What Does Convection Heat Transfer Mean?
Convection heat transfer is the process of transfer of heat energy between a surface and a fluid in motion. The transfer takes place from the solid surface to the fluid and is commonly observed in heat exchangers. The dominant form of heat transfer in liquids and gasses is through convection and involves heat diffusion (conduction) and heat transfer (advection) by bulk fluid flow.
Trenchlesspedia Explains Convection Heat Transfer
Convection heat transfer depends on the flow conditions of the fluid and is affected by factors such as fluid velocity, viscosity, heat flux, roughness of the surface and type of flow. Heat transfer by convection can be forced or assisted convection OR natural or free convection. Forced or assisted convection takes place when the flow of a fluid is induced by external factors such as a pump, fan or mixer.
Natural or free convection takes place when a difference in density is induced by temperature variations in the fluid resulting in buoyancy forces. The density change in the boundary layer due to heating causes the fluid to rise and be replaced by cooler fluid that will in turn heat up and rise.