Title: Numerical simulation on explosion overpressure features of methane-air premixed gas at different concentrations in utility tunnels

Authors: Shang-Qun Xie; De-Ying Li; