Experimental Study of Dusty Flow - Surface Interactions on Heat-Shield Materials at Martian Atmospheric Entry Conditions

Kurzfassung

This work presents an experimental methodology for the characterization of particle-laden high-enthalpy flows and the investigation of material behaviour under conditions representing entry into the Martian atmosphere during dust storms. Experiments in the DLR L2K arc-heated wind tunnel used micrometric MgO particles in CO2/N2 flow to replicate dusty entry environments. Diagnostics including PIV, TDLAS, and SEM/EDX characterised particle dynamics and two-phase flow features, supported by CFD simulations identifying key phenomena such as velocity lag and particle agglomeration. Material response tests on cork-based ablators employed infrared thermography, embedded thermocouples, X-ray imaging, and in-situ laser-sheet profile tracking (LPT), revealing particle-induced effects like enhanced surface recession, increased heat transfer, and transient emissivity artefacts. A one-dimensional model was developed to predict thickness evolution accounting for swelling, ablation, and erosion, successfully reproducing experimental data. The study demonstrates the feasibility of replicating and quantifying complex particle-material interactions in ground facilities, providing valuable insight for future Martian TPS design and qualification.