Kombination von Thermografieaufnahmen mit numerischen Strömungssimulationen zur Bestimmung des Volumenstroms durch Leckagen

Combining thermal imaging with computational fluid dynamics to determine the volume flow through leakages.

Energy-saving building requires in addition to a good thermal building insulation an airtight building envelope. Leakages in exterior building elements therefore have to be avoided or repaired, also in consideration of the fact that they can lead to structural damage by moisture. Thermal imaging can be used to detect leakages. However, to date only the positioning of the leakage is possible, while the energy loss through the leakage cannot be specified yet. The aim of the analysis at hand was to assess the potential of thermal imaging regarding a simple, fast and precise method to determine the quantity of the energy loss due to the air flow through a leakage. For this purpose an experimental setup was developed and experiments were conducted. Those were compared to results from computational fluid dynamics. In doing so, a very good agreement between experiment and simulation was found. Furthermore, it could be shown that the thermographic image is highly sensitive to the fluid velocity and the structural-physical parameters of the building material which exhibits the leakage. This demonstrates great potential for drawing conclusions from a thermal image of a leakage with an air flow about the energy loss through this leakage.