Influence of Flame Characteristics on Fast Cook-off
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摘要: 为研究快速烤燃下池火中火焰特征量对烤燃弹的影响,建立了池火的快速烤燃模型,得到了烤燃弹的传热特性,分析了烤燃过程中烤燃弹放置高度和油池尺寸对火焰特征量的影响。结果表明:随着烤燃弹放置高度的增加,烤燃弹表面最高温度区域由上表面转移到下表面,辐射热通量峰值由烤燃弹上方转移到烤燃弹下方;随着油池尺寸增加,烤燃弹各表面温度更加均匀,烤燃弹吸收的热通量增加,烤燃弹表面温度升高。因此,快速烤燃试验中烤燃弹的放置高度与油池尺寸均会对火焰特征量造成影响,进而影响烤燃弹的快速烤燃特性。Abstract: In order to study the influence of flame characteristics on cook-off bomb in pool fire under the condition of fast cook-off, a fast cook-off model of pool fire was established, and the heat transfer characteristics of the cook-off bomb were obtained, then the influences of the placement height of the cook-off bomb and the size of the oil pool on the flame characteristics during the burning process were analyzed. The results show that with the increasing placement height of the bomb, the highest temperature region of the bomb surface shifts from the upper surface to the lower surface, and the peak radiation heat flux shifts from the top to the bottom of the bomb. With the increasing size of the oil pool, the surface temperature of the bomb becomes more uniform, the heat flux absorbed by the bomb increases, and the surface temperature of the bomb increases. Therefore, in the fast cook-off test, both the placement height of the bomb and the size of the oil pool affect the flame characteristics, and then the fast cook-off characteristics of the bomb.
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Key words:
- fast cook-off /
- numerical simulation /
- pool fire /
- pool size /
- flame characteristics
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表 1 炸药和壳体的物性参数
Table 1. Physical parameters of explosives and shell
Material ρ/(kg·m−3) cV/(J·kg−1·K−1) λ/(W·m−1·K−1) RDX 1640 1130 0.25 TNT 1510 1611 0.20 Steel 8030 502 43.00 表 2 炸药反应动力学参数
Table 2. Reaction kinetic parameters of explosives
Explosive $ i $ Ei /(J·mol−1) Zi /s−1 Qi /(J·kg−1) RDX 1 2.04×105 6.40×1017 2.68×106 2 1.89×105 4.74×1017 −8.03×106 3 1.43×105 9.54×1014 −6.56×107 TNT 4 1.95×105 1.59×1015 1.26×105 5 1.60×105 1.96×1012 −3.40×105 6 1.47×105 2.39×1011 −3.40×105 表 3 JP-8燃料的燃烧参数
Table 3. Combustion parameters of JP-8 fuel
$\Delta H/\text{(J}\cdot {\text{kg} }{^{ {-1} }})$ $ \alpha $ $\dot{Q}/(\text{kW}\cdot{\text{m} }{^{ {-2} }})$ ρ/(g·cm−3) 43000 1000 1600 0.81 表 4 烤燃弹放置高度不同时各表面的温度
Table 4. Temperatures of each surfaces at different heights of the cook-off bomb
Height/m Temperature/℃ Surface1 Surface 2 Surface 3 Surface 4 Surface 5 Surface 6 0.33 797.5 772.9 804.4 776.3 764.2 765.4 0.36 805.4 766.8 799.0 759.3 764.4 767.3 0.39 817.1 771.8 798.5 749.6 754.9 756.8 0.42 842.4 769.5 791.9 751.1 736.5 755.4 表 5 烤燃弹放置高度不同时各表面的热通量
Table 5. Heat flux of each surface of the cook-off bomb with different heights
Height/m ${\dot q''_{\rm {tot} } }$/(kW·m−2) Surface 1 Surface 2 Surface 3 Surface 4 Surface 5 Surface 6 0.33 78.9 73.4 80.2 74.5 71.2 71.6 0.36 80.6 71.3 78.2 70.0 71.4 72.0 0.39 84.0 72.8 78.3 67.9 69.4 69.6 0.42 92.1 73.1 76.8 68.9 65.3 69.5 Height/m ${\dot q''_{\rm {rad} } }$/(kW·m−2) Surface 1 Surface 2 Surface 3 Surface 4 Surface 5 Surface 6 0.33 74.8 67.6 76.5 68.7 65.9 66.2 0.36 76.9 66.0 74.9 64.4 65.9 66.6 0.39 80.4 67.3 74.9 62.1 63.8 63.9 0.42 88.2 66.8 73.2 62.5 59.6 63.7 表 6 油池尺寸不同时烤燃弹各表面温度
Table 6. Each surface temperature of the bomb burned in the oil pool with different sizes
Oil pool size/
(mm×mm)Area/m2 Surface temperature/℃ Surface 1 Surface 2 Surface 3 Surface 4 Surface 5 Surface 6 1500×1200 1.80 817.1 771.8 798.5 750.0 754.9 756.8 2100×1700 3.57 853.9 821.7 862.9 802.5 851.4 856.4 3000×2400 7.20 838.8 876.1 903.2 878.6 868.3 868.4 表 7 油池尺寸不同时烤燃弹各表面热通量
Table 7. Heat flux of each surface of the bomb burned in the oil pool with different sizes
Oil pool size/
(mm×mm)${\dot q''_{\rm {tot} } }$/( kW·m−2) Surface 1 Surface 2 Surface 3 Surface 4 Surface 5 Surface 6 1500×1200 84.0 72.8 78.3 67.9 69.4 69.6 2100×1700 95.8 87.7 98.7 82.0 97.1 98.7 3000×2400 91.4 105.0 112.9 105.7 103.2 103.1 Oil pool size/
(mm×mm)${\dot q''_{\rm {rad}} }$/( kW·m−2) Surface 1 Surface 2 Surface 3 Surface 4 Surface 5 Surface 6 1500×1200 80.4 67.3 74.9 62.1 63.8 63.9 2100×1700 91.9 81.8 94.9 76.3 91.4 92.8 3000×2400 87.3 99.4 109.2 100.3 97.5 97.4 -
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