Experimental Determination of Gas Properties at High Temperatures and/or Pressures
Final rept. Sep 1971-Oct 1973
PANAMETRICS INC WALTHAM MA
Pagination or Media Count:
A new technique for the accurate 1-0.01 determination of transport and thermodynamic properties of gases is described. This technique consists of measuring the linewidth of a small acoustic resonator. The linewidth of more than one type of resonance allows the transport properties thermal conductivity and viscosity to be determined independently. The center frequency gives the sound speed. The theory of the acoustic resonator is presented including the effects of relaxation in the gas, slip and accommodation on the cavity walls, and acoustic transmission into the walls. The contributions of transducer coupling and feed through are also included in the cavity theory. Realization of cavities and transducers suitable but not optimized for measurements at temperatures up to 1000K and pressures up to 500 atm are discussed. Measurements employing the resonator technique are presented in Ar, N2, air and H2. High pressure measurements p 460 atm span temperatures between 300 and 600K. Measurements at 1 atm at temperatures up to 1000K are also presented.
- Physical Chemistry