Axial Diffusion in Microscale Ducts

Loop While Ttime 3 End of false transient Ttime = 0 Sum = 0 

It is desired to study the effect of cross-channel and axial diffusion, that is, the effects of varying on reactor performance. In a reactor design problem, 

Using finite-difference approximations for the spatial derivatives gives da dr 

Code for Example 16.3 contains parameters chosen to allow a solution in a few minutes. Accurate calculations require a large number of cross-channel increments. This forces a small time step and running times of afew hours. The numerical solution of Equation 16.13 becomes ill conditioned at high values of D = 23/J. Eor first-order reactions, the analytical solution 

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