- Author
-
Kendall, R. M.
|
Bartlett, E. P.
|
Rindal, R. A.
|
Moyer, C. B.
- Title
- Analysis of the Coupled Chemically Reacting Boundary Layer and Charring Ablator. Part 1. Summary Report.
- Coporate
- National Aeronautics and Space Admin., Washington, DC
- Sponsor
- Itek Corp., Palo Alto, CA
- Report
-
NASA CR-1060,
June 1968,
110 p.
- Contract
- NAS-9-4599
- Keywords
-
boundary layers
|
ablation
|
charring
|
chemical reactions
|
reaction models
|
thermal diffusion
- Abstract
- This report summarizes analyses and computational procedures for predicting the transient in-depth response of charring ablation materials, either coupled to a nonsimilar, laminar, multicomponent, chemically-reacting boundary-layer computational procedure or partially decoupled through the use of convective transfer coefficients. The detailed developments are presented in companion documents. The computational procedure for charring ablators is an implicit finite difference procedure for an ablating surface material with several nonablating backup materials. It considers one-dimensional heat and mass transfer along thermal streamtubes of arbitrary cross-sectional area and permits a multiple-reaction model for gas decomposition and a general thermochemical surface boundary condition. The boundary-layer procedure utilizes a newly developed integral matrix solution procedure. It applies for general chemical systems, allowing rate-controlled surface reactions, and incorporates approximate formulations for mixture transport properties, including unequal diffusion and thermal diffusion coefficients for all species. Analyses are also presented for extending the boundary-layer computational procedure to include mixed equilibrium-nonequilibrium, homogeneous or heterogeneous general chemical systems and to include radiation absorpiton and emission, and for extending the charring ablation procedure to include char-density buildup due to coking reactions in depth.