Optimal design of multi-channel microreactor for uniform residence time distribution

• Published in: Microsystem technologies 2012-02, Vol.18 (2), p.209-223
• Main Authors: Renault, Cyril, Colin, Stéphane, Orieux, Stéphane, Cognet, Patrick, Tzédakis, Théo
• Format: Article
• Language: English
• Subjects: Applied fluid mechanics; Applied sciences; Electronics; Electronics and Microelectronics; Engineering; Engineering Sciences; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Instrumentation; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical Engineering; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Nanotechnology; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Techincal Paper
• ISSN: 0946-7076; 1432-1858
• DOI: 10.1007/s00542-011-1334-7

Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow.