Molar Flux of Diffusing Component A through Non-Diffusing B based on Mole Fractions of A and LMMF Calculator

Molar Flux Formula:

\[ N_A = \frac{D_{AB} \cdot P_t}{\delta} \cdot \frac{y_{A1} - y_{A2}}{y_{B,lm}} \]

Diffusion Coefficient (D_AB):

m²/s

Total Pressure of Gas (P_t):

Film Thickness (δ):

Mole Fraction of A in 1 (y_A1):

Mole Fraction of A in 2 (y_A2):

Log Mean Mole Fraction of B (y_B,lm):

Molar Flux of Diffusing Component A (N_A):

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1. What is Molar Flux of Diffusing Component A?

Definition: Molar flux (N_A) is the amount of substance per unit area per unit time that diffuses through a medium.

Purpose: This calculator determines the molar flux of component A through non-diffusing component B based on mole fractions and the log mean mole fraction of B.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_A = \frac{D_{AB} \cdot P_t}{\delta} \cdot \frac{y_{A1} - y_{A2}}{y_{B,lm}} \]

Where:

\( N_A \) — Molar flux of component A (mol/(s·m²))
\( D_{AB} \) — Diffusion coefficient (m²/s)
\( P_t \) — Total pressure of gas (Pa)
\( \delta \) — Film thickness (m)
\( y_{A1} \) — Mole fraction of A at point 1
\( y_{A2} \) — Mole fraction of A at point 2
\( y_{B,lm} \) — Log mean mole fraction of B

Explanation: The formula calculates the molar flux based on the concentration gradient, diffusion coefficient, and system geometry.

3. Importance of Molar Flux Calculation

Details: Accurate molar flux calculations are essential for designing separation processes, chemical reactors, and mass transfer equipment.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Mole fractions must be between 0 and 1. Default values are provided for common scenarios.

5. Frequently Asked Questions (FAQ)

Q1: What is the log mean mole fraction?
A: It's the logarithmic average of the mole fractions of component B at two different points in the system.

Q2: What are typical values for the diffusion coefficient?
A: Diffusion coefficients typically range from 10^-5 to 10^-9 m²/s for gases and liquids respectively.

Q3: How do I determine film thickness?
A: Film thickness depends on system geometry and flow conditions, often determined experimentally or through correlations.

Q4: Can this be used for liquid systems?
A: The basic principle applies, but liquid-phase diffusion coefficients and system pressures differ significantly.

Q5: What if component B is also diffusing?
A: A different formulation (Maxwell-Stefan equation) would be needed for equimolar counter-diffusion.