Accession Number : AD0668442

Title :   MERGED STAGNATION SHOCK LAYER OF NONEQUILIBRIUM DISSOCIATING GAS,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF EL SEGUNDO TECHNICAL OPERATIONS

Personal Author(s) : Chung,Paul M. ; Holt,James F. ; Liu,Shaowen W.

Report Date : JAN 1968

Pagination or Media Count : 47

Abstract : The paper presents the formulation of the problem, the numerical method leading to solution, and the physical significance of the results obtained for the fluid flow of a viscous merged layer with nonequilibrium chemical reactions. The solution is limited to the stagnation region of a blunt body. The chemical reactions considered are the dissociation and the recombination of air. It is first shown that the reduced Navier-Stokes equation and the corresponding energy and species conservation equations, wherein certain curvature effects have been neglected, are sufficiently accurate for the flow regime in which Re > or approx. 20, where Re is the Reynolds number behind the bow shock. It is also shown that only in this regime are the nonequilibrium chemical reactions important. From the solutions it was found, as was expected, that a strong coupling exists between the chemical reactions and the rarefaction of the shock layer. One of the unexpected results is that, for a given flight condition, increase of the surface catalycity causes the shock layer to become thinner. Since the increase in surface catalycity reduces the degree of dissociation within the merged shock layer, it had been expected that it would increase the shock layer thickness instead of decreasing it. The physical interpretation of the phenomenon and its possible implications are discussed. (Author)

Descriptors :   (*REENTRY VEHICLES, NONEQUILIBRIUM FLOW), (*ATMOSPHERE ENTRY, CHEMICAL REACTIONS), DISSOCIATION, RECOMBINATION REACTIONS, SHOCK WAVES, GAS IONIZATION, NUMERICAL ANALYSIS, STAGNATION POINT, BLUNT BODIES, NAVIER STOKES EQUATIONS, REYNOLDS NUMBER, SURFACE PROPERTIES, THICKNESS, VISCOSITY

Subject Categories : Aerodynamics
      Physical Chemistry
      Fluid Mechanics
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE