Condensation Number
or
The Condensation number (Co) is a dimensionless parameter used in fluid dynamics to characterize the relative importance of heat transfer due to conduction to that due to condensation during phase change processes. It’s particularly relevant in the analysis of condensation phenomena, such as in heat exchangers, refrigeration systems, and atmospheric science.
Condensation number is used in heat transfer in general and as the name implies in condensation calculations in particular. It is normally defined in one of the following forms :
Where: | ||
delta-T | = | Temperature difference |
lambda | = | Latent heat |
g | = | Gravitational acceleration |
h | = | Heat transfer coefficient |
k | = | Thermal Conductivity |
L | = | Characteristic length |
mu | = | Viscosity |
rho | = | Density |
The Condensation number helps determine whether heat transfer is primarily controlled by conduction through the solid wall or by convection and condensation at the fluid-solid interface. Depending on the value of the Condensation number, different heat transfer regimes can be identified:
- If Co ≪ 1, conduction through the solid wall dominates over convection and condensation at the interface. This typically occurs when the thickness of the fluid film is relatively small compared to the thermal conductivity of the solid wall.
- If Co ≫ 1, convection and condensation at the interface dominate over conduction through the solid wall. This typically occurs when the thickness of the fluid film is relatively large compared to the thermal conductivity of the solid wall.
The Condensation number is an important parameter in the design and analysis of heat transfer systems involving condensation, providing insights into the relative contributions of different heat transfer mechanisms.
