The co-current vertical downward flow of a turbulent gas stream and a thin liquid film in a rectangular duct.

This thesis was undertaken to at least partially close the enormous gap which exists in the understanding of the behaviour of liquid films flowing co-currently with a gas stream. A review of previous studies is presented. A theoretical model is established which considers the gas stream to be influenced by both the motion of the film and the “non-smooth” nature of the film surface. The subject experimental investigation of a water film flowing on one face of a vertical rectangular duct is described. Liquid Reynolds numbers in the range 150-1500 and mean air velocities up to 55 fps were encountered Values of mean, maximum and minimum film thickness as well as records of the film surface profiles were obtained by use of a photometric measuring technique