Real gas effects and boundary layer suction in reflected shock tunnel

In a hypersonic reflected shock tunnel the useful flow test time (steady uncontaminated period), during which the experiments can be done, depends greatly on the time-homogeneity of the reservoir conditions. These conditions may be affected by real gas effects (shock/boundary layer interaction, air chemistry, molecule vibration). Therefore numerical simulations, including real gas effects, have been carried out to evaluate their influence. Navier-Stokes equations for a multi-component reactive air flow are solved with a multi-block finite volume method in a reflected shock tunnel. The numerical results show the influence of the non-equilibrium effects on the flow structure. The use of a conical ring enabled helium contamination to be deferred significantly with an improvement in the useful test time by a factor of 2.3.