The results of free convection heat transfer investigation from a horizontal, uniformly heated tube immersed in a nanofluid are presented. Experiments were performed with five base fluids, i.e., ethylene glycol (EG), distilled water (W) and the mixtures of EG and water with the ratios of 60/40, 50/50, 40/60 by volume, so the Rayleigh (Ra) number range was 3 104 Ra 1.3 106 and the Prandtl (Pr) number varied from 4.4 to 176. Alumina (Al2O3) nanoparticles were tested at the mass concentrations of 0.01, 0.1 and 1%. Enhancement as well as deterioration of heat transfer performance compared to the base fluids were detected depending on the composition of the nanofluid. Based on the experimental results obtained, a correlation equation that describes the dependence of the average Nusselt (Nu) number on the Ra number, Pr number and concentration of nanoparticles is proposed.
Authors
- mgr Dorota Sawicka,
- prof. dr hab. inż. Janusz Cieśliński link open in new tab ,
- Slawomir Smolen
Additional information
- DOI
- Digital Object Identifier link open in new tab 10.3390/en14102909
- Category
- Publikacja w czasopiśmie
- Type
- artykuły w czasopismach
- Language
- angielski
- Publication year
- 2021
