火灾条件下开敞空间LPG储罐的BLEVE试验

Experimental study of LPG storage tank BLEVE in unconfined space under fire

为研究火灾条件下开敞空间液化石油气(liquefied petroleum gas, LPG)储罐沸腾液体膨胀蒸汽爆炸(boiling liquid expansion vapor explosion,BLEVE)的荷载特征及爆炸波传播规律,研制了带滤波片的储罐爆炸试验装置,开展了小尺寸LPG储罐BLEVE试验,分析了LPG储罐的BLEVE过程及超压荷载特征,讨论了滤波片、LPG质量、储罐形状等因素对爆炸超压的影响,总结了已有BLEVE超压荷载的简化计算模型,对比试验数据与简化模型预测结果,给出了简化计算模型的适用范围。研究结果表明:次生蒸气云爆炸对开敞空间BLEVE超压荷载影响有限;BLEVE超压荷载峰值随爆源中心距离的增加而减小,随储存介质质量的增大而增大;在BLEVE超压荷载简化计算模型中,使用Brode模型计算爆炸能量最为保守,Planas模型仅能较准确地预测大尺度试验的结果,Birk模型则能较准确地预测大、中、小尺度试验的结果,但其结果略低于实验结果;规范建议的超压荷载计算方法中,Baker-Tang爆炸曲线法预测效果优于TNT当量法。

Ten batches of liquefied petroleum gas(LPG)tank explosion tests under fires were conducted to investigate the overpressure load characteristics and blast wave propagation of LPG tank boiling liquid expansion vapor explosion(BLEVE)in unconfined space.Five different LPG tanks were considered in the tests with the variations of filters,LPG mass and tank shape.The explosion process and overpressure load of BLEVE were recorded by high-speed camera and overpressure sensors.The effects of filters,LPG mass,tank shape on the overpressure loads of BLEVEs were revealed and discussed.The empirical models of BLEVE overpressure loads are reviewed and the predictions of the simplified models are compared with the data of multi-scale BLEVE tests.The limitation and suggestion of the simplified empirical models are proposed.It is found that the existence of filters during explosion tests brings about the secondary gas cloud explosion of LPG tank BLEVE and the effect of secondary vapor cloud explosion on overpressure loads of BLEVE in unconfined space is limited due to the specific testing conditions.Typically,the overpressure loads of BLEVE have two positive phases and one negative phase,which is significantly different from the loads of TNT and gas explosions.The peak value of BLEVE overpressure loads decreases with the increase of distance and the decrease of LPG mass.Among the existed empirical models,the Brode model is the most conservative in predicting the BLEVE overpressure loads and the Planas model can predict the large scale BLEVE reasonably.The Birk model shows good predictions for large,medium and small scale tests,while the results are prone to danger.With the increase of scaled distance,the peak value of BLEVE overpressure loads decays exponentially.Moreover,the performance of the Baker-Tang blast curve method is better than that of the TNT equivalent method in the prediction of BLEVE loads.