THERMAL CONDUCTIVITY OF PHENOLIC-CARBON CHARS
Final rept. 1 Apr 1968-30 Dec 1969
BOEING CO SEATTLE WA AEROSPACE SYSTEMS DIV
Pagination or Media Count:
The thermal conductivity of several phenolic-carbon and phenolic- graphite ablative composites was established as a function of layup angle and temperature for ablation heating or cooling from -10F to over 5000F. Conductivity was measured on virgin and charred FM-5055A phenolic-carbon as a function of layup angle and heating or cooling temperature to 5000F. These measurements were made by the steady-state, unidirectional, comparative disk method. Furnace charred conductivity specimens were shown to represent ablation chars by detailed characterization and by comparative thermal diffusivity measurements. Theory relating the constituent cloth and matrix and composite conductivities was used to correlate the new conductivity data and literature data on composites having the same reinforcements. The procedure provides correlated constituent conductivities for CCA-1 standard and high purity carbon cloth, WCA and WCB graphite cloth, and carbon powder filled and unfilled 91-LD and SC 1008 virgin or charred phenolic resins, from which the conductivity of virgin or charred composites is obtained within the accuracy of composite conductivity measurements. All results are expressed as equations for direct substitution in ablation computer programs, which was demonstrated for ballistic reentry ablation of FM-5055A phenolic carbon. The thermal conductivity of all carbon or graphite cloth reinforced phenolics increases versus layup angle and reinforcement volume fraction, is reduced by pyrolysis generated porosity, and increases in the mature char versus temperature and the degree of graphitization.
- Refractory Fibers
- Laminates and Composite Materials