Density, Heat Capacity, Viscosity, and Thermal Conductivity of Mixtures of CO2,He, H2, H2O, N2, and O2

摘要

The thermodynamic properties of gas mixtures are not always well approximated bythe average properties of pure gases weighted by the fractional composition. In order to improve our calculations we have turned to the literature to find formulas said to be useful for calculating the properties of mixtures in the range of temperatures and pressures encountered in human diving. Very little has been published on experimental determinations of properties of mixtures, so we have sought principally to verify that the formulas for mixtures give a good match to data on pure gases. In order to match data on pure gases, the values for the critical temperature (TC) and the critical pressure (PC) for H2 and He were modified. In addition, ad-hoc adjustments have been made to the critical volumes (VC) to make viscosity at low pressures match tables for these two gases. Omega, the acentric factor in the formulas, is taken as zero for all gases. The properties for which we have subroutines are thermal conductivity in watts/meter x degree/ K, viscosity micropoise, density in moles/cu cm, heat capacity in Joules/mole x degree /K, and the vapor pressure of water in torr.