High-voltage Electric Field Drying Characteristics And Model Analysis Of Lycium Barbarum

High pressure electric field drying has the advantages of normal temperature drying,good quality after drying,simple equipment and low energy consumption,which is widely used in drying fruits and vegetables and Chinese herbs.As an economic forest fruit with the same source of medicine and food,the drying method has a great influence on the quality of dried Lycium barbarum.In this paper,a simulation model of multi-physics field of high-voltage electric field drying is established,a high-voltage electric field drying test bench of needle-net system is built,and the changes of electric field characteristics and drying characteristics of Lycium barbarum are investigated under different voltages,needle tip-plate distance and needle spacing with Lycium barbarum as the research object.And the response surface test was designed to obtain the optimal parameters for drying Lycium barbarum by high voltage electric field.Finally,a comparison of the quality characteristics and drying characteristics of Lycium barbarum dried by high voltage electric field and hot air was carried out to verify the advantages of high voltage electric field drying technology for Lycium barbarum drying.The main findings of this paper are shown as follows:(1)High-voltage electric field drying is used in a needle-plate electrode drying system,and Comsol multiphysics is used to simulate the effects of different voltage magnitudes,needle tip-plate distance,and needle spacing on the electric field characteristics of the needle-plate high-voltage electric field.The simulation results show that increasing the voltage,shortening the needle tip-plate spacing,and decreasing the needle spacing can increase the electric field strength and energy density of the needle-plate electrode system.(2)The simulation results were verified by high voltage electric field drying experiments on Lycium barbarum.The test results showed that with increasing voltage and decreasing needle tip-plate spacing,the final moisture content of Lycium barbarum decreased and the average drying rate increased.The effect of needle spacing on the average drying rate of Lycium barbarum showed a trend of increasing and then decreasing with the increase of needle spacing.Based on the results of the single-factor experiment,a three-factor,three-level response surface test was designed,and the test results showed that the best drying effect was achieved at a voltage of--35 kV,a needle tip-plate spacing of 4 cm,and a needle spacing of 4 cm,and the average drying rate under this condition was 0.0549 g/(g·h).(3)The comparison of quality and drying characteristics of Lycium barbarum dried by high voltage electric field and hot air showed that Lycium barbarum dried by high voltage electric field was significantly better than hot air drying in terms of appearance and nutrient composition,and the drying performance was slightly worse than that of hot air drying.