The Second Virial Coefficient of Ordinary Water Substance: A New Correlation

Abstract

It is shown that the specific second virial coefficient for ordinary water substance, expressed as a function of temperature, is correlated by

This correlation, motivated by recent observations from low-pressure steady-flow calorimetry from 20°C to 140°C, also covers older tabulated values of the second virial coefficient extending to 800°C. The Boyle temperature is found to be 1498 K.

B₂ = a₁f₁ + a₂f₂ + a₃f₃

where f₁ = 1/(1 + T/α), f₂ = (1 - e^-β/T)^5/2(T/β)^1/2e^β/T, f₃ = β/T, α = 10000 K, β = 1500 K, a₁ = 0.0015 m³/kg, a₂ = −0.000942 m³/kg and a₃ = −0.0004882 m₃/kg.