Computational-analytical simulation of microsystems in process intensification

Heat and mass transfer enhancement techniques, either passive or active, have an important role in the more general goal of process intensification in modern engineering developments. In this context, the study of transport phenomena at the nano- and micro-scales aims far beyond the plain miniaturization of devices, being mainly directed towards process efficiency improvement and lower energy and raw materials consumption. The analysis of heat and mass transfer at such scales has required the development or extension of both theoretical and experimental methodologies. In light of the inherent multiscale nature of microfluidic devices, classical fully numerical methodologies often require large refined meshes with associated costly computations. A hybrid numerical-analytical approach for the analysis of microfluidic and thermal micro-systems is here reviewed, which includes a computational-analytical integral transform method for partial differential direct problems, that, together with mixed symbolic-numerical computations, lead to robust cost-effective algorithms for micro-scale transport phenomena analysis. Examples of this hybrid approach in selected applications are then examined more closely, including micro-reactors for continuous biodiesel synthesis with multiple reactive interfaces and three-dimensional thermal micro-devices with solid-fluid thermal conjugation.