Which type of convection relies on mechanical means to move a fluid to increase heat transfer?

The correct choice is that forced convection relies on mechanical means to move a fluid, enhancing heat transfer. In forced convection, an external force, such as a fan or pump, actively circulates the fluid. This movement increases the rate at which heat is transferred between the fluid and its surroundings, making it more efficient for applications where rapid heating or cooling is necessary, such as in heating, ventilation, and air conditioning systems.

Unlike natural convection, where fluid movement occurs due to buoyancy differences caused by temperature variations, forced convection allows for a controlled and often more effective means of heat transfer. Passive convection relies purely on these natural buoyancy forces, while thermal convection is a broader term often used interchangeably with natural convection.