23. Calculation of Thermal-Physical Properties of Gaseous Xenon

Annotation: This article contains information on the calculation of the thermodynamic and translational properties of the gaseous xenon in the amount sufficient for the most engineering applications. The equation of state of xenon was obtained in dimensionless form, enabling calculations of the thermodynamic values using already known methods, developed for the air and other extensively used gases. An example is made on the implementation of the method based on this equation for calculation of the density, enthalpy and entropy of the gaseous xenon. The accuracy of calculation of these properties in the temperature range from 300 to 3000 K from 0,1 up to 120 MPa pressure was from 0,2 to 1,6%. Sufficiently accurate and simple dependencies were obtained for calculation of the enthalpy and heat of vaporization at the saturation line. Accuracy of the enthalpy calculation of the liquid xenon at the saturation line is not below 0,2%, the accuracy of the calculation of the heat of vaporization is not below 0,5%. New, simpler method, as compared to standard reference data, to calculate the translational properties (thermal conductivity, viscosity) of xenon at atmospheric pressure has been proposed. It is shown that thermal conductivity and viscosity can be calculated from the expression of the same type with different coefficients. Accuracy of the calculation of these properties using the proposed method is not below 2,2%. Considering the unsatisfactory test results of the well-known methods of calculation of the translational properties at high pressures, the effective method for approximating the table values of these properties has been proposed. In this case, at first, the temperature data at fixed pressures are approximated, then using these approximations, the values of the properties are calculated at the given temperature and various pressure values. After this, the value of the property is interpolated at the given high pressure. As an example of the implementation of this method, the Mathcad software for calculations of the thermal conductivity of gaseous xenon at high pressure is given. The materials of the article are intended for the specialists dealing with heat exchange processes.