Wohl Parameter (a) Formula:
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Definition: Wohl parameter a is an empirical parameter characteristic to equation obtained from Wohl model of real gas.
Purpose: It helps in describing the behavior of real gases, accounting for intermolecular forces and molecular volume.
The calculator uses the Wohl equation:
Where:
Details: Accurate calculation of Wohl parameters is essential for modeling real gas behavior in chemical engineering applications, particularly at high pressures and temperatures.
Tips: Enter all required parameters. Reduced properties are dimensionless ratios. Critical properties are substance-specific and can be found in reference tables.
Q1: What are typical values for Wohl parameters?
A: Parameters vary by substance. For example, for CO₂: a ≈ 0.365, b ≈ 0.0427, c ≈ 0.00014 (in appropriate units).
Q2: How do I find critical properties for a substance?
A: Critical properties are tabulated in chemical engineering reference books and databases like NIST Chemistry WebBook.
Q3: What's the difference between reduced and critical properties?
A: Reduced properties are ratios of actual to critical properties (dimensionless), while critical properties are substance-specific constants.
Q4: When is the Wohl equation most accurate?
A: The Wohl equation works best for moderately non-ideal gases at conditions not too far from critical.
Q5: What are the units of Wohl parameter a?
A: The units depend on the equation form, but typically Pa·m⁶·K⁰.⁵/mol² or similar.