MODEL OF CALORIC-FORM WIDE-RANGE EQUATIONS OF STATE OF MATERIAL

K.V. Khishchenko, I.V. Lomonosov, V.E. Fortov
VANT. Ser.: Mat. Mod. Fiz. Proc 1997. Вып.1. С. 54.

      The equation of state within a wide density and pressure range is a necessary element for mathematical simulation of time-dependent hydrodynamic processes of intense energy flux pulsed effect on material [1]. Owing to serious problems involved in computation of a complex collective inter-particle interaction in a heated multi-component medium [2], semi-empirical models are traditionally used to uniquely describe thermodynamic material properties within a wide parameter range on the phase diagram where the general form of the functional dependencies of the thermodynamical potential is determined without theoretic representations being involved, while the experimentally measured data at high energy densities are used to estimate numerical values of free coefficients in these dependencies. This work presents the caloric form of wide-range equations of state which allows to effectively describe properties of various materials (both elements and compounds) in the condensed and quasi-gaseous phases. The developed semi-empirical model which in the analytical form expresses the relation of internal energy, pressure and volume extends the Mie-Grueneisen equation to the region of rarefied states and arbitrary energies. Various options to estimate the volume dependencies for the cold curve and Grueneisen factor are discussed. The computed results are given which were obtained on the base of the developed caloric model of thermodynamical characteristics of molybdenum, iron, lead and plexiglas under shock loading and isentropic unloading. For each material studied the computed dependencies were compared with the set of experimental data, within a high energy density range.
      1. Bushman A.V., Kanel G.I., Ni A.L., Foriov V.E. Thermal physics and dynamics of intense pulsed effects. Ghernbgolovka: USSR Academy of Sciences OIKhF, 1988.
      2. Bushman A.V., Foriov V.E. // UFN. 1983. Vol. 140. P. 177.