Wohl Parameter (a) of Real Gas using Wohl Equation given Actual and Reduced Parameters Calculator

Wohl Parameter a Formula:

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

Temperature of Real Gas (T):

Reduced Temperature (T_r):

Molar Volume of Real Gas (V_m):

m³

Reduced Molar Volume (V'_r):

Pressure of Gas (P):

Reduced Pressure (P_r):

Wohl Parameter b:

Wohl Parameter c:

Wohl Parameter a:

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1. What is Wohl Parameter (a) of Real Gas?

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, particularly accounting for intermolecular forces in non-ideal conditions.

2. How Does the Calculator Work?

The calculator uses the Wohl equation:

Where:

\( a \) — Wohl parameter a (result)
\( R \) — Universal gas constant (8.314 J/mol·K)
\( T \) — Temperature of real gas (K)
\( T_r \) — Reduced temperature (dimensionless)
\( V_m \) — Molar volume of real gas (m³)
\( V'_r \) — Reduced molar volume (dimensionless)
\( P \) — Pressure of gas (Pa)
\( P_r \) — Reduced pressure (dimensionless)
\( b \) — Wohl parameter b
\( c \) — Wohl parameter c

3. Importance of Wohl Parameter Calculation

Details: Accurate calculation of Wohl parameters is essential for modeling real gas behavior in chemical engineering, thermodynamics, and industrial processes.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Default values are provided for reference.

5. Frequently Asked Questions (FAQ)

Q1: What are reduced parameters?
A: Reduced parameters are ratios of actual parameters to their critical values (e.g., reduced temperature = T/T_c).

Q2: How do I find reduced parameters?
A: Divide the actual parameter by its critical value for the substance (available in thermodynamic tables).

Q3: What are typical values for Wohl parameters?
A: Parameters vary by substance. For example, for CO₂: a ≈ 0.365, b ≈ 0.0427, c ≈ 0.00042.

Q4: When is the Wohl equation most useful?
A: For moderately non-ideal gases at high pressures and low to moderate temperatures.

Q5: What are the limitations of the Wohl equation?
A: It may not be accurate near the critical point or for highly polar gases.