Computational Fluid Dynamics Modeling of Heat Transfer and Condensation in a Modified Laval Nozzle

Abstract

In this present study, numerical modeling based on computational fluid dynamics has been employed to study the condensation phenomenon in a modified Laval nozzle. During condensation, part of the latent heat is transferred by the convective heat transfer from the droplet to the steam. This study aims to find the effect of the employed blades on this phenomenon. In the first stage, a plain Laval nozzle was modeled, and the validation is undertaken with the experimentally reported results in the literature. Consequently, a new six-blade Laval nozzle was inserted at the entrance region of the aforementioned nozzle. The effects of this modification on the temperature, pressure, Mach number, the amount of condensation, and average radius of the droplet were analyzed. The results show that this geometrical modification causes a decrease in the overall condensation rate. However, the size of the droplet increases significantly, in a way that the average radius of the droplet near the nozzle wall increases from for the plain nozzle to for the modified one. Therefore, separating the liquid droplets from the vapor in the modified Laval nozzle is easier in comparison with the plain one.