What is convection in heat transfer?

Convection refers specifically to the process of heat transfer that occurs through the movement of fluids, which can be liquids or gases. In this context, convection involves the transfer of thermal energy by the bulk movement of the fluid itself. As a fluid is heated, it becomes less dense and rises, while cooler, denser fluid moves in to take its place. This movement creates a circulation pattern that effectively transfers heat throughout the fluid.

Understanding convection is critical in commercial drying applications because it helps in controlling and optimizing the drying process. For instance, using fans or blowers can enhance the convection around wet materials to promote quicker moisture evaporation. This process is distinct from other forms of heat transfer, such as conduction, which occurs through direct molecular contact, or radiation, where energy is transferred in the form of electromagnetic waves. Therefore, the definition of convection as energy transferred through the movement of a heated fluid is foundational for understanding how to manage temperature and moisture content effectively in drying scenarios.