A corona is a visible luminous emission that occurs in the vicinity of sharp edges where the electric field is intense. This phenomenon is associated with gas ionization and acceleration of ions in strong electric fields, dragging the gas particles and generating a secondary flow, known as corona wind. Corona wind may be employed as an active enhancement technique for heat transfer. The effect of corona wind is entitled electrohydrodynamic (EHD) that may significantly improve convective heat transfer coefficient in the developing and developed regions of a tube. An experimental research was conducted to investigate the level of heat transfer enhancement in the developing region of a circular tube by helical electrode. This wire electrode, charged with a high negative voltage, was coiled around a non-conductive circular cylinder. The wire was contacted to a high voltage supply. The study focused on the laminar to lower range of turbulent flows with Reynolds number and voltage ranging from 1500 to 10,000 and 0 to 17.1 kV, respectively. Also three different constant heat fluxes were applied to the outer surface of the tube. Maximum enhancement occurred between Re=2500 and 4000. Energy consumption of this enhancement technique is very low . Also in this study, the effect of electrode geometry, such as diameter and pitch of the coiled wire electrode were investigated and the optimum values of mentioned parameters were specified. The results can be summarized as follow: By increasing the applied voltage and current, convective heat transfer is increased. By increasing the applied heat flux, the convective heat transfer is increased with or without applying EHD. EHD is more effective at lower heat fluxes. Also EHD is more effective at lower Reynolds numbers. The higher the diameter of the coiled wire electrode, the higher the inception voltage is. Also, at a constant applied voltage it is observed that the smaller electrode diameter leads to larger enhancement. At a constant applied voltage, Power consumption by EHD is inversely proportional to the electrode diameter. In general, an increase in the gamut of the coiled wire electrode, leads to a decrease in the average convective heat transfer. K eyWords : Corona wind; EHD; Heat transfer; Enhancement; Tube; Helical electrode; Geometry.