Experiments
The classical approach to determining material parameters requires data from multiple experiments. The individual experiments, such as thermogravimetric analysis (TGA) or cone calorimetry, do not directly measure the necessary parameters but rather integral quantities such as mass loss rate or ignition time. The material parameters can only be implicitly derived through a pyrolysis model and an optimization process. Evolutionary optimization methods are increasingly being used, especially when dealing with a high number of parameters. Due to the high computational cost, which also increases non-linearly with the number of parameters, the set of parameters is divided among multiple experiments. For example, the pyrolysis parameters are determined using TGA data, while the thermophysical properties are determined using cone calorimetry.
In the field of fire dynamics, different scales are used to cover various aspects. The classification used in this project is as follows:
Micro Scale – The smallest scale involves mass samples in the microgram range, which are used, for example, in thermogravimetric analysis (TGA) or a micro combustion calorimeter (MCC). This scale is commonly used for determining the reaction kinetics of pyrolysis.
Small Scale – Samples on the order of approximately 10 cm, such as those used in a cone calorimeter, belong to this scale. In this scale, the fire behavior is observed without considering the spread of the fire itself. From these observations, information about the thermodynamic properties of the sample can be derived.
Intermediate Scale – In this scale, using samples in the kilogram range and dimensions ranging from 20 cm to 50 cm, controlled laboratory experiments are conducted where fire spread is possible. This scale serves for the validation of the modeling approach.
Real Scale – At this scale, experiments are conducted in real-life dimensions using generic geometries based on rail vehicles and corresponding mockups. In the context of the BESKID project, this could involve seating arrangements with side wall elements, for example. The primary objective at this scale is model validation.
In the project, it is planned to conduct experiments at all scales.
