Flow and Mass Transfer inside Networks of Minichannels, In : Advanced topics in mass transfer

Florian Huchet (1)

1 IFSTTAR/MAT - Département Matériaux

The process miniaturization constitutes a challenge for the Chemical Engineering domain. The particular benefit in term of the increase of the ratio between the transfer surface area and the fluid volume inside microfluidic system is really promising for the conception of efficient apparatus such as microreactors, micromixers and microseparators allowing a better chemical reaction control and heat and mass transfer intensification in order to realize sustainable industrial equipments. On other hand, a proper design of a microstructured platform where miniaturized reactors, mixers and separators are implemented with integrated sensors is crucial for the fabrication of new materials, chemical or bio-chemical products and testing new catalyst and reagent (Gunther & Jensen, 2006). Flow and mass transfer characterization inside these new tools of development and production is fundamental for their optimal design. Yet, these new pieces of equipment are made in stainless steel integrating about hundreds of microchannels either about several tens of microexchangers. These microstructured exchangers can operate at high pressure and present three-dimensional geometries. Hessel et al. (2005) report the order of magnitude of the flow rate in various microstructured reactors. The flow rates range between 10 and 10000 l.h-1 and the flow regime is usually transitional or turbulent. In spite of new experimental methods (Sato et al., 2003; Natrajan & Christensen, 2007), it remains difficult to measure simultaneously a scalar quantity (concentration, temperature, velocity) at different locations of the microstructured reactors. Thus, a lot of difficulties occur in the prediction of wall transfer phenomena (heat, mass, momentum) in the microstructured reactors in view of their integration in chemical manufacture. A characterization of the flow behaviour and of heat and mass transfer performance is needed in order to develop and improve these microsystems for their application in process engineering. A large number of studies dealing with flow through microsystems of different shapes and flow configurations is available in the literature since a few years. Among them, T-microchannel (Bothe et al., 2006) or hydrodynamics focusing (Wu & Nguyen, 2005) are some promising classes of flow configurations for microfluidics apparatus applications. Various complex geometries are usually studied by using numerical approaches or global measurements to characterize transfer phenomena in heat exchangers (Brandner et al., 2006) or microreactors (Commenge et al., 2004). The flow inside these microreactors or microexhangers are usually in the transitional or turbulent regime and the experimental description of all the hydrodynamics scales become more difficult than in classical macrodevices.

Mots clés: METHODE ELECTROCHIMIQUE; TRANSFERT DE MASSE

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Florian Huchet. Flow and Mass Transfer inside Networks of Minichannels, In : Advanced topics in mass transfer. Flow and Mass Transfer inside Networks of Minichannels, In : Advanced topics in mass transfer, InTech, pp 229-264, chapitre 12, 2011. ⟨hal-00971306⟩