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应用CFD软件FDS对小室火灾过程中细水雾与火灾烟气相互作用进行模拟,研究了火源距离喷头轴向分别为1.0m、2.0m和3.0m,细水雾粒径分别为50μm、100μm和200μm,通风风速分别为1.0m·s~(-1)、2.0m·s~(-1)、3.0m·s~(-1)和4.0m·s~(-1)条件下热烟气的降温效果。结果表明,火源位于喷头正下方时,烟气温度由1000℃降至50℃需要15s,降温速率大于火源偏离喷头正下方情况。细水雾粒径为50μm与200μm相比较,50μm时烟气降温效果较好,由140℃降至50℃需要20s,而粒径为200μm时需要40s。不同风速对烟气降温效果与火源位置有一定相关性,火源位于喷头正下方时,风速由1.0m·s~(-1)增加到4.0m·s~(-1)烟气温度峰值逐渐减小,降温速率逐渐增大;火源偏离喷头正下方时,烟气温度峰值变化相反,降温速率没有明显变化。
The CFD software FDS was used to simulate the interaction between water mist and fire smoke during the chamber fire. The results show that the axial distance of the fire source from the spray head is 1.0m, 2.0m and 3.0m respectively. The particle size of the water mist is 50μm and 100μm And 200μm, the ventilation velocity was 1.0m · s -1, 2.0m · s -1, 3.0m · s -1 and 4.0m · s -1 respectively Gas cooling effect. The results show that it takes 15s for the flue gas temperature to drop from 1000 ℃ to 50 ℃ just below the sprinkler, and the cooling rate is greater than that of the fire source just below the sprinkler. When the water mist particle size is 50μm, compared with 200μm, the flue gas cooling effect is better at 50μm, 20s from 140 ℃ to 50 ℃, and 40s when the particle size is 200μm. The effect of different wind speed on the cooling effect of flue gas is related to the location of fire source. When the fire source is directly below the nozzle, the wind speed increases from 1.0m · s -1 to 4.0m · s -1 Gradually decreases, and the cooling rate gradually increases. When the fire source is directly below the nozzle, the peak temperature of flue gas changes in the opposite direction, and the cooling rate does not change significantly.