Laminar Film Condensation on a Porous Vertical Wall With Uniform Suction Velocity

A perturbation method developed by Chen for laminar film condensation on a vertical, constant-temperature wall, taking into account condensate subcooling and vapor drag, is refined and extended to the case where some of the condensate is sucked off at constant velocity through a porous wall. The refinement consists of a single, rather than a double, power-series expansion in the heat capacity and the acceleration parameters. The extension consists of an exact solution of the Nusselt problem with constant suction velocity, followed by a perturbation procedure to take into account the heat capacity and acceleration effects. The results show that substantial increases in heat transfer can be effected in this manner, especially at high Prandtl numbers.