Unsteady Natural Convection in Condenser tank containing Al2O3–DI Water Nanofluids (original) (raw)

The effect on natural convection in a condenser tank containing Al 2 O 3-DI water nanofluids is studied. The tank is located on one end of a copper pipe whose other end is heated electrically. The nanofluids are prepared by twostep method by dispersing non-metallic oxide Al 2 O 3 particles of 32 nm in DI water at volume fractions of 0.05, 0.1 and 0.15%. The analytical and experimentally obtained thermo-physical properties of the nanofluids are within the acceptable limits. Unsteady temperature profiles in the pipe and the condenser tank are plotted. The use of nanofluids in the condenser enhances the conduction heat transfer in the pipe and the convection in the fluid. The thermal resistance of the pipe with nanofluids in the condenser tank is lower than DI water. A higher Nusselt number is obtained for the nanofluids and the corresponding Rayleigh number is lower. Keywords Natural convection Á Al 2 O 3-DI Water nanofluids Á Condenser tank Nomenclature A Cross-sectional area (mm 2) c p Specific heat (J kg K-1