Efficiency of a Wire-Rod Type Electrohydrodynamic Gas Pump Under Negative Corona Operation

A wire-rod type electrohydrodynamic (EHD) gas pump was driven by a negative applied voltage with pipes of different inner diameters. An EHD gas flow was generated from a wire electrode to a rod electrode under a negative corona discharge. The flow velocity was proportional to the applied voltage and the square root of the discharge current. Before spark onset, the maximum volumetric flow rate of 43 L/min was achieved with a pipe having an inner diameter 20 mm, and the pump efficiency was higher than that of a conventional dc motor fan. In a narrow channel, the corona discharge became unstable. In addition, the EHD gas flow velocity was smaller because a pressure loss due to the rod electrode became significant, resulting in a lower electromechanical efficiency.