Thermal conductivity and dynamic viscosity of aqueous-silver nanoparticle dispersion J. Sunil, M. Dhayanithi Pooja, R. Ginil, S.N. Alex, A. Ajith Pravin Department of Mechanical Engineering, V V College of Engineering, Tisaiyanvilai, Tirunelveli, Tamilnadu, India article info Article history: Received 12 April 2020 Accepted 21 April 2020 Available online xxxx Keywords: Silver nanofluids Dispersion stability Thermal conductivity Dynamic viscosity Distilled water abstract In this study, the silver nanoparticles are dispersed into the distilled water which is miscible with dis- tilled water at any ratio and has excellent dispersion stability at room temperature. The temperature dependent thermal conductivity and dynamic viscosity of the silver nanofluids are estimated by KD2 pro thermal conductivity analyzer and digital viscometer, respectively. The results show that the silver nanofluids exhibits enhanced thermal conductivity and viscosity than the base fluids for the measured temperature range. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Confer- ence on Newer Trends and Innovation in Mechanical Engineering: Materials Science. 1. Introduction A homogeneous suspension of metallic or non-metallic particles below 100 nm in size into a conventional base fluid, usually termed as nanofluid, habitually shows an outstanding enhancement in thermo-physical characteristics. The well dispersed nanoparticles within nanofluids undergo Brownian motion and frequently collide with the heat source. During these collisions, rapid heat exchange occurs between the nanoparticles and heat source within few picoseconds, which almost instantaneously raises or drops the temperature of the nanoparticles [1]. This concept of nanofluid is first reported by Michael Faraday (1857) in the study on the syn- thesis and colors of colloidal gold, but it was possible to put it into practice only after the tremendous development of nanotechnolo- gies during the last decade [2]. It has been shown that nanofluids containing a small amount of metallic or nonmetallic particles, such as Al, Al 2 O 3 , CuO, Cu, Ni, NiO, NiO 2 , SiO 2 , TiO 2 , SiC, ZnO have increased thermal conductivity and dynamic viscosity compared with that of the base fluid. Based on the reviewed studies, various factors affect thermal conductiv- ity of nanofluids such as temperature, the shape of nanoparticles, concentration and etc. Results indicated the increase in tempera- ture and concentration of nanoparticles usually leads to the higher thermal conductivity and viscosity of nanofluids [3–29]. In this study, the silver nanoparticles are dispersed into the dis- tilled water which is miscible with distilled water at any ratio and has excellent dispersion stability at room temperature. The tem- perature dependent thermal conductivity and dynamic viscosity of the silver nanofluids are estimated by KD2 pro thermal conduc- tivity analyzer and digital viscometer, respectively. 2. Materials and methods In this study, the colloidal silver is made of tiny silver nanopar- ticles dispersed into the distilled water. This is colloidal silver is miscible with distilled water at any ratio and has excellent disper- sion stability at room temperature. The specifications and proper- ties of silver nanofluids are Silver concentration: 10 wt%, Density: 1.1 kg/m 3 and the dispersion stability of about 12 months at room temperature. Further, the temperature dependent thermal conduc- tivity and dynamic viscosity of the silver nanofluids are estimated by KD2 pro thermal conductivity analyzer and digital viscometer, respectively. 3. Results and discussion The Electron microscope image of agpure silver nanoparticles is shown in Fig. 1 in which the average dimension of the mean silver particle size is observed as 15 nm. The temperature dependent thermal conductivity of distilled water and silver nanofluids are estimated through the KD2 pro https://doi.org/10.1016/j.matpr.2020.04.575 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Newer Trends and Innovation in Mechanical Engineering: Materials Science. E-mail address: sunil@vvcoe.org (J. Sunil) Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: J. Sunil, M. Dhayanithi Pooja, R. Ginil et al., Thermal conductivity and dynamic viscosity of aqueous-silver nanoparticle dispersion, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.04.575