The principal mechanism
in EHD drying is based on convective heat without the need for
direct heat application.
This makes it useful for drying heat sensitive
materials.
The enhancement in mass transfer rate could be
attributed to the electric wind induced by EHD as the main driving
force. The air ions, which originated from a small region around the
needle points, are accelerated by the applied electric force. Momentum
is transferred from the ions to the air molecules. This
causes the air movement as a whole which constitutes the electric
wind. The impingement of this wind on wet materials produces an
impact and thus, enhances mass transfer rates of water through
increased turbulence. The difference in the pressure of vapor in the
ambient air and the ambient close to EHD set up, causes migrate
moisture (Chen & Mujumdar, 2002)