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为了确定公路隧道火灾模型试验相似律,基于对火灾烟气运动方程的理论分析,给出了区分火源近区与火源远区的临界距离,近区、远区适用的相似准则及相似比尺关系,临界弗劳德数计算式参数取值及临界风速计算模型,并依据相关文献资料对临界风速计算模型进行了验证。结果表明:火源及近区烟气为自然扩散,垂向受浮力作用明显,模型试验可采用弗劳德准则,火源远区浮力作用在隧道纵向不明显,烟气流动模拟不宜采用弗劳德准则;火源远区比尺关系与隧道通风模型试验比尺关系相同,速度比尺为1∶1,火源功率比尺与几何比尺的2次方成正比;模型试验时应区分近、远区,基于不同比尺关系进行模型设计;临界风速计算模型合理;烟气厚度替换隧道高度,临界弗劳德数接近1.0。
In order to determine the similarity law of fire model tests for highway tunnels, based on the theoretical analysis of the fire smoke equation, the critical distance to distinguish the near fire region from the far fire region is given. The applicable similarity criteria and similar ratios Ruler relationship, the critical Froude number and the critical wind speed are calculated, and the critical wind speed calculation model is verified according to relevant literature. The results show that the fire source and the near area flue gas diffuse naturally, and the vertical buoyancy effect is obvious. The Froude criterion can be used in the model test. The buoyancy in the far area of the fire source is not obvious in the longitudinal direction of the tunnel. German criterion; the relationship between the fire far scale and tunnel ventilation model tests the same scale, the speed ratio scale is 1: 1, the fire source power ratio is proportional to the square root of the geometric scale; the model test should distinguish between , Far region, based on the relationship between the different scale model design; critical wind speed calculation model is reasonable; flue gas thickness to replace the tunnel height, the critical Froude number close to 1.0.