Coolant properties are calculated from the unified coolants database. The base consists of a set of tables prepared for each coolant from a known source [2]. Enthalpy H and pressure P are accepted as independent variables for these tables and form a common 2D mesh for all thermodynamic and thermo-physical properties of the coolant. Special subroutines provide an appropriate approximation accuracy of 0.2% for coolant properties in arbitrary (P,H)-point. A two-phase coolant region is simulated as a homogenous mixture. An equation of state for such mixture has a form

where ρ', ρ", are the liquid and vapor coolant densities on the boundary line of coolant TS-diagram; H',H" are the liquid and vapor enthalpies as a function of pressure P. 

back to Mathematical Models: