Accession Number : ADA308517
Title : An Investigation of Ablation Behavior of Avcoat 5026/39M Over a Wide Range of Thermal Environments.
Descriptive Note : Technical memo.,
Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
Personal Author(s) : Crouch, Roger K. ; Walberg, Gerald D.
PDF Url : ADA308517
Report Date : APR 1969
Pagination or Media Count : 39
Abstract : Ablation studies have been carried out on the ablation material Avcoat 5026-39/M (a low-density glass-filled epoxy-novolac system) over a wide range of pressures, heat-transfer coefficients, and oxygen fluxes. At values of heat-transfer coefficient less than 0.17 lbm/7ft(2)-sec (0.83 kg/m(2)-sec), measured char recession rates were comparable to those predicted for diffusion-controlled char oxidation. At high values of heat-transfer coefficient, the ablation rate increased rapidly with increasing heat-transfer coefficient and severe mechanical char failure was observed. The structure, composition, and removal rate of the char were significantly influenced by stream oxygen content at low heat-transfer coefficients but not at high heat-transfer coefficients.
Descriptors : *EPOXY COMPOSITES, *EPOXY RESINS, *AERODYNAMIC HEATING, ABLATION, GLASS, HEAT SHIELDS, FAILURE(MECHANICS), ENTHALPY, STAGNATION TEMPERATURE, HEAT TRANSFER COEFFICIENTS, ABLATIVE MATERIALS, CHARRING.
Subject Categories : Laminates and Composite Materials
Distribution Statement : APPROVED FOR PUBLIC RELEASE