What is convective heat transfer?
Convection involves the transfer of heat by the motion and mixing of “macroscopic” portions of a fluid (that is, the flow of a fluid past a solid boundary). The term natural convection is used if this motion and mixing is caused by density variations resulting from temperature differences within the fluid. The term forced convection is used if this motion and mixing is caused by an outside force,such as a pump. The transfer of heat from a hot water radiator to a room is an exampe of heat transfer by natural convection. The tansfer of heat from the surface of a heat exchanger to the bulk of a fluid being pumped through the heat exchanger is an example of forced convection.
