nPIV velocity measurement of nanofluids in the near-wall region of a microchannel
Colloidal suspensions of nano-sized particles in a base fluid, nanofluids, have recently gained popularity as cooling fluids mainly due to their enhanced heat transfer capabilities. However, there is controversy in the literature on the reported properties of nanofluids and their applicability, espe...
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2012
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| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433388/ |
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pubmed-34333882012-09-05 nPIV velocity measurement of nanofluids in the near-wall region of a microchannel Anoop, Kanjirakat Sadr, Reza Nano Express Colloidal suspensions of nano-sized particles in a base fluid, nanofluids, have recently gained popularity as cooling fluids mainly due to their enhanced heat transfer capabilities. However, there is controversy in the literature on the reported properties of nanofluids and their applicability, especially since there is no fundamental understanding that explains these enhancements. A better understanding of these fluids and how they interact with a solid boundary may be achieved by a detailed near-wall fluid flow study at nanoscale. This work presents for the first time the near-wall velocity measurements for nanofluids using nanoparticle image velocimetry. This novel technique uses evanescent illumination in the solid–fluid interface to measure near-wall velocity field with an out-of-plane resolution on the order of O(100 nm). Nanofluids of different concentrations were prepared by dispersing silicon dioxide particles (10 to 20 nm) in water as the base fluid. Initially, viscosity measurements were conducted for the prepared nanofluids. The near-wall velocity data were then measured and compared with that of the base fluid at the same flow condition. It was observed that even though nanofluid viscosity had increased with particle loading, the near-wall velocity values were similar to that of the base fluid for a given flow rate. Together, these measurements vindicate the homogenous and Newtonian characteristics of the nanofluids in the near-wall region. Despite the low particle concentrations investigated, the present work also discusses the complexity involved in utilizing the methodology and possible errors arising during experimentation so as to implement this measurement tool more effectively in the future. Springer 2012-05-31 /pmc/articles/PMC3433388/ /pubmed/22651240 http://dx.doi.org/10.1186/1556-276X-7-284 Text en Copyright ©2012 Anoop and Sadr; licensee Springer. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
| repository_type |
Open Access Journal |
| institution_category |
Foreign Institution |
| institution |
US National Center for Biotechnology Information |
| building |
NCBI PubMed |
| collection |
Online Access |
| language |
English |
| format |
Online |
| author |
Anoop, Kanjirakat Sadr, Reza |
| spellingShingle |
Anoop, Kanjirakat Sadr, Reza nPIV velocity measurement of nanofluids in the near-wall region of a microchannel |
| author_facet |
Anoop, Kanjirakat Sadr, Reza |
| author_sort |
Anoop, Kanjirakat |
| title |
nPIV velocity measurement of nanofluids in the near-wall region of a microchannel |
| title_short |
nPIV velocity measurement of nanofluids in the near-wall region of a microchannel |
| title_full |
nPIV velocity measurement of nanofluids in the near-wall region of a microchannel |
| title_fullStr |
nPIV velocity measurement of nanofluids in the near-wall region of a microchannel |
| title_full_unstemmed |
nPIV velocity measurement of nanofluids in the near-wall region of a microchannel |
| title_sort |
npiv velocity measurement of nanofluids in the near-wall region of a microchannel |
| description |
Colloidal suspensions of nano-sized particles in a base fluid, nanofluids, have recently gained popularity as cooling fluids mainly due to their enhanced heat transfer capabilities. However, there is controversy in the literature on the reported properties of nanofluids and their applicability, especially since there is no fundamental understanding that explains these enhancements. A better understanding of these fluids and how they interact with a solid boundary may be achieved by a detailed near-wall fluid flow study at nanoscale. This work presents for the first time the near-wall velocity measurements for nanofluids using nanoparticle image velocimetry. This novel technique uses evanescent illumination in the solid–fluid interface to measure near-wall velocity field with an out-of-plane resolution on the order of O(100 nm). Nanofluids of different concentrations were prepared by dispersing silicon dioxide particles (10 to 20 nm) in water as the base fluid. Initially, viscosity measurements were conducted for the prepared nanofluids. The near-wall velocity data were then measured and compared with that of the base fluid at the same flow condition. It was observed that even though nanofluid viscosity had increased with particle loading, the near-wall velocity values were similar to that of the base fluid for a given flow rate. Together, these measurements vindicate the homogenous and Newtonian characteristics of the nanofluids in the near-wall region. Despite the low particle concentrations investigated, the present work also discusses the complexity involved in utilizing the methodology and possible errors arising during experimentation so as to implement this measurement tool more effectively in the future. |
| publisher |
Springer |
| publishDate |
2012 |
| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433388/ |
| _version_ |
1611554071739629568 |