Convection
Convection heat transfer takes place by the movement of flow and its coming into contact with a body. The quantity of transfered energy depends on the velocity, the temperature and the material property of the flow and the body.
The heat transfer by convection is described by the following equation:
Q = α ∙ A ∙ ( TA - TB )
α = Coefficient of heat transfer [W / ( m² ∙ K) ]
A = Area of heat transfer [m²]
TA - TB = Difference in temperature between involved mediums [K]
Some typical coefficients of heat transfer [W / ( m² ∙ K)]:
| Air, stationary at a steel wall | 03 - 35 |
| Air with little velocity at a steel wall | 23 - 0 |
| Air with high velocity at a steel wall | 58 - 290 |
| Water in a vessel | 580 - 2300 |
| Water, flowing | 2300 - 4700 |
| Steam, condensing | ca. 11600 |