Heat transfer by convection - Essay Example

A square cavity was used whereby its bottom and top walls were insulated. One of the side walls was presumed cold while the other side hot. Alumina/water nanofluid was used as the working fluid. It was concluded that using different thermophysical models might lead to opposite trend estimations for Nusselt number especially in high solid volume fractions. Effects of inclination angle (between 00 and 1200) of a square cavity filled with Cu/water nanofluid on heat transfer (Abu-Nada and Oztop).

The boundary conditions of both experiments were similar. Different water based nanofluids containing Cu, Ag, CuO, Al2O3 and TiO2 nanoparticles were placed in a cavity with volume fraction up to 20%. One side of the walls was heated using heater mounted on the wall; cavity angle varied between 00 and 900 (Ogut). Increased concentration increases heat transfer rate. Average Nusselt number has a high sensitivity to viscosity compared to the thermal conductivity at high Rayleigh numbers; suitable viscosity model should be selected (SAEED ZEINALI HERIS, Masoumeh Borhani Pour, Omid Mahian, Somchai Wongwises, 2014).

Flow of Cu, Al2O3, and TiO2 nanoparticles is suspended in water in a cavity where top and bottom walls are insulated; right wall is kept cold while the left wall is subjected to the periodic heat flux. Use of Cu and TiO2 with volume fractions up to 20% leads to maximum and minimum heat removal from heat source respectively (Ghasemi and Aminossadati). Flow of Cu/water nanofluid (volume fractions up to 5%) in a square cavity and the bottom subjected to constant heat flux while cooling is conducted by entering a nanofluid flow from the left wall and exiting from the right wall (Shahi et al).

It was concluded that an increase in the volume fraction increased the average Nusselt number in the cavity. Lin and Voili simulated the effects of particles size on natural convection flow of Al2O3/water nanofluid with volume fraction up to 5% in square cavity