Motivation

The use of fire spread modeling has been demanded for rail vehicles in national and international vehicle projects for many years. The aim of this modeling is to determine relevant design fires, which means obtaining generalized information about the temporal evolution of heat release rate for a variety of predefined and idealized scenarios. These scenarios can vary in various ways, including the position, type of ignition source, or ventilation, which are three central aspects of such investigations. It becomes evident that the complex physical and chemical processes occur at very different scales, and when calculating with models, these processes must be represented with the given boundary conditions. Overall, due to the complexity, simplified modeling, often unknown or simplified boundary conditions, and lack of detailed requirements for such calculations, the results of design fires can vary significantly. The Fire Dynamics Simulator (FDS) is a commonly used computational fluid dynamics (CFD) program for this type of calculation. In addition to simulating fire spread, this tool is primarily used for calculating smoke propagation and temperature distribution in building fires, for example in structural fire protection.