Mathematical Simulation of the Swirling Flow of a Thermoviscous, Pseudoplastic Sisco Fluid in a Cylindrical Channel
- PDF / 467,503 Bytes
- 12 Pages / 594 x 792 pts Page_size
- 84 Downloads / 255 Views
Journal of Engineering Physics and Thermophysics, Vol. 93, No. 4, July, 2020
TRANSFER PROCESSES IN RHEOLOGICAL MEDIA MATHEMATICAL SIMULATION OF THE SWIRLING FLOW OF A THERMOVISCOUS, PSEUDOPLASTIC SISCO FLUID IN A CYLINDRICAL CHANNEL O. V. Matvienkoa,b and A. E. Aseevaa
UDC 665.455:006.354
The swirling flow of a thermoviscous, pseudoplastic Sisco fluid in a cylindrical channel was investigated. It was established that, in the case of irrotational flow of a pseudoplastic fluid in such a channel, the effective viscosity of the fluid in the neighborhood of the channel axis is substantially increased. A swirling of this flow leads to an increase in the rate of shear deformation of the fluid in the axial region of the flow and to a decrease in its effective viscosity. As the swirling of the flow in the channel increases, the fluid near the channel walls and the fluid at the boundary of the recirculation zone are subjected to a dissipative heating leading to a decrease in their effective viscosity. The intensity heating of the fluid in the channel increases with increase in the rate of swirling (the Rossby number) of its flow. Keywords: rheology, non-Newtonian fluid, thermoviscous fluid, pseudoplastic Sisco fluid, heat exchange, swirling flow, viscous dissipation, computational hydrodynamics. Introduction. The development of chemical technologies makes the study of the mechanisms of flow of nonNewtonian media and heat exchange in them a pressing problem in current research [1]. A parameter of a flow of fluid, determining its structure, is the viscosity of the fluid. Every so often a flow of fluid under real conditions occurs with temperature drops. It is known that the viscosity of non-Newtonian solutions and polymer melts is substantially dependent on their temperature [2, 3]. Therefore, the mechanisms of flow of such media in the channels of heat exchangers should be investigated with regard for the dependence of their viscosity on temperature. The need for studying the flow of fluid in a channel with regard for the dependence of the viscosity of the fluid on its temperature was noted as early as 1955 [4] in the process of investigating the movement of oil in a pipe with regard for the heat, released in the near-wall region of the oil flow due to its viscous dissipation, and the change in the viscosity of the oil caused by its cooling as a result of the heat exchange between it and the surrounding medium. In [5, 6], the problems on the convective heat exchange in heat-transfer agents with constant and variable physical properties and on the hydrodynamics of these agents in the process of their movement in pipes were considered. In [7], results of numerical calculations of the flow of an incompressible fluid with variable viscoplastic properties in a pipeline with a local viscous resistance are presented. Analysis of these results shows that the pressure loss in the flow of a thermoviscous fluid in a pipeline is determined by the spatial distribution of high-viscosity fluid zones in the flow. In [8], a numerical inves
Data Loading...
