© 2010, TSI Incorporated MicroPIV Particle Image Velocimetry System for Micron Resolution Flow Measurements

© 2010, TSI Incorporated Key Aspects Non-invasive global flow measurement technique Systems provide accurate measurement of fluid flow in micro fluidic environments Utilizes special concepts in –illumination, scattered light collection, seed particle concentration, optical design and data analysis to offer the most powerful and versatile system Worked with pioneers in MicroPIV to incorporate unique ideas into the system ( Meinhart, Adrian, Wereley, Santiago )

© 2010, TSI Incorporated Bio-MEMS applications Chemical and biological analysis – “lab-on-a-chip” for medical and defense applications Microfabricated needles for drug delivery Flow sorter (Caltech) Lab-on-a-chip, Caliper Caltech

© 2010, TSI Incorporated Aero-MEMS applications Micron scale supersonic nozzles (MIT) Remote surveillance aircraft (UCLA, Caltech) Micro Air Vehicle (MAV): –flapping-wing vehicle < 15 cm in all directions (UCLA) Micro-jet engine (Epstein et al., MIT) Microfabricated supersonic nozzle (MIT) MEMS-controlled remote aircraft (Caltech) 500  m

© 2010, TSI Incorporated Micro PIV Issues Reduce flare from walls by using fluorescent particles and –filter the illuminating wavelength Particles must be very small to fit in small measurement volume –Small particles have significant Brownian motion Volume illumination instead of light sheet. –Creates unwanted images from out-of-focus particles Reduce background glow – Implies shallow channels or low concentrations of particles Short times between pulses and short pulses, even in slow flows –Need pulsed lasers

© 2010, TSI Incorporated Details on Microflow Measurement Flow In Flow Out Flood Illumination Microscope Objective GlassPlate Flow Model Focal Plane Laser beam

© 2010, TSI Incorporated System for Microflow Measurements System for microflow measurements utilizes many of the same components as the standard PIV system Main components: Dual Nd:YAG laser at energy level of 15 mJ to 50 mJ P OWERVIEW Plus and PIVCAM series of cameras I NSIGHT 3G software for Data capture and analysis, with enhanced capabilities for microflow measurements Microscope optics

© 2010, TSI Incorporated Laser illumination system for Microflow Measurements Nd:YAG laser –15 mJ to 50 mJ energy level Laser light attenuator –used with the laser to provide more precise control of the intensity of illumination Diffusion optics –employed in the Model microscope to ensure uniform light intensity to the flow model Option to use laser light guide –to deliver the light to the microscope

© 2010, TSI Incorporated Cameras for MicroFlow Measurements Powerview Plus and PIVCAM family of cameras are applicable for microflows measurements Powerview Plus 2MP, 4MP, 11MP, HS-200 –with high pixel resolution and 12-bit dynamic range PIVCAM –with 1360 by 1024 pixel resolution. 12-bit dynamics range

© 2010, TSI Incorporated INSIGHT 3G software for MicroFlow Measurements Image capture –With full pixel resolution or Area of Interest capture Image analysis schemes –including FFT, Hart correlation and Direct correlation as Plug-ins Image enhancement algorithms for microflows measurements including –the averaging of correlation functions, image averaging and image subtraction Different filter schemes –to improve signal-to noise level of correlation function

© 2010, TSI Incorporated Removing the background Image with backgroundBackground

© 2010, TSI Incorporated Image with background removed Flow around a bubble

© 2010, TSI Incorporated Average Correlation Algorithm Image A (t = t 0 ) Image B (t = t 0 +  t ) Correlation R AB Image Sequence N A1A1 B1B1 A2A2 B2B2 B3B3 BNBN ANAN A3A3 RA1B1RA1B1 R A N B N RA2B2RA2B2 RA3B3RA3B3 (Ensemble Ave.) Peak Search Courtesy: C. Meinhart

© 2010, TSI Incorporated Arithmetic Average Correlation RA1B1RA1B1 RA2B2RA2B2 RA3B3RA3B3 RANBNRANBN Courtesy: C. Meinhart

© 2010, TSI Incorporated Key Aspects Configuration based on unique ideas developed by –Carl Meinhart, Juan Santiago, Steve Wereley and Ron Adrian Special concepts in illumination, image capture, seeding and data analysis (Patented) PowerView cameras – cameras with mask designed for PIV I NSIGHT – unique tools designed in for PIV –Background removal, averaging, correlation averaging –Plug-ins (make the package always the most advanced) –Plug-in library

