THE PROPULSION OF AN ISOLATED SLUG THROUGH A PIPE AND THE FORCES PRODUCED AS IT IMPACTS UPON AN ORIFICE PLATE

This paper is concerned with the propulsion of an isolated slug of liq uid along a pipeline by an expanding gas. The particular case in mind is when a body of liquid accumulates behind a closed valve in a piping system carrying a wet or condensing gas, and that valve is suddenly o pened to expose the slug of liquid to a high-pressure gas. The slug wi ll be driven along the pipeline by an expansion wave which weakens as the slug accelerates, whilst its motion will be resisted by friction a nd by the compression wave ahead of it. This situation has been analys ed and compared with slug velocities measured in a 50 mm pipe. Also pr esented in this paper are measurements of the considerable forces gene rated by the slug as it impinges onto an orifice plate installed in th e pipe.