ULTRASONIC TEMPERATURE DETERMINATIONS IN A PLASMA
Abstract
An ultrasonic pulse technique for measuring gas temperatures in an internal combustion engine was used to determine temperatures in an electric arc plasma jet. Measurements of sound velocity at one mc per sec were obtained in hightemperature air, argon, and helium at atmospheric pressure. Temperatures are calculated from these sound speeds on the assumption that only the translational and rotational degrees of freedom are excited by the sound wave, while vibration, dissociation, and electronic excitation remain frozen. The temperatures determined in this way range from 3500 to 8000 K. In the case of the air arc, the ultrasonic temperature measurements are compared with temperatures determined from an energy balance on the plasma jet. The average temperatures obtained by the two methods agree within 10 percent over the temperature and enthalpy range considered. The results also show that temperature fluctuations as high as 50 percent can occur during a given arc run. A discussion of the experimental apparatus, method of measurement, experimental results, and analysis is presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 19, 1961
- Accession Number
- AD0269363
Entities
People
- Edmund H. Carnevale
- Howard L. Poss
- Jerrold M. Yos