Field- and Shear-Driven Collective Phenomena in Suspensions (21 pages)

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Field- and Shear-Driven Collective Phenomena in Suspensions



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Field and Shear Driven Collective Phenomena in Suspensions Boris Khusid New Jersey Institute of Technology Andreas Acrivos The Levich Institute at CUNY Support NASA NSF DARPA Dielectrophoresis The force acting on a particle subject to a gradient electric field is Fe QE P E Electrophoresis is the motion of a charged particle in a DC field Dielectrophoresis is the motion of a neutral particle in gradient DC and AC fields The time average dielectrophoretic force in an AC field Fd 2 0 f a3 Re E2rms p f p 2 f Positive Re 0 dielectrophoresis Negative Re 0 dielectrophoresis Field induced Phase Transition A homogeneous random arrangement of particles E 0 A variety of ordered aggregation patterns Wel k B T Electrorheological fluids Measuring the Particle Polarization Dussaud Khusid Acrivos J Appl Phys 88 2000 Dielectric spectroscopy for measuring particle polarization for E 1 V mm s c f c The Maxwell Wagner model s c 2 f Validated the equation for dielectrophoretic force for E 1 kV mm Dielectric Spectroscopy sample DS measures the relation between time varying voltage and current through a sample E 1 V mm NJIT W M Keck Laboratory Field induced Phase Separation Microscopic theory for field induced phase transitions 0 f E 2 v p k BT relative field strength a 1 m a 1 nm Phase Diagram spinodal METASTABLE Khusid Acrivos Phys Rev E 1995 1996 1999 UNSTABLE coexistence curve ccrcr particle volume fraction c Dielectrophoretic Particle Concentrator 40 m W 6 m H 570 m L 10 Vptp 15 30 MHz monolithic multilayer device Sandia s SwIFTTM process 0V 10V Dielectrophoretic gates 6 m 0V 10V Electrodes Flow E2 rms Gate Source Bennett Khusid Galambos James Okandan TRANSDUCERS 03 Boston MA Experimental Results 1 m polystyrene spherical beads in DI water 0 1 v v Particle polarization 0 45 0 27i Flow rate 0 24 pL s to 9 6 pL s Re 10 5 10 3 Flow 10Vptp 30 MHz 10s 70s Phase transition Dielectrophoretic gates 10V 0V Flow Electrodes 6 m 20 m 120s 180s E2rms Gate Fd Source Bennett Khusid Galambos James Okandan Jacqmin Acrivos Appl Phys Lett 2003 Flowing Heterogeneous Mixture Beads and bacterial cells heat killed staphylococcus aureus 10 Vptp 15 MHz Flow rate 0 24 pL s to 9 6 pL s Flow Cells Beads 20 m Source Bennett Khusid Galambos James Okandan Jacqmin Acrivos Appl Phys Lett 2003 Electro hydrodynamic Model Chemical potential Phys Rev E 1995 9 k B T df 0 E2 s p 0 v p dc c tc 2 Entropic factor f 0 c ln c 1 c c Z 1 c dc 0 Quasi steady electrodynamic equations D r 0 E r 0 E 2 1 2 E r 2 Electric displacement D 0 s c E Suspension flow v s v v p s vis c p c p f g v 0 t 2 v v i 1 5c j vis s Viscosity 1 Shear stress ij s s f 1 c cm x j x i 2 c 1 c v p c cv jp 0 jp p p f g Particle balance t 6 a s The particle polarization can be measured at low fields Re Flow velocity 10s Particle velocity 10s Modeling Single bolus 8 73 45 2 m s 49 8 m s 70s 0 1 v v suspension Flow rate 8 64 pL s 70s Voltage 10Vptp 45 4 106 3 m s 180s 78 8 m s Average flow velocity 36 m s 180s 1 concentration 56 4 110 4 m s 120s 151 4 m s 2 field strength 120s Two boluses 139 9 m s 171 6 m s Electric Field Configuration Flow Electric field Dussaud Khusid Acrivos J Appl Phys 88 2000 160 mm y 3 mm 80 mm x Electrodes Computational cell 0 0 0 x Electrodes 0 x 2 Suspension 1 0 y 0 1 y 0 Log E2 Electric field Strength Channel cross section Vrms d 2 3 mm Low Field Region HV d 2mm GR HV Neutrally buoyant suspension Polyalphaolefin spheres 0 92 g cm3 90 m in corn oil 0 92 g cm3 0 06 Pa s eps 2 2 Particle polarization in low field 1V mm The Maxwells f Re 0 15 Wagner model s 2 f for 100 1000 Hz Source Kumar Qiu Khusid Jacqmin Acrivos Phys Rev E 2004 Field induced Segregation 3 6mm Top view 10 GR HV 0s 45s Neutrally buoyant polyalphaolefin spheres in corn oil Re 0 15 for 100 1000 Hz GR HV 90s 150s 5kv 100Hz without flow Vrms d 2 5 kV mm GR HV 300s 2325s Source Kumar Qiu Khusid Jacqmin Acrivos Phys Rev E 2004 5 41min 10 38min GR HV GR 3 6mm Front Formation Top view HV 20 28min 15 30min GR HV GR HV 30 30min 25 36min GR GR HV HV Source Kumar Qiu Khusid Jacqmin Acrivos Phys Rev E 2004 5kV 100Hz without flow Vrms kV 2 5 mm d 0 50 0 45 0 40 5 5kV 2kHz 5 3kV 2kHz 10 5kV 100Hz 10 3kV 100Hz 15 5kV 2kHz 15 3kV 2kHz GR L Front Position L D 0 55 HV 0 35 15 0 30 0 25 0 20 10 5 0 15 t d 0 10 20 30 40 50 60 70 80 90 100110120130 3d f d 2 2 a 0 f Re Vrms 4 Dielectrophoretic time Source Kumar Qiu Khusid Jacqmin Acrivos Phys Rev E 2004 D 3 6mm Comparison with Experiments Field Strength and Frequency Effects Top view 10 suspension 5kV 100Hz 3kV 100Hz 3kV 2000Hz t 20 5min t 54 5min t 52 5min t d 63 4 t d 60 8 t d 58 6 Source Kumar Qiu Khusid Jacqmin Acrivos Phys Rev E 2004 Multi Channel Apparatus Electrodes parallel to the flow Silicon Wafer outlet Electrodes perpendicular to the flow outlet Al electrodes 6 mm 3 mm Electrode spacing 2 5 10 m inlet inlet inlet Transparent Glass Cover 150 chambers on the 4 wafer NJIT H 30 m outlet electrodes Source Markarian Yeksel Khusid Farmer Acrivos Appl Phys Lett 82 2003 Model for Dilute Suspensions Qiu Markarian Khusid Acrivos J Appl Phys 92 2002 Dussaud Khusid Acrivos J Appl Phys 88 2000 The balance of drag dielectrophoretic and gravitational forces 4 3 2 p f a 3 ge 2 0 f a Re E rms 6 a u v f f 3 The field induced particle displacement dr u dt r t 0 r0 The asymptotic expression for the spinodal 1 3 Re 2 0 f E 2 v p The particle polarization can be measured at low fields k BT Re Experimental Results Dioctyl Terephthalate f 0 98 g cm3 f 76 cp Al2O3 p 3 8 g cm3 a 0 5 2 m Re 0 35 for 1 10 kHz AC Field 20V 1kHz 0 1 v v Q 0 05 l min Re 10 5 0 sec X GR HV Z Measurement of Gray Level GL 160 m GR HV Flow Movie 0 900 s GR HV GR HV 240 m GL 0 900 …


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