Release:2017, Vol. 3. №4
About the authors:Artem A. Velizhanin, Postgraduate Student, Earth Cryosphere Institute of the Siberian Branch of the RAS; email@example.com
The problems of the flows of viscous liquids in capillaries at low Reynolds numbers are relevant in connection with development of nanotechnologies in electronics engineering, medicine, and other fields of human practice. Yet, the results of numerous experimental studies of such currents demonstrate unsatisfactory correlation to their theoretical description. In the presence of the second phase in the flow, the movement becomes complex, which complicates the theoretical model operation.
This work aims at obtaining the quantitative experimental data a) about single-phase flows of water and oil in a cylindrical capillary at low Reynolds numbers and b) about process of replacement of one liquid by another. During the experiments, the authors measured pressure drop and mass of the liquid (which passed through a capillary), as well as took photo and video of fronts movements of replacement in the wide range of Reynolds numbers (0.002 < Re < 500).
The authors have established that in a single-phase flow, the movement of a liquid in the conditions of the experiment never is stationary, and its key parameters do not match the theoretically predicted. The reference stages of the flow at replacement of one liquid by another are revealed and described. Oil replacement by water happens in the “piston’ mode, the border oil-water has spherical shape, and after its passing on walls of a capillary there is an oil film. Features of behavior of a film at a single-phase flow of water are described. At water replacement by oil the current mode with unambiguously expressed border is not implemented, in a flow numerous drops and crossing points are observed. It is noted that the existence of an oil film on the surface of a capillary leads to an increase in the rate of flow passing through it.