Performance of Five Ablation Materials as Coatings for Structures in a Region of Separated Flow.
Abstract
An investigation was made of several commercially available ablation materials for use as thermal protection for the sidewalls of advanced air-to-air missiles. Material specimens of different thickness were tested on the cylindrical section of a rounded-ogive-cylinder model. The tests were conducted in the Langley 11-inch ceramic heated tunnel at a heating rate, enthalpy, and free stream Mach number typical of the values of these parameters encountered during a missile trajectory. Oil flow and pressure tests showed that the boundary layer had separated from the cylindrical section of the model and that the entire specimen region was immersed in separated flow. In the separated flow environment, a phenolic cork composition was found to be superior to the other materials studied in limiting the substrate temperature rise. The phenolic cork composition experienced considerably greater erosion than the phenolic nylon, asbestos phenolic, and subliming salt compositions, which ranked second, third, and fourth, respectively, in limiting the substrate temperature rise; however, these materials developed either surface cracks or large fissures in the char layer. Preconditioning of the phenolic cork, asbestos phenolic, and epoxy solid materials by heat cycling to 400 deg F (478 deg K) did not decrease their thermal performance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1965
- Accession Number
- ADA310374
Entities
People
- Allen G. Mclain
- Louis E. Clark
Organizations
- Langley Research Center