Thesis
Experimental measurements of thermal conductivity of nanoparticle packed beds
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/101650
Abstract
This thesis presents the fabrication and thermal characterization of packed beds of ceramic and metallic nanoparticles. Methods for measuring the effective thermal conductivity of a packed bed and examining the arrangement of nanoparticles are developed. Experiments are performed using silica and copper nanoparticles at low pressure and atmospheric pressure. Packed beds are formed by pressing nanoparticle powder into a cylindrical mold. This produces packed nanoparticle disks approximately 1.1 mm in height and 6.75 mm in diameter, with a volume fraction around 0.5. SEM images are taken of the disk surface to characterize the sphericity, size and arrangement of nanoparticles. Silica particles are observed to be quite spherical, uniform in size close to 200 nm, and some short range order is visible; whereas, the copper particles are not all spherical, range in size and are packed totally randomly. Thermal conductivity of the packed beds is measured with a steady state apparatus called a guard heated calorimeter. At a reduced air pressure of 0.13 torr and applied load of 42 kPa, the effective thermal conductivity is found to be 0.018 ± 0.007 W/m-K for silica and 0.054 ± 0.006 W/m-K for copper. The similarity of values indicates that the bulk material thermal conductivity, particle size distribution and sphericity have little effect on the effective bed conductivity. The effective conductivity of a copper disk at atmospheric pressure is measured to be 0.33 W/m-K ± 0.024 W/m-K at an applied load of 85 kPa. These measurements are in the same range as v previously published experimental measurements. This work demonstrates a proof of concept for measuring thermal conductivity of packed beds of nanoparticles.
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Details
- Title
- Experimental measurements of thermal conductivity of nanoparticle packed beds
- Creators
- Kevin Douglas Clarke
- Contributors
- Robert F. Richards (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525114501842
- Language
- English
- Resource Type
- Thesis