caa a22 4500 463235428 CHVBK 20180405153255.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s10404-007-0149-4 doi (NATIONALLICENCE)springer-10.1007/s10404-007-0149-4 Simulation and characterization of microreactors for aerosol generation [Elektronische Daten] [Norbert Kockmann, Simon Dreher, Michael Engler, Peter Woias] This paper shows the application of T-shaped micromixers for the generation of aerosols with nanoscale droplets by the mixing of a hot vapor-gas mixture with a cold gas. The fast mixing within a T-shaped micromixer leads to a high supersaturation of the vapor and therefore to an instantaneous, homogeneous nucleation and particle growth. Different mixer geometries, mixing ratios, and gas temperatures have been investigated by numerical simulation to yield optimum mixing results over a wide range of operational parameters. Optimized microreactor geometries were designed and fabricated in silicon with Pyrex glass lids. Special attention was paid to thermal insulation and particle deposition at the channel walls. This concerns not only the mixing chip, but also the design of the fluidic mount with only few bends and corners. Initial experimental results for particle deposition and aerosol generation are presented. High temporal temperature gradients up to 106K/s lead to a rapid condensation and forming of nanosized particles with a mean diameter of 20-50nm and a narrow size distribution. Springer-Verlag, 2007 Aerosol nationallicence Nanoparticle nationallicence Micromixer nationallicence Microreactor nationallicence Process engineering nationallicence A M : cross section area of mixing channel (m2) nationallicence C : friction correction factor (-) nationallicence d h : hydraulic diameter (m) nationallicence d p : particle diameter (m) nationallicence h : specific enthalpy (J/kg) nationallicence L : channel length (m) nationallicence L m : characteristic mixing length (m) nationallicence L m90 : mixing length 90% mixed (m) nationallicence P : momentum density (kg/m2s) nationallicence Re : Reynolds number (-) nationallicence St : Stokes number (-) nationallicence T : temperature (K or °C) nationallicence Δ T L : spatial temperature gradient (K/m) nationallicence Δ T τ : temporal temperature gradient (K/s) nationallicence u : (fluid) velocity (m/s) nationallicence $${\bar{u}}$$ : mean (fluid) velocity (m/s) nationallicence $${\dot{V}}$$ : volume flow (m3/s) nationallicence x : spatial coordinate along channel (m) nationallicence Y : mass fraction of vapor in gas (kg/kg) nationallicence $${\alpha _{\dot{V}}}$$ : mixing quality (-) nationallicence η : dynamic viscosity (kg/sm) nationallicence λ : heat conductivity (W/m2K) nationallicence ρ : density (kg/m3) nationallicence ρP : particle density (kg/m3) nationallicence $${\sigma _{\dot{V}\max}(T)}$$ : maximal standard deviation of temperature over volume flow (K) nationallicence τ m : characteristic mixing time (s) nationallicence τ m90 : mixing time 90% mixed (s) nationallicence φ : relative saturation (φ =1 means saturated state) (-) nationallicence Kockmann Norbert Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut Dreher Simon Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut Engler Michael Siemens VDO Automotive, Siemens AG, VDO-Str. 1, 64832, Babenhausen, Germany aut Woias Peter Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut Microfluidics and Nanofluidics Springer-Verlag 3/5(2007-10-01), 581-589 1613-4982 3:5<581 2007 3 10404 https://doi.org/10.1007/s10404-007-0149-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10404-007-0149-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kockmann Norbert Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut NATIONALLICENCE 700 1- Dreher Simon Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut NATIONALLICENCE 700 1- Engler Michael Siemens VDO Automotive, Siemens AG, VDO-Str. 1, 64832, Babenhausen, Germany aut NATIONALLICENCE 700 1- Woias Peter Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany aut NATIONALLICENCE 773 0- Microfluidics and Nanofluidics Springer-Verlag 3/5(2007-10-01), 581-589 1613-4982 3:5<581 2007 3 10404 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer