Optimisation of film condensation with periodic wall cleaning

This is a theoretical and experimental study of the time-optimisation of condensation on a vertical wall when the film is removed periodically by a mechanical device. The objective is to fine-tune the periodic process so that the production of condensate and the heat transfer rate are maximal. The first part of the paper develops the scales of the periodic condensation process, and predicts the existence of an optimal condensation time interval. The analysis also predicts that the augmentation of condensation increases as the mechanical cleaning time decreases. These design optimisation opportunities are confirmed in the second part of the paper, which reports measurements of steam condensation on a vertical surface scraped periodically.