Controlling the Intensity and Location of Spontaneous Condensation in a 2-D Laval Nozzle by Spraying Water Droplets at the Throat

During expansion in a Laval nozzle, the steam at first supercools and then reverts to equilibrium through spontaneous condensation to become a two-phase mixture. This paper describes a numerical method for the solution of two-dimensional, two-phase flow of steam in a Laval nozzle. The unsteady Navier-Stokes equations, including the Baldwin-Lomax turbulence model are combined with non-isothermal-Courtney's correction and droplet growth equations; then treated by Jameson's time marching scheme. In this study, pressure distribution and droplet size are predicted and compared with available empirical results. For further validations, spraying water droplets at the throat of nozzle is considered theoretically to control the spontaneous condensation intensity and its location. Since condensation shock is the origin of aerodynamic and thermodynamic losses, the idea can lead to improved design.