Flashing Two-Phase Releases from the Desert Tortoise and Jack Rabbit Tests

摘要

There has been a great deal of discussion over several years about the predicted release rate andsource conditions for a flashing two-phase release from pressurized storage of a liquid above itsboiling point (of particular importance are ammonia and chlorine). The Desert Tortoise testswere designed to release ammonia from pressurized storage with sufficient overpressure todeliver a subcooled ammonia stream to the release point through a long pipe. However, it wasevident that the mass release rates were not as high as expected. This experience was used toguide the design of the release mechanism used in the Jack Rabbit tests (which releasepressurized ammonia and chlorine). Despite these efforts, visual observations indicated thatflashing flow occurred inside the vessel in the Jack Rabbit tests for both ammonia and chlorine.This paper discusses one approach to describing the flow under these conditions and makes theargument that releases from large openings will result in flashing flow inside the vessel. Theseeffects are important for the downwind transport and diffusion of material because flashinginside the vessel results in larger fluid velocities outside the vessel when compared with a liquidonly discharge, and these higher velocities result in more initial air dilution due to jetting.