S. M. Kharlamov

Specific features of a transition from the regular two-dimensional to three-dimensional waves on falling liquid films

The transition from a regular two-dimensional to three-dimensional (3D) flow in vertically falling liquid films has been experimentally studied. This transition is accompanied by a significant redistribution of liquid in the lateral direction. Characteristic shapes of 3D structures developing in the course of the transition are described.

Stationary solitary three-dimensional waves on a vertically flowing fluid film

Three-dimensional waves appear at the final stage of the evolving wave regime of a fluid-film flow [1]. At this stage, for values of the Reynolds number of the film flow that are sufficiently low (Re < 100), the wave regime manifests itself as a soliton gas. The film surface is covered by numerous horseshoe-shaped waves, which propagate over a thin residual layer, randomly interacting with each other and explicitly demonstrat-

Formation of rivulets in isothermal liquid film flow during transition to a three-dimensional wave regime

We present the results of an experimental investigation of the transition from a two-dimensional to three-dimensional (3D) flow in a liquid film flowing down a vertical plate of large dimensions. It is established that this transition is accompanied by the formation of rivulets. At large distances from the initial region, the wave regime can be almost completely suppressed in inter-rivulet regions.

An image analysis method as applied to study the space-temporal evolution of waves in an annular gas-liquid flow

The secondary instability of the surface of a liquid film sheared by an intensive gas flow was first discovered using high-speed modification of the laser-induced fluorescence method. To study the space-temporal evolution of waves of different types, we used image analysis tools, in particular, the Canny method. As a result, we obtained the quantitative characteristics for both wave types and the phenomenon of the back slope instability of primary waves.

The influence of aluminum anode alloys and alkaline electrolyte composition on performance of aluminum-air cells for portable applications

The influence of the composition of alkaline electrolyte and some anode alloys on performance of cells of aluminum-air power sources without electrolyte regeneration and circulation circuits is investigated in order to elaborate proposals for construction of portable sources. It is shown that with pure aluminum anodes, the cell capacity grows with increasing electrolyte concentration; At the same time, the use of potassium electrolytes with the same molar concentration as that of sodium electrolytes at lower electrolyte temperatures yields a considerable gain in specific capacity of cells. The use of aluminum alloys doped with indium and gallium or bismuth and gallium permits one to increase the specific capacity of cells with sodium electrolyte by 100–150 A·h per liter of electrolyte in a wide range of concentrations and at various electrolyte temperatures.

Experimental study of the evolution of solitary three-dimensional waves on the surface of a heated liquid film

Results of an experimental investigation of the features of evolution of a solitary three-dimensional (3D) wave on the surface of a vertically falling liquid film heated by a constant heat flux are presented. It is established that the wave weakly influences the film surface temperature. The interaction of a 3D wave with thermocapillary rivulet structures on the falling film surface results in that the wave is pulled toward the center of a rivulet.

On the peculiarities of work of promising anode alloys for portable aluminum-air current sources

Peculiarities of Work of promising anode alloys for portable current sources, referred to Al-In-Ga and Al-Sn-Ga systems, are considered. The use of such alloys makes it possible to increase specific energy of portable aluminum-air current sources (AA CSs) without external service circuits by a factor of 2.5–3 compared to the two-component alloys proposed in the literature. The use of anodes of promising alloys in aluminum-air current sources with flow-through cells and an external electrolyte regeneration circuit appreciably simplifies restart of the source after long continuance in the no-load condition.

Characteristics of solitary three-dimensional waves on vertically falling liquid films

Results of systematic investigations of the characteristics of stationary solitary three-dimensional (3D) waves in vertically falling films of liquids with various physical properties are presented. Experimentally determined characteristics of the stationary 3D waves are compared to theoretically predicted values. A domain of film flow regimes is established in which the theory well agrees with experiment.

Secondary instability of waves in annular two-phase flow with and without entrainment

Spatio-temporal evolution of disturbance waves and ripple waves in annular gas-liquid flow was studied using high-speed modification of laser-induced fluorescence technique. Both flow regimes with and without entrainment were studied. It was shown that all the ripples in regimes with entrainment arise due to instability of back slopes of the disturbance waves, and their further evolution is predefined by the point of appearance. In regimes without entrainment two types of waves were detected, where waves of one type arise due to instability of back slopes of waves of the other type. Thus, similarity of wavy structure of flow regimes with and without entrainment was established.

Application of the image-analysis method to studies of the space-time wave evolution in an annular gas-liquid flow

A secondary instability of the surface of a liquid film sheared by an intense gas flow was found for the first time by our team using the high-speed modified laser-induced fluorescence method. An image-analysis toolkit (in particular, the Canny method) was used for studying space-time evolution of various types of waves. As a result, quantitative characteristics of both the types of waves and the characteristics of the instability phenomena of back slopes of primary waves were obtained.