圆柱形可燃气云爆炸实验研究与数值模拟

Experimental and numerical study on cylindrical flammable gas cloud explosion

与半球形可燃气云模型相比,圆柱形模型更接近于气云爆炸事故的实际情况。进行了乙炔浓度7.75%、气云体积0.26m3的圆柱形可燃气云爆炸实验,记录了距气云中心1.2 m与1.6 m两点的爆炸超压。建立了描述气云爆炸的理论模型,采用SIMPLE算法编制了计算程序。计算结果经实验数据考核,最大与平均相对偏差分别为18.3%与5.4%,证实程序满足气云爆炸模拟与预测的要求。研究结果显示:爆炸流场不具备球形对称的性质,爆炸超压与火焰传播方向有关,当气云高径比0.2时,沿地面方向的最大超压可达垂直方向的3.3倍;气云体积不变而形状变化时,爆炸强度随着高径比的增大而增大,高径比1.0时的最大超压可达高径比0.1时的3.1倍;气云高径比降低时,火焰传播距离增大,燃烧时间增长,气云释能速率下降,因此爆炸超压降低。研究结果对可燃气云爆炸灾害的预测具有一定的指导意义。

Compared with semi-spherical flammable gas cloud model,cylindrical model could represent cloud explosion accidents more exactly.Experiments of cylindrical gas cloud explosion were performed with 7.75 % of ethyne and 0.26 m^3 of gas cloud volume and overpressures at 1.2 m and 1.6 m points from cloud center were recorded.A theoretical model of cloud explosion was established and SIMPLE algorithm was adopted in writing calculated codes.Compared with the test data,the maximum and average relative deviations of calculation results were 18.3% and 5.4% respectively,which showed that the codes met the need to simulate the cloud explosion.This work indicated that the explosion intensity was related to flame spread direction and the explosion field was not spherically symmetric.The maximum explosion overpressure close to the ground was about 3.3 times higher than that along the vertical direction when the ratio of height and radius of the cloud was 0.2.The explosion intensity increased with increasing ratio of height and radius of gas cloud,and the maximum overpressure should increase by 3.1 times when the ratio changed from 0.1 to 1.0.When the ratio decreased,the distance of flame spread increased and the time of inflammation delayed,which led to decreasing energy transfer of gas cloud and falling explosion overpressure.The research results are of some significance to predict the disaster of flammable gas cloud explosion.