Problems coupling mass transfer physics to two phase laminar flow (phase field)

Hello all,

I am in the process of coupling Transport of Diluted Species to Two Phase Laminar Flow (Phase Field) and having some difficulty. I was wondering if anyone could possibly help me out.

The scenario is a water droplet resting on a surface and it is being cooled by air. I hope to simulate the evaporation of water into the air. I expect to see deformation of the water droplet (mass is tracked by the Phase Field, correct?) and a water concentration profile as it evaporates.

The problem I am having is that the volume fraction of the water goes to zero very early on in the simulation. This appears to be a numerical error to me, but I cannot locate what is causing it. I’ve tried increasing the mesh density around the droplet, which did help control the volume fraction marginally but I still feel that the physical results aren’t making sense. Shouldn’t the plot showing the water concentration profile show a reduction in volume as well?

I would greatly appreciate any input.

Best regards,
Alex

P.S. Model is attached, but without solutions because the output file size was too big.