Accession Number : ADA306854

Title :   Comparative Evaluation of Ablating Materials in ARC Plasma Jets.

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Hiester, Nevin K. ; Clark, Carroll F.

PDF Url : ADA306854

Report Date : DEC 1968

Pagination or Media Count : 192

Abstract : In a round-robin ablation study monitored by Stanford Research Institute in 1964, Teflon and high-density phenolic-nylon models were evaluated at various enthalpies and heating rates under supersonic conditions. The results of that study, published in NASA Contractor Report CR-379, showed that the best description of the test environments for twelve different plasma arc heater facilities was given by the stagnation point heating rate, and pressure. The mass loss rates from all facilities could be correlated in terms of these parameters with a standard deviation of approximately 11 percent for both the Teflon and phenolic-nylon material. The second phase of this study, described in this report, also involved twelve facilities, most of them the same as in the first phase. The same two high-density materials, Teflon and phenolic-nylon, were evaluated at stagnation pressures up to 10 atmospheres for the former and 30 atmospheres for the latter. The effect of model size was also evaluated using both hemispherical and flat-faced Teflon models having effective radii varying from one- quarter to four times the radius used previously. The mass loss rates again correlated with the results from the earlier study, except that high-density phenolic-nylon models showed a rapid increase in ablation above a stagnation pressure of about 2.5 atmospheres. These higher rates were also correlated, and found to agree, with literature data for this same pressure regime.

Descriptors :   *PLASMA JETS, *ABLATIVE MATERIALS, TEST AND EVALUATION, ENVIRONMENTS, HIGH RATE, MODELS, MASS, NYLON, HEATING, HIGH DENSITY, PRESSURE, LOSSES, ENTHALPY, RADIUS(MEASURE), STAGNATION PRESSURE, STAGNATION POINT, PHENOLIC PLASTICS, TETRAFLUOROETHYLENE RESINS, ARC HEATERS.

Subject Categories : Laminates and Composite Materials
      Plastics
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE