Compressibility of Fluids
In a Nut Shell: A
property used to characterize compressibility of a fluid is bulk modulus, EV
. For gases a change in pressure
results in a change in volume giving rise to the definition of bulk modulus.
Or
in terms of density
The
table below list dimensions and common units. Quantity Dimensions Common Units
The
“ideal” gas law is: P =
ρ R T
(relates pressure to density and temperature) P =
absolute pressure, ρ =
density, R =
gas constant (a property depending on gas) T =
absolute temperature
Note: R = 1716 ft lb/slug oR for air For
a isothermal process P / ρ = constant. For an isentropic process P / ρK = constant where K is
the ratio of specific heats of the gas
K = CP / CV |
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