Convection-Fluent-Thesis

CONVECTION: Free (natural) and Forced Convection.
-Heat energy transferred between a surface and a moving fluid at different temperatures is known as convection.

-In reality this is a combination of diffusion and bulk motion of molecules.

-Near the surface the fluid velocity is low, and diffusion dominates.

-Away from the surface, bulk motion increase the influence and dominates.

-Convective heat transfer may take the form of either forced or assisted convection and natural convection

-Natural convection is caused by buoyancy forces due to density differences caused by temperature variations in the fluid.

-In FLUENT:

#use Bousinessq Parameters (Bousinessq Model) to consider Bouyancy effects .
#the default operating temperature is setting under Boussinesq Parameters.
#it is tempting to specify an operating density here too, but the help panels say that it is not necessary to specify operating density when using the Boussinesq approximation.

-So?, For thesis: The air movement in any zone in RSC areas is normally promoted by temperature difference between warm zones (4th ventilating lids @ 0.6 m x 0.6m) and cold zone (ambient temperature about 26.7oC (Promptong and Tekasakul, 2007)) under natural convection situations, and/or by pressure difference due to wind or mechanical ventilation (about 7th pressure outlet). It is known that the airflow pattern plays a fundamental role in the deposition, migration and distribution of aerosol particles in the multi-zone area (Lu and Howart, 1996). During particle transport due to convection/advection particles are transported by directed macroscopic movements ín the gas (fluid,air) phase. So, driving force is the drag force a moving gas exerts on a dispersed particle. In steady state and in the absence of external forces, the particle velocity is equal to the gas velocity. The convective particle flux is equal to: