Critical aspects of a thermal protection system, such as the effectiveness of high temperature seals or the heat flux increase due to steps and gaps between adjoining tiles often cannot be simulated satisfactorily with numerical methods and therefore have to be investigated experimentally. In gap regions, in particular, small changes in geometry can, in combination with a hypersonic flow, result in huge local variations in thermal load.
When studying gap and step configurations, the hot and cold wind tunnels of the department complement each other. The purely thermal effects, such as the thermal stability of a structure are investigated in the arc-heated wind tunnels L2K and L3K whereas the heat flux and flow topology details are determined in the hypersonic wind tunnel H2K at realistic Mach and Reynolds numbers.
The objective of the IMENS and IMENS+ projects is to develop a simulation platform for the simulation of thermomechanical flow-structure-interactions, which is close to reality. For validation purposes the results of coupled simulations are compared with the experimental results.
During the IMENS project the simulation environment was successfully validated on two generic configurations. The follow-on project IMENS+ addresses active cooling for inner and outer structures of space transportation systems exposed high thermal loads. In addition to stationary coupled simulation, time accurate coupled simulation is also carried out. These coupled simulations are validated with dedicated wind tunnel experiments on generic models.