O. G. Martynenko

Heat and mass transfer in porous media

A brief survey of works concerned with transfer processes in porous media is given.

A. V. Luikov’s scientific legacy (on the 90th anniversary of his birth)

The search in science is endless: therefore for a true scientist the discovery of a new phenomenon does not become the conclusion of his work. It lays the foundation for the beginning of new research, a new field of knowledge. And then — a new road to the unknown ....

Free convective flow on a vertical plate with a constant heat flux in the presence of one or more steps

We carried out an experimental investigation of free convective heat transfer on a vertical plate subjected to a constant heat flux in the presence of one or several rectangular steps. Temperature fields were investigated with the help of a Mach-Zehnder interferometer. During the experiment the Rayleigh number changed from zero to Ra=2.8·103. The flow was observed by the method of track visualization by means of a laser knife. Durectly behind a step we observed a circulating free convective flow having the shape of two oppositely rotating vortices.

Relaxation phenomena in nonstationary evaporation of liquid

Based on the phenomenological theory — the thermodynamics of irreversible processes — an analysis of a nonstationary process of liquid evaporation is carried out. It is shown that a sharp change in the heat‐flux magnitude causes the occurrence of processes of oscillating relaxation of vapor generation in the system.

Unsteady free-convection heat transfer during vortex flow in a horizontal tube

We conducted a theoretical and experimental investigation of the hydrodynamic structure and unsteady free-convection heat transfer in a round horizontal tube under different conditions of the second kind. During the experiment the Grashof number varied from Gr=1.54·105 to Gr=7.9·105. Using the interferometric method we investigated the distribution of the temperature field for different structures of free-convection flow in the tube.

Heat transfer by natural convection and hydrodynamics on a vertical plate with a discontinuity in the heat flux

It is observed that the temperature distribution in the boundary layer changes qualitatively and the heat transfer in the upper part of a plate intensifies substantially in comparison with a surface with a continuous heat flux. For the case of substantial heat flux density in the initial stage of formation of a free convective flow a two-dimensional vortex is found to appear.

Experimental investigation of the special features of heat transfer through glass packets

We consider experimental procedures for determining the thermal resistances of certain types of commercial glass packets based on investigation of thermal and temperature fields on the outer packet surfaces at a stationary temperature head (∼40°C), which corresponds to extreme climatic conditions of the middle belt. We evaluate the inhomogeneity of thermal losses over the glass-packet area coused by edge effects. The error in measuring the thermophysical parameters does not exceed ±3%.

Investigation of gaseous light-beam wavefront correctors as adaptive optics elements

The possibility of increasing the rate of variation of the optical parameters of gaseous focusing systems by directing a light beam perpendicular to the gas flow direction is investigated experimentally. It is shown that the rate of vartation of the focal length can reach considerable values close to those of adaptive optics.

Intensity distribution of light scattered by a turbulent jet flow

Results are presented of a computation of the farzone distribution of the intensity of radiation scattered by a turbulent nonisothermal air jet.

Local optical-parameter distributions in tubular shear flows

Schlieren measurements have been made on the scattering-coefficient distributions in a two-dimensional nonisothermal turbulent air jet.