Non-Grey Absorption Models of Ablator Vapors at High Temperatures with Application to Hypersonic Flow Fields
PICATINNY ARSENAL DOVER NJ DOVER
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A representation of the exact spectral absorption coefficients due to the atomic continua and molecular bands of typical ablators containing C, H, O, and Si was constructed. This representation then was fitted by a multi-band model using 12 bands between hv 0.1 and 24.4 eV. The band model permits much more rapid calculation in applications than an exact model, while retaining the non-grey characteristics of the actual absorption coefficient with good accuracy as shown by various comparisons. The effect of the large uncertainties in the molecular f-numbers is investigated and found to be significant for hv 10 eV at temperatures below about 15000 to 10000 deg K at pressures from 10 to 0.1 atmospheres. Spectral absorption coefficients and Planck and Rosseland mean absorption coefficients for carbon phenolic are also presented for a range of pressures from 0.1 to 10.0 atmospheres at temperatures from sublimation to 18000 deg K. Instructions for the utilization and application of the model are provided.