Capabilities and limitations of 2-dimensional and 3-dimensional numerical methods in modeling the fluid flow in sudden expansion microchannels

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• 作者：Chien-Hsiung Tsai ; Han-Taw Chen ; Yao-Nan Wang ; Che-Hsin Lin and Lung-Ming Fu
• 关键词：Sudden expansion microchannel ; Reynolds numbers ; Flow separation vortex
• 刊名：Microfluidics and Nanofluidics
• 出版年：2007
• 出版时间：February, 2007
• 年：2007
• 卷：3
• 期：1
• 页码：13-18
• 全文大小：446 KB
• 刊物类别：Engineering
• 刊物主题：Engineering Fluid Dynamics
  Medical Microbiology
  Polymer Sciences
  Nanotechnology
  Mechanics, Fluids and Thermodynamics
  Engineering Thermodynamics and Transport Phenomena
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1613-4990

文摘

This paper deals with computational and experimental investigations into pressure-driven flow in sudden expansion microfluidic channels. Improving the design and operation of microfluidic systems requires that the capabilities and limitations of 2-dimensional (2-D) and 3-dimensional (3-D) numerical methods in simulating the flow field in a sudden expansion microchannel be well understood. The present 2-D simulation results indicate that a flow separation vortex forms in the corner behind the sudden expansion microchannel when the Reynolds number is very low (Re∼0.1). However, the experimental results indicate that this prediction is valid only in the case of a sudden expansion microchannel with a high aspect ratio (aspect ratio >> 1). 3-D computational fluid dynamics simulations are performed to predict the critical value of Re at which the flow separation vortex phenomenon is induced in sudden expansion microchannels of different aspect ratios. The experimental flow visualization results are found to be in good agreement with the 3-D numerical predictions. The present results provide designers with a valuable guideline when choosing between 2-D or 3-D numerical simulations as a means of improving the design and operation of microfluidic devices.