Study On Storage Ventilation Model And Numerical Simulation Of Grain Temperature And Moisture Variation In Ventilation Process

The agriculture of China is gradually moving towards industrialization with the rapid development of science and technology,and the proper preservation of grain before use is one of the important factors for the development of agricultural industrialization.Wheat is a kind of complex porous media.The storage of wheat is affected by various factors as its biological characteristics,such as temperature,moisture and mold,and two essential factors of safety storage of Wheat are grain moisture and temperature.The researchers have done a lot of work to study the change law of wheat temperature and moisture content during storage.Pure theory with small scale experimental study is the mainly way of the former with the limit of various factors,which lack of actual storage process support.The researchers have developed a variety of simulation software based on previous theories with the widespread use of computer,computer simulation of the ventilation process makes the change of wheat more intuitive.However the defects such as the long period of calculation and the high requirement of computer memory in the process of software using may cause some trouble.A new storage model using Fortran program is developed in this paper,which based on the principle of local heat and mass balance and combined the physical properties of wheat and air enthalpy.In the model,the R value defined as the ratio of the moisture delivered in the grain layer to the moisture delivered in equilibrium is first put forward,which makes the water transfer closer to the actual situation,and the new storage model overcomes the defects of computer simulation software effectively.And it strive to achieve an immediate response to the grain on the basis of the accuracy of the simulation results,the main research contents areas follows:First of all,the paper analyzes the study of wheat storage research of the domestic and foreign scholars and expounds the current situation of China’s grain storage.The new mathematical model of grain ventilation is established with a series of hypotheses according to the existing theory achievement,and it is verified in theory with the four basic changes of wheat temperature and moisture content during storage.The feasibility of the model is verified by the simulation of the small-scale experimental conditions,and the corresponding parameters are corrected for the low temperature ventilation process.On this basis,the Grain temperature and moisture changes in warehouse ventilation process was simulated in the light of the vertical ventilation and vertical ventilation,the result are compared to verify the reliability of the model,and the change regulation of wheat temperature and moisture content are further explored during the ventilation.The results show that the model can reflect the variation of wheat temperature and moisture content in the ventilation process of wheat very well,The results show that the model error is within the acceptable range,and the accuracy and feasibility of the model are verified.The model can not only realize the timely corresponding during grain ventilation but also can make the judgment on the ventilation process with the analysis of the weather to determine the optimal amount of ventilation and achieve scientific and green grain storage.The model has a series of advantages comparing with other models,such as simple operation,high accuracy,prompt response,low requirement for computer configuration and so on.However,the model still has room for development,especially the selection of R value in the process of low temperature ventilation has great influence on the accuracy of the simulation.It is very important to determine the relationship between R value and grain ventilation parameters to improve the accuracy of the model.There are a variety of methods and ways for us to realize safe storage by using science and technology with the rapid development of computer technology,and it can save lots of manpower,material and financial resources.The proposed model provides a new way for grain storage research work,and it has very important application value to strengthen the grain monitoring and improve the quality of wheat.