Estimate coefficients from concentration driving force or diffusion data. Compare methods and save reports easily. Practical for absorbers, strippers, towers, membranes, and lab analysis.
| Case | Method | Key Inputs | Coefficient Result |
|---|---|---|---|
| 1 | Direct flux | N = 0.015, C_i = 0.50, C_b = 0.20 | k = 0.05000000 |
| 2 | Sherwood relation | Sh = 120, D = 2.0×10⁻⁹, L = 0.004 | k = 0.00006000 |
| 3 | Resistance model | R1 = 8, R2 = 12, Rf = 5 | K = 0.04000000 |
k = N / (C_i - C_b)
N is mass flux. C_i is interfacial concentration. C_b is bulk concentration. This method is useful when flux and the concentration driving force are known.
k = Sh × D / L
Sh is the Sherwood number. D is molecular diffusivity. L is characteristic length. This approach is common when transport correlations are available.
K = 1 / (R_1 + R_2 + R_f)
K is the overall coefficient. R_1 and R_2 are transfer resistances. R_f is extra fouling or added resistance.
Always keep unit systems consistent. The numerical result is only meaningful when flux, concentration, diffusivity, length, and resistance units match the selected formula.
Mass transfer coefficient is a core design parameter. It shows how fast a species moves between phases or across a boundary layer. Engineers use it in absorption, stripping, drying, humidification, extraction, membranes, and reaction systems. A reliable coefficient helps size equipment and predict performance.
There is no single path for every process. Some studies use measured flux and concentration difference. Others use dimensionless correlations. Many design checks use an overall resistance model. The best method depends on the data you have and the stage of the project.
The direct method is useful in lab work and pilot testing. You measure mass flux. Then you divide by the concentration driving force. The result gives a practical film coefficient. This approach is simple and clear when the interfacial value is available or estimated well.
The Sherwood number method is common in transport analysis. It links diffusion, geometry, and flow behavior. Engineers often combine Sherwood, Reynolds, and Schmidt relations during scale up. That makes it helpful for packed beds, pipes, plates, and external flow problems.
Real systems often have more than one resistance. Gas side resistance may matter. Liquid side resistance may also matter. Fouling can add another penalty. The resistance model combines these effects into one overall coefficient. That makes comparison and design review easier.
Use consistent units. Check whether your coefficient is local or overall. Confirm the correct characteristic length. Review data quality before using the result in design. A clean calculation supports better process control, stronger equipment selection, and more confident engineering decisions.
It represents the rate of species transfer per unit driving force. A higher value means faster transfer through the fluid film or combined resistances.
Use the direct method when flux and concentrations are known. Use the Sherwood method when correlation data exists. Use the resistance model when several resistances act together.
The formulas return meaningful results only when all inputs use compatible units. Mixed unit systems can create wrong coefficients and wrong design decisions.
k usually refers to a local or single-film coefficient. K usually refers to an overall coefficient that combines multiple resistances into one value.
Yes. It is useful for many gas-liquid estimates, especially screening calculations. Just ensure your chosen method and units match the physical model you are applying.
It needs a Sherwood number, diffusivity, and characteristic length. Those values often come from transport correlations, experiments, or design references.
It is helpful when transfer is limited by more than one step. It is also useful when fouling or additional resistance must be included.
Yes. Use the CSV button for tabular data and the PDF button for a simple report file based on the current result section.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.