Description of numbering-up effects in heterogeneous microchannels

1. Description of numbering-up effects in heterogeneous microchannels Reporter : Lexiang Zhang Supervisor : Feng Xin 2012.04.12

2. Contents introduction tasks and scheme distributor fabrication and design a network model perspectives Tianjin University

3. Multi-scale notion make the transitions from the microscale up to the macroscale progressive catalystparticles The key scale-out consideration requires us to match the mean residence times or mean contact times in multiphase systems. Scale out challenge is equivalent to the task of implementing the rational flow distribution and control. Tianjin University

4. Flow patterns standards for flow description and evaluation N. Shao, A. Gavriilidis, P. Angeli. Flow regimes for adiabatic gas–liquid flow in microchannels[J]. Chemical Engineering Science. 2009,64:2749-2761. other used coordinates: And Weber number Tianjin University

5. General numbering-up methods M.N. Kashid, A. Gupta, A. Renken et al. Numbering-up and mass transfer studies of liquid–liquid two-phase microstructured reactors[J]. Chemical Engineering Journal.2010, 158:233-240. Václav Tesaˇ. Bifurcating channels supplying “numbered-up” microreactors[J]. Chemical Engineering Research and Design.2011,89:2507-2520. an integrated approach: internal numbering-up for distributing single phase fluids and external numbering-up for two-phase contacting Tianjin University

6. Most commonly used arrangements monolithic microreactors 、tree-like networks 、comb-like networks Zhiwei Fan, Xinggui Zhou, Lingai Luo et al. Experimental investigation of the flow distribution of a 2-dimensional constructal distributor[J]. Experimental Thermal and Fluid Science.2008,33:77-83. M. Saber, J.-M. Commenge,L. Falk. Heat-transfer characteristics in multi-scale flow networks with parallel channels[J]. Chemical Engineering and Processing: Process Intensification.2010,49:732-739. L. Luo, D. Tondeur, H. Le Gall et al. Constructal approach and multi-scale components[J]. Applied Thermal Engineering.2007,27:1708-1714. Tianjin University

7. Main tasks • Describe flow conditions at distributors • When flow fully develops , describe the contribution to mass transfer and flow stability made by each microchannel Tianjin University

8. Rough scheme • devise 2-3 rational distirbutors • experimental research, utilizing micro sensors and optical methods • build models and process data Tianjin University

9. Lithography and etching etching liquid: HF(HNO3,NH3F) thermal bonding: 500-1000℃ Si-O-H…H-O-Si → Si-O-Si + H2O Daniel Haller, Peter Woias, Norbert Kockmann. Simulation and experimental investigation of pressure loss and heat transfer in microchannel networks containing bends and T-junctions[J]. International Journal of Heat and Mass Transfer.2009,52:2678-2689. Tianjin University

10. Principles for distributors design • ensure every microchannel has the same inlet conditions , giving the channce for uniform flow distribution • universality , self-similarity , modularization • representativeness for characteristic scales “If we were look at a picture of a portion of an ideal fractal boundary, we wouldn’t know the magnification of the photograph from the ruggedness of the boundary, since it always looks the same at every magnification. This “look-alike” feature of ideal fractal boundary at various magnification is describled by the mathematician as silf-similarity.” Mandelbrot.A Random Walk Through Fractal Dimensions[M]. VCH Verlagsgesellschaft, Weinheim.1989 Tianjin University

11. Nascent design …… Future “scale up” : Tianjin University

12. An equivalent electrical resistance network model Minqiang Pan, Yong Tang, Liang Pan et al. Optimal design of complex manifold geometries for uniform flow distribution between microchannels[J]. Chemical Engineering Journal .2008,137:339-346. Hagen–Poiseuille Equation: adapted for single phase or a pseudo-phase This model should take into account inertial effects and fluid properties. J.-M. Commenge, M. Saber, L. Falk. Methodology for multi-scale design of isothermal laminar flow networks[J]. Chemical Engineering Journal.2011,173:541-551. Tianjin University

13. An equivalent electrical resistance network model RA,i=0 C. Amador, D. Wenn, J. Shaw et al. Design of a mesh microreactor for even flow distribution and narrow residence time distribution[J]. Chemical Engineering Journal.2008,135:259-269. Nuria de Mas, Axel Gunther, Tobias Kraus et al. Scaled-Out Multilayer Gas - Liquid Microreactor with Integrated Velocimetry Sensors[J]. Ind. Eng. Chem. Res.2005,44:8997-9013. J.-M. Commenge, M. Saber, L. Falk. Methodology for multi-scale design of isothermal laminar flow networks[J]. Chemical Engineering Journal.2011.173:541-551. Tianjin University

14. Perspectives • Learn the micro sensor, AFM and μ-LIFexperimental setups and corresponding data processing methods from references • Consult the descriptions for stochastic effects and stochastic models in conventional reactors • Expand the microreactor knowledge hierarchy Tianjin University

15. Thank you!