  The QCD equation of state at finite temperature and densities of conserved
charges is considered in the framework of a Hagedorn bag-like model,
incorporating both the finite sizes of hadrons as well as their exponential
mass spectrum. Augmented with non-zero masses of quarks and gluons in the bag
spectrum, the model yields a fair quantitative description of lattice data on
thermodynamic functions, the conserved charges susceptibilities, and Fourier
coefficients of net-baryon density. Both at zero and finite baryon densities a
broad crossover transition between hadronic and quark-gluon matter is observed.
The model thus provides a thermodynamically consistent construction of a
crossover equation of state for finite baryon number, electric charge and
strangeness chemical potentials, which can be used in fluid dynamical
simulations of heavy-ion collisions.
