Simulations of finite-size evaporating droplets in weakly-compressible homogeneous shear turbulence*

We perform interface-resolved simulations of finite-size evaporating droplets in weakly-compressible homogeneous shear turbulence (HST). The study is conducted by varying three dimensionless physical parameters: the initial gas temperature over the critical temperature, the initial droplet diameter over the Kolmogorov scale and the surface tension, i.e. the shear-based Weber number. We first discuss the impact on the evaporation rate of the three thermodynamic models employed to evaluate the gas thermophysical properties: a constant property model and two variable-properties approaches where either the gas density or all the gas properties are allowed to vary. Taking this last approach as reference, the model assuming constant gas properties and evaluated with the "1/3" rule, is shown to predict the evaporation rate better than the model where the only variable property is the gas density. Next, we show that the ratio between the actual evaporation rate in turbulence and the one computed in stagnant condition is always much higher than one for weakly deformable droplets. Finally, we examine the overall evaporation rate and the local interfacial mass-flux, showing a positive correlation between evaporation rate and interfacial curvature.