Research On FDS-based Sprinkler Protective Effect Of Thermal Radiation

With the last two decades of rapid economic growth, the usage of energy, especially of the oil, has increased day by day and large oil tank and oil tank farm have become a trend. Tank farm which stores the massive oil is easy to have the fire explosion accident and have a great amount of loss once the fire prevention is not in position. The main reason why the tank fire is difficult to control and extinguish is that the high strength thermal radiation caused by the violent fire and the swift flame can ignite the neighboring oil tanks and makes the fire to further expand. Therefore the attention is paid to the security and fire protection of the tank increasingly. In case a fire occurs in a oil tank, the water spray cooling system can provide protection against the heat radiation. In order to make deeper study of the weakening influence and the protective action of the water spray cooling system on the fire thermal radiation, this thesis researches this question deeply using the numerical simulation method. Firstly, this thesis analyzes the hazards of the oil and tank fire, the thermal radiation principle, the fire's heat radiation harm as well as tank farm's layout and protective measures. Secondly, through the comparative analysis, the specialized fire simulation software FDS is chose to carry on the numerical simulation to the tank fire, confirm that the FDS has a higher accuracy and credibility. Take the 5000m3 tank for example, in respect of flame height, the simulation results for the tank flame height is 21.25m, is identical with the theory height-19.5m, and the error is only 8.97%; The error of the flame inclination is 20-30%; In terms of flame temperature, the simulation results 1250℃and the theory 1200℃are basically consistent. At the same time, study the distribution of the burning oil tanks thermal radiation, different initial parameters-air speed and distance influence on thermal radiation. Most importantly, detect the thermal radiation distribution of the adjacent oil tanks in cases on water sprinkling or not, and analyzed the its cooling effect. By analyzing the thermal radiation of adjacent oil tanks, come to the conclusion that the latest surface to burning oil tanks is the hardest area by thermal radiation, and strengthen this area of the firefighting cooling measures, are effective ways to prevent secondary accidents. Water spray system, works to adjacent tank, played a good cooling and protective effect of heat radiation, 5L/min, 10L/min, 30L/min, 50L/min spray protection rates are about 39%, 48% 64%, 69%. By the action of spray system, thermal radiation intensity reduced stably, which the adjacent suffered, It can protect the adjacent oil tanks in varying degrees. The heat-resisting degree of the oil tank material is considered, this thesis studies the domestic and foreign science reference about formulating security spacing using the heat radiation harm criterion.