Some Amplification by Relaxation Processes in Nitrogen and Mixtures of Nitrogen with Helium and Hydrogen.
Abstract
Experimental investigation of the sound amplification by relaxation processes in vibrationally excited gases has been made. Experiments were conducted in pure nitrogen and mixtures of nitrogen with helium and hydrogen. The nitrogen was vibrationally excited by an electrical discharge. A sound pulse, propagated through the excited gas under study, was Fourier analyzed to determine the absorption and velocity as a function of time and frequency. A numerical solution developed by Shields 22 was used to calculate the absorption and velocity in unexcited gases. The observed and calculated absorption and velocity were then compared to determine the gain and temperature of the gas. In pure nitrogen and mixtures of nitrogen and helium, in which the vibrational relaxation time was much longer than the sound period, gain was not observed. Gain was observed in three cases: 50% He - 50% N2 at 40 Torr, 10% H2 - 90% N2 at 40 and 20 Torr. In the first two mixtures it was possible to observe the change in gain with time as the vibrational temperature decayed away. Originator supplied keywords include: Sacer, Vibrational relaxation, Nonequilibrium gases, Nitrogen, and Sound waves.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 27, 1985
- Accession Number
- ADA153620
Entities
People
- D. Iskandar
- F. Douglas Shields
Organizations
- University of Mississippi