Chemical reactions in hypersonic flows have a potential to produce much more various species than those in a static chamber because of its nonequilibrium nature. In the present study, we propose a new experimental technique of a "chemical factory" in a hypersonic wind tunnel flow. The hypersonic chemical factory is composed of a model with ablative part as a materials supplier, a pair of electrodes for electric discharge as an energy supplier, and a wake flow behind the body in frozen chemistry as a products transporter. To demonstrate this concept and to experimentally simulate the formation of prebiotic materials in high temperature shock layer around an ablating icy object entering the early earth's CO2/N2 atmosphere, a model with an ablative nose part made from water ice and dry ice is tested in the hypersonic wind tunnel at Mach number 7 in Kashiwa campus, the University of Tokyo. When the plasma discharge is ignited between the electrodes located on the side surface of the model, we observed the emission probably from CN species produced from the N element in the air and the C element in the ablation gas. The presence of CN suggests the production of HCN, which is one of the most important prebiotic materials, in hypersonic flows around extraterrestrial icy entry objects on the early earth. On the other hand, no signal of CN is observed in case of the nose made from water ice only. To assist the design of the experimental setup and to deepen our understanding on the phenomena, the thermochemical nonequilibrium Navier-Stokes analysis with C-H-O-N 28 species is also conducted. The results show reasonable agreement with the experimental observation. The present technique of the hypersonic chemical factory seems promising for investigation on nonequilibrium chemical process in a flow.
- SCOPUS ID : 84883549899