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Optimization on drying conditions of a solar electrohydrodynamic drying system based on desirability concept.

Dalvand MJ, Mohtasebi SS, Rafiee S - Food Sci Nutr (2014)

Bottom Line: Electrohydrodynamic (EHD) has been applied for drying of agricultural materials due to several advantages such as energy saving, low cost equipment, low drying temperatures, and superior material quality.The results indicated that increasing the applied voltage from 6 to 15 kV, moisture ratio (MR) decreased, though energy efficiency and energy consumption were increasing.On the other hand, field strength of 5.2 kV cm(-1) was the optimal point in terms of MR.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran Karaj, Iran.

ABSTRACT
The purpose of this article was to present a new drying method for agricultural products. Electrohydrodynamic (EHD) has been applied for drying of agricultural materials due to several advantages such as energy saving, low cost equipment, low drying temperatures, and superior material quality. To evaluate this method, an EHD dryer based on solar (photovoltaic) energy was designed and fabricated. Moreover, the optimum condition for the EHD drying of kiwi fruit was studied by applying the Box-Behnken design of response surface methodology. The desirability function was applied for optimization in case of single objective and multiobjective functions. By using the multiobjective optimization method, maximum desirability value of 0.865 was obtained based on the following: applied voltage of 15 kV, field strength of 5.2 kV cm(-1), without forced air stream, and finally a combination of 17 discharge electrodes (needles). The results indicated that increasing the applied voltage from 6 to 15 kV, moisture ratio (MR) decreased, though energy efficiency and energy consumption were increasing. On the other hand, field strength of 5.2 kV cm(-1) was the optimal point in terms of MR.

No MeSH data available.


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The mechanism of a corona wind.
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fig01: The mechanism of a corona wind.

Mentions: Basically, due to the interactions of the numerous charges in a strong electric field, presenting a mathematical model for an EHD drying system is very difficult and complicated. Moreover, due to the different dielectric properties of the liquid and solid states of the material being dried, theoretical treatment is even more complex. EHD drying uses a secondary bulk flow which is known as corona wind or ionic wind. By applying a high voltage to an electrode, ionization of gas occurs due to a high electric field and thus ions are produced. These ions migrate toward the electrode plate (Fig.1) and along the electric field lines, and thus collide with air molecules, and part of their energy is used for overcoming the frictional resistance due to collisions with neutral molecules. Ion momentum is transferred from the ions to the air molecules causing air movement and thus the electric (corona) wind is produced (Fig.1).


Optimization on drying conditions of a solar electrohydrodynamic drying system based on desirability concept.

Dalvand MJ, Mohtasebi SS, Rafiee S - Food Sci Nutr (2014)

The mechanism of a corona wind.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256582&req=5

fig01: The mechanism of a corona wind.
Mentions: Basically, due to the interactions of the numerous charges in a strong electric field, presenting a mathematical model for an EHD drying system is very difficult and complicated. Moreover, due to the different dielectric properties of the liquid and solid states of the material being dried, theoretical treatment is even more complex. EHD drying uses a secondary bulk flow which is known as corona wind or ionic wind. By applying a high voltage to an electrode, ionization of gas occurs due to a high electric field and thus ions are produced. These ions migrate toward the electrode plate (Fig.1) and along the electric field lines, and thus collide with air molecules, and part of their energy is used for overcoming the frictional resistance due to collisions with neutral molecules. Ion momentum is transferred from the ions to the air molecules causing air movement and thus the electric (corona) wind is produced (Fig.1).

Bottom Line: Electrohydrodynamic (EHD) has been applied for drying of agricultural materials due to several advantages such as energy saving, low cost equipment, low drying temperatures, and superior material quality.The results indicated that increasing the applied voltage from 6 to 15 kV, moisture ratio (MR) decreased, though energy efficiency and energy consumption were increasing.On the other hand, field strength of 5.2 kV cm(-1) was the optimal point in terms of MR.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran Karaj, Iran.

ABSTRACT
The purpose of this article was to present a new drying method for agricultural products. Electrohydrodynamic (EHD) has been applied for drying of agricultural materials due to several advantages such as energy saving, low cost equipment, low drying temperatures, and superior material quality. To evaluate this method, an EHD dryer based on solar (photovoltaic) energy was designed and fabricated. Moreover, the optimum condition for the EHD drying of kiwi fruit was studied by applying the Box-Behnken design of response surface methodology. The desirability function was applied for optimization in case of single objective and multiobjective functions. By using the multiobjective optimization method, maximum desirability value of 0.865 was obtained based on the following: applied voltage of 15 kV, field strength of 5.2 kV cm(-1), without forced air stream, and finally a combination of 17 discharge electrodes (needles). The results indicated that increasing the applied voltage from 6 to 15 kV, moisture ratio (MR) decreased, though energy efficiency and energy consumption were increasing. On the other hand, field strength of 5.2 kV cm(-1) was the optimal point in terms of MR.

No MeSH data available.


Related in: MedlinePlus