Tutorial/HW Week #8 WRF Chapter 23; WWWR Chapters 25-26 ID Chapter 14 To be discussed on March 14, 2017. By either volunteer or class list.

Special Forms Combining the flux equation with the continuity equation,

Assuming constant r and DAB, we get Additionally, if there are no reactions, then or

And if there is also no fluid motion, v = 0, Which is Fick’s second law of diffusion For steady state process, constant r and DAB,

With no chemical reaction and no fluid flow, becomes which is the Laplace equation for molar concentration.

Initial and Boundary Conditions Initial condition: e.g. t = 0, CA=CA0. Boundary condition: (a) The concentration of the transferring species A at a boundary is specified. (b) A reacting surface boundary is specified.

Example 1

Example 2

Example 3

R2 R2 R1

Review #2: Convective Heat Transfer & Mass Transfer Fundamentals Please Refer to Appendix 8.