This study is the continuation of the work devoted to electrochemical electrohydrodynamic (EHD) converters. The goal of this study is the computer simulation of the formation and development of the EHD flow in a symmetric and grid electrode system located in a channel with dielectric walls. Three types of EHD grid converters, namely, defocusing, symmetric, and focusing systems were investigated. The physical causes of the appearance of return vortices in defocusing electrode systems are explained. This is due to the formation of the charge plug in the behind-the-electrode region, which retards the through pumping of the fluid. It is shown that, in order to eliminate the charge plug, it is necessary to arrange one counter electrode along the flow’s axis and to select the impurity composition of the fluid so that the injection also occurs on the surface of the passive electrode rather than the active one only. In this case, the bipolar charge structure compensating for the return retarding effect is formed in t