Benedict-Webb-Rubin PVT Formula and Calculator

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Benedict-Webb-Rubin PVT Formula and Calculator

Heat Transfer Engineering
Thermodynamics Resources

Benedict-Webb-Rubin (BWR) equation of state, is often the most convenient way of representing the PVT surface of a fluid and of calculating its thermodynamic properties.

The fact that many of the derived thermodynamic properties can be calculated explicitly in closed, analytic form greatly enhances the usefulness of the equation and the speed of machine calculations. This characteristic of the equation also allows it to be fit to several properties simultaneously (e.g., density and specific heat). Such multi-property fitting virtually assures the accuracy of most derived thermodynamic properties, provided sufficient good data are available.

Related (Basic, Free Membership required):

Modified Benedict-Webb-Rubin equation of state for gaseous and liquid oxygen

Application of the Benedict-Webb-Rubin to State of Argon

Preview: Benedict-Webb-Rubin Calculator

Eq. 1

P = R · T · ρ + ( ( B · R · T - A - C / T² ) · (ρ² ) ) + (ρ³ ) ( b · R · T - a ) + a · α · (ρ⁶) + ( c · ρ³ / T² ) · ( 1 + γ · (ρ² ) ) exp ( ( -1 ) · γ · (ρ²))

Where:

R = Gas Constant (BTU/mol psi K)
T = Temperature (K)
ρ = Density (g/cc)
A = Correlation Constant (dimensionless)
B = Correlation Constant (dimensionless)
C = Correlation Constant (dimensionless)
a = Correlation Constant (dimensionless)
b = Correlation Constant (dimensionless)
c = Correlation Constant (dimensionless)
α = Correlation Constant (dimensionless)
γ = Correlation Constant (dimensionless)
P = Pressure (psi)

Source:

John M. Campbell, Gas Conditioning and Processing, Campbell Petroleum Series, Oklahoma, 1992, Vol. 1, Page: 48.

Van der Waals Constants for Gases
Ideal Gas Properties of Oxygen O2 (SI Units), Entropies at 0.1 MPa (1 Bar) Pressure, Mass Basis
Thermodynamic Properties of Ammonia for Temperatures 0 to -40 °C Specific Volume, m3/kg and Internal Energy, kJ/kg
Superheated Nitrogen Thermodynamic Properties Table, Specific Volume, m3/kg, Internal Energy, kJ/kg, Enthalpy, kJ/kg, and Entropy, kJ/kg-K at pressure 400 kPa, 600 kPas, 800 kPa, and 1000 kPa.
Effects of Pressure Changes on Fluid Properties
Saturated and Superheated Vapors
Ideal Gas Assumptions, Properties of Pure Substances, Property Tables, Class 2