Branch line pipewhip

There are many cases on power plant where large diameter pipes containing high pressure gas or steam have branch connections of a much smaller diameter. Frequently branch lines contain a closed valve. Here, pipe rupture adjacent to the main pipe means that the section of pipe on the valve side of the break is subject to a transient thrust, as the limited quantity of fluid between the closed valve and the open end is expelled. This section of pipe may also experience a force exerted by the impingement of the jet emerging from the main pipe. This paper considers the resulting pipewhip motion. The relative significance of the thrust resulting from the expulsion of the limited volume of fluid within the pipe and the subsequent jet impingement force, are explored. In addition the extent of the hazard zone and the peak kinetic energy of the pipe are determined. (Author)