MOLLIER ENTHALPY-ENTROPY CHARTS FOR HIGHTEMPERATURE PLASMAS,

Energy changes and heat transfer in high-temperature gaseous plasma flows are becoming increasingly important in technology. Mollier enthalpy-entropy diagrams have proved to be valuable tools in this development. Enthalpyentropy diagrams for hydrogen and argon plasmas at temperatures up to 100,000K and for pressures from 0.01 to 100 atm are presented. The diagrams are shown with lines of constant pressure, density, temperature, and sonic velocity. These graphs are further plotted in logarithmic co-ordinates in order to present the low-temperature region more clearly. The diagrams are only valid for plasmas existing in thin layers where the energy and entropy content of the enclosed radiation is not important. Radiation must be taken into account for plasma layers of large thickness. As an example of the application of these charts, the stagnation temperature of a body flying at 8,000 meters sec in a hydrogen or argon atmosphere at 0.01 atm pressure and 300K temperature is calculated. For the case of a hydrogen atmosphere, the wall temperature at the stagnation point T sub w 2000K wall radiation neglected and T sub w 1820K with wall radiation. In argon, these values are 16,500K without and 5800K with wall radiation. The great importance of both the medium and the wall radiation is apparent. In these calculations it is assumed that no magnetic field exists. Author