In the present work an experimental investigation has been carried out on the influence of the air humidity or the water vapor injected in the incoming air flow on DC corona discharge parameters in a wire-to-planes electrostatic precipitators. To characterize the behavior of the corona discharge for both positive and negative corona, the current-voltage characteristics are subjected to an analysis using the model of Cooperman which derives the quadratic Townsend law and the general formula proposed by Meng et al. The experimental results show that the discharge current is strongly influenced by the level of air humidity. Moreover, the corona current becomes very small with the applied voltage beyond Hr = 90%, because the particle size is increased by condensation. It was demonstrated that the Coopeman model is reliable to determine the mobility of the charge carriers in this system.

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