Large eddy simulation of cold evaporating dilute sprays

To study the characteristics and influencing factors of droplet dispersion and evaporation in gas turbulent flows and to deepen the awareness of the gas-liquid couple, numerical simulations of the cold evaporating dilute sprays were conducted in the Eulerian-Lagrangian framework. The gas turbulent flow in Eulerian framework was simulated using large-eddy simulation while the discrete liquid phase was described using the Lagrangian particle trajectory model, considering interphase mass, momentum, and energy stransfer. And the equilibrium evaporation model was adopted to describe the evaporation effect. The simulation result of droplet velocity field, particle size distribution and mass flow rate are in good agreement with experimental data. In the confined spray with recirculation zone, droplets with big stokes number are affected by the initial inertia obviously while small droplets with stokes number around 'one' are controlled more by the gas structures, and the evaporation rate in unit volume is closely related to the droplet dispersion. In the free spray case, big and small droplet dispersion are in consistent and the droplet velocity field is almost self-similar.