Circular Underground Reinforced Concrete Bulk Grain Storage Silos Ambient Temperature Field Simulation Based On CFD And Research

Reinforced concrete underground silos overcame the granary built in dependence on terrain limitations such as, grain storage environment affected by the external environment temperature and solar radiation is small, is a good prospect of application of new type of shallow constant temperature underground storage structure. This article is based on national "Twelfth five-year" national science( 2011BAD03B01) and Technology support project and 863 plan corpus(2012AA101608), underground storage of grain environment research of the phenomenon of "condensation" as the main rely on.Unique environment based on the underground soil temperature, on the heap of grain storage and structure, grain storage, the internal temperature and humidity field change warehouse wall thickness influence to grain heap of internal temperature field,numerical model with the help of CFD(computational fluid dynamics) software, set up nearly the temperature of the formation and the grain in pile actual situation, to study the reinforced concrete underground bunker heap of grain storage and ecological environment, the internal temperature and humidity field migration change rule. The main research content is as follows:1. Based on the theory of heat transfer, by the test of underground storage grain real-time monitoring data, the introduction of CFD software to simulate storage grain bulk temperature field distribution, for storage and a numerical simulation of the temperature field between the special environment of underground room temperature conditions, statistical monitoring temperature data, selected boundary conditions, simulation analysis of the underground temperature field, flow field trend change rule. By comparing the simulation results and the development trend of the statistical data, verify the CFD(computational fluid dynamics) for food in pile wet coupling temperature field heat transfer mathematical model of dynamic real-time control storage grain internal temperature field changes.2. In view of the underground silos test, using Gambit software to establish the three-dimensional model of the underground silos, the meshing of the model, by adopting the method of CFD numerical simulation research of underground ventilation state granary grain storage process grain heap change laws of temperature field. By writing and import UDF function, the improvement of quality control in the CFD software equation, momentum equation and wall heat transfer control equations, and through iterative calculation based on CFD software simulation was obtained under the condition of underground silos of ventilation status change laws of temperature field. The research results show that as the underground storage time longer, positions around the grain bulk temperature and maintain between structure, grain piles continuously, for heat and mass transfer on the final temperature gradually become the local underground constant temperature near the temperature value.3. The outside wall of grain bulk temperature and soil temperature, the internal storage structure under the premise of the same material, different thickness of capsule wall as restrictive conditions, the different warehouse wall thickness of palisade structure inside and outside the traditional heat transfer model were compared. Results show that the different concrete underground CangCang wall thickness in the mechanism of heat and mass transfer process is the same, but as a result of the different, resulting in the underground bunker in the process of grain storage temperature field of concrete wall and the mutual coupling between the grain storage temperature field changes.4. In view of the reinforced concrete underground warehouse environment and inside the granary storage grain temperature field, to study of condensation mechanism of grain, from the paper analyzed the cause of condensation may granary storage temperature condensation temperature changes on the food. Using CAE desorption equation and adsorption equation, can map out the grain heap internal balance absolute humidity. The research results show that the underground reinforced concrete silo in the process of grain storage, grain piles and positions between palisade structure, food grain and food particles, capsule palisade structure between the soil environment with the outside world is in constant heat mass transfer, plus food life activities for aerobic respiration and anaerobic respiration will generate heat, heat mass transfer at the same time accompanied by moisture diffusion, these factors lead to the entire grain in pile temperature field and humidity field in carrying on the migration and changes.