This study experimentally investigates non-uniform particle distributions and evaporation characteristics of nanofluid droplets containing 50 nm average diameter alumina (Al2O3) particles, on a hydrophilic glass surface. Using an inverted microscope, the size distribution of aggregated nanoparticles was visualized and analyzed at different sight-of-view locations. From the digital images captured using CMOS cameras and a magnifying lens, the effect of particle concentrations on droplet evaporation rates was examined. In particular, in order to understand the significance of the early stage of droplet evaporation, the dynamics of a corresponding triple line were visualized using a high-speed imaging technique. From the results, it was found that as the volume fraction of nanoparticles in nanofluids increased the total evaporation time and the initial contact angle decreased, while the corresponding perimeter of the droplet increased. Local aggregation was observed when a nanofluid droplet was in contact on the surface, suggesting that the non-homogeneous characteristics should be considered in estimating thermal conductivity of a nanofluid droplet.
|Number of pages||9|
|Journal||International Journal of Heat and Mass Transfer|
|Publication status||Published - 2014 May|
Bibliographical noteFunding Information:
This work was sponsored by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0016837). Also, this work was supported by the Ministry of Trade, Industry & Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy ( No. 20114030200020 ). This research was sponsored, in part, by a Michigan Technological University Research Initiation Grant and by the Multi-Scale Technologies Institute (CKC).
- Nanofluid thin layer
- Spatial non-uniformity
- Total evaporation time
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes