Simple, lightweight electrohydrodynamic pumps having no moving parts and producing no mechanical vibration or noise can enhance heat transfer, control fluid flows, and increase drying. This paper reports a numerical investigation of electrohydrodynamic (EHD) pumps having one centrally located emitter and two collector electrodes. Results show that optimum sizes exist in the length of and spacing between the collectors. Collector electrodes with triangular cross-sections can yield better performance than those having rectangular cross-sections. The magnitude and distribution of the charge density significantly influence pump performance.