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

Abstract

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 molecular 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.