Non-equilibrium thin-film flow in rotating disk and cone

The acceleration of a continuous feed liquid stream in a film "down" the rotating cone and disk is of great interest in centrifuges [1, 2], thin-film reactors and process intensifiers. The mechanism of feed acceleration is determined by an interaction of several different effects. Circumferential viscous forces act to increase the angular momentum. The centrifugal field thus produced establishes a body-force component along the cone/disk surface, thereby driving the flow "down" toward larger radius. The longitudinal flow is however impeded by longitudinal resistance forces. These different effects compete with each other as the flow proceeds, never quite coming to an unchanging equilibrium state. An approximate integral method which was used to explore the "near-equilibrium" flow behavior in earlier work has been extended to investigate the case with large departure from equilibrium. The latter exhibits complicated highly nonlinear effect. Despite this, useful information can be obtained from the theoretical analysis. Experimental results on feed acceleration of liquid streams at various feed rates and rotation speeds in a rotating cone have been used to validate the study. The theoretical study with complementary experimental tests provides insights into how continuous liquid stream in form of a thin film is being accelerated using rotating cones and disks, and the associated shear rates involved. The latter has important bearing in processing shear-sensitive mammalian cells in biopharmaceutical separation with centrifuges and mass transfer in thin-film reactors.