Numerical Simulation On Grain Temperature Field Of Semi-underground Double-storey Squat Silos

Grain is the basic guarantee for human survival and development.Grain temperature is an important indicator that affects the safe storage of grain.High grain temperature can cause mold and insect infestation,which can damage the quality of grain.Therefore,the study of the temperature field variation of the grain pile during the natural storage and ventilation phase is of practical significance.Based on the Key Research and Development and Promotion Project of Henan Province(No.212102110191),this article used a combination of numerical analysis and experimental verification to study the temperature field of the grain pile in the static storage and ventilation cooling process of the semi-underground double-storey squat silo.The main research content is as follows:1.The numerical analysis model of grain temperature field in semi-underground double-layer shallow round storage is established and verified by experiments.Through theoretical analysis and using large-scale finite element simulation software,a numerical model of the temperature field of grain piles in storage was established.Through field tests of the squat silo and underground silo,the validity of the model in predicting the temperature field of above-ground and underground grain storage was verified by comparing the test results with the simulation results,which laid the foundation for the study of the temperature field of semi-underground double-storey squat silos.2.The variation of grain pile temperature field under static storage of grain at low temperature for one year was studied numerically.The results showed that the overall temperature of the grain pile in the upper layer of the semi-underground double-storey squat silo has little change.Only the grain temperature near the silo wall was easily affected by the external temperature,and the highest local grain temperature was 27.37℃.Due to being in a relatively closed low-temperature area,the grain temperature of the underground layer grain pile did not exceed the underground constant temperature zone temperature of 17℃throughout the year.3.The variation law of temperature field of grain pile under different ventilation conditions is studied.The results showed that during the process of ventilation and cooling,there would be obvious stratification in the cold and hot exchange zone of the grain pile,and there would be some dead zones of ventilation in the areas far from the air outlet of the grain pile.When other ventilation parameters were constant,the lower the inlet air temperature,the faster the average grain temperature decreased,and the higher the inlet air velocity,the colder air would enter the grain pile within a unit time,resulting in better cooling effect.4.By comparing and analyzing the temperature field of grain storage,it was found that thermal insulation measures for the silo wall and roof can effectively reduce the impact of external temperature on grain temperature.Compared with traditional squat silos and underground silos,the upper and lower layers of the semi-underground double-storey squat silo have better grain storage environment,which is beneficial to ensure the quality of grain.This article studied the variation of the grain temperature field during the static storage and ventilation process of the semi-underground double-storey squat silo,which can provide technical support for the design and promotion of the ventilation system of this type of silo,and is of great significance for the realization of national food security storage.