| Autor: |
Alsboul M; Physics Department, College of Science, Al Hussein Bin Talal University, Maan 71111, Jordan.; Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Terengganu 21030, Malaysia., Ghazali MSM; Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Kuala Terengganu 21030, Malaysia., Gomaa MR; Mechanical Engineering Department, Faculty of Engineering, Al Hussein Bin Talal University, Maan 71111, Jordan.; Mechanical Engineering Department, Benha Faculty of Engineering, Benha University, Benha 13512, Egypt., Albani A; Renewable Energy & Power Research Interest Group (REPRIG), Eastern Corridor Renewable Energy (ECRE), Faculty of Ocean Engineering Technology and Informatics, Universiti Malaysia Terengganu, Kuala Terengganu 21030, Malaysia. |
| Abstrakt: |
Solid particles scattered in a base fluid for a standard no larger than 100 nm, constituting a nanofluid, can be used to improve thermophysical characteristics compared to the base fluid. In this study, theoretical and experimental investigations were carried out to estimate the density, viscosity, and effective thermal conductivity of Co 3 O 4 in distilled water (DW), ethylene glycol (EG), and DW-EG mixture nanofluids. Co 3 O 4 nanoparticles with diameters of 50 nm were dispersed in different base fluids (i.e., EG, DW, 60EG:40DW, 40EG:60DW, 20EG:80DW) with varying concentrations of 0.025-0.4 vol.%. Thermal conductivity was estimated by the hot-wire technique, and viscosity was determined using a viscometer apparatus. According to the measurements, the viscosity of Co 3 O 4 nanofluids decreased with increasing temperature, and increased with increasing volume fraction. The results revealed that the thermal conductivity of Co 3 O 4 nanofluids increased with increasing temperature and volume concentrations. Moreover, the measurements found that the maximum thermal conductivity of 10.8% and the maximum viscosity of 10.3% prevailed at 60 °C in the volume fraction of 0.4%. The obtained viscosity and thermal conductivity results of the present experiments on Co 3 O 4 nanofluids were compared with previous results. The results showed good agreement with theoretically proposed models to predict nanofluids' viscosity and thermal conductivity. Thus, the thermal conductivity results of Co 3 O 4 nanofluids are promising with respect to the use of nanofluids in solar thermal applications. |
