Mixed convection in straight and curved channels with buoyancy orthogonal to the forced flow

Laminar heat transfer in the “MLLM” static mixer

“…There is no consensus on the effect of mixed convection inside a heat exchanger, especially in a complex geometry as the MLLM. Nevertheless, referring to more classical situations like straight channels, it was found by Ligrani and Choi [41] that buoyancy effects become effective when the Richardson number is higher than 50, for a Péclet number of 240. Besides, they observed that Nusselt numbers systematically decrease when Ri is increased at a fixed Reynolds number that is consistent with present experimental results which show lower Nusselt numbers for the first element of the MLLM compared to the Graetz analytical solution when Pe < 200.…”

Heat Transfer Enhancement Using Cu-Water Nanofluid in an Enclosure with Moving Cold Sidewalls

“…As such an innovative way in improving thermal conductivities of a fluid is to suspend metallic nanoparticles within it. The resulting mixture referred to as a nanofluid possesses a substantially large thermal conductivity compared to that of the traditional fluids [1]. There are a number of studies on the convective heat transfer in enclosures filled with a nanofluid [2][3].…”

“…Depending on their relative directions to the direction of inertia-driven flow, the buoyancy forces may aid or oppose the forced flow, causing an increase or decrease in heat transfer rates. Mixed convection in straight and curved channels was investigated by Ligrani and Choi [1] when buoyant forces were perpendicular to the bulk flow direction. Four different regimes of behaviours were defined depending on the values of Re and Ri.…”