Plate versus mesh collecting electrode for electrohydrodynamic (EHD) drying

Abstract

Electrohydrodynamic (EHD) drying is considered a highly efficient technology due to its ability to create powerful convective airflow with low energy consumption. EHD efficiency depends on multiple factors, such as voltage, current, environmental conditions, drying material, and electrodes geometry. This research is exploring the effect of collecting electrode geometry on the drying rate and energy efficiency of EHD drying. Although numerical studies predict a better performance of mesh collectors compared to solid plate collectors, experimental verification is still missing. This research addresses this gap by comparing the performance of plate versus mesh collecting electrodes in drying experiments with three discharge electrodes (nails, needles, pins) and two materials (wet paper and apple slices). Our experiments confirmed the benefits of mesh collector compared to the plate, namely up to 25% higher drying flux and a 20–35% smaller specific energy consumption. For example, EHD drying of apple slices with the mesh resulted in specific energy consumption of 719–731 kJ/kg compared to 935–968 kJ/kg with the plate collector. The better energy efficiency of the mesh collector provides a unique opportunity for the industrial upscaling of EHD drying technology.