On the occasion of the 100th anniversary of K. I. Shchelkin, his publications on the detonation spin theory are reviewed. In those publications, he was the first one to indicate the gas-dynamic nature of the phenomenon, predicted the presence of a break on the detonation wave front, and predetermined further studies of the flow structure in the case of spin detonation.

An approach is developed for estimating the availability of materials for fabrication of nozzles to be used in aerodynamic facilities with extremely high pressures, where commercial nitrogen and air are used as test gases. Some promising materials are analyzed.

Results of an experimental study of the action of a nitrogen-air flow on nozzles made of various materials and sapphire at pressures in the settling chamber up to 1 GPa are presented. Formulas necessary for estimating thermal stresses in materials similar to sapphire in their properties are derived.

A principal possibility of approximate reconstruction of the chemical composition in combustion of a hydrogen-air mixture at the end of the scramjet duct from incomplete experimental data (measured concentration of OH radicals and temperature) under the assumption of detailed chemical equilibrium of exchange reactions is analyzed. A closed algebraic system of equations including the concentration of OH radicals and the temperature as parameters is derived in this approximation. A code for solving this system numerically is developed for approximate determination of reaction completeness from the measured temperature and concentration of OH radicals. The model was tested by results of exact thermodynamic calculations of the Jouguet state and overdriven waves in a stoichiometric hydrogen-air mixture and various hydrogen-oxygen mixtures. In the range of pressures of 0.2 to 500 atm and temperatures of 2500 to 3500 K, this method allows the molecular weight and heat release to be reconstructed with accuracy sufficient for gas-dynamic calculations.

The laminar-turbulent transition is experimentally studied in boundary-layer flows on cones with a rectangular axisymmetric step in the base part of the cone and without the step. The experiments are performed in an A-1 two-step piston-driven gas-dynamic facility with adiabatic compression of the working gas with Mach numbers at the nozzle exit M ∞ = 12–14 and pressures in the settling chamber P 0 = 60–600 MPa . These values of parameters allow obtaining Reynolds numbers per meter near the cone surface equal to Re 1e = (53–200) · 10 6 m −1 . The transition occurs at Reynolds numbers Re tr = (2.3–5.7) · 10 6 .

The use of high pressures in a hypersonic aerodynamic experiment is founded on physical grounds. Calculation results of Mach and Reynolds numbers reachable at the line of gas condensation are given as functions of the temperature and pressure in the plenum chamber. Approaches to solving problems of designing ultrahigh-pressure facilities that ensure outflow with pressures up to 20,000 atm are described. These problems include the stop of the first-stage piston at the point of maximum pressure, suppression of the reaction force, provision of normal operation of seals of the moving piston, and reduction of friction forces in the seals. The principles considered are used in an actually operating facility.

It is commonly known that the existing hypersonic wind tunnels do not ensure full-scale simulation of Reynolds numbers, suitable purity of the now and running time necessary for testing the models of scramjet-powered vehicles. Capability of existing hypersonic wind tunnels in simulation the processes of mixing and combustion are discussed in detail. The suggested presentation deals with analysis of state-of-the-art of simulation of flows formed in the hypersonic flying vehicles, including those powered by scramjets and/or ramjets. Experimental data on the influence of now contamination by the products of air dissociation on ignition delay are analyzed. A new concept of wind tunnels of adiabatic compression with pressure multipliers is presented. It forms the basis for the wind tunnel AT-303 that is under construction at ITAM SE RAS.

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