Nonlinear stability of forced vapour flow condensation (Q1115265)

Nonlinear stability of a liquid condensate film flowing on an inclined isothermal surface and adjacent to a flowing pure vapour is investigated by the method of multiple scales. Results from the analysis are discussed for the special class of forced flow steam condensation on vertical surfaces, under horizontal surfaces, and above horizontal surfaces. It is found that increasing cocurrent steam velocity has a stabilizing effect on thin condensate films flowing on vertical surfaces and under horizontal surfaces when the vapour velocities are small. It is also found that thin condensate films flowing above horizontal surfaces under the action of cocurrent low velocity forced steam flow are stable with respect to both infinitesimal and finite amplitude disturbances but become unstable at high vapour velocities.