>>10915118Do you understand heat conduction/diffusion? Convection is the combination of conduction and advection. Heat transfer by advection is simply heat transfer due to a portion of fluid being displaced by a flowing fluid of different temperature. In convection, since both phenomena occur simultaneously, you have bigger local gradients (due to cold or hot fluid being displaced), leading to more heat transfer by conduction.
Notice that some authors don't like the concept of advection, because it nevers occurs alone, conduction is always present due to temperature gradient created by advection. But the important thing to understand is that flowing fluid increases local temperature gradients.
