Steady and Transient Mathematical Models of Steam Jets

Exhaust steam into the atmosphere is the most powerful source of noise in the energy, chemical and many other industries. Excess of sanitary industry norms up to 60 dBA at a distance of 15 m from the release point. Knowing processes of steam efflux into the atmosphere allows us to calculate correctly noise levels at a distance from them and to realize measures for noise attenuation. The study of mechanisms of noise generation by jets had begun in the end of 1940s and had been generally related to investigations of air jets and exhaust gas jets of aircrafts. Problems of noise emission by steam jets have been studied insufficiently until recently. The stationary and transient simulation models of the steam jets are discussed. The limitations of a stationary model and the possibility of transient mathematical model of the radiation steam jets are shown. The difference between the simulation results in the stationary and transient models are given. It is shown that the simulation of steam flowing under transient state condition gives the possibility to trace not only regular but also coherent structures and, thereby, to describe processes of noise generation most completely.