Sergei V. Alekseenko

Experimental study of liquid distribution in a column with a structured packing

Reflective fiber optic sensors are used to measure the thickness of a liquid film on geometrically complex surfaces inside a distillation column with a structured packing and countercurrent flow of gas and liquid. Distributions of the liquid-film thickness as a function of flow-rate parameters for an elementary region (cell) of a geometrically repeated pattern in a structured packing consisted of Koch 1Y corrugated plates and for the column cross section are presented. It is shown that the flow conditions characterized by the detachment of liquid films from the plate by air flow (until the complete column “flooding”) is accompanied by a sharp increase in the pressure drop in the column. Inside the cell, the liquid forms menisci in the zone of plate contact points. The countercurrent air flow reduces the fluctuations of the film thickness by 1.5 to 2 times on the edge and side downslopes of the corrugation.

Rivulet flow on the outer surface of an inclined cylinder

A study of the three-dimensional flow of a liquid film (rivulet) over the external part of an inclined cylinder was conducted for liquids with various physical properties. Patterns of the flow regimes were constructed. Good agreement is observed between the experimental data on the thickness and wall friction with the calculation with an asymptotic model in the case of a waveless rivulet. A comparison of the evolution of natural waves on rivulets with the theory of waves of maximal growth shows good agreement for small Re numbers. During the experiments, the wave characteristics of excited waves on a rivulet were investigated. The thickness, amplitude, frequency, and phase velocity of the waves over a wide range of variable parameters are given. Phase velocity integrated functions of the amplitude are constructed for various liquids. The friction on the cylinder wall is measured in the presence of natural and excited waves. The effects of wave regimes on the average values and RMS (root-mean-square) friction pulsations are studied.

Measurements of the Liquid-Film Thickness by a Fiber-Optic Probe

A technique for measuring the frequency responses of the thickness of a film of liquid at difficultly accessed locations and on intricately shaped objects has been developed on the basis of reflection-type fiber-optic sensors. The static, dynamic, and angular characteristics of these sensors are presented, as well as the results of test measurements of the film thicknesses of liquid nitrogen and an aqueous ethanol solution flowing down a vertical plate.

Suppression of large-scale structures in a gas-saturated impact jet

The suppression of large-scale vortex formations under gas-saturation conditions is detected on the basis of measurements of the pulsation component of the surface friction when an axisymmetric hot jet of a fluid impinges on an obstacle. The conditions for the resonant enhancement of coherent structures and the suppression of broad-band turbulence are determined for single-phase and gas-saturated impact jets. The evolution of various pulsation components in the gradient region of an impact jet is analyzed.

PREFACE: DROPS, BUBBLES, AND THIN FILMS, SPECIAL ISSUE HONORING PROFESSOR OLEG KABOV

On January 10th, 2016, Professor Oleg Kabov, a world renowne d expert in the field of interfacial heat and mass transfer and the founding Editor-in-Chief of the journal Interfacial Phenomena and Heat Transfer (IPHT), celebrated his 60th birthday. To mark the occasion, several of his colle agues conceived the idea of a special issue to celebrate his achievements and to provide an overview of some recent de velopments in the research areas pioneered and/or enhanced by Professor Kabov. We review his contributions to these areas here while also providing some biographical information. Oleg Kabov graduated from Tomsk Polytechnic Institute (now National Tomsk Polytechnic Research University) in 1978, and in the same year he moved to Novosibirsk to join th e laboratory of Professor S.S. Kutateladze at the Institute of Thermophysics. For many decades, this institu te has been one of the leading heat and mass transfer research centers in the world, in part due to the pioneering c o tributions of Kutateladze and his collaborators toward the understanding of physical mechanisms of boiling and con densation. Other important research areas developed at the Institute of Thermophysics include studies of waves o n liquid films, vortex flows, heat and mass transfer in disperse systems, phase transformation at cryogenic tempe ratur s, detonation, rarified gas dynamics, and synthesis of advanced materials. Professor Kabov defended his PhD the sis at the Institute of Thermophysics in 1987 under the direction of Professor I.I. Gogonin by working on proble ms of film condensation on arrays of finned tubes. The photograph in Fig. 1 (left) goes back to the early days at the K utateladze laboratory. The colleagues at the Institute of Thermophysics quickly recognized Oleg’s scientific potent ial. In 1987, at the age of just 31, he became the head of a new laboratory for heat transfer enhancement, see Fig. 1 (ri ght). Professor Vladimir E. Nakoryakov, an outstanding scientist who was the Director of the Institute of Thermophy sics between 1986 and 1997, proposed and strongly supported the establishment of this laboratory. In search of novel research directions for his laboratory, P rofessor Kabov turned his attention to studies of gravitydriven liquid films flowing over heated surfaces. This work re sulted in a remarkable discovery (Kabov, 1998). While