Search results
Results from the WOW.Com Content Network
Compressibility factor values are usually obtained by calculation from equations of state (EOS), such as the virial equation which take compound-specific empirical constants as input. For a gas that is a mixture of two or more pure gases (air or natural gas, for example), the gas composition must be known before compressibility can be calculated.
The compressibility factor is defined as = where p is the pressure of the gas, T is its temperature, and is its molar volume, all measured independently of one another. In the case of an ideal gas, the compressibility factor Z is equal to unity, and the familiar ideal gas law is recovered:
In physics and thermodynamics, the Redlich–Kwong equation of state is an empirical, algebraic equation that relates temperature, pressure, and volume of gases. It is generally more accurate than the van der Waals equation and the ideal gas equation at temperatures above the critical temperature.
The parameters should be expressible in terms of the critical properties and the acentric factor. The model should provide reasonable accuracy near the critical point, particularly for calculations of the compressibility factor and liquid density.
3 Practical Calculation. 4 Correlated terms. 5 References. Toggle the table of contents. Residual property (physics) ... and denotes the compressibility factor. This ...
These dimensionless thermodynamic coordinates, taken together with a substance's compressibility factor, provide the basis for the simplest form of the theorem of corresponding states. [1] Reduced properties are also used to define the Peng–Robinson equation of state, a model designed to provide reasonable accuracy near the critical point. [2]
The virial expansion is a model of thermodynamic equations of state.It expresses the pressure P of a gas in local equilibrium as a power series of the density.This equation may be represented in terms of the compressibility factor, Z, as = + + + This equation was first proposed by Kamerlingh Onnes. [1]
It reads: = + [()] where is the number density, g(r) is the radial distribution function and () is the isothermal compressibility. Using the Fourier representation of the Ornstein-Zernike equation the compressibility equation can be rewritten in the form: