Droplet Vaporization and Secondary Breakup Effects in Aerated-Liquid Injection into a Supersonic Crossflow

摘要

Large-eddy simulations of aerated-liquid jet injection into a supersonic crossflow are presented in this work. The aerated-liquid jet is assumed to have a core-annular structure, with the outer annular region idealized as a collection of large droplets (～25 microns) and the inner region represented as a log-normal distribution of smaller droplets. The subsequent evolution of the spray is tracked using a Lagrangian approach considering hydrodynamic drag, vaporization, and droplet breakup. The Lagrangian tracking approach is combined with an Eulerian model for compressible, two-phase flow, and the system is evolved as a large-eddy simulation. Simulations correspond to experiments performed at Argonne National Labs using a small-scale supersonic wind tunnel - data generated includes time-resolved and time-averaged shadowgraph imagery and line-of sight effective path length measurements in the near-field of the spray. The results show that rapid droplet breakup in the initial jet injection region leads to the predominance of smaller droplets (＜ 10 microns) that closely follow the flow. Jet penetration characteristics are sensitive to the model used for the sound speed of the two-phase mixture, and droplet vaporization effects are generally negligible for this flow.