ce 318: transport process 2 (heat and mass transfer) lecture 18: convective mass transfer (chapter...
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CE 318: Transport Process 2(Heat and Mass Transfer)
Lecture 18: Convective Mass Transfer(Chapter 28)
NSC 2104/16/2015
2
Overview of Mass Transfer
• Steady State Molecular Diffusion
Fick’s Law for Molecular Diffusion
DA: gas, liquid, solid, biological materials
calculation: different geometries and flow conditions
• Convective Mass-Transfer Coefficient
• Unsteady State Diffusion
dx
dCDJ AAA
dx
dCA
21 AAAA CCkJ )(Re,ScfkA
2
2
x
CD
t
C AA
A
Different parameters for driving forceMulti-components
• 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 ?
TThA
qs
x
Pr)(Re,fk
hLNu
• 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: kc Values ?
)(Re,ScfD
LkSh
AB
c
ABDSc
2,1,, AAczA CCkN
• 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: kc Values ?
)(Re,ScfD
LkSh
AB
c
ABDSc
2,1,, AAczA CCkN
• 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 ?
TThA
qs
x
Pr)(Re,fk
hLNu
pck
Pr
• 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: kc Values ?
)(Re,ScfD
LkSh
AB
c
ABDSc
2,1,, AAczA CCkN