Aleksandr N. Pavlenko.

Professor, Head of the Laboratory of Low-Temperature Thermophysics. Kutateladze Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia. Corresponding Member of Russian Academy of Sciences.

E-mail: pavl@itp.nsc.ru

Invited lecture at the “The 6th International Symposium on Thermal-Fluid Dynamics” (ISTFD 2025), Qingdao, China, July  25-28, 2025.

Topic

HEAT AND MASS TRANSFER ENHANCEMENT IN MULTI-PHASE SYSTEMS TO IMPROVE ENERGY EFFIENCY AND ENERGY SAVING IN THE POWER, CHEMICAL INDUSTRIES AND ELECTRONICS”.

Introduction

experimentally and theoretically investigated the mechanisms of  the development of self-sustaining evaporation front in metastable liquids and the dynamics of change of boiling regimes; - for the first time the regularities of heat transfer and development of crisis phenomena in the falling wave liquid films at nonstationary heat release was investigated; methods of heat transfer enhancement during evaporation and boiling under different hydrodynamic conditions using micro-/nanostructured surfaces were developed; - developed scientific bases of processes of mass transfer in distillation using structured packings serving as a base for the creation of new modern efficient energy and cryogenic technologies. He is the author and co-author of  more than 600  research works, 4 patents and two monographs. 

He is Member of the Research Council of the Intern. Comm. for Heat and Mass Transfer, the Editor-in-Chief of the "Journal of Engineering Thermophysics", Editorial Board Member of the  "Journal of Enhanced Heat Transfer”,  "High Temperature" and  "Heat Processes in Engineering".  Prof. A. Pavlenko was the Chairman of the Organizing Committee of the Intern. Conf.  "5th Intern. Workshop on Heat /Mass Transfer Advances for Conservation and Pollution Control (IWHT2019)", Organizer and Chairman of Organizing Committee of 7 Intern. Workshops ISHM-I–ISHM-VII (2014–2018), Co-Chairman, Deputy Chairman, Member of the Organizing Committee of  50 Intern. and Russian conferences. 

Under his leadership, a large cycle of fundamental and applied research was carried out under major programmes, projects with domestic and foreign industrial companies and universities. In terms of application main practical achievements of A. Pavlenko are bound with the development of the methods increasing mixture separation efficiency in the cryogenic packed columns, heat transfer enhancement methods in compact plate fin heat exchangers and spiral heat exchangers for liquefaction of natural gas. For successful and fruitful cooperation with the largest company of cryogenic machine building he was awarded with four Certificates of Recognition ("Air Products”, 2002, 2009). He is the laureate of the Intern. A.V. Lykov award (2020), prize of academician S.S. Kutateladze (1998).

Abstract

In plenary lecture the analysis of the modern state in the field of development of methods of heat transfer enhancement, control of extreme processes of heat and mass transfer at boiling and evaporation in various hydrodynamic conditions, including regimes at free convection, at jet/spray irrigations, at film flows and in liquid layers, including in the field of mass forces of considerable intensity is carried out. The basic physical mechanisms determining in interconnection significant intensification of heat and mass transfer processes, increase of critical heat flux in the considered regimes at use of various types of modification of the heat-emitting surface are considered. The factors of decrease in efficiency of mixtures separation in large-scale distillation columns with structured packings and means of suppression of their negative influence are considered. 

As part of this analysis, the latest results obtained using various methods of heat transfer intensification (micro-nanostructured capillary-porous coatings created by plasma method; 3D printing methods; metal foams, composite porous surfaces and structures; micro-arc oxidation method, micro-deformable cutting method; mesh coatings; methods for creating contrast wettability; electrochemical methods for deposition and coating creation; combined methods), including experimental data of the author and his colleagues, are discussed. 

In the first section, the possible physical mechanisms and factors responsible for the enhancement of heat transfer during bubble boiling under conditions of free convection are analyzed, depending on the degree of proximity to the critical heat flux, and the type of liquid. The issues of the specifics of the development of methods for increasing the critical heat flux with the simultaneous possibility of increasing the heat transfer coefficient at bubble boiling are discussed. 

In the second part of the lecture, there is the comparative analysis of heat transfer efficiency and critical heat flux in the film flows of liquids and liquid mixtures over a vertical cylinders and horizontal tubes with the horizontal microtexture, diamond-shaped cut, artificial roughness, nanoFLUX, LbL and other commercial surfaces, the structures obtained with a deformable cutting (MDC), micro-arc oxidation method (MAO), mesh covers of various forms. The features of the mechanisms of heat transfer intensification and increase of the critical heat flux under the conditions of heat transfer in flowing liquid films in comparison with pool boiling  and boiling in liquid layers (including dielectric fluids) of different thicknesses are discussed. 

The prospective and problematic issues of conducting research on the development of methods for cooling modern electronics with high and ultrahigh heat fluxes are considered.  

The final part of the report presents the results of an extensive series of experimental studies conducted on a large-scale distillation column to investigate the relationship between the separation efficiency of mixtures and the distribution of liquid and vapor phase flow parameters in structured packings of different geometry. The results on the use of the method of dynamic irrigation proposed by the author and his colleagues to improve the efficiency of separation of mixtures are presented. New modern high-efficiency technologies for the creation of so-called distillation columns with separating walls are considered, which serve as an important and necessary basis for the creation of new high-efficiency distillation columns for the separation of multicomponent mixtures (so-called  Dividing-Wall Columns (DWC)).