Numerical calculations of enthalpy and entropy chart of CH₄ gas based on Soave−Redlich−Kwong gas state equation and related application program development

Using the Redlich−Kwong−Soave real gas equation of state (SRK equation), combined with the full differential forms of enthalpy and entropy, the charts of enthalpy and entropy of CH₄ gas are calculated numerically using Mathematica software. Based on the interactivity and update function of Mathematica, with experimental heat capacity of CH₄ gas under the zero−pressure condition, instant calculation and query program for enthalpy and entropy differences of CH₄ between two arbitrary thermodynamics states are developed. Taking into account the error of the real gas state equation, referencing experimentally measured data of enthalpy and entropy charts, a linear correction code is added to the program to correct the theoretical calculation values. For randomly generated thermodynamics states, the program calculated results of enthalpy and entropy differences are compared with the experimental results. It is found that the developed program has comparatively high accuracy.