^a,* and N. Neimarlija^bFaculty of Technology, University of Tuzla, Tuzla, Bosnia and Herzegovina
^bFaculty of Mechanical Engineering, University of Zenica, Zenica, Bosnia and Herzegovina

Thermodynamic properties of CO₂ are derived from speed of sound in the temperature range 300 to 360 K (from 0 to 6 MPa), and 300 to 220 K (from 0 to 90% of the saturation pressure). The density, the specific heat capacity at constant pressure, and the specific heat capacity at constant volume are obtained by numerical integration of differential equations connecting the speed of sound with other thermodynamic properties. The set of differential equations is solved as the initial value problem, with the initial values specified along the isotherm at 300 K in terms of several accurate values of the density and the specific heat capacity at constant pressure. The density, the specific heat capacity at constant pressure and the specific heat capacity at constant volume are derived with the absolute average deviations of 0.018%, 0.19%, and 0.18%, respectively. The results of numerical integration are extrapolated to the saturation line for r, c_p, and c_v with the absolute average deviations of 0.056%, 2.31%, and 1.32%, respectively.

Carbon dioxide, Density, Heat capacity, Speed of sound

Keywords:

(Received 12 July 2007, Accepted 13 September 2007)

M. Bijediæ