This paper investigates the effect of inlet shape, entrance length and
turbulence promoters on mass transfer by using 3D printed electrolyzers.
Our results show that the inlet design can promote turbulence and lead
to an earlier transition to turbulent flow. The Reynolds number at which
the transition occurs can be predicted by the ratio of the
cross-sectional area of the inlet to the cross-sectional area of the
electrolyzer channel. A longer entrance length results in more laminar
behavior and a later transition to turbulent flow. With an entrance
length of 550mm, the inlet design did no longer affect the mass transfer
performance significantly. The addition of gyroid type turbulence
promoters resulted in a factor 2 to 4 increase in mass transfer
depending on inlet design, entrance length and the type of promoter.
From one configuration to another, there was a minimal variation in
pressure drop (<16 mbar).