Previously, we studied solution crossover in the standard membraneless microfluidic MFC as a function of electrode distance. In those simulations the anolyte and catholyte flow rates were balanced. In the following work, we simulated three different flow conditions on both the standard 6 mm membraneless MFC design (Figure ) and the present membrane MFC (Figure ): (i) Qa=Qc=0.5 mL h -1 (balanced flow), (ii) Qa=0.7 mL h -1 , Qc=0.3 mL h -1 , and (iii) Qa=0.3 mL h -1 , Qc=0.7 mL h -1 . For the membraneless MFC under balanced flow (Qa=Qc), the simulated acetate concentration profile was as expected (Figure The contour line of 2 mM acetate for membrane submillimeter MFCs was plotted with an imbalanced flow (ii) (Figure ). The contour line showed a less shift at the PDMS side due to the block of the membrane. While the contour line shift was more obvious on the glass side with 5 μm gap. The same trends was observed with contour line of 6 mM ferricyanide at an imbalanced flow (iii) (Figure ).