ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-469-4
ISBN Online: 978-1-56700-470-0
Second Thermal and Fluids Engineering Conference
EFFECT OF NUMBER OF BLOCKS ON THE PERIODIC NATURAL CONVECTION INSIDE AN ENCLOSURE HEATED FROM THE SIDE
Аннотация
Numerical simulation results are reported investigating the effects of placing discrete and disconnected solid
blocks inside an enclosure filled with a fluid undergoing periodic natural convection. The blocks are square,
conductive, distributed uniformly inside the enclosure in a regular "lattice" square pattern, with a fixed solidvolume
fraction – i.e., as the number of blocks inside the enclosure increases, their sizes decrease as to maintain
the same total volume of solid material. The natural convection inside the enclosure is achieved by imposing a
time-periodic and spatially uniform high temperature condition at one of the walls of the enclosure, while the other
wall is maintained at a constant, uniform and low temperature; the horizontal surfaces are set as adiabatic. The
number of blocks varies from 4 to 36, while the solid-volume fraction is kept at 36%. With this small number of
blocks, the natural convection process is modeled using the continuum-approach rather than the porous-continuum
approach for more accurate predictions. Heat transfer results are reported on a parametric form with the Prandtl
number fixed equal to 1, and the Rayleigh number inside the enclosure equal to 104 and 107. The boundary layer
interference phenomenon, observed in constant horizontal heating, is also observed in the case of periodic heating,
and is strongly affected by the number of blocks inside the enclosure. Isotherms and streamlines, together with the
periodic (time-varying) Nusselt number, allows the identification of a singular dynamic behavior within the
investigated parametric range, including the heating and cooling of the enclosure through the heated wall.