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

Numerical study of smoke flow control in tunnel fires using ventilation systems

Sa ciljem procenjivanja mogućnosti jednog tunelskog ventilacionog sistema, da u incidentnom radnom režimu kontroliše širenje dima i da tako obezbedi uslove za bezbednu evakuaciju ljudi iz vatrom zahvaćenog prostora, izvršena je CFD (Computational Fluid Dynamics) simulacija požara u jednom dvocevnom tunelu. Korišćenjem eksperimentalnih rezultata, o dinamici sagorevanja zapaljenog automobila i prema preporukama PIRAC-a određenih radnih režima ventilatora, izvršena je provera kritične brzina strujanja vazduha kojom će se sprečiti prodor dima u evakuacione hodnike, te izvršena provera potrebnog broja i rasporeda ventilatora u tunelskim cevima.With the aim of evaluating capabilities of a tunnel ventilation system to control the spread of smoke in the emergency operating mode, thereby providing conditions for safe evacuation of people from a fire-struck area, a CFD (Computational Fluid Dynamics) simulation of a fire in a double tube tunnel was done. By the use of experimental results regarding the combustion dynamics of a passenger car, that is truck on fire and ventilation system operating modes determined according to PIRAC recommendations, a check of critical air velocity required to prevent smoke penetration into the evacuation hallways was performed, as well as the check of the optimum number and positions of ventilators in the tunnel tubes

Numerical study of smoke flow control in tunnel fires using ventilation systems

Sa ciljem procenjivanja mogućnosti jednog tunelskog ventilacionog sistema, da u incidentnom radnom režimu kontroliše širenje dima i da tako obezbedi uslove za bezbednu evakuaciju ljudi iz vatrom zahvaćenog prostora, izvršena je CFD (Computational Fluid Dynamics) simulacija požara u jednom dvocevnom tunelu. Korišćenjem eksperimentalnih rezultata, o dinamici sagorevanja zapaljenog automobila i prema preporukama PIRAC-a određenih radnih režima ventilatora, izvršena je provera kritične brzina strujanja vazduha kojom će se sprečiti prodor dima u evakuacione hodnike, te izvršena provera potrebnog broja i rasporeda ventilatora u tunelskim cevima.With the aim of evaluating capabilities of a tunnel ventilation system to control the spread of smoke in the emergency operating mode, thereby providing conditions for safe evacuation of people from a fire-struck area, a CFD (Computational Fluid Dynamics) simulation of a fire in a double tube tunnel was done. By the use of experimental results regarding the combustion dynamics of a passenger car, that is truck on fire and ventilation system operating modes determined according to PIRAC recommendations, a check of critical air velocity required to prevent smoke penetration into the evacuation hallways was performed, as well as the check of the optimum number and positions of ventilators in the tunnel tubes

Grouping behaviour and decision making in road tunnels evacuation in smoke conditions Experimental approach

We have performed a set of evacuation experiments in a road tunnel. In each experiment pedestrians were gathered in a bus, the bus was stopped in the tunnel, next the tunnel was filled with artificial smoke and pedestrians had to evacuate. We compared evacuation times and behaviours for different levels of visibility, defined by extinction coefficient Cs range

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

Assessment and simulation of evacuation in large railway stations

Evacuation systems in buildings are frequently assessed to improve emergency response processes. This paper proposes a method to evaluate the performance of different evacuation modes, and determine a rational mode for large railway stations. We developed a simulation for the evaluation of fire safety in large buildings based on an analytic hierarchy process (AHP) method. This approach includes AHP-based exploration and simulation-based refinement. We considered a typical railway station for validation, conducted a field survey to collect the data, and calculated the influencing factors based on expert opinion. The influencing factors were further processed based on the principles of a hierarchical model. The relative weights of the influencing factors were calculated through a series of pairwise comparisons using the AHP. Further, we applied factor refinement based on the evacuation simulations to determine the degree and status of influence of each factor. The influence of external factors was generally stronger than that of the internal factors. Among them, the building component characteristics and people’s physiological capabilities were the core of the evacuation assessment in large railway stations. Additionally, the exit width, seat layout, visibility, speed, and reaction capabilities were crucial to the evacuation process. The proposed method is practical as it demands limited computations to provide useful information, such as a priority ranking of each influencing factor, for the evaluation process

Dynamics of pedestrians in regions with no visibility - a lattice model without exclusion

We investigate the motion of pedestrians through obscure corridors where the lack of visibility (due to smoke, fog, darkness, etc.) hides the precise position of the exits. We focus our attention on a set of basic mechanisms, which we assume to be governing the dynamics at the individual level. Using a lattice model, we explore the effects of non-exclusion on the overall exit flux (evacuation rate). More precisely, we study the effect of the buddying threshold (of no-exclusion per site) on the dynamics of the crowd and investigate to which extent our model confirms the following pattern revealed by investigations on real emergencies: If the evacuees tend to cooperate and act altruistically, then their collective action tends to favor the occurrence of disasters.Comment: 20 page

VIRTUAL REALITY EXPERIMENTS ON THE IMPACT OF WAY-FINDING LIGHTING SYSTEMS ON EGRESS FROM SMOKE-FILLED RAILWAY TUNNEL

The thesis presented below presents an experimental study, performed at Lund University, Sweden, focused on the evacuation of a railway tunnel filled with smoke. The experiment is aimed at the evaluation of the efficiency of high-bright and dynamic lights located at the intersection between the tunnel walls and the sidewalk. The experiment is carried out in a Virtual Reality environment using a head mounted display. The behaviour of 60 test participants has been investigated given the presence or absence of this particular way-finding installation. The final goal of this study is to determine if the use of dynamic and flashing lights can reduce the total time needed to evacuate in an emergency situation

On Realization of Cinema Hall Fire Simulation Using Fire Dynamics Simulator

Currently known fire models are capable to describe fire dynamics in complex environments incorporating a wide variety of fire-related physical and chemical phenomena and utilizing large computational power of contemporary computers. In this paper, some issues related to realization of the simulation of fire in a cinema hall with sloping floor and curved ceiling furnished by upholstered seats modelled by FDS (Fire Dynamics Simulator) are discussed. The paper concentrates particularly on the impact of a computational meshes choice on resolving flow field and turbulence in the simulation and indicates problems related to parallelization of the calculation illustrated comparing sequential and parallel MPI calculation using 6 CPU cores. Results of the simulation described and their discussion demonstrate the ability of FDS simulation to capture main tendencies of smoke spread and to forecast the related safety risks realistically

Coupling models of road tunnel traffic, ventilation and evacuation

As road tunnel accidents can result in numerous fatalities and injuries, attention must be paid to accident prevention and management. To address this issue, use of integrated tunnel model for system evaluation and training of road tunnel operators on computer simulator is presented. A unified tunnel model, including traffic, meteorological conditions, ventilation and evacuation that is presented. An overview of simulation models, simulator architecture and challenges during the development are discussed. The integrated tunnel model is used as a core of a simulation system that is capable of reproducing tunnel accidents in real time and it interfaces with Supervisory Control And Data Acquisition (SCADA) interfaces used in real tunnel control centres. It enables operators to acquire experience they could otherwise get only during major accidents or costly exercises. It also provides the possibility for evaluation of tunnel control algorithms and Human Machine Interfaces (HMIs) for efficient operation of all safety systems during upgrades and maintenance. Finally, application of the model for accident analysis and optimization of emergency ventilation control is presented where it was used to identify cause of emergency ventilation malfunction and design fault. First published online 20 February 202