  Context. Cometary dust particles are subjected to various forces after being
lifted off the nucleus. These forces define the dynamics of dust, trajectories,
alignment, and fragmentation, which, in turn, have a significant effect on the
particle distribution in the coma. Aims. We develop a numerical thermophysical
model that is applicable to icy cometary dust to study the forces attributed to
the sublimation of ice. Methods. We extended the recently introduced synoptic
model for ice-free dust particles to ice-containing dust. We introduced an
additional source term to the energy balance equation accounting for the heat
of sublimation and condensation. We use the direct simulation Monte Carlo
approach with the dusty gas model to solve the mass balance equation and the
energy balance equation simultaneously. Results. The numerical tests show that
the proposed method can be applied for dust particles covering the size range
from tens of microns to centimeters with a moderate computational cost. We
predict that for an assumed ice volume fraction of 0.05, particles with a
radius, r >> 1 mm, at 1.35 AU, may disintegrate into mm-sized fragments due to
internal pressure build-up. Particles with r < 1 cm lose their ice content
within minutes. Hence, we expect that only particles with r > 1cm may
demonstrate sustained sublimation and the resulting outgassing forces.
