Experiments On Grain Temperature Field In Quasi-low Storage And Conventional Of Warehouses

Food security is the foundation of people’s livelihood,and ensuring food quality is the fundamental requirement to meet the growing and better life of the people.Grain temperature is an important ecological factor in grain storage and the primary factor that affects the quality of grain storage.Research shows that the storage quality of grain could be basically guaranteed when the average grain temperature was lower than 20 ℃,too high a temperature would promote the accelerated reproduction of microorganisms and pests,leading to mildew and deterioration of grain quality.Therefore,it is important to study the temperature field of grain piles during grain storage to find out the temperature change law during grain storage in order to achieve safe grain storage and ensure grain quality.Under the sponsorship of the National Food Public Interest Industry Science and Technology Special(No.201413007-01),the method of combining on-site testing and numerical analysis was used to conduct on-site testing and numerical simulation of the temperature field during storage of conventional storage and quasi-low temperature storage conditions for large bungalows,respectively,and obtain the law of temperature change inside the grain pile.The studies are as follows:1.A Continuous temperature monitoring test was conducted on warehouse of quasi-low temperature storage and conventional storage to analyze the variation rule of temperature,warehouse temperature and grain temperature during storage.And it was found that the average grain temperature of quasi-low temperature storage is less than 20 degrees,and the local maximum grain temperature is not higher than 25 degrees;during the storage period,the temperature of conventional grain piles in the summer high temperature,season local maximum grain temperature can reach more than 35 degrees.2.Based on the boundary conditions of the initial temperature,the physical properties of the warehouse,and the physical parameters,numerical analysis is carried out on the change law of the grain pile temperature field with the external temperature during the quasi-low and conventional static storage process.By comparing the field test data with the simulation results,it is better to compare the two,and to show the rationality and validity of numerical analysis.Further research reveals that during the static storage process,the internal temperature of a grain pile is layered under the influence of the external environment,the internal temperature of the grain pile is relatively stable under the quasi-low temperature storage method,and the grain pile under conventional storage is impacted by the outside world.3.Numerical analysis of the temperature field inside the grain pile during the cooling of different storage conditions is carried out,and the comparison of the field test data with the simulation results shows that the numerical simulation can effectively analyze the temperature field change law in the cooling process of the grain pile.Further research found that the grain piles closer to the ventilation channel cooled down faster,the grain piles farther away from the ventilation channels cooled down for a longer time,and at the end of ventilation,the average temperature of the grain pile tended to enter the wind temperature.4.Comparing the quality and economy of grain under two different storage methods,the quality of quasi-low temperature storage grain is better than that of conventional storage,the price of quasi-low temperature storage grain is higher,and the economic benefits are considerable.In this paper,a numerical analysis method is obtained to simulate the temperature field of grain piles in large bungalows,which can provide reference for the study of grain storage temperature fields in other warehouses,and at the same time,it provides technical guidance for the popularization and application of low temperature storage.