(12d) On Development of Equation of State for Air in Full Operational Range of Hypersonic Flight

In this study the formulation and validation of a thermodynamic equation of state for air is discussed. During the development of missile interceptors, a EOS for air covering the full range of hypersonic flight is needed. Equations that have been offered lack validation data for air at high pressures and temperatures. The NIST physical property databases contains data for nitrogen, N2, only upto pressures of 100 MPa. By use of a combination of this high accuracy data, thermodynamic theory, and scaling of N2 and air an EOS for air was developed for the entire range of upto 2000 MPa. Data at pressures higher than 100 MPa are sparse. An experimental database at high pressures for air is needed to validate the NIST empirical data set. Molecular interactions can be accounted for at high pressures for nitrogen. An experimental apparatus is proposed that is capable of measuring EOS parameters for air at pressures of upto 2000 MPa and temperatures in the range of 300 - 1000 K. This high pressure air can also be used in decaffeination of beverages.