Numerical simulation of flow through microchannels with designed roughness

A three-dimensional numerical simulation of flow through serpentine microchannels with designed roughness in form of obstructions placed along the channels walls is conducted here. CFD-ACE+ is used for the numerical simulations. The effect of the roughness height (surface roughness), geometry, Reynolds number on the friction factor is investigated. It is found that the friction factor increases in a nonlinear fashion with the increase in obstruction height. The friction factor is more for rectangular and triangular obstructions and it decreases as the obstruction geometry is changed to trapezoidal. It is observed that the obstruction geometry, i.e., aspect ratio plays an important role in prediction of friction factor in rough channels. It is also found that the pressure drop decreases with the increase in the roughness pitch. Hence, the roughness pitch is an important design parameter for microchannels.

[1]  G. Mala,et al.  Pressure-driven water flows in trapezoidal silicon microchannels , 2000 .

[2]  J. Koo,et al.  Analysis of surface roughness effects on heat transfer in micro-conduits , 2005 .

[3]  G. Croce,et al.  Numerical analysis of roughness effect on microtube heat transfer , 2004 .

[4]  Dongqing Li,et al.  Flow characteristics of water in microtubes , 1999 .

[5]  S. Kandlikar,et al.  Characterization of surface roughness effects on pressure drop in single-phase flow in minichannels , 2005 .

[6]  A. D. Young,et al.  An Introduction to Fluid Mechanics , 1968 .

[7]  J. Koo,et al.  Computational Analysis of Wall Roughness Effects for Liquid Flow in Micro-Conduits , 2004 .

[8]  S. Kandlikar,et al.  EFFECTS OF REPEATING MICROSTRUCTURES ON PRESSURE DROP IN RECTANGULAR MINICHANNELS , 2005 .

[9]  W. Janna,et al.  Introduction to Fluid Mechanics , 2012 .

[10]  Bimlesh Kumar,et al.  Friction Factor For Pipe Flow: Basic Formulations , 2007 .

[11]  M. Yovanovich,et al.  Pressure Drop of Fully-Developed, Laminar Flow in Microchannels of Arbitrary Cross-Section , 2006 .

[12]  G. Peterson,et al.  Convective heat transfer and flow friction for water flow in microchannel structures , 1996 .

[13]  Carsten Werner,et al.  Influence of Three-Dimensional Roughness on Pressure-Driven Flow Through Microchannels , 2003 .

[14]  C F Colebrook,et al.  TURBULENT FLOW IN PIPES, WITH PARTICULAR REFERENCE TO THE TRANSITION REGION BETWEEN THE SMOOTH AND ROUGH PIPE LAWS. , 1939 .

[15]  Majid Bahrami,et al.  Pressure Drop of Fully Developed, Laminar Flow in Rough Microtubes , 2006 .