Suppression of Condensation Shock in Wet Steam Flow by Injection of Water Droplets in Different Regions of a Laval Nozzle


Department of Mechanical Engineering,Ferdowsi University of Mashhad


In this paper, a compressible, one-dimensional and two-phase
ow is analytically modeled
by using a homogeneous classical nucleation rate equation in a Laval nozzle. For droplet growth
calculations, the heat transfer between the droplets and the surrounding steam is modeled by a free
ow model and a semi-empirical two-layer model which is deemed to be valid over a wide
range of Knudsen numbers. In order to reduce the condensation shock strength, the water droplets are
injected at the inlet, and just after the throat of the Laval nozzle. According to the results, the nucleation
rate is considerably suppressed due to the small droplet injection, and, therefore, the condensation shock
nearly disappears, particularly for the inlet injection of water droplets.