Coupling Between Radiation and Gas Dynamics
Abstract
Detailed experimental and analytic studies of microwave thermal propulsion are presented. Results are obtained for four geometric configurations: bluff-body stabilized resonant cavity plasmas; swirl-stabilized resonant cavity plasmas; free-floating plasmas in resonant cavities; and propagating, bluff-body stabilized plasmas in waveguides. Swirl stabilization proved to be less effective than bluff-body stabilization and was not modeled analytically. The experimental studies included both helium and nitrogen plasmas, while the analytic results are for helium only. In the free-floating plasmas, non-axisymmetric effects in the experimental setup led to arcing to the wall, limiting maximum power levels to about 500 W, although analysis suggests substantially higher upper power levels for this configuration. The bluff-body stabilized, resonant cavity plasmas, however, allowed power absorptions up to the maximum source power of 2.5 kW and 5 atm pressure for helium, although experiments in nitrogen were limited to lower powers. The analytic predictions agree well with the experiments in terms of plasma size, location, and response to parameters such as input power, mass flow rate, electromagnetic wave form, and pressure. The predicted coupling efficiencies and peak temperatures also agree well with measurements. Coupling efficiencies of near 100% can be obtained for the resonant cavity configurations, with somewhat lower efficiencies for the propagating plasmas.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 1991
- Accession Number
- ADA240004
Entities
People
- Charles L. Merkle
- Michael M. Micci
Organizations
- Pennsylvania State University