Ice Ablation Experiments in Hypersonic Flow

抄録

Ablation phenomena due to aerodynamic heating were experimentally studied using a spherical model made from ice in the Mach 7 hypersonic wind tunnel at Kashiwa campus, the University of Tokyo. A series of experiments conducted so far is re-viewed, with a focus on characteristic features of shape changes over time. Detailed observations were made of recession of the surface due to melting, re-freezing into ice columns like frost pillars in the outer edge region, spallation of small ice particles released from tips of ice columns, and fragmentation into relatively large blocks of ice with a massive puff of water mist. Spin motion of the ice model around its center axis and a method for shape change control were also experimentally demonstrated. Results from ice ablation experiments give us useful insights for designing thermal protection systems of atmospheric entry vehicles, for understanding phenomena occurring around meteorites, and so on.