Stability of nanofluids in quiescent and shear flow fields
Sanjeeva Witharana1, Haisheng Chen, Yulong Ding
1Institute of Particle Science and Engineering, University of Leeds, Leeds LS2 9JT, UK. pmsw@leeds.ac.uk.
Nanoscale Research Letters
|June 30, 2011
Summary
Titanium dioxide nanoparticle suspensions (nanofluids) show stable structures up to 60°C and within specific shear rates. This research clarifies heat transfer mechanisms in nanofluids.
Area of Science:
- Materials Science
- Nanotechnology
- Fluid Dynamics
Background:
- Nanofluids, suspensions of nanoparticles in base fluids, offer enhanced thermal properties.
- Ethylene glycol-based titanium dioxide nanofluids are promising for heat transfer applications.
- Understanding nanofluid structural stability is crucial for predicting their thermophysical behavior.
Purpose of the Study:
- To investigate the structural stability of ethylene glycol-based titanium dioxide nanoparticle suspensions.
- To determine the influence of particle concentration, temperature, shear rate, and duration on nanofluid stability.
- To provide insights into the thermal conduction and convective heat transfer mechanisms of nanofluids.
Main Methods:
- Preparation of titanium dioxide nanofluids using a two-step method.
- Characterization of particle size and thermal conductivity in a quiescent state.
- Shear stability tests conducted over a range of temperatures, shear rates, and durations.
Main Results:
- Particle size and thermal conductivity measurements indicated stable aggregates at temperatures up to 60°C.
- Shear stability tests revealed that nanoparticle aggregate structures remain stable within a shear rate interval of 500-3000 s-1.
- Stability was confirmed across a temperature range of 20-60°C under tested shear conditions.
Conclusions:
- Ethylene glycol-based titanium dioxide nanofluids exhibit significant structural stability under specific temperature and shear conditions.
- The findings contribute to resolving debates regarding the heat transfer mechanisms in nanofluids.
- This study provides essential data for the practical application of these nanofluids in thermal systems.
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