluster is studied with the aim to increase the computational performance and enable practical application of such simulations for fire safety measures. The geometrical model and material properties of the cars used in the simulation have been verified by a full-scale fire experiment in open air. We describe the results of a series of simulations of several fire scenarios with different numbers of parked cars and ventilation configurations and determine times and locations at which conditions in the car park become untenable for human life. The simulation indicates that proper ventilation prolongs tenable conditions by several minutes

Computing Aspects of Simulation Based on Conservation Laws Conducted on HPC Cluster

The large amount of computing resources required for the simulation of complex natural processes demands a thorough analysis of the efficiency of the calculations and the conditions that influence it. This study investigates computing aspects of fire simulation conducted on a compute cluster. Current fire simulators based on principles of computational fluid dynamics are capable to realistically model majority of complex phenomena related to fire. Fire simulations are highly computationally demanding itself, however, they often lead to extensive parametrical studies requiring high performance computing systems. Smoke stratification and visibility during fire in a road tunnel with two emergency lay-bys are investigated by parametrical study comprising of 24 fire scenarios with the tunnel geometry modifications and various heat release rates and fire locations. Main tendencies of smoke spread in the downstream lay-by are identified and their mutual interactions are analysed. The simulation efficiency of particular simulations is analysed and the reasons of their varied elapsed times are investigated. The analysis indicates that the main reason of this variability are different jet fans velocities influenced by simulation scenario settings

Parallel Computer Simulation of Fire in Road Tunnel and People Evacuation

Advances in CFD (Computational Fluid Dynamics) and significant increase of computational power of current computers have led to widespread use of CFD in aerodynamics, fluid dynamics, combustion engineering and other academic disciplines. One of such disciplines is computer modelling and simulation of fire in human structures. Fire is a very complicated and complex phenomenon. Fire research deals with such processes as combustion, radiation, heat transfer, turbulence, fluid dynamics, and other physical and chemical processes. Several advanced fire and smoke simulation systems have been developed to solve various aspects of fire safety in various conditions and environments. In this paper, the use of parallel version of the CFD simulator FDS (Fire Dynamics Simulator) for the simulation of fire spread and smoke development in a short road tunnel is described. In order to study the impact of the computational domain decomposition on the accuracy and reliability of simulation results, several simulations of a chosen fire scenario ran on the HP blade cluster utilizing different numbers of processors. The obtained parameters of fire and smoke were used to investigate the influence of the fire on people evacuation in the tunnel with active ventilation for a given traffic situation

Stratification of fire smoke and testing aerosol in a road tunnel: computer simulation

The damage of the road tunnel during tunnel ventilation tests is prevented by using specific testing aerosol representing fire smoke. This study compares optical density profiles of aerosol and fire smoke using the well-known FDS simulation system, testing the suitability of aerosol to represent fire smoke realistically. The movement of aerosol and fire smoke downstream of the aerosol/fire source is investigated for a case of a 240 m long section of a road tunnel. Similarity of optical density profile for both cases under given conditions is confirmed. The influence of mesh resolution and the way of computational domain decomposition is evaluated as well. In case of fire smoke, the influence of domain decomposition and mesh resolution is very slight, while in case of aerosol it is more pronounced due to effect of relatively course numerical grid. The results support the hypothesis that the aerosol is suitable to represent the fire smoke for steady-state conditions occurring downstream of the fire in tunnel ventilation tests

The impact of car park fire on concrete structure, Parallel computation

This study examines the influence of automobile fire in a car park on concrete parts of the structure. In 2009, a series of full-scale fire experiments in open air was conducted, including the fire in automobile interior and its influence onto a vehicle in its vicinity. We performed a set of simulations of this scenario, using the NIST FDS system, version 5.5.3. Comparison with experimental data confirmed the simulation reliability. In this paper, we use material properties of car interior materials established by our research to simulate a car fire in a small part of car park containing two burning cars and its influence on concrete ceiling and a pillar in the vicinity of the cars. We use here the calculation with 48 and more MPI processes to evaluate the ability of high performance computing to solve problems of structural fire safety