Electrohydrodynamic drying of sand

ABSTRACT

This study analyzes the electrohydrodynamic (EHD) drying characteristics of sand. Effect of process parameters (independent variables) including air speed, electrode gap, and applied voltage on drying kinetics and dependent variables including percentage water removed (%), Sherwood number, EHD number, and specific energy consumed (SEC) (kJ/kg) were also investigated using a central composite design and response surface methodology. Maximum drying was obtained for process parameter combination of air speed (2 m/s), electrode gap (1.5 cm), and applied voltage (15 kV). Air speed and electric field intensity (ratio of applied voltage to electrode gap) were found to have a significant effect on percentage water removed (%) and Sherwood number. In case of EHD number and SEC during the EHD drying process, all process parameters had a significant effect on them. The SEC increased with an increase in applied voltage but reduced with an increase in air speed at any given applied voltage suggesting that the EHD drying process, in combination with cross flow, will lead to higher drying rate and low energy consumption under ambient conditions. Regression models were also developed describing the relation between independent and dependent variables.

KEYWORDS:

• Drying kinetics
• electric field intensity
• electrohydrodynamic drying
• specific energy consumption

Acknowledgment

The authors would like to acknowledge Dr. F. C. Lai, School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, Oklahoma, USA, for his contributions in the field of electrohydrodynamic heat and mass transfer.