Internal Flashing Flow of Ammonia

Ammonia is considered a carbon-free alternative fuel for energy systems. Its low boiling point makes liquid ammonia prone to flash boiling, especially under standard temperature and pressure. The phase change occurs on a timescale similar to the nozzle’s flow-through time, requiring finite-rate modeling. This study presents a numerical simulation of internal flashing flow in superheated ammonia using a multidimensional thermal nonequilibrium model. The model was validated against experimental data, with simulations at two different back pressures showing a significant increase in vapor formation as back pressure decreased.