Experimental And Simulation Of Temperature Characteristics In Potato Pile Based On Porous Media Theory

The suitable storage temperature in potato storage room is the main condition for scientific storage and quality control.In order to study the internal temperature difference of potato piles with different mass sizes under the same storage conditions,the semi underground potato storage room of Inner Mongolia Agricultural University was used as the experimental site,and the edible "Jizhang 226" potatoes were graded according to the mass sizes,and stacked separately in baskets,The temperature monitoring system was used to monitor the internal temperature of potato storage room and potato pile in real time and record the data,then the data were analyzed and compared.The steady-state numerical simulation was carried out by using the hydrodynamics software to analyze the temperature change law and the interaction with the small environment in the storage room.The results showed that:(1)In the whole process of potato grading storage,the internal temperature of potato pile at all levels was less affected by the outdoor temperature,and the change was relatively slow(compared with the drastic change of temperature difference between day and night outside),the change rule was first decreased and then increased,and a small period of stability appeared in the middle.In the decreasing stage,the temperature changes slowly at the rate of 0.06～0.07℃ per day,and in the rising stage,the temperature increases at the rate of 0.2～0.23℃ per day,which is about three times of the decreasing rate.In the early stage of temperature decrease and the late stage of temperature rise,the temperature inside the potato pile was higher than the optimal temperature for potato storage;(2)There are some differences in the internal temperature changes among different grades of potatoes in a small range.The smaller the mass of potato pile,the smaller the decline and rise of internal temperature during storage,and the higher the stability of internal temperature.Grading storage can optimize the internal structure of potato during storage,and make the internal temperature of potato pile more stable,To reduce the temperature change range of potato during storage,and provide scientific temperature control data support for intelligent storage facilities;(3)In the numerical simulation,the typical climate in northern China was selected,and the potato was regarded as porous medium structure by CFD method.The quality of potato was classified and stored separately to form different porosity structure.The simulation results show that the comparison between the measured value and the simulated value is within the allowable range of calculation error,and the model is feasible.The temperature inside the potato storage room showed a gradient distribution in the vertical direction;In the case of only considering porosity,for the porous media structure with different porosity,the smaller the porosity is,the higher the internal temperature of potato pile is in the stage of pit door closing,and the smaller the porosity is,the lower the internal temperature of potato pile is in the stage of pit door opening.