Experimental and large eddy simulation study on gasoline-air mixture explosions in semi-confined pipe with 90° right-angle bend

doi:10.11949/j.issn.0438-1157.20180519

Abstract

Abstract:

The characteristics of oil and gas pressure and explosion in a confined space with a 90° right-angle bend structure are studied. The pressure transient and flame morphology were collected by high-speed photography. At the same time, the large eddy simulation of the experiment is carried out. The overpressure, field structure and the shape of the flame passing through the pipe are accurately simulated, and the results are compared with the experimental results. The results showed that:(1) The bend has an effect on the flame structure during the explosion, and in the shape change. (2) The brush-like flame formed at the bend is caused by the vortex generated by the local pressure gradient of the bend. (3) The superposition of the local diffracted wave and the reflected wave in the bend have an enhanced effect on the peak value of the explosion overpressure. (4) During the explosion process, the peak value of explosion overpressure, flame speed and flame front area show significant coupling and close internal relationship. The three have strong consistency with time.

Key words: deflagration, overpressure, bend, numerical simulation, flame structure, experimental validation, model

摘要：

针对含90°直角弯管结构受限空间油气泄压爆炸特性进行了研究，采用高速摄影等技术对爆炸过程中的压力瞬变、火焰形态进行了采集，同时对实验进行了大涡模拟，精确模拟了火焰经过弯管时的超压特性、流场结构以及火焰形态，并与实验结果进行了对比分析。结果表明：（1）弯管结构对于爆炸过程中火焰结构有影响，在受限空间内火焰形态发生“半球形—指尖形—毛刷状”三种形态转变。（2）在弯管处形成的毛刷状火焰是由弯管局部压力梯度形成的涡流导致的。（3）衍射波与反射波在弯管处的叠加对爆炸超压峰值具有强化作用。（4）爆炸过程中，爆炸超压峰值、火焰速度、火焰锋面面积表现出显著的耦合性，具有密切的内在联系，三者随时间变化趋势存在较强的一致性。

关键词: 爆燃, 超压, 弯管, 数值模拟, 火焰结构, 实验验证, 模型

CLC Number:

X932

LI Meng, DU Yang, LI Guoqing, WANG Shimao, LIU Chong, WEI Shihao. Experimental and large eddy simulation study on gasoline-air mixture explosions in semi-confined pipe with 90° right-angle bend[J]. CIESC Journal, 2018, 69(12): 5370-5378.

李蒙, 杜扬, 李国庆, 王世茂, 刘冲, 韦世豪. 含90°直角弯管结构受限空间油气泄压爆炸实验与大涡模拟研究[J]. 化工学报, 2018, 69(12): 5370-5378.

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