Evaporation of droplets in a turbulent jet *

We experimentally investigate the evaporation and dispersion of liquid droplets in a turbulent air flow. Droplets with diameters of the order of a few micrometers are produced by a spray nozzle and then injected into a homogeneous isotropic turbulence field, which is generated in a purpose-built enclosed dodecahedron chamber. The chamber has an axial fan mounted on each vertex, and it is capable of generating a homogeneous isotropic turbulence field with a Reynolds number based on Taylor microscale up to 160. The ambient temperature and relative humidity in the chamber are carefully controlled. Droplet sizes and velocities at various background turbulence intensity levels are measured by Phase Doppler Anemometry and Interferometric Particle Imaging. The evaporation of droplets will be studied from both Eulerian and Lagrangian perspectives, which will be linked to the mixing of the humid droplets-containing jet with dry ambient air. These results will lead to a deepened understanding of how turbulence affects the evaporation of droplets by modifying the scalar vapour mass field.