Flujo En Microcanal

International Journal of Heat and Mass Transfer 49 (2006) 815–824 www.elsevier.com/locate/ijhmt

Review

Characterization of liquid flows in microfluidic systems
Tuba Bayraktar
a b

a,*

, Srikanth B. Pidugu

b

Department of Chemical Engineering, School of Engineering and Technology, Hampton University, Hampton, VA 23668, United States Department of Engineering Technology, DonagheyCollege of Information Science and Systems Engineering, University of Arkansas at Little Rock, Little Rock, AR 72204, United States Received 15 September 2005; received in revised form 8 November 2005 Available online 10 January 2006

Abstract The microfluidic devices have recently attracted tremendous interest due to their potential of bringing novel applications into reality in many areasincluding biomedical industry. However, the challenges in the design of microfluidic devices still remain since all aspects of fluid flow in microchannels have not been yet fully understood. This paper presents major findings in the literature on fundamentals of flow physics in microchannels. The review is intended to provide an extensive overview on the available knowledge base as well as the areas thatrequire intensive investigation. It includes studies on both pressure-driven and electro-osmotic flows in microchannels. Ó 2005 Elsevier Ltd. All rights reserved.
Keywords: Microchannels; Electroosmotic flows; Pressure measurements; Joule heating; Miniaturization

Contents 1. 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . Theory of miniaturization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Types of flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Microchannels cross-sections and entrance effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4. Pressure drop and friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5. Flow control in microchannels . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6. Mixing in microchannels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7. Joule heating and viscous dissipation effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Velocimetry techniques for microchannelflows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. PIV measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Velocimetry techniques using dye tracers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Future directions inmicrofluidics research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....