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Simulation and Analysis of Equally Distributed Flow for Use in Ultrasonic Atomization. Lindsay Rogers University of Wisconsin, Platteville Mechanical Engineering Dr. Chen S. Tsai University of California, Irvine Department of Electrical Engineering and Computer Science Dr. Shirley C. Tsai
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Simulation and Analysis of Equally Distributed Flow for Use in Ultrasonic Atomization Lindsay Rogers University of Wisconsin, Platteville Mechanical Engineering Dr. Chen S. Tsai University of California, Irvine Department of Electrical Engineering and Computer Science Dr. Shirley C. Tsai California State University, Long Beach Department of Chemical Engineering
Background • Applications • Medical: Pulmonary Drug Delivery • Thin, Even Spray Coating • Material Science • MEMS Fabrication (photoresist coating) • Nanoelectronics (deposition of conductor material) • History • Bulk Metal-based Ultrasonic Nebulizer • Ink-Jet Printer Nozzles (drop-on-demand)
Overview • The Nozzle • Fourier Horn: half-wavelength design and vibration amplitude magnification of two • Constant cross-sectional area of inner channel permits cascading horns • Nozzle Holders placed at nodes allowing proper vibration 3-Fourier Horns Transducer Drive Section Nozzle Holder Nodal Bar
Ultrasonic Atomization Mechanism • Piezoelectric plate excited, causing the formation of a standing longitudinal wave throughout fluid • Liquid issues from nozzle, creating thin film at tip with capillary wave generated on liquid surface • Operation at resonance causes wave instability and breaks liquid into drops upon ejection • Drop size uniform
Advantages • Can operate at higher frequencies than conventional ultrasonic nozzles while requiring less electric drive power • Smaller, more uniform drops • Reduction in overall size • Integration • Arrays of multiple nozzles • Combine piezoelectric plate application with nozzle fabrication process
Array of Nozzles Increase Production of Monodisperse Droplets
Manifold • Supply equally distributed fluid flow to each nozzle • Manufactured on same wafer as nozzle array • Optimize parameters including: • Junction Angles • Length of straight sections and overall length
Simulation • ANSYS, finite element software • Utilized program code instead of graphically drawing profile for ease of controlling parameters
Analysis • Procedure • Model a range of channel profiles by varying optimization parameters • Acquire FEM solutions (velocity, pressure drop) Vector Plot of Velocity Contour Plot of Pressure
Analysis • How results interpreted • Visually study plots (velocity, pressure) • Minimize overall pressure-drop
Closing Thoughts • Silicon-based nozzle created which produces monodisperse drops • Manifold of microfluidic channels simulated and optimized • Further work being conducted on channels with more than two branch angles and arrays which don’t follow 2n pattern (2, 4, 8, 16…)
Acknowledgements • Professors Chen and Shirley Tsai • Graduate Students • Ning Wang • Eugene Huang • National Science Foundation • IM-SURE Program • Said Shokair (major props) • G.P. Li • Goran Matijasevic • IM-SURE participants