Home – Home – Jornals – Thermophysics and Aeromechanics 2003 number 3

The paper describes results on testing a model scramjet with a three-dimensional inlet in the new adiabatic-compression wind tunnel AT303 recently put into operation at the Institute of Theoretical and Applied Mechanics, SB RAS. The wind tunnel operates, covering the range of free-stream Mach numbers M

Numerical-analytical and experimental investigations of the flow around a symmetric airfoil are performed within the range of low subsonic to near-critical flow velocities; the emphasis is made on identification of the role of medium compressibility. It is shown that there are no grounds to believe that the compressibility effect for streamlined bodies whose relative thickness is smaller than 12

The experimental data of stability of a 3D supersonic boundary layer on a swept wing are presented. Development of artificial wave trains and their interaction with a steady disturbance have been studied. The experiments have been performed on a swept wing with a lenticular airfoil at swept angle of the leading edge 40^o and under zero angle of attack. The wave characteristics of travelling disturbances were determined. It was found that evolution of the controlled disturbances at an energy-carrier frequencies is similar to the development of the travelling waves for subsonic velocities. It results from the investigations that a nature of the stability in gradient-plane and spatial supersonic boundary layers is radically different. It is shown that a crossflow secondary instability is the main mechanism of a turbulence initiation in the supersonic boundary layer on the swept wing.

Laminar-turbulent transition was studied experimentally for the water flow in a long circular pipe at a temperature change from 0.8 to 50 ^oC. A glass capillary 300 mm in length and 1.2 mm in diameter was used in these experiments. It was shown that the critical Reynolds number is a universal value for the whole range of temperatures.

Results of experimental studies of relaxation properties of an incompressible two-dimensional turbulent boundary layer under the conditions of moderately elevated free-stream turbulence and disturbed by a circular cylinder with D/_o

The numerical analysis of the evolution of a momentumless turbulent wake in a linearly stratified medium has been carried out by using two mathematical models. The numerical results are compared with experimental data. The model based on improved algebraic representations of triple correlations of the velocity field and the transfer equation for dissipation rate gives a satisfactory description of the process of anisotropic decay of turbulence in the wake.

Mathematical model of laser ablation of sublimating solid material into vacuum at moderate laser fluencies was proposed. Thermal model based on non-stationary one-dimension heat equation with a volume thermal source was used for the description of laser radiation absorption and solid material heating. The direct simulation Monte Carlo (DSMC) method was applied for modelling of vapour expansion into vacuum. The thermal and gas dynamic problems were bound at the surface by their boundary conditions. Laser ablation of a graphite target in nanosecond pulse duration range was considered as a test for applicability of the model.

The planar one-dimensional and radially symmetric problems of the heating of a porous permeable medium saturated with a liquid by a heat supply through a boundary, which is impermeable for water or vapor, are considered. Self-similar solutions are constructed, which describe the propagation of the pressure field arising by virtue of thermal expansion or liquid boiling. The thermal shock dependence on heating intensity and porous medium parameters is investigated. The main part of the heat supplied through the boundary is found to be spent for the porous medium heating; the heat expenses for phase transitions are insignificant.

The results are presented on the heat-and mass exchange in thermal installations for rapid processes on the basis of the theory of locally nonequilibrium processes for supersonic and hypersonic flow speeds.

A solution is presented for the convective diffusion equation for particles with size

The regularities of vortex structure formation were studied during outflow of propane-air combustion products out from a semiopen tube. It was discovered that the vortex structure may consist of two-three vortex rings generated consequently out of the tube. This vortex structure is born by relaxation oscillations of gas column in the tube and sustained by flame propagation through the rich flammable mixture. The conditions for formation of vortex structure were formulated as a function of dimensionless energy released during combustion and of Strouhal number. The mechanism of relaxation combustion related to development of low-frequency gas oscillations in a tube was proposed.

The characteristics of an electric arc burning in the plasmatorch duct with a porous interelectrode insert in conditions of an intense gas injection were computed on the basis of magnetogasdynamics equations. The turbulent flow characteristics were taken into account by the k

An induction model has been developed to predict the temperature fields in steel specimens under high-frequency pulsed heat-treatment. Experimental data on the fields of hardness in the specimens and a comparison of these fields with the predicted temperature fields are reported.

A technique is considered for the optimization of parameters of a combined heat producing plant with heat pump accounting for its functioning with variable heat demand during its design period. A mathematical model is developed for a combined heat producing plant whose components are the gas turbine installation, the utilizer boiler, and the heat pump installation of a vapour compression type. The optimal design solutions for the installation and the tariffs for the heat produced, which ensure a given internal norm of investments return, are determined in a broad range of the variation of prices for fuel.

The technique and some results are considered for a scheme and parameter optimization of the boilers of thermoelectric plants (TEPs) with an annular furnace.

On July 30, 2003 Professor Alexei Kuzmich Rebrov, a famous scientist in the fields of physical gasdynamics, dynamics of rarefied gases and thermophysics, academician of RAS, celebrated his 70th anniversary.