I see. Thank you for referring to the rules.
Well, I am trying to find Peclet number for reactor I and reactor II. For reactor I, Pe = uL/D, where u is bulk fluid velocity, L is length of the reactor, and D is axial dispersion coefficient.
I think that D' (in reactor II) should be equal to D (in reactor I) as uniform dispersion is considered in both reactors. Further, bulk velocity (u) is also constant for both cases.
Therefore, for reactor II, Peclet number Pe' = u(L/2)/D' = uL/2D = Pe/2.
Hence, Pe' = Pe/2, and D' = D.
Is this approach correct?