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Nanoscience and Technology: An International Journal

ISSN Print: 2572-4258
ISSN Online: 2572-4266

Nanoscience and Technology: An International Journal

Formerly Known as Nanomechanics Science and Technology: An International Journal

DOI: 10.1615/NanomechanicsSciTechnolIntJ.v6.i4.60
pages 319-334

INTENSIFICATION OF MASS TRANSFER IN LAMINAR AND TURBULENT CHANNEL FLOWS BY APPLYING SUBMICRON CAVITIES ON THE CHANNEL WALL SURFACE

V. A. Aleksin
A. Ishlinsky Institute for Problems in Mechanics, Russian Academy of Sciences, 101/1 Vernadskii Ave, Moscow, 119526, Russia
A. A. Markov
A. Ishlinsky Institute for Problems in Mechanics, Russian Academy of Sciences, 101/1 Vernadskii Ave, Moscow, 119526, Russia

ABSTRACT

A model of reduction of the friction drag in laminar and turbulent liquid and gas flows in channels by creating air-filled microcavities (micropores) on the channel walls and applying, to the surface, special coatings consisting of hydrophobic (water repellent) materials with organized structure of cavities of submicron size is suggested. It is proposed to use the slip parameters of gas phase on the surface of micropores at large Knudsen numbers. The value of the macrointensity of slip on the pipe wall has been found by applying averaging of gas microflows and gas velocity gradients in nanocavities on the basis of the model of mutually penetrating continua of the solid and gas phases. The detailed structure of gas flows in the cavities is not considered. The intensities of the slip processes are presented in dimensionless variables as functions of the coefficients of gas molecules reflection from the cavity surfaces. Calculations of the mass transfer rate were made with varied intensities of slip processes. The theoretical model makes it possible to predict the characteristics of mass transfer intensification both at small and large Reynolds numbers. The possibilities of applying the differential model of turbulence in the case of simultaneous action of two factors − the high intensity of turbulence in the incoming flow and slip on the wall − have been established.