Numerical investigation of the multi-pin electrohydrodynamic dryer: Effect of cross-flow air stream

Abstract

This article presents the results of numerical simulation and experimental study of a multi-pin electrohydrodynamic (EHD) dryer. Combined effect of EHD flow and the external air cross-flow on drying performance was investigated with 3-D numerical model, which accounts for electric field, electric charge transport, external air cross-flow and material-gas moisture transport. Effect of cross-flow air stream on drying was positive in the range of low velocities, changing to negative at high velocities due to counteracting with EHD flow. Numerical simulation predicted previously unknown effect of EHD flow on the cross-flow air stream, which was quantified as an increase of airway resistance. This prediction was fully validated by experiments. Both numerical simulation and experiment proved that for given intensity of EHD flow there is an optimum value of the cross-flow, resulting in maximum drying performance. The numerical model can be applied to determine the optimal operating parameters for multi-pin EHD dryer.

Keywords:

• Electrohydrodynamic drying
• corona discharge
• ionic wind
• numerical simulation
• FEM

Acknowledgments

The authors would like to thank Dr. Tadeusz Kudra for the valuable suggestions related to model verification and CMC Microsystems for providing access to the COMSOL commercial software. Chaoao Shi’s help in numerical simulation is highly appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the scholarship awarded to C. Zhong from China Scholarship Council (CSC 2016-06355025) for his work at the Western University (London, Canada) during the academic year 2016–2017. The work was also partially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC Discovery Grant 2017-04005).

Notes on contributors

Chongshan Zhong

Chongshan Zhong received his bachelor's, master's and PhD's degrees in high voltage technology of electrical engineering from China. As an associate professor at China Agricultural University, he focuses on the applications of high voltage techniques to the area of agriculture and food engineering, such as EHD drying, plasma nitrogen fixation, plasma fruit preservation, and PEF sterilization, etc.

Alex Martynenko

Alex Martynenko is a professor of bioelectronics engineering in Dalhousie University, Canada. He received his education as electromechanical engineer from National Agricultural University, Ukraine and from Guelph University, Canada. His research interests include electrotechnologies for drying and innovative food processing.

Patrick Wells

Patrick Wells is computer engineering student Department of Engineering, Dalhousie University.

Kazimierz Adamiak

Kazimierz Adamiak is a professor of electrical engineering at the University of Western Ontario in London, Ontario, Canada. His research interests include gas discharges and electrohydrodynamics.