Flow Realization in Hypersonic Air Inlet with Spatial Compression

Abstract
The results of a numerical and experimental study of a hypersonic air inlet with spatial compression and a compact cross section of the internal channel are presented. Reducing the surface area of the channel simplifies the heat protection of the air inlet and the combustion chamber. Experimental studies were carried out in a blow-down wind tunnel for Mach numbers M_∞ = 2–6. The pressure distributions on the compression surfaces and in the air inlet channel are obtained, the coefficients of the total pressure recovery and flow rate, the Mach number in the throat of the air inlet are determined. The influence of the side cheeks and of the boundary layer bleed has been found. It is determined that in a convergent air inlet significantly higher compression ratios are realized than in a two-dimensional air inlet with less drag. It was established that on the basis of solving the three-dimensional Euler equations and the boundary layer, it is possible to reliably predict the characteristics of the air inlet in off-design modes and determine the structure of the flow.

Keywords
hypersonic aircraft, spatial air inlet, flat air inlet, cheeks, flow gas-dynamics, boundary layer, calculation and experiment 
Acknowledgements
The research was carried out within the framework of the Program of Fundamental Scientific Research of Russian state academies of sciences in 2013–2020 (project АААА-А17-117030610126-4)
УДК 533.697.2, 533.6.07

Flow Realization in Hypersonic Air Inlet with Spatial Compression