Effects of Porosity on the Performance of EHD-Enhanced Drying

Abstract

Several earlier studies have demonstrated the effectiveness of electrohydrodynamic (EHD) drying. The use of glass beads in the previous studies helps to quantify the material structure. To evaluate the effects of porosity, one of the most important parameters in the characterization of material structure, experiments have been performed in the present study using 5-mm perforated glass beads. To generate the needed corona wind for accelerating drying, two types of electrodes (a thin wire and a sharp needle) were used and were charged with a DC high voltage. In addition, experiments were carried out using two different cross-flow velocities and at a voltage range from 10 to 25 kV (with both positive and negative polarities). The results thus obtained are compared with those of solid glass beads of various sizes to evaluate the dependence between the material structure (in terms of its porosity) and the effectiveness of corona wind in drying.

Keywords:

• Corona wind
• Drying enhancement
• Electrohydrodynamics (EHD)
• Porosity