Session: 11-13-01 Fundamentals and Applications of Evaporation, Boiling and Condensation

Paper Number: 69545

Start Time: Wednesday, 10:05 AM

69545 - Experimental Study of Heat Transfer Characteristics of Drying Process with Dielectrophoresis Mechanism 

Abstract: Drying of moist porous media, such as paper and pulp, is an extremely energy-consuming process. Traditional drying techniques are mostly associated with convection, conduction and thermal radiation, either alone or combined. It is desirable to develop innovation of non-thermal and high-efficiency drying techniques. In the previous study, a novel drying technology making use of the Dielectrophoresis (DEP) mechanism has been experimentally proved to be an energy efficient method to enhance the drying rate of the moist porous media [1]. DEP is a translational motion of neutral matter caused by polarization effects in a non-uniform electric field. In the presence of DEP force, the vapor phase gets extracted away from the porous medium, which results in the increase of the evaporation rate and decrease of sample surface temperature. This paper extends previous studies by including the heat transfer characteristics analysis, specifically, the heat flux rate underneath the moist paper sample is monitored during the drying process. The sample surface temperature is monitored through an Infrared (IR) camera. Parametric studies regarding the sample initial moisture content and sample basis weight are studied as a function of drying time. Additionally, a theoretical drying model for a saturated porous medium containing excess water is used to investigate the convective heat transfer coefficient (h) in the presence of the DEP mechanism [2]. The numerical model is first validated with the experimental data, then the numerical model is used to estimate the heat transfer coefficient in the presence of the DEP mechanism. The experimental results show that the heat flux rate increases in the presence of DEP force, and an up to 130% increase of heat flux rate is achieved due to the application of electric field compared to that of regular drying without electric field application. The experimental results also illustrate the effects of DEP diminish as the decrease of the initial moisture sample. The numerical simulation results show good agreement with the experimental data. The experimental and simulation results illustrate the detailed heat transfer analysis and provide the foundation for the enhancement of moist porous media with the DEP mechanism.

Keywords: Drying, dielectrophoresis, evaporation, numerical prediction, heat transfer coefficient.

 

[1] M. Yang and J. Yagoobi, "Enhancement of Drying Rate of Moist Porous Media with Dielectrophoresis Mechanism " Journal of Drying Technology, 2020 (under review)

[2] M.E. Asar and J. S. Yagoobi, “A Numerical Study: Drying of a Fully Saturated Porous Medium with Excess Water Layers”, IMECE 2021 (Abstract Submitted #68157)

Presenting Author: Mengqiao Yang Worcester Polytechnic Institute

Authors:

Mengqiao Yang Worcester Polytechnic Institute
Munevver Elif Asar Worcester Polytechnic Institute
Jamal Yagoobi Worcester Polytechnic Institute