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A master's thesis from Aalborg University
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Multiphase Modelling of Liquid Atomisation using VoF-LES in an Internal Mixing Twin-Fluid Swirl Nozzle

Term

4. term

Publication year

2024

Submitted on

Pages

58

Abstract

Twin-fluid nozzles are widely used for atomization applications such as fuel injection, spray painting, and gas cooling. In this study, an internal mixing twin-fluid swirl nozzle has been investigated numerically using CFD. Air and water were used as working fluids at low Reynolds numbers of 1980 to 5650. Large eddy simulations were carried out using the volume of fluid method. The simulated Sauter Mean Diameter (SMD) deviated 16.9 % from experimental data. The effect of varying the gas-to-liquid mass flow ratio (GLR) on the atomization performance revealed that a 20 % increase in GLR resulted in a 2.8 % decrease in the SMD. The spray symmetry was also investigated using the time-averaged water volume fractions. The analysis revealed asymmetrical spray patterns downstream of the nozzle. Geometrical changes were made to study the influence of the inclination angle of the inlet pipes on the droplet size distribution and spray symmetry. The simulations showed that the SMD decreased by 11.9 % at an inclination angle of 0 ° compared to the baseline case of 27.5 °. When the inclination angle increased to 55 ° the SMD increased by approximately 8.3%. The spray symmetry was slightly improved at inclination angles of 0°and 55 ° compared to 27.5 °.