Multiphysics modeling of wire-to-plate electrohydrodynamic drying with air crossflow

Abstract

Electrohydrodynamic (EHD) convective drying is a non-thermal energy-efficient technology to preserve heat-sensitive materials by dehydration. A high-voltage electrode is used to induce corona wind that increases convective heat and mass transfer in the material and air interface. A chamber used for EHD drying with a wire-to-plate configuration and additional air crossflow was modeled considering the finite element method in COMSOL Multiphysics (v.6.1). The concepts of electrostatics, turbulent flow, heat transfer in fluids and moisture and energy transport physics were combined iteratively to solve and predict the electric field strength, airflow, convective heat transfer coefficient and moisture removal. Different electric potential and air crossflow velocities were tested and their impact on the drying rate was quantified. Combining high voltage (0, 10, 15 and 20 kV) and air crossflow velocity (0, 1, and 2 m/s) was found to have a significant effect on the convective heat transfer coefficient and moisture removal; however, the increase in one of the drying factors had a low effect on drying time. The main results show that the proposed model can adequately simulate the EHD airflow phenomena and the drying process and can be used for product quality improvement, energy efficiency analysis and optimization studies.