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The electrochemical technique  is utilized to test  local  mass transfer coefficient and flow
transition in simple cubic  packed beds.  The microelectrodes are placed at the tube wall and
inner particle surfaces  to study local flow and mass transfer behaviors  with particle Reynolds
number (Re) ranging from 20 to 1100.  The mass transfer coefficients can be obtained based
on  the  limiting  current.  It  was  found  that,  the  mass  transfer  coefficient  at  inner  probes  is
higher  than that  of  the tube wall probes.  Compared with  the mass transfer in random packed
bed, mass  transfer is enhanced  with  ordered  pore  structures  in simple cubic  packed bed.  The
effects of aspect ratios (N=3,  N=4 and  N=5) on mass transfer are discussed and no obvious
influence is observed.  Meanwhile,  three  different  flow  regimes  in  the  packed beds, including
laminar,  transition  and  turbulent  flow  regimes  are  identified  according  to  the  analysis  of
Fluctuating  Rate  (FR)  of limiting current signals.  Compared  with  flow transition in random
packed bed, the flow transition is delayed due to the ordered  pore  structure in simple cubic
packed  beds.  The  effects  of  aspect  ratios  (N=3,  N=4  and  N=5)  on  flow  transition  are  also
discussed. The transition flow regime occurs at Reynolds number ranging from 200 to 390 for
most electrodes in simple cubic packed beds with N≥4.

Electrochemical technique, Mass transfer, Flow transition, Simple cubic packing