Simulation And Experimental Research On Temperature Controlled Storage Of Summer Cereals In South China

With the advancement of science and technology,our country’s agriculture has developed rapidly,and the amount of food produced each year is huge.After the food is harvested,it faces an important problem of food storage.The methods of grain storage are directly related to the safe storage of grain.The study found that temperature and humidity are the two most important factors affecting grain storage.Since our country has a wide area and a large regional climate difference,various regions can make use of the regional climatic conditions that are conducive to grain storage,and choose the grain cooling method reasonably.In southern China,the temperature is high and the outdoor climatic conditions are not suitable for mechanical ventilation.Especially in summer,both the outdoor humidity and temperature are high,so it is not suitable to reduce the grain temperature by mechanical ventilation.Because the air conditioning cooling and ventilation technology is not affected by outdoor conditions,it can adjust the temperature and humidity of the air entering the warehouse as needed and as an effective grain ventilation and cooling method under high temperature and high humidity conditions,it has been widely used in the southern region.In this paper,based on the principle of mass conservation and local heat balance,a three-dimensional physical model and mathematical model of grain pile ventilation are established,and the correctness of the model is verified by experimental methods.The method of numerical simulation was used to study the influence of different return air outlet layouts and different air outlet spacing on the surface temperature of the grain pile under the grain cooling and ventilation method.The mathematical model describes the method of equipping the number of special air conditioners under different air supply conditions,which provides guidance for the use of special air conditioners in the granary.Through the temperature control test research of theNational Grain Storage in Mianyang City of Sichuan Province during the summer,an economically feasible layout of air-conditioning vents was found,and the effect of the distance between the air supply and return air vents on the temperature of the surface grain pile was explored.The provision of the number of air-conditioning units in the grain warehouse and the layout of the tuyere provided a reference.Through the research,it is found that the numerical simulation technology can be used as an effective technical method to replace the experiment to study the law of the temperature change of the grain heap during the actual grain storage ventilation process.Through the use of air-conditioning to control the temperature of the experimental warehouse and the comparison warehouse during the summer,it was found that the layout of the air outlet of the granary can affect the ventilation and cooling rate of the granary.Compared with the layout of the air inlet of the prototype warehouse on the same side and the linear arrangement,when the air outlets are alternately arranged on the opposite side,the uniformity of the ventilation of the grain pile is better and the energy consumption is lower.In addition,it was found that when the spacing between the supply and return air outlets was changed,the cooling temperature of the grain pile also changed.Compared with the distance between the prototype silo and the return air inlet of 2m,the grain stack ventilation when the spacing between the supply and return air outlets was increased to 3m Cooling effect is better.According to the data of surface grain temperature change of the cooling and ventilation of the experimental warehouse for 5 days,it is found that the temperature in the warehouse and the average grain temperature of the surface layer drop faster,and cooling through the grain cooler can be used as an effective technical means to reduce the temperature of the rice and the surface grain in a short time.