Thermal conductivity of dry anatase and rutile nano-powders and ethylene and propylene glycol-based TiO2 nanofluids |
| |
| Institution: | 1. Faculty of Mechanical Engineering/Automotive Engineering Centre, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia;2. School of Mechanical Engineering, Ningxia University, China;3. Centre for Energy Studies, Department of Mechanical Engineering, JNTUH College of Engineering Kukatpally, Hyderabad 500085, India;1. Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Isfahan, Iran;2. Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut''s University of Technology Thonburi, Bangmod, Bangkok 10140, Thailand;3. Faculty of Mechanical Engineering, Semnan University, P.O. Box 35131-19111, Semnan, Iran;4. Department of Mechanical Engineering, Semnan Branch, Islamic Azad University, Semnan, Iran;5. Young Researchers and Elite Club, Mashhad Branch, Islamic Azad University, Mashhad, Iran;6. Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia |
| |
| Abstract: | Thermal conductivity behaviour was studied for two TiO2 nano-powders with different nanocrystalline structures, viz. anatase and rutile, as well as nanofluids formulated as dispersions of these two oxides up to volume concentrations of 8.5% in two different glycols, viz. ethylene and propylene glycol. Because it is known that titanium dioxide can exhibit three different crystalline structures, the dry nano-powders were analysed using X-ray Diffraction to determine the nanocrystalline structure of the powders. Two different techniques were employed in the thermal conductivity study of the materials. Dry nano-powders, with and without compaction, were analysed at room temperature by using a device based on the guarded heat flow meter method. Nanofluids and base fluids were studied with a transient hot wire technique over the temperature range from (283.15 to 343.15) K. The base fluid propylene glycol was measured by using both techniques in order to verify the good agreement between both sets of results. The experimental measurements presented in this work were compared with other literature data for TiO2 nanofluids in order to understand the thermal conductivity enhancement as a function of nanoparticle concentration. Different theoretical or semi-theoretical approaches such as Maxwell, Peñas et al., Yu-Choi were evaluated comparing with our experimental values. A parallel model was used to predict thermal conductivities employing experimental values for dry nanopowder. |
| |
| Keywords: | Anatase Rutile Ethylene glycol Propylene glycol Thermal conductivity |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
