Experimental Investigation of the Effect of Nano- and Microroughnesses on the Intensity of Swirled Flow

The effect of nanoroughnesses on the structure of a closed vortex flow generated in a motionless vertical cylindrical container by an upper rotating disk with various roughnesses deposited on its surface is investigated. An increase in the Reynolds number is found in the presence of roughnesses on a rotating disk, which leads to an increase in the length along the axis of the vortex cell with circulating motion leading to the intensification of mixing and mass transfer. It is shown for the first time that, for the case of the Wenzel interaction of fluid with a surface (without an “air” interlayer between them), a 5–11% increase in the size of the vortex cell is observed for nanoroughnesses simulating the superhydrophobic surface of a lotus leaf. The results obtained are of interest for the further development of the vortex apparatus and reactors providing the complex vortex motion of ingredients, the optimization of the operation of existing installations, and the designing of new devices.