RADAR ATTENUATION BY SOLID-PROPELLANT-ROCKET EXHAUST.
Abstract
Transverse microwave-attenuation measurements of static-fired-rocket exhaust plumes from 1 1/2 to 30 nozzle-exit diameters along the flow axis, and use of a nitrogen sheath to displace entrainment of air into the exhaust steam have demonstrated that afterburning is the most significant single source of attenuation with both plastisol-nitrocellulose and inert-binder composite propellants. Aluminum is a second major cause of radar attenuation. Calculations show that at concentrations above 15% the contribution of aluminum can outweigh that attributable to alkali-metal contaminants in the oxidizer. Simultaneous measurements with X-, K-, and K sub alpha-band microwave-radiation sources have enabled calculation of free-electron concentrations and collision frequencies in the product gases; for plastisol-nitrocellulose propellants attenuation at one frequency can be inferred from measured values at two other frequencies. In this report experimental details and results are presented; the nature of microwave interaction with exhaust species as well as quantitative approximation methods are also discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 17, 1965
- Accession Number
- AD0365671
Entities
People
- W. A. Wood