  Results from a large set of hydrodynamical SPH simulations of galaxy clusters
in a flat LCDM cosmology are used to investigate cluster X-ray properties. The
physical modeling of the gas includes radiative cooling, star formation, energy
feedback and metal enrichment that follows from the explosions of SNe type II
and Ia. The metallicity dependence of the cooling function is also taken into
account. It is found that the luminosity-temperature relation of simulated
clusters is in good agreement with the data, and the X-ray properties of cool
clusters are unaffected by the amount of feedback energy that has heated the
intracluster medium (ICM). The fraction of hot gas $f_g$ at the virial radius
increases with $T_X$ and the distribution obtained from the simulated cluster
sample is consistent with the observational ranges.
