  We consider a spherical volume of hot and dense hadronic matter (fireball)
expanding into a vacuum. It is assumed that initially the fireball matter is in
local thermal and chemical equilibrium with vanishing collective velocity. The
time evolution of the fireball is studied in parallel within the GiBUU
transport model and an ideal hydrodynamic model. The equation of state of an
ideal hadronic gas is used in the hydrodynamic calculation. The same set of
hadronic species is used in transport and fluid-dynamical simulations. Initial
coordinates and momenta of hadrons in transport simulations have been randomly
generated by using the Fermi and Bose distributions for (anti)baryons and
mesons. The model results for radial profiles of densities and collective
velocities of different hadronic species are compared at different times. We
find that two considered models predict essential differences in time evolution
of hadron abundances, which are especially pronounced for hyperonic species.
This gives an evidence of a strong deviation from chemical equilibrium in
expanding hadronic matter.
