The behaviour of the interface between stratified thin liquid films bounded by parallel solid surfaces and subject to van der Waals forces which drive dewetting is studied in this work. Chemically homogeneous surfaces are considered first; this is followed by an investigation of chemically heterogeneous surfaces. The lubrication approximation is applied to obtain a single nonlinear evolution equation which describes the interfacial behaviour, and both the linear stability and nonlinear development of the interface are examined. The sensitivity of the interfacial rupture time to problem parameters such as the viscosity ratio, initial interfacial height, interfacial tension, and magnitude of the van der Waals forces is characterized in detail for the homogeneous case. This serves as a basis for a study of the heterogeneous case, where the strong dependence of the rupture time on the length scale of the heterogeneity is found to be relatively independent of changes in the remaining problem parameters. The mechanisms underlying the rupture-time behaviour are also explored in detail. The results suggest a route by which one liquid can become emulsified in the other, and may be beneficial to industrial processes such as lithographic printing which are based on wettability phenomena.

The steady behavior of the interface between two immiscible liquid layers flowing in a channel where one wall is flat and the other exhibits isolated or periodic step-changes in surface topography is considered in this work. A one-dimensional model based on the lubrication approximation is used to describe the interfacial shape and explore its behavior over a wide range of problem parameters. The density and thickness ratios, as well as the periodicity of the topography, strongly influence interfacial shape, whereas the viscosity ratio has a relatively minor effect. In some cases, interfacial features that are present in the flow of single liquid layers over surfaces with topography can be completely suppressed by large pressure gradients that arise due to the bounded geometry. A scaling analysis is applied to explain variations in the capillary length scale. The results presented in this work are potentially relevant to a range of applications including microfluidics, oil recovery, lubricated piping, and lithographic printing.

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A model of a rapid temperature swing adsorption CO 2 capture module using sorbent-loaded hollow fibers is presented. The system incorporates an integrated heat recovery technique using a thermal wave to reduce the external thermal input and operational energy costs of the capture facility. The model includes a detailed heat and mass transport model for the sorbent-loaded fibers to address accurately the rapid radial kinetics of the adsorption process. The local heating and cooling of the sorbent possible with the use of coupling fluid in the bore of the fibers significantly reduces the time required for each adsorbing and desorbing phase. Results for a representative operating condition indicate that a capture facility based on the sorbent-loaded hollow fibers can achieve significantly higher sorbent productivities (∼1400%) than that of other thermally driven capture technologies with moderate energy consumption (∼5.9 MJ kg −1 ). The very fast cycle times (∼100 s) achievable with this adsorption process enable this high productivity that can substantially reduce the footprint of a plant-scale CO 2 capture facility.