An experiment system of tubes with one weakly covered end was established, and the outfield characteristics of fuel vapor explosions were studied through experiments. The results are as follows. After the rupture of the weakly covered end, three outfield overpressure peaks appeared due to the rupture of the weakly covered end (P1), the venting of the flame (P2), and external explosion (P3). The value of overpressure peaks showed a downward trend with an increase in distance, and the maximum overpressure was formed due to the external explosion. The value of overpressure peaks were related to the L/D ratio of the tube. With an increase in the L/D ratio, P1 and P3 in the near field showed an upward linear trend, while P2 and P3 in the far field showed a quadratic trend. In the case of the same L/D ratio, the maximum overpressure largely depended on the fuel volume fraction and external distance. The flame shape showed a changing process of jet flame - radial tension - mushroom cloud-shaped flame. The mushroom-shaped flame was formed mainly due to the Kelvin-Helmholtz instability and vortex effect, and the value of axial flame parameters were greater than those of radial ones. With an increase in the L/D ratio, the axial flame parameters showed an upward linear trend, the radial flame parameters showed a downward linear trend, and their ratio showed an upward linear trend.

建立了单端弱覆盖管实验系统，通过实验研究了燃料蒸气爆炸的外场特性。结果如下。弱覆盖端破裂后，由于弱覆盖端破裂（P1）、火焰泄放（P2）和外爆（P3），出现了3个外场超压峰值。超压峰值随距离的增加呈下降趋势，最大超压是外爆形成的。过压峰的值与管子的L / D比有关。随着L / D的增加近场P1和P3呈线性上升趋势，远场P2和P3呈二次趋势。在L / D比相同的情况下，最大超压很大程度上取决于燃料体积分数和外部距离。火焰形态呈现喷射火焰-径向张力-蘑菇云状火焰的变化过程。蘑菇形火焰的形成主要是由于开尔文-亥姆霍兹不稳定性和涡流效应，且轴向火焰参数值大于径向火焰参数值。随着L / D比的增大，轴向火焰参数呈线性上升趋势，径向火焰参数呈线性下降趋势，它们的比值呈线性上升趋势。