Revisiting d2-law for the evaporation of dilute droplets

TL;DR

This paper revises the classical d2-law to more accurately predict droplet evaporation times in dilute conditions, addressing overestimations in traditional models by incorporating asymptotic droplet properties, validated through numerical simulations.

Contribution

The paper introduces a revised d2-law that improves evaporation rate predictions for dilute droplets by considering asymptotic properties, enhancing accuracy over classical assumptions.

Findings

Revised d2-law aligns well with numerical simulation data.

Traditional d2-law overestimates evaporation in dilute conditions.

Model accurately predicts evaporation time in turbulent jet-sprays.

Abstract

In a wide range of applications, the estimate of droplet evaporation time is based on the classical d2-law, which, assuming a fast mixing and fixed environmental properties, states that the droplet surface decreases linearly with time at a determined rate. However, in many cases the predicted evaporation rate is overestimated. In this Letter, we propose a revision of the d2-law capable to accurately determine droplet evaporation rate in dilute conditions by a proper estimate of the asymptotic droplet properties. Besides a discussion of the main assumptions, we tested the proposed model against data from direct numerical simulations finding an excellent agreement for predicted droplet evaporation time in dilute turbulent jet-sprays.