Abstract

Jets of liquid are widely used to distribute cleaning solution and promote removal of soiling layers from the walls of reactor vessels, storage tanks and even military vehicles. Whereas the flow patterns created by liquid jets impinging normally downwards on flat plates has been studied from before the speaker was born, little attention has been paid to the case of liquid jets impinging on vertical or inclined walls, and despite the fact that this is familiar to at least half the population as the flow in a urinal.

This seminar will describe how a robust and accurate model describing these flow patterns has been developed based on a relatively simple momentum balance. The influence of surfactants and the nature of the wall have also been studied. The tendency of the draining film to split or form a falling sheet can also be predicted. This information is then used to construct quantitative models for the rate of cleaning of soft solid layers from the wall, not only when the jet is static but also when it is moving.