Study On Cotton Combustion Capability And Cotton Warehouse Fire Properties

The cotton industry plays an important role in the national economy.With the continuous development of the cotton industry,the amount of cotton used in China has been increasing year by year.One of the most important macro-control of cotton prices for Chinese government is cotton reserve management.However,the fire accidents of cotton warehouse happened frequently in recent year.So,it is of great significance to study the influencing factors of fires in cotton warehouses.First of all,this paper started with the characteristic of cotton combustion,by using the CONE to do a combustion experiment of different compression densities under different heat radiation intensity,to analyze the effect of cotton density and heat radiation intensity on the cotton bale combustion performance.Then,select a cotton warehouse as the object of fire accident simulation by using Pyrosim software to analyze the effects of different fire source locations,different ventilation conditions,and different channel interval between cotton on fire spread in cotton warehouses.The experiment of the cotton characteristic combustion shows that:(1)The combustion process of cotton bales was the open flame on the cotton bales surface and smoldering combustion in the internal,with the action of heat radiation.The compression density of cotton bales affected the supply of internal smoldering oxygen.The combustion of bales is affected by these two steps.(2)With the same thermal radiation intensity,the combustion rate of the high-density cotton bales was determined by the oxygen content due to the internal had less oxygen.under the same heat radiation intensity,the combustion of low-density cotton bales was controlled by oxygen density.The combustion is rapid and intense.The combustion of high-density will change into material quality controlled from oxygen density controlled.The greater of the density of cotton bales,the proceed of material quality controlled will last longer.The higher heat radiation intensity,the more fully the cotton bales can be burned,and will achieve a higher heat release rate peak;the exponential relationship between the cotton bales density and the maximum fire growth factor of the cotton bales.The results show that:(1)The development of cotton fire in the warehouse was caused by the combustion of a single cotton bale through the flame to the entire cotton stacking warehouse,spread through heat radiation from the firing cotton stacking to the adjacent cotton stacking,and eventually possible causing the flashover;(2)The location of fire source,interval and ventilation conditions of the cotton warehouse all have an impact on the fire,among of them,the distance between the channels is well set,and it is difficult to control the location of fire,so it is important to control the ventilation condition;(3)Regardless of the influence of natural ventilation,When the fire occurred in the middle of the warehouse,and the distance between the cotton bales is 3m,in about 100 seconds the fire can spread quickly.A flashover will occur in the warehouse in about 600 seconds,the maximum temperature will reach about 1000.°C;(4)In different height,the temperature growth rate is different,due to the impact of the ceiling jet,the higher the position,the faster the temperature increases.This paper study the characteristic of fire in a cotton warehouse by simulating,analyzed the effect of interval between cotton stacking,the ventilation conditions and the location of fire source on the fire development of cotton warehouses,and proposed suggestions for the prevention and control of fires in cotton warehouses.This will have a great significance in controlling the spread of fire and reducing economic losses.