方管内汽油-空气混合气体密闭爆炸和泄爆特性研究

为研究汽油-空气混合气体密闭爆炸和泄爆特性，采用可视化方管进行了两种爆炸模式实验研究，并基于壁面自适应局部涡黏(wall-adapting local eddy-viscosity,WALE)模型和Zimont预混火焰模型进行了数值模拟研究。结果表明:（1）泄爆工况超压-时序曲线峰值数量多于密闭爆炸工况，且泄爆工况超压-时序曲线存在剧烈的类似简谐振动的振荡，而密闭爆炸工况的爆炸超压特征参数显著高于泄爆工况；（2）密闭爆炸工况最大火焰传播速度明显小于泄爆工况，但前者在火焰传播初期即达到最大值，而后者在火焰传播末期才达到最大值；（3）密闭爆炸工况出现郁金香形火焰，而泄爆工况出现蘑菇形火焰，郁金香火焰的形成与管道内火焰锋面、流场和流场动压三者之间耦合效应相关，蘑菇形火焰由外部流场湍流和斜压效应的共同作用引起。

Characteristics of closed and vented explosions of gasoline-air mixture in a square tube

In order to investigate the closed explosion and venting characteristics of gasoline-air mixture, two kinds of explosion modes were studied by using a visualized square tube, and numerical simulation was carried out based on the wall-adapting local eddy-viscosity (WALE) model and Zimont premixed flame model. The results show the followings. (1) The number of the peaks on the overpressure time series curve for the vented explosion is greater than that for the closed explosion, and there is a violent oscillation similar to a simple harmonic vibration on the overpressure time series curve of the vented explosion, while the characteristic parameters of explosion overpressure in the closed explosion are significantly higher than those in the vented explosion. (2) The maximum flame propagation speed in the closed explosion is significantly lower than that in the vented explosion, but the former reaches the maximum at the beginning of flame propagation, while the latter reaches the maximum at the end of flame propagation. (3) Tulip-shaped flame appears in the closed explosion condition, while mushroom-shaped flame appears in the venting condition. The formation of the tulip-shaped flame is related to the coupling effects of flame front, flow field and dynamic pressure of flow field in the pipe, while the mushroom-shaped flame is caused by the combined action of turbulence and baroclinic effect in the external flow field.