© 2010, TSI Incorporated Optical Systems for Microflow Measurements Two types of Optical systems are available to make measurements in microchannels of different dimensions System with the Model Microscope –Offers a complete microscope and is used to measure flows in channels with width down to even less than 100 µm! System using the Model special optics assembly –provides flexibility in system arrangement and is suitable for measuring flows in channels with width greater than 1000 µm

© 2010, TSI Incorporated Components of the assembly include –a relay lens, microscope traverse body, a long working distance microscopic objective, fluorescent filter and fluorescent particles The assembly offers –high flexibility in flow model arrangements. –It can be positioned either vertically or horizontally to accommodate the model configuration. This is especially attractive if the model is part of a larger assembly from which the model could not be separated Designed to make flow measurements for –Channel width larger than 1000 µm Model Special Optics Assembly

© 2010, TSI Incorporated Model Special Optics Assembly

© 2010, TSI Incorporated POWERVIEW 4MP Camera with Model Optics Assembly Model Special Optics Assembly

© 2010, TSI Incorporated Stereoscopic MicroPIV System

© 2010, TSI Incorporated System using the Model Microscope Model microscope is –an inverted microscope with all the accessories to be used as a stand-alone unit. –epi-fluorescent attachment, a double lamp housing with halogen lamp and a 10X microscope objective are part of the microscope Components to be used with the Microscope for PIV –Model laser light attenuator assembly –Model laser light guide assembly –Camera relay lens

© 2010, TSI Incorporated System using Model Microscope

© 2010, TSI Incorporated Microscope with epi- fluorescent optics Computer (Post processing) Laser Microscope Objective Filter Cube BeamExpander 12 bit CCD Camera (2048 x 2048 pixels) Focal Plane Exciter 532 nm Emitter Sample Cover Vector Plot Fluorescent Particles Pulsed green laser (532 nm) illuminates flow volume and excites particles. Particles fluoresce, emitting light of a different wavelength Emitted light image is captured by digital camera. Images are processed to produce vector flow plots.

© 2010, TSI Incorporated Microscope-based System System Capabilities Microscope with all the accessories to be operated as a stand-alone unit Inverted microscope configuration and side-mounted camera arrangement –offer the utmost stability for microflows measurements Upright Microscope configuration can also be used Epi-Fluorsecent attachment with filter cube –uses the same optical train for the illumination and particle emission collection Collection of fluorescent emission from particles –so that only the particle images are captured and not reflected light from the model

© 2010, TSI Incorporated MicroPIV System using Upright Microscope

© 2010, TSI Incorporated Microscope-based System System Capabilities Diffusion optics provide –sufficient and uniform laser intensity to the flow model Various microscope objective lenses –(from 4X to 40X) to allow imaging of flow in different model sizes Combination of the camera relay lenses and microscope objective lenses –provides the best illumination quality for various imaging areas Attachment for laser light guide –provides flexibility of laser light delivery from the laser

© 2010, TSI Incorporated Microscope-based System System Capabilities Can Switch between laser illumination and white light illumination –Facilitates alignment and focusing of the model Laser safety optics included in the system –Prevents viewing laser light by the operator Flow model holder –Accommodate models of varies sizes and shapes System is capable of measuring microflows in a wide range of channels (or channel widths) –Even within channels with width less than 100 µm

© 2010, TSI Incorporated Micro PIV example Santiago, et al Hele-Shaw flow around a red blood cell. (Santiago, et al. 1998)

© 2010, TSI Incorporated Application of micro-PIV Inkjet meniscus visualization and micro  PIV results (courtesy of Meinhart et al., 1999)

© 2010, TSI Incorporated Examples of MicroFlow Measurements Flow in a diverging micro-channel Image field Vector field

© 2010, TSI Incorporated Examples of Microflow

© 2010, TSI Incorporated Microchannel flow 150  m 500  m

© 2010, TSI Incorporated Kobayashi, Taniguchi Oshima Lab University of Tokyo Microchannel measurements

© 2010, TSI Incorporated Microflow Channels

© 2010, TSI Incorporated Flow around an obstacle