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An experimental setup has been developed to measure the thermal state of a conical antenna cooled by means of porous media saturated with water-based copper nanofluid. Thermal conductivity of the used porous materials varies between 4 and 41.2 times that of the water which constitutes the base fluid of the nanofluid whose volume fraction ranges from 0% (pure water) to 5%. The antenna is placed in the center of a coaxial concentric cavity of the same shape. Aspect ratio of the enclosure varies between 0.2 and 0.6. Its base is inclined with respect to the horizontal plane with an angle ranging between 0° and 180° corresponding to a horizontal circular base with the top of the cone oriented upwards and downwards, respectively. Measurements validate the calculations obtained in a recent numerical approach based on the finite volume method. They confirm that the Maxwell and Brinkman models remain valid for the ranges of the Rayleigh number considered here (3.32 x 10 5 − 6.74 x 10 7) and Water based-Copper nanofluid volume fraction (0–5%). This work also confirms the effectiveness of porous materials saturated with nanofluids to ensure the thermoregulation of electronic equipment dissipating a large amount of thermal power. [ABSTRACT FROM AUTHOR]

Three-dimensional reconstructions of thermal field in a differentially heated cylindrical cavity with dilute concentrations of nanofluids as the working medium have been reported. Experiments have been conducted in a specially designed tomography cell filled with dilute concentrations of Al2O3 nanofluids with ethylene glycol dimethacrylate (EGD) as the basefluid. The two horizontal walls of the cell have been differentially heated to apply the temperature potential across the fluid layer. Multiple projection data in the form of interferometric images have been recorded at every 20° view angle by slowly turning the cell over the range of 0 to 360°. The two-dimensional temperature fields retrieved through the quantitative analysis of interferometric images recorded at various view angles have been used to reconstruct the complete three-dimensional temperature field at select horizontal planes of the fluid layer. Iterative multiplicative algebraic reconstruction technique (MART) has been employed for tomography reconstructions. Based on the tomography reconstructions, possible fluid movement in the test cavity and the strong dependence of convective field on varying nanofluid concentrations and cavity temperature differences have been explained. Distribution of local temperature fields near the cavity wall surfaces revealed the phenomena of breakdown of large length scale fluid structures into multiple roll-like patterns with increasing concentration of nanoparticles. The distribution of the local Nusselt number, on select horizontal planes near the top and bottom wall surfaces of the cavity, highlighted the possible role of nanoparticles enhancing the heat transfer rates. An overall energy balance in the cavity was also to be seen based on the reconstructions of the local profiles of Nusselt numbers. [ABSTRACT FROM AUTHOR]