Flow Recovery Downstream from Nanoposts Grown at the Wall of a Microchannel

Abstract

In this article, hydraulic responses to a linear array of finite-length nanoposts attached at the bottom wall of square microchannels under viscous flow conditions are investigated with lattice Boltzmann simulations. Different configurations of the array are considered because these changes can directly contribute to flow pattern deformation. Simulation results indicated that the flow structure strongly depends on nanopost height and space between two adjacent nanoposts in the nanopost line but not on the Reynolds number in the range examined. However, if nanoposts are grown far apart from each other, a fully developed velocity profile can be recovered at sufficiently long distance downstream and an empirical correlation for calculating the recovery length is proposed. In the studied low Reynolds number regime, energy loss due to friction drag was found to be inversely proportional to an appropriately defined Reynolds number that accounts for both the channel size and the nanopost aspect ratio.

Keywords:

• drag coefficient
• entry length
• nanopost arrays

ACKNOWLEDGEMENTS

This work was supported by the Department of Energy–funded Center for Applications of Single-Walled Carbon Nanotubes (ER64239-0012293). We also acknowledge support by DOD-EPSCOR: FA9550-10-1-0031. Computations were carried out at the University of Oklahoma Supercomputing Center for Education & Research.

Notes

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/umte.