Reduced Pressure Formula:
From: | To: |
Definition: Reduced pressure is the ratio of the actual pressure of a fluid to its critical pressure, used in corresponding states calculations.
Purpose: It helps in thermodynamic calculations and phase behavior predictions using the Redlich-Kwong equation of state.
The calculator uses the formula:
Where:
Explanation: The formula relates the actual pressure to reduced pressure through the Redlich-Kwong parameters.
Details: Reduced pressure is crucial for thermodynamic property estimation, phase equilibrium calculations, and process design in chemical engineering.
Tips: Enter the system pressure in Pascals, Redlich-Kwong parameter a (Pa·m⁶/mol²), and parameter b (m³/mol). All values must be > 0.
Q1: What are typical values for parameters a and b?
A: These vary by substance. For example, for water: a ≈ 142.59 Pa·m⁶/mol², b ≈ 2.13×10⁻⁵ m³/mol.
Q2: Why is reduced pressure dimensionless?
A: Because it's a ratio of two pressures (actual/critical), the units cancel out.
Q3: What's the range of reduced pressure values?
A: Typically 0 to 1, where 1 represents the critical pressure.
Q4: How accurate is the Redlich-Kwong equation?
A: It's reasonably accurate for non-polar gases at moderate pressures but less accurate near critical conditions.
Q5: Can I use this for liquid phases?
A: The Redlich-Kwong equation is primarily for gas phases, though modified versions exist for liquids.