Fluid pattern inside of flow electrochemical reactors is strongly affected by geometric inlets design and the use of net-like spacers (or turbulence promoters). In this report a comparison of the hydrodynamic behavior between empty and net-like spacer-filled channel of a parallel plate reactor based in CH-0 electrolyzer of Asahi Glass Co. is presented. RANS equations were solved by means of a Computational Fluid Dynamics (CFD) package (COMSOL 4.4a™). Simulations were validated through experimental flow characterization techniques such as flow visualizations and residence time distribution (RTD) tests. CFD studies evidenced that net-like spacer homogenizes flow distribution for all flow rates studied in this report (0.15–0.63 m s⁻¹), causing an increase in local Reynolds numbers in this configuration in comparison with typical empty channel. The flow behavior generated by these spacers could improve mass transport performance, nevertheless, an additional cost for electrolyte pumping must be considered. Comparisons of theoretical and experimental RTD curves and flow visualizations showed that the formulation of the numerical simulation proposed here is appropriate to reproduce the flow pattern inside the net-like spacer-filled channel of a filter press type electrolyzer and can be used for further scaling-up studies.