Heat and Mass Transfer
Content
Dept of Chemical and Biomolecular Engineering
CN2125 Heat and Mass Transfer Dr. Praveen Linga, E5-02-23, 6601-1487 (Radiation, Mass Transfer)
Tutorial/HW Week #9 WWWR Chapters 26-27 ID Chapter 14 • Tutorial #9 • WWWR #26.17, 26.27, 27.6, 27.22 & ID #14.33 • To be discussed during the week of Mar 19 - 23, 2012. • By either volunteer or class list.
• Homework #9 (self practice) • WWWR # 26.22, 27.16 & ID #14.39
Molecular Diffusion • General differential equation
∇⋅
N A
+
c A ∂∂ t
−
RA
=
0
• One-dimensional mass transfer without reaction
N A, z =
− cD AB
dy A dz
+ y A ( N A, z +
N B , z )
Unimolecular • Diffusivity of gas can beDiffusion measured in an Arnold diffusion cell
• Assuming – Steady – Steady state, no reaction, and diffusion in zdirection only
• We get
dN A, z dz
=
0
• And since B is a stagnant gas,
dN B , z dz
=
0
CN2125 Heat and Mass Transfer Dr. Praveen Linga, E5-02-23, 6601-1487 (Radiation, Mass Transfer)
Tutorial/HW Week #9 WWWR Chapters 26-27 ID Chapter 14 • Tutorial #9 • WWWR #26.17, 26.27, 27.6, 27.22 & ID #14.33 • To be discussed during the week of Mar 19 - 23, 2012. • By either volunteer or class list.
• Homework #9 (self practice) • WWWR # 26.22, 27.16 & ID #14.39
Molecular Diffusion • General differential equation
∇⋅
N A
+
c A ∂∂ t
−
RA
=
0
• One-dimensional mass transfer without reaction
N A, z =
− cD AB
dy A dz
+ y A ( N A, z +
N B , z )
Unimolecular • Diffusivity of gas can beDiffusion measured in an Arnold diffusion cell
• Assuming – Steady – Steady state, no reaction, and diffusion in zdirection only
• We get
dN A, z dz
=
0
• And since B is a stagnant gas,
dN B , z dz
=
0
