HEAT-TRANSFER TO A HORIZONTAL DISC USING A BUOYANCY-INDUCED JET

A study of the buoyancy-induced flow from a hot vertical tube impingin g on a cold horizontal disc has been carried out. This geometry is ana logous to a single pan biomass stove, with a vertical tube followed by a horizontal radial diffuser. Flow visualization experiments have bee n conducted to observe the flow in the diffuser. These visualizations show a recirculation zone at the entrance of the diffuser whose size d epends on the diffuser spacing. A numerical simulation of the system h as been carried out using a finite difference technique to study the d ependence of fluid flow and heat transfer on Grashof number and the ge ometrical parameters. The details of the buoyancy induced flow structu re are elucidated. The size of recirculation zone and the flow pattern in the diffuser predicted by the calculations is similar to those obs erved in experiments. The spacing between the diffuser discs is found to have a strong influence on the flow pattern, mass flow and heat tra nsfer to the horizontal disc. The outer radius of the diffuser mainly affects the total heat transfer to the disc.