Graphite Ablation in Several Gas Environments.
JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
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The design of a passively cooled combustor for a hypersonic tactical missile poses many severe structural problems whose solutions are beyond the current state of the art. To design such a combustor, the designer must predict accurately the erosion rate of candidate materials so that a realistic balance can be achieved among weight, performance, and cost. To make these predictions, basic experimental data must be taken to determine ablation rates as a function of surface temperature, pressure, gas flow rate, and gas composition. An experimental procedure has been developed to obtain this information for graphite materials exposed to various gases, such as CO, CO2, argon, and H2O, and simulated Shelldyne H-air combustion products. The data agree well with data obtained from the literature and indicate that at temperatures above 3500 degrees F a the ablation rate is diffusion limited, b CO2 in the stream reacts with carbon at the surface to form CO, and c water vapor reacts with the surface this was not anticipated prior to the tests. At 2000 degrees F, ablation is controlled by reaction rate, and both CO2 and water vapor in the stream react with the surface. Author
- Laminates and Composite Materials
- Guided Missiles
- Combustion and Ignition
- Rocket Engines