The effects of pipe length on gas cloud explosion characteristics in the contraction pipe

ABSTRACT

To study the influence of pipe length on premixed gas explosion characteristics in a contraction pipe. A Large Eddy Simulation (LES) and Zimont combustion model was used to simulate the propane/air explosion process at different pipe lengths. The results show that the flame propagation velocity in the contraction pipe increases first and then decreases and reaches its peak at the change of pipe diameter. Compared with the diameter pipe, the flame propagation velocity in the first half of the contraction pipe is reduced by adding the contraction structure. Although the flame propagation velocity increases suddenly after the flame passes through the contraction pipe, the flame propagation process is effectively delayed. Compared with the diameter pipe, the total combustion time of the contraction pipe increases by 44.4%, 30%, and 30%, respectively. Under different pipe lengths, the trend of pressure change is to increase first and then decrease, and the longer the pipe, the greater the maximum explosion pressure in the pipe. The existence of the variable diameter structure leads to a significant increase of the peak pressure in the pipe, and the peak pressure in the contraction pipe is, respectively, 8, 4, and 7 times that in the diameter pipe of the same length. Therefore, in actual industrial production, it is necessary to take safety measures such as pressure relief at the change of pipe diameter to avoid accidents.

KEYWORDS:

• Premixed gas
• pipe length
• flame propagation velocity
• contraction pipe
• vortex cluster

Acknowledgments

This work was financially supported by National Key R&D Program of China [No.2017YFC0805100]; The Natural Science Research Project of Higher Education Institutions of Jiangsu Province[No.20KJB620004]; Special Funding Project of Basic Scientific Research Business Fee of China Academy of Safety Production[No.2019JBKY08]; Innovative Talents Team Project of “Six Talents Peaks” in Jiangsu Province[No.TD-JNHB-013]; Major Projects supported by the Natural Science Research of Jiangsu Higher Education Institutions [No.17KJA440001]; Open Project of Jiangsu Key Laboratory of Oil and Gas Storage and Transportation Technology[No.CDYQCY202104].

Additional information

Funding

This work was supported by the Major Basic Research Project of the Natural Science Foundation of the Jiangsu Higher Education Institutions [No.17KJA440001]; National Key Research and Development Program of China [No.2017YFC0805100]; Natural Science Research of Jiangsu Higher Education Institutions of China [No.20KJB620004]; Open Project of Jiangsu Key Laboratory of Oil and Gas Storage and Transportation Technology [No.CDYQCY202104]; Six Talent Peaks Project in Jiangsu Province [No.TD-JNHB-013].

Notes on contributors

Xue Li

Xue Li, Female, Ph.D, mainly engaged in the research of petrochemical safety technology and management, petroleum engineering safety technology.

Ning Zhou

Ning Zhou, Male, Ph.D, Professor, mainly engaged in the research work of petrochemical safety emergency technology and management.

Bing Chen

Bing Chen, Male, Ph.D, associate researcher, mainly engaged in the research work of petrochemical safety production management.

Yingying Xu

Yingying Xu, Female, Master, mainly engaged in the research of oil and gas storage and transportation safety.

Xuwei Li

Xuwei Li, Male, postgraduate, mainly engaged in the research of oil and gas storage and transportation safety.

Weiqiu Huang

Weiqiu Huang, Male, Ph.D, Professor, mainly engaged in oil and gas recovery and environmental protection.

Xiongjun Yuan

Xiongjun Yuan, Male, associate professor, mainly engaged in safety engineering technology and other research work.

Xuanya Liu

Xuanya Liu, Male, Ph.D, research institute, mainly engaged in petrochemical fire protection technology and other aspects of research.