  The evaporation of a liquid drop of initial diameter (Ddrop) migrating in a
tube of diameter (D0) is investigated using the coupled level set and volume of
fluid (CLSVOF) method focusing on determining the heat and mass transfer
coefficients for a deforming drop. A robust phase change model is developed
using an embedded boundary method under a finite difference framework to handle
vaporizing flows. The model is extensively validated through simulations of
benchmark problems such as arbitrary evaporation of a static drop and
reproduction of psychrometric data. The results show that the Sherwood number
(Sh) and the Nusselt number (Nu) reach a steady value after an initial
transient period for the drop subjected to Hagen-Poiseuille flow. A parametric
study is conducted to investigate the effect of drop deformation on the rate of
evaporation. It is observed that Stefan flow due to evaporation has a
negligible impact on the drop deformation dynamics. We also observed that, for
different values of Ddrop/D0, the Sh follows a linear correlation with
Re^{1/2}Sc^{1/3}.
