A Research On The Mechanism Of The Granary Fires And The Key Prevention Technology

The quantities, quality and safety of grain is directly related to national economic development and social stability. The grain’s safety work during storage is very important.At present most of our country’s grain is used in accordance with the standard of national standard warehouse; it is generally reinforced concrete structures, although the size is different, but the fire hazard is basically the same. Therefore, it’s very necessary to study the the mechanism of the granaries’fire and the prevention technology to ensure the safety of the grain’s storage.Through the study of the type and mechanism of the granaries’fire,it is found that the fire occurred mainly in two forms:the spontaneous combustion fire and the dust explosion fire. In view of the granary fire elements:temperature and oxidizer, proposed prevention granaries’fire technical measures-mechanical ventilation grain storage technology and nitrogen atmosphere grain storage technology. Through two kinds of granaries’fire fault tree analyses, we know the importance of the mechanical ventilation to control the temperature for preventing granaries’fire.First, use wireless grain monitoring system to detect the change of the temperature in the squat silos. Then based on the research of the porous medium heat transfer theory, analyzes the internal heat transfer characteristics in the granary, based on the theory of CFD, the granary of the internal heat transfer mathematical model is established,the numerical simulation of mechanical ventilation process is done.The ventilation time that the numerical simulation of the temperature inside the heap of grain down to a safe temperature and the theoretical calculation of the required ventilation time are very close, comparing the simulation results and the experimental data,they are nearly consistent,which proves the correctness of the numerical model. The CFD numerical simulation will play a guide role in the research of granary mechanical ventilation technology. After improving the ventilation program inside the granary,based on the theoretical analysis,use the CFD numerical simulation solutions to get the conclusions of the improved ventilation program which will provide a guiding role in the mechanical ventilation design of thegrain storage companies.Finally, this paper analyzed the fire performance of the nitrogen atmosphere grain storage, whether it is to say from a technical level or the economic performance,nitrogen atmosphere for grain storage technology is feasible. Raised the issue that we are faced with and need to solve to promote the nitrogen grain storage technology at this stage, it provides a theoretical guidance for the promotion of the future fire nitrogen grain storage technology.