According to nature of flow, convective heat transfer is classified into natural convection and forced convection. By taking specific examples, explain how the natural convection and forced convection arises in them.
According to nature of flow, convective heat transfer is classified into natural convection and forced convection. By taking specific examples, explain how the natural convection and forced convection arises in them.
Natural convection and forced convection are to be explained with the help of some examples.
NATURAL CONVECTION:-
It is the convective mode of heat transfer in which the motion of fluid does not occur due to the presence of any external force. It is also known as free convection.
Gravity is the main driving force here.
The density difference makes the process to occur by natural convection.
EXAMPLES OF NATURAL CONVECTION:-
1. HEATING OF SOLUTION IN A BEAKER:-
In laboratories, when heat is applied to a solution placed in a beaker, liquid present at the bottom gets heat at first and there is a decrease in the density of the liquid.
The liquid present at the upper end of beaker is at a lower temperature and has high density.
Due to this difference in the density of the liquid, a buoyant force comes into the foreplay where lighter liquid at bottom moves up while the heavier one moves downward and thus a free convection current is created.
The flow is natural convection as the flow is free from any type of mechanical device or external force.
2. MELTING OF ICE:-
Ice loses its temperature to the surrounding air and thus changes to the liquid form from the solid form without any type of external agent.
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