Sound velocity and isentropic exponents of real air on its compressibility chart

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1991 (EN)
Sound velocity and isentropic exponents of real air on its compressibility chart (EN)

Kouremenos, DA (EN)
Antonopoulos, KA (EN)

N/A (EN)

In previous publications, three real-gas isentropic exponents k(pv), k(Tv), and k(pT) have been introduced, which, when used instead of the classical exponent k = C(p)/C(v) in the ideal-gas isentropic-change equations, may be applied with great accuracy to real gases. The first of the exponents may also be employed for calculating the real-gas sound velocity as alpha = (k(pv)pv)1/2. The purpose of this study is to present the generalized compressibility chart (of the Nelson-Obert type) of real air and place on this chart the values of the real-air isentropic exponents and sound velocity based on its virial equation of state. The usefulness of such diagrams lies in the fact that they provide in a compact and concise form information about the thermodynamic behavior and the isentropic flow of real air, and they allow straightforward comparisons between air and other real gases. Using the Redlich-Kwong-Soave correlation with acentric factor omega = 0.035, similar diagrams for the air are presented and compared successfully with the corresponding exact ones. (EN)


Sound Velocity (EN)
Acoustic Variables Measurement--Calculations (EN)
Isentropic Flow (EN)
sound velocity (EN)
compressibility chart (EN)
Real Gas (EN)
real air (EN)
Air (EN)
isentropic exponents (EN)

Εθνικό Μετσόβιο Πολυτεχνείο (EL)
National Technical University of Athens (EN)

International Journal of Heat and Fluid Flow (EN)



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