Reduced Pressure of Real Gas using Wohl Equation given Reduced and Critical Parameters Calculator

Reduced Pressure Formula (Wohl Equation):

\[ P_r = \frac{\frac{[R](T_r T'_c)}{(V'_r V'_c - b)} - \frac{a}{(T_r T'_c)(V'_r V'_c)(V'_r V'_c - b)} + \frac{c}{(T_r T'_c)^2 (V'_r V'_c)^3}}{P'_c} \]

Reduced Temperature (T_r):

Critical Temperature (T'_c) (K):

Reduced Molar Volume (V'_r):

Critical Molar Volume (V'_c) (m³/mol):

Wohl Parameter b:

Wohl Parameter a:

Wohl Parameter c:

Critical Pressure (P'_c) (Pa):

Reduced Pressure (P_r):

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1. What is Reduced Pressure of Real Gas using Wohl Equation?

Definition: This calculator determines the reduced pressure of a real gas using the Wohl equation of state, given reduced and critical parameters.

Purpose: It helps in thermodynamic calculations for real gases where ideal gas assumptions don't apply.

2. How Does the Calculator Work?

The calculator uses the Wohl equation formula:

\[ P_r = \frac{\frac{[R](T_r T'_c)}{(V'_r V'_c - b)} - \frac{a}{(T_r T'_c)(V'_r V'_c)(V'_r V'_c - b)} + \frac{c}{(T_r T'_c)^2 (V'_r V'_c)^3}}{P'_c} \]

Where:

\( P_r \) — Reduced Pressure (dimensionless)
\( T_r \) — Reduced Temperature (dimensionless)
\( T'_c \) — Critical Temperature (K)
\( V'_r \) — Reduced Molar Volume (dimensionless)
\( V'_c \) — Critical Molar Volume (m³/mol)
\( a, b, c \) — Wohl parameters
\( P'_c \) — Critical Pressure (Pa)
\( [R] \) — Universal gas constant (8.314 J/mol·K)

3. Importance of Reduced Pressure Calculation

Details: Reduced properties are crucial for corresponding states theory and help predict gas behavior under various conditions.

4. Using the Calculator

Tips: Enter all required parameters. The reduced temperature and reduced molar volume are dimensionless ratios. Critical parameters and Wohl parameters are substance-specific.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for Wohl parameters?
A: Wohl parameters vary by substance. Parameter 'a' relates to intermolecular forces, 'b' to molecular volume, and 'c' to molecular interactions.

Q2: How do I find reduced temperature and volume?
A: Reduced temperature = T/T_c, Reduced volume = V/V_c, where T and V are actual conditions.

Q3: What's the range of validity for this equation?
A: The Wohl equation works best for moderate pressures and temperatures, away from the critical point.

Q4: Why use reduced properties?
A: Reduced properties allow generalized correlations that work for many substances.

Q5: How accurate is the Wohl equation?
A: It's reasonably accurate for many engineering applications but less precise than modern equations like Peng-Robinson.