4. Nusselt Theory of Laminar Film Condensation

Nusselt made the following assumptions, in deriving the expression for heat transfer coefficient for condensation:

  • The vapour is at rest and does not offer any shear at the interface.

  • The flow of liquid is only by gravity and viscosity (no shear at the interface).

  • The acceleration of liquid film (inertia) is negligible.

  • Heat transfer is by pure conduction across the film.

  • Properties are constant across the film and there is no interface resistance.

  • The vapour is at saturation temperature.