Numerical investigation of liquid mass fraction and condensation shock of wet-steam flow through convergence-divergence nozzle using strategic water droplets injection

Abstract

Abstract Spontaneous condensation occurs due to high steam speeds, leading to droplets in the stream that not only decrease performance but also hazard the security of the nozzle. This study aims to predict the position and size of suitable injected water droplets due to reduced losses due to liquid mass fraction. Firstly, the model of steam flow has been confirmed by experimental data using the Eulerian–Eulerian approach in Moore’s nozzle B. Then, the flow turbulence caused by phase change is modelled by k–w sst model. Then, the injection has applied in three sizes (coarse, medium, and fine) at four different positions of the nozzle and has analysed, which according to the findings of fine droplet size, has led to an enhancement in Mach number and on the other hand, injection in nucleation zone has resulted in a 7 % and 3 % reduction in wetness losses for the radius of coarse and fine droplets, respectively. It is predicted that the nucleation rate will decrease the smaller the injected droplets are in the nucleation region. Injection with a number droplet of 1.015 × 1018 and a radius of 0.013 (μm) in the nucleation zone of 10 mm after the throat increased by 4.5 % of Mach number.