Interfacial area generation by disintegration of a liquid sheet

The process of breaking up liquid into a spray is of widespread practical importance in increasing interfacial area and subsequently interfacial heat (or) mass-transfer. The proposed research activity is devoted to the theoretical analysis of interfacial area generation by disintegration of a liquid sheet. - A process which is still a major area of uncertainty in many applications. The application of particular interest is the disintegration of the incoming liquid film in an apparatus called static low-pressure homogenizer, which is operating based on an injector principle. In this process the film disintegration occurs after the liquid forming the film is sucked radially inward through an injection gap. The disintegration is the first step of a process further leading to complete emulsification of the film fluid in the carrier phase stream. Considerable interest in this homogenization concept is recognised in various branches of industry, including pharmaceutical, cosmetical and food engineering applications. The theoretical framework for investigation of liquid sheet disintegration as a starting point for the generalized study of atomization and emulsification was identified in the area of linear and non-linear instability analysis. Especially the shear induced Kelvin-Helmholtz type of liquid sheet instability should be investigated. It is intended to extend the more classical analysis of liquid-in-air systems to cases of a liquid sheet disintegration in carrier fluids of similar density. Thereby the viscosity ratio of the phases and the interfacial tension effect are expected to introduce new characteristic features not known in the disintegration behaviour of liquid/gas-systems. It is intended to investigate the momentum coupling between the liquid sheet and the outer flow more closely. Thereby all non-linear and viscous terms will be included. A vorticity-streamfunction formulation will be a possible candidate for the representation of the Navier-Stokes equation system (at least in a two-dimensional case). The Volume-of-Fluid method of Hirt & Nichols (1981) will be implemented to treat the free boundary problem. Based on this approach it should be possible to track the temporal evolution of the interface profile and to reveal the influence of the non-linear terms on the deformation mode.