VSR-Seminar

1st talk: Binding of antagonists to Human Adenosine Receptor A2A in Nearly Physiological Condition

Speaker: Prof. Dr. Giulia Rossetti, IAS-5/INM-9

no abstract available

2nd talk: Fire Simulations – Fires in Underground Stations

Speaker: Dr. Lukas Arnold, JSC

Dr. Lukas Arnold, JSC

Complex buildings pose a challenge for fire safety engineers as these are hardly covered by prescriptive regulations. Numerical models, like zone and field models, provide tools for performance-based approaches, which can be applied to any building structures. These models describe the mass and heat transport from fires. Field models are based on computational fluid dynamics (CFD) and allow for the most detailed description of phenomena like turbulent flows, combustion, radiative and conducting heat transfer and pyrolysis - at the cost of complexity and high computational demands.

The mainly applied CFD software in fire safety engineering is FDS (Fire Dynamics Simulator). It is a LES (Large Eddy Simulation) code with a multitude of sub-models with a hybrid OpenMP and MPI parallelization. It uses second order finite differences for the spatial discretization and an explicit time stepping method. Depending on the problem size, it scales up to a few hundred cores of JURECA. The application of FDS in this project ranges from the modelling of bench scale (few centimeter) pyrolysis experiments up to real scale (hundred meter) field experiments.

This talk presents one of the multiple applications in this project: the simulation of smoke spread in complex underground stations. This work is part of the ORPHEUS project, in which both numerical simulations as well as real scale experimental fires in Berlin’s underground stations are considered. The safety of the passengers in a fire accident is one of the main safety targets. The simulation of the smoke spread results in an estimation of the available safe egress time for the passengers. This time strongly depends on the scenario choice, i.e. position of the fire, underground climate conditions or the heat release rate. Therefore, a design of experiment is created to cover the reasonable scenarios. The computed data, e.g. smoke density, may then be coupled to an evacuation model to compute the requested safe egress time. Both times, the available and requested safe egress times, are used to assess the safety level.

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