EFFECTS OF CHARGE SEPARATION IN HYPERSONIC IONIZED FLOWS

THE SHOCK LAYER FLOW FIELD AROUND HYPERSONIC VEHICLES MANEUVERING IN THE UPPER ATMOSPHERE SUCH AS AFE, AOTV AND NASP IS CHARACTERIZED BY CHEMICAL AND THERMAL NONEQUILIBRIUM DUE TO SIGNIFICANT DISSOCIATION AND IONIZATION. ELECTRIC FIELDS ARE INDUCED AS A CONSEQUENCE OF CHARGE SEPARATION DUE TO AMBIPOLAR DIFFUSION OF IONS AND ELECTRONS IN SHOCK AND SURFACE REGIONS. THE RESULTING FORCED DIFFUSION OF CHARGED SPECIES IN THE MULTICOMPONENT GAS MIXTURE AFFECTS THERMOPHYSICAL PROPERTIES AND FLOW FIELDDYNAMICS OF THE GAS. THE SIGNIFICANCE OF CHARGE SEPARATION EFFECTS HAS NOT BEEN ASSESSED IN CURRENT COMPUTER CODES APPLIED TO FLOW FIELD ANALYSIS. IT IS PROPOSED TO ESTABLISH THE THEORETICAL AND COMPUTATIONAL PROCEDURE TO INCLUDE CHARGE SEPARATION EFFECTS INTO CURRENT COMPUTER CODES AND TO ASSESS THE SIGNIFICANCE FOR FUTURE CFD MODELS. IN PHASE I, A PROPER SET OF SPECIES AND FLUID DYNAMICS EQUATIONS WILL BE DEFINED, A CALCULATION PROCEDURE FOR THERMOPHYSICAL AND TRANSPORT PROPERTIES FOR MULTICOMPONENT GAS MIXTURES WILL BE ESTABLISHED, AND AN EFFICIENT PROCEDURE TO DECOUPLE SPECIES AND THERMOPHYSICAL CALCULATIONS FROM FLUID DYNAMICS SOLUTIONS WILL BE DEVELOPED. THIS PROCEDURE WILL BE IMPLEMENTED IN THE PARC NAVIER-STOKES CODES IN PHASE II TO ASSESS THE SIGNIFICANCE OF THE PHENOMENON.