Numerical simulation of methane-air explosion in a connected device with volume fraction gradient

XU Xiaoyuan; SUN Jinhua; LIU Xuanya

doi:10.11883/bzycj-2020-0086

Volume 41 Issue 4

Apr. 2021

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XU Xiaoyuan, SUN Jinhua, LIU Xuanya. Numerical simulation of methane-air explosion in a connected device with volume fraction gradient[J]. Explosion And Shock Waves, 2021, 41(4): 045401. doi: 10.11883/bzycj-2020-0086

Citation:

XU Xiaoyuan, SUN Jinhua, LIU Xuanya. Numerical simulation of methane-air explosion in a connected device with volume fraction gradient[J]. Explosion And Shock Waves, 2021, 41(4): 045401. doi: 10.11883/bzycj-2020-0086

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Numerical simulation of methane-air explosion in a connected device with volume fraction gradient

doi: 10.11883/bzycj-2020-0086

1.
University of Science and Technology of China, Hefei 230026, Anhui, China
2.
Tianjin Fire Research Institute of MEM, Tianjin 300381, China

Received Date: 2020-03-26
Rev Recd Date: 2020-10-10

Available Online: 2021-03-05

Publish Date: 2021-04-14

Abstract

Abstract

A connected vessel is a common typical chemical plant, and its explosion hazard is much higher than that of an independent vessel. In an actual explosion accident, the combustible gas volume fraction in the connected device presents a non-uniform state, and there is a volume fraction gradient. A connected device was chosen as the research object. The device was formed by connecting two cylindrical vessels with the volumes of 60 litres and 20 litres, respectively, through a square pipe as long as 3 meters, with a cross section of 35 mm×35 mm. To explore the methane-air explosion characteristics in the connected device with combustible gas volume fraction gradient, the Fluidyn software was applied to numerically simulate the methane-air explosions in the connected devices with uniform and non-uniform combustible gas volume fractions, respectively. The results show as follows. When the volume fraction of the methane in the connected device is uniform and ranges from 6.517% to 8.067% and the ignition is located in the center of the large vessel, the maximum explosion pressure, the maximum explosion pressure rise rate, the maximum temperature and the maximum velocity as well as their arrival times change linearily with the volume fraction of the methane. When the volume fraction of the methane in the large vessel of the connected device is 6.0%, the volume fraction gradient of the methane is 2.0% to 8.0%, and the ignition is located in the center of the large vessel, the maximum values of the parameters, including explosion pressure, explosion pressure rise rate, flame temperature and velocity, increase firstly and then decrease with increasing volume fraction gradient. When the ignition is located in the center of the large vessel, the maximum explosion pressure is in the small vessel, the maximum pressure rising rate is in the pipe connected to the large vessel, and the maximum flame velocity is in the pipe connected to the small vessel, and the flame velocity can reach 400-600 m/s. The research results can provide a theoretical guidance for preventing and controling combustible gas explosion accident in connected devices.
- connected device,
- volume fraction gradient,
- methane explosion,
- pressure rise rate

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References

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