Article outline

Modeling of fluid flow in channels with a cavity is relevant for solving engineering problems, for example, related to the design features of devices associated, for example, with the processing and transportation of hydrocarbons, cooling systems. The presence of a cavity can lead to the occurrence of local hydrodynamic effects, such as self-oscillations or other complex flow regimes. The influence of rheological parameters of the fluid, heat exchange conditions and geometric parameters of the cavity and channel on the flow characteristics is numerically studied. The mathematical model of the problem consists of continuity equations, modified Navier-Stokes equations taking into account variable viscosity and energy conservation. To numerically solve these equations, the control volume method and the SIMPLE algorithm modified to take into account the variable viscosity coefficient were used. To demonstrate the influence of various heat exchange conditions on the flow character, a plate was located at the bottom of the cavity, on which a temperature was set that differed from the ambient temperature. An experimental measurement of the viscosity of a 45% aqueous solution of propylene glycol was performed in the temperature range from -8 to 70 ^°C using a Thermo Scientific HAAKE MARS rotational rheometer of the Experimental Hydrodynamics laboratory of the Institute of Mechanics of the Ufa Federal Research Center of the Russian Academy of Sciences. The results of numerical modeling were compared with photographs of the experiment of a creeping flow around a rectangular cavity for three cases with the ratio of geometric parameters b/h = 0.5, 1, 2. The influence of the height of the main liquid layer and the cavity parameters on the main flow and on the process of vorticity formation in the cavity was considered. In this work, the flow of a thermoviscous liquid in a flat channel with a cavity was investigated and it was shown that the hydrodynamic features of the flow are determined by the size and shape of the cavity. At a fixed pressure drop, the position and shape of the vortex depend on the height of the main flow. An increase in the depth of the cavity (h) leads to an increase in the vorticity inside it. Reducing the height of the main layer leads to a decrease in the center of the stable vortex, its division into two and displacement toward the channel walls, and the main flow enveloping the cavity. These results emphasize the importance of taking into account both geometric and rheological parameters when analyzing fluid flow.