Effect of position of a square-shaped heat source on buoyancy-driven heat transfer in a square cavity filled with nanofluid

Buoyancy-driven heat transfer, due to a square-shaped heater placed insidea square cavity lled with tio2-water nanouid, is investigated numerically. the heateris maintained at a constant temperature, th, while the cavity walls are kept at a lowerconstant temperature, tc. the governing equations are solved using the nite volumemethod and the simpler algorithm. the simulations are performed for six dierentpositions of the heat source inside the cavity, a range of rayleigh numbers from 103 to 106,and dierent volume fractions of the nanoparticles. the ratio of the height (width) of theheat source to that of the cavity is taken as 0.2. the results shows that the uid ow andheat transfer characteristics inside the cavity strongly depend on the location of the heatsource. for ra = 103, i.e. a conduction-dominated heat transfer regime, maximum heattransfer rate is achieved by placing the heat source close to the corners of the cavity, while,for ra = 106, positioning the heat source near the middle of the cavity's bottom wall yieldsthe maximum average nusselt number. moreover, it is observed that the average nusseltnumber is generally an increasing function of the volume fraction of the nanoparticles.