Transport Phenomena II


Understanding of mass transfer fundamentals. Mathematical formulation of mass transfer problems for different geometries.Evaluation of diffusion coefficients and mass transfer coefficients. 

General characterization





Responsible teacher

Isabel Maria Rola Coelhoso


Weekly - 4

Total - 70

Teaching language





Cussler, E.L., " Diffusion: mass transfer in fluid systems", 3rd ed., Cambridge University Press, UK, 2009.


Bird, R.B.; Stewart, W.E.; Lightfoot, E. N. Transport Phenomena. 2nd ed. J Wiley & Sons, 2007.


Welty, J.R; Wicks, C.E.; Wilson, R.E.; Rorrer G.L. Fundamentals of momentum, heat and mass transfer. 5th ed. John Wiley &Sons, Inc, N.Y., 2010.


Teaching method

The teaching comprises lectures and solving problems sessions which cover all the contents according to the syllabus. Example problems are solved to illustrate the given concepts.


Evaluation method

The continuous assessment of the discipline is carried out through 2 tests, each worthing 50% of the final grade. The first test covers the material in chapters 1, 2, 3 and 4 of the course syllabus. The second test covers the material given in the remaining chapters.

The duration of the tests is 1h30 minutes. Each test is evaluated from 0 to 20 values. The assessment is individual and without consultation. A minimum classification of 10 (9.5) values ​​is required, on a scale from 0 to 20, in the average of the test scores.

If the student does not pass the continuous assessment or chooses not to do so, he/she will be entitled to an appeal exam. The student can choose to take only the part corresponding to each of the tests. In this case, the test score will be replaced by the corresponding part of the exam.

A minimum classification of 10 (9.5) values, on a scale from 0 to 20, is required in the exam grade for approval in the discipline.


Subject matter

  1. Fundamentals of mass transfer. Definitions of concentrations, velocity and flux; Fick’s first law. Nernst-Planck equation. Diffusion coefficients; Methods for estimating diffusion coefficients. Diffusion of ionic species. Multicomponent diffusion.
  2. Differential equations of mass transfer. Boundary conditions. Steady state molecular diffusion; Diffusion through a stagnant film; Equimolal counterdiffusion;
  3. Diffusion with heterogeneous chemical reaction. Pseudo steady state diffusion.
  4. Unsteady state molecular diffusion. Stefan-Maxwell equations. Analytical solutions of Fick’s secondlaw.
  5. Convective mass transfer; Dimensional Analysis; Concentration boundary layer; Models and analogies of Reynolds and Chilton-Colburn; Empirical correlations.
  6. Interphase mass transfer; Equilibrium gas- liquid and liquid- liquid; Two-resistance theory; Overall and individual mass transfer coefficients.
  7. Diffusion with homogeneous chemical reaction; Hatta number; First and second order reactions.


Programs where the course is taught: