Numerical study on effects of nozzle hole spacing distance on steam submerged jet condensation from triangular holes spray nozzle

Steam-water direct contact condensation (DCC) is a phenomenon which is frequently found in the industrial sector due to its rapid and efficient heat and mass exchange rates. In this work, three dimensional numerical study of steam injection from triangular hole nozzles (with different holes pitch circle diameter, PCD = 6, 8,10 and 12 mm) into subcooled water tank has been carried out using Eulerian multiphase flow model along with realizable k-epsilon turbulence model. The thermal phase change model as User Defined Function (UDF) was employed in Fluent software for capturing submerged steam jet condensation. The simulation results were validated using experimental results as well as previously published numerical study and a fairly good agreement was observed. The effects of nozzle hole spacing distance on distributions of various thermal hydraulics parameters including velocity, pressure, temperature, heat and transfer characteristics have been studied. The axial distribution of the velocity, temperature, heat transfer coefficient and mass transfer computed at the centerline of the nozzle was found weaker than observed at the centerline of the nozzle holes. However, these distributions were not weak at nozzle centerline for nozzle with PCD 6 mm. The heat transfer coefficient has been found in the ranges of 1.75�2.3 MW/m2 K. The results reveal that the heat transfer coefficient for nozzle PCD 8 mm is higher than rate obtained for other nozzles. The rate of mass transfer at the holes centerlines has been found increasing with the holes PCD. The axial distribution of the mass transfer curve shifts downstream for nozzle with smaller PCD. Additionally, the mutual shielding effect of the jets weakens as holes PCD increases. © 2023 Elsevier Ltd