Evaporation of a droplet larger than the Kolmogorov length scale immersed in a relative mean flow

• Published in: International journal of multiphase flow 2017-01, Vol.88, p.63-68
• Main Authors: Marti, Ferran, Martinez, Oscar, Mazo, David, Garman, John, Dunn-Rankin, Derek
• Format: Article
• Language: English
• Subjects: Kolmogorov; N-heptane; Suspended droplet evaporation; Turbulence active grid; Wind tunnel
• ISSN: 0301-9322; 1879-3533
• DOI: 10.1016/j.ijmultiphaseflow.2016.09.019

•Turbulence intensity has a small effect in droplet evaporation when there is a relative mean flow.•If the eddy turnover time is much smaller than the relaxation time of the droplet, a large eddy is felt like a temporary relative mean flow.•A vertical wind tunnel with an active grid generates high intensity turbulence at relatively low mean flow velocity. An experimental effort to understand the contribution of turbulence to the evaporation rate of fuel droplets has been performed with particular attention to conditions when the turbulence scale is smaller than the droplet diameter. N-heptane has been chosen as working fluid to give measurable evaporation rates from droplet images over relatively short experiment times. An active turbulence grid wind tunnel is built for the requirements of this experiment. A camera triggered by a pulse generator takes images of the droplets pinned on wires across the tunnel. The results show a small increase in evaporation rate with increasing turbulence intensity, and that mean flow around the droplets has more impact on evaporation than does the turbulence state.