Drying Characteristics Of Corn Under High Voltage Electrical Field And Airflow

There exist some problems in agricultural products drying at present,such as long time consuming,high cost and poor quality.This paper proposed a high-voltage ambient-temperature drying technology with low power consumption,drying uniform,environment friendly and quality maintaining.For corn drying,the effects of the electrode forms,the number of needle electrodes,the electrode connection method,the combined high voltage electric field and gas flow,and the combined high voltage electric field and hot air,were studied.(1)In high voltage drying,the plate-plate electrode is superior to the plate-net electrode;In the same needle-plate electric field,the corn drying rate is faster than that of rice,there is a better value for the number of needle electrodes,and the best values of different materials are different.The optimal number of needle electrodes for corn drying is 4,and the grain is 2;negative high voltage drying rate is slightly faster than positive voltage.(2)Ventilation can accelerate the high-voltage electrostatic drying,when the voltage is between 10 kV and 25 kV,there is a great influence on the electrostatic field.At a certain voltage,the drying rate increases with airflow velocity increases.When the voltage increases from 10 kV to 30 kV,the dehydration rate difference between the single electric field and the composite field decreases.and the dehydration rate of 30 kV electrostatic field is the fastest and the effect of the airflow on the electric field is weakened.(3)At 20 kV static voltage,the temperature from 15?,30? to 40?,airflow from 0 m/s,1.8 m/s,3 m/s changes.It is concluded that: when voltage,airflow velocity is constant,the composite field drying rate is accelerated with the temperature increases from 30?to 40?,the drying time to reach the safe moisture content standard is shortened from 15.5 hours to about 7 hours,and the time is shortened by 54.8%.When the temperature is lower than 40?,the electrostatic field combined heatand airflow on the corn drying,heat and airflow all play a role in strengthening the high voltage electric field;When the temperature is increased to 40 ?,the gap between the composite field and the single field is increased,and the temperature in the composite field has a great influence on the drying of corn.(4)The crack rate of corn has a great correlation with high voltage electric field,temperature and airflow.The cracking rate of corn in each field is lower than 30% at30 ?.The color sensory characteristics of corn is related to the air velocity and temperature,no obvious relationship with the electric field.(5)At 30?,the drying efficiency of corn of 20kV+30?+1.8m/s composite field are highest.At 40?,air velocity increases and the production efficiency is increased,the drying efficiency of 20 kV+40 ? +3 m/s composite field are highest,reaching19.794 kg/(m2·d).In the high-voltage electric field,the energy utilization efficiency of corn is the highest,which is about 5.57%,which is about 6 times the efficiency of hot air drying energy utilization efficiency of 0.5% ~ 1%.