1. CE 318: Transport Process 2 (Heat and Mass Transfer) Lecture 18: Convective Mass Transfer (Chapter 28) NSC 210 4/16/2015

2. 2 Overview of Mass Transfer Steady State Molecular Diffusion  Fick’s Law for Molecular Diffusion  D A : gas, liquid, solid, biological materials  calculation: different geometries and flow conditions Convective Mass-Transfer Coefficient Unsteady State Diffusion Different parameters for driving force Multi-components

3. 3 Mass Convective Transfer: Drying the Paint

4. 4 Mass Convective Transfer: Dryer

5. 5 Mass Convective Transfer: Membrane Coater

6. Film Concept: Convective Mass Transfer 6

7. Fundamental view of heat convection  Dimensional analysis  Exact analysis of the boundary layer  Approximate integral analysis of the boundary layer  Analogy between momentum and heat transfer Empirical equations (next lecture) 7 Outline: h Values ?

8. 8 Heat Convective Transfer

9. 9

10. Combining of Momentum and Heat Transfer 10 (Chapter 12)

11. Blasius’s Solution for Heat Transfer 11

12. Semi-Empirical Method to Estimate h 12 Prandtl Number Nusselt Number

13. 13 Outline: h Values ?

14. 14 Outline: h Values ?

15. Fundamental view of heat convection  Dimensional analysis  Exact analysis of the boundary layer  Approximate boundary layer analysis  Analogy between momentum, energy and mass transfer Empirical equations (in the future lecture) 15 Outline: k c Values ?

16. 16 Momentum, Heat and Mass Transfer

17. 17 Mass Convective Transfer

18. 18 Mass Convective Transfer

19. Combining Momentum and Mass Transfer 19 25.17

20. Blasius’s Solution 20 Blasius’s solution:

21. Blasius’s Solution (See Chapter 12) 21

22. Blasius’s Solution for Mass Transfer 22

23. Blasius’s Solution for Mass Transfer 23 When Sc=1

24. Blasius’s Solution for Mass Transfer 24 Average mass convective coefficient

25. Semi-Empirical Method to Estimate k c 25 Schmidt Number Sherwood Number

26. Fundamental view of heat convection  Dimensional analysis  Exact analysis of the boundary layer  Approximate boundary layer analysis  Analogy between momentum, energy and mass transfer Empirical equations (in the future lecture) 26 Outline: k c Values ?

27. 27 Outline: h Values ? Sc = Pr = 1

28. 28 Outline: h Values ?

29. 29 k c Values ?

30. Fundamental view of heat convection  Dimensional analysis  Exact analysis of the boundary layer  Approximate integral analysis of the boundary layer  Analogy between momentum and heat transfer Empirical equations (next lecture) 30 Outline: h Values ?

31. Fundamental view of heat convection  Dimensional analysis  Exact analysis of the boundary layer  Approximate boundary layer analysis  Analogy between momentum, energy and mass transfer Empirical equations (in the future lecture) 31 Outline: k c Values ?

32. Example