This equation computes the acentric factor (`omega`)^[1],  a measure of the non-sphericity of molecules.

The acentric factor characterizes the phase of gases.

Inputs

The acentric factor computed here is a function of the reduced pressure at the reduced temperature, `T_r` = 0.7. 

Description

The acentric factor, `omega`, is one of the set of state description parameters that includes: molecular weight, critical temperature, critical pressure, and critical volume.

The reduced properties of fluids are a set of state variables which are normalized by the fluid's state properties at the fluid's critical point.  In this equation two reduced properties are used:

• The reduced temperature is: `T_r = T/T_c` is the
• The reduced pressures saturation is: `p_r^"sat" = p^"sat" / p_c`

Reference

[1] Acentric factor
Source: Wikipedia
URL: https://en.wikipedia.org/wiki/Acentric_factor
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