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Free Convection of Al2O3 and TiO2 Nanofluids in Enclosure with Two Models of Thermal Conductivity
| International Journal of Computer Applications |
| Foundation of Computer Science (FCS), NY, USA |
| Volume 117 - Number 2 |
| Year of Publication: 2015 |
| Authors: Manal Al-hafidh |
10.5120/20528-2868
|
Manal Al-hafidh . Free Convection of Al2O3 and TiO2 Nanofluids in Enclosure with Two Models of Thermal Conductivity. International Journal of Computer Applications. 117, 2 ( May 2015), 29-34. DOI=10.5120/20528-2868
Abstract
This paper presents a numerical study of natural convection of nanofluids contained in horizontal cylindrical annular enclosure filled with porous media and subjected to uniform heat flux along the inner cylinder wall. Governing parameters of the problem under study are the modified Rayleigh number Ra (10 ?Ra*? 500) and the solid volume fraction of nanoparticles (0???0. 3. Two types of nano-particles are taken into consideration Al2O3 and TiO2 with water as the based fluid. Two models are used for calculating the effective viscosity and thermal conductivity of nanofluids. The finite difference approximation and the MATLAB-7 program are used to obtain the results. It is found that Adding 0. 5 percent of TiO2 particles cause to increase the value of the local Nu number to 4. 128 for model 1 and to 3. 748 for model 2. Adding Al2O3 particles of 0. 5 percent volume fraction cause an increase the local Nu to 4. 988 for model 1 and to 4. 542 for model2. A maximum value of the average Nu of TiO2 nanofluid is equal 16. 446 for model1 with ?=0. 5 and Ra* =500, while Nu equal 4. 54 for model 2. A maximum value of the average Nu of 18. 0007 for Al2O3 nanofluid for model 1 and 5. 004 for model 2 is obtained with ?=0. 5 and Ra* =500. A correlation of Nu with Ra* and ? is obtained for Al2O3 nanofluid and TiO2 nanofluid model 1.
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