TY - GEN
T1 - Mixing enhancement due to viscoelastic instability in serpentine microchannels at very large Weissenberg numbers
AU - Nolan, Kevin P.
AU - Agarwal, Akshat
AU - Lei, Shenghui
AU - Dalton, Eric
N1 - Publisher Copyright:
© 2016 IEEE.
PY - 2016/7/20
Y1 - 2016/7/20
N2 - The flow of shear-thinning viscoelastic fluids is investigated experimentally in a serpentine microchannel at very large Weissenberg numbers (Wi > 104) undergoing elastic instability. The effects of geometric curvature on local flow instability and the consequent heat transfer enhancement are reported. Unlike previous studies where fluids with large zero-shear viscosities (up to 300 mPa.s) were used, we employ a working fluid with a lower viscosity (η0 = 9 mPa.s) more suited to microfluidic heat transfer applications while exhibiting viscoelastic characteristics. This results in Elasticity number (EI = Wi/Re) flows an order of magnitude larger than previously reported in the literature with apparent viscosities close to the solvent viscosity under flow conditions. Detailed Micro Particle Image Velocimetry (μPIV) measurements reveal the local enhancements due to instantaneous flow structures which result in vigorous local mixing at sub-critical Reynolds numbers. In addition the pressure drop increase is moderate as mixing occurs locally and the flow is maintained undisturbed elsewhere throughout the flow path.
AB - The flow of shear-thinning viscoelastic fluids is investigated experimentally in a serpentine microchannel at very large Weissenberg numbers (Wi > 104) undergoing elastic instability. The effects of geometric curvature on local flow instability and the consequent heat transfer enhancement are reported. Unlike previous studies where fluids with large zero-shear viscosities (up to 300 mPa.s) were used, we employ a working fluid with a lower viscosity (η0 = 9 mPa.s) more suited to microfluidic heat transfer applications while exhibiting viscoelastic characteristics. This results in Elasticity number (EI = Wi/Re) flows an order of magnitude larger than previously reported in the literature with apparent viscosities close to the solvent viscosity under flow conditions. Detailed Micro Particle Image Velocimetry (μPIV) measurements reveal the local enhancements due to instantaneous flow structures which result in vigorous local mixing at sub-critical Reynolds numbers. In addition the pressure drop increase is moderate as mixing occurs locally and the flow is maintained undisturbed elsewhere throughout the flow path.
UR - http://www.scopus.com/inward/record.url?scp=84983371847&partnerID=8YFLogxK
U2 - 10.1109/ITHERM.2016.7517564
DO - 10.1109/ITHERM.2016.7517564
M3 - Conference contribution
AN - SCOPUS:84983371847
T3 - Proceedings of the 15th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2016
SP - 301
EP - 306
BT - Proceedings of the 15th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2016
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 15th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2016
Y2 - 31 May 2016 through 3 June 2016
ER -