AERODYNAMICALLY-DRIVEN CONDENSATE LAYER THICKNESS DISTRIBUTIONS ON ISOTHERMAL CYLINDRICAL SURFACES

A simple yet rather general mathematical model is presented for predicting the distribution of condensate layer thickness when aerodynamic shear is the dominant mechanism of liquid flow along the surface. The Newtonian condensate film is treated using well-known "thin layer" ( lubrication theory) approximations, and condensate supply is taken to be the result of either convective-diffusion (Sc = 0(1) or Sc >> 1), or inertial impaction. Illustrative calculations of the angular distribution of steady-state condensate layer thickness on a circular cylinder in a high Reynolds number cross flow (Re = 10(5)) reveal the consequences of alternate condensate arrival mechanisms and the existence of thicker reverse-flow films behind the position of gas boundary layer separation. However, separation points are singular points in the present theory, which deliberately neglects body-force and surface tension phenomena. The present formulation is readily generalized to include transient liquid layer flows on non-circular objects of variable surface temperature, as encountered in turbine blade materials testing or operation.