Question

Why does the heat transfer coefficient increase with velocity?

Answer 1

Explanation:

1. Heat transfer-The movement of heat from one place to another by conduction, convection, or radiation is called heat transfer.
2. Heat transfer coefficient-It is the heat transferred per unit area per kelvin.
3. It is denoted by $h$.
4. $h=\frac{q}{\Delta T}$, $q$=heat flux density & $\Delta T$ = temperature difference in kelvin.
5. The heat transfer coefficient is directly proportional to the velocity of the liquid.
6. That is, it increases with an increase in the velocity of the liquid.
7. This is because, when the velocity of the liquid increases, many eddies are formed.
8. Eddies have an irregular and different flow compared to the normal flow of liquid.
9. Eddies are circular movements formed in a liquid. They cause whirlpools.
10. With an increase in velocity the fluid gains more energy, which causes its path to change and form eddies.
11. Eddies are responsible for the transfer of heat.

The above-mentioned points are the reason for the increase in heat transfer coefficient with an increase in velocity.