High Temperature Hypersonic Flow Field Around Basic-Shape Biodies and The Metal Component Alterationin

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The objectives of the research are to study flow characteristics around a basic-shape body in high temperature hypersonic flow field, to obtain the aerodynamic force acted on the model, and to investigate the metal component alteration of the model owing to the high temperature for developing new materials or disposal of such a difficult-treatment material as an injection needle. Three type of basic-shape bodies, a disc, a hemisophere and an ogive cylinder were exposed to the flow of the arc-plasma wind tunncl which was made for the research, and the flow fields were examined by a spectroscopic measeurement. The alloy ingredient alteration of the models made by brass or stainless steel were also investigated by an electron probe microanalyzer (EPMA) along the model surface. On the other hand, a compact inexpensive force balance was made to measure the drag of the basic-shape bodies in the plasma flow and the drag coeflients were deduced.The temperature near the stagnation point of the … More disc and hemisophere models were calculated to be 3,500 K from the results of the Boltzman plots, which is a little bit lower than that we expected, that is 4,000 K.The number densities of the neutral and ionized argon atoms along the stagnation line in the cases of the disc and hemisophere models were drastically increased just in the front of the stagnation point. Then, the densities of the neutral argon atoms decreased towards the stagnation point on the contrary to the ionized results, since the neutral argons were converted to ionized ones due to extreamely high temperature near the stagnation point. On the other hand, the variation of the number density of the ogive cylinder was almost constant upstream of the stagnation point simillar to the result of the no-model flow.The alloy ingredient alteration of the disc and hemisophere bodies were inversely changed from the initial component of zinc and copper on the front-side surface, that is zinc was increased and vice versa for copper. It could be explained from the point of the high diffusivity of zinc compared with copper and the flow field in front of the models with the existence of the stagnation. It was also found that the drag coefficients for these models in the case of the high enthalpy flow might be smaller than those in the no-plasma flow case. Their details and the reason should be investigated in the next stage research. Farthermore, these data mentioned above will take a part in the varidation data for numerical simulation programs in near future. Less