SIMULATION OF TRANSIENT HYDRAULIC BEHAVIO R PROCESS ENGINEERING-PLANTWITH LONG PIPES

A knowledge of transient flow processes is becoming increasingly impor tant for the reliable design and control of process engineering plant. Transient flow processes occur, of example, in long liquid-carrying p ipes: on start-up and shut-down of plant, in emergency shut-downs and fast closure, i.e. when liquid is rapidly decelerated or accelerated. The consequence of such an event is a hammer effect, i.e. a short, oft en violent change of pressure placing considerable stress on structure s. Such hammer effects are readily calculated by numerical methods in single phase media. Technical devices for prevention of inadmissibly h igh pressure surges can also be designed by means of simulation calcul ations. However, hammer effects also occur by sudden condensation of v apours. A number of systems in which condensation hammer effects can o ccur are considered at the end of this contribution. Two special dampi ng measures are presented.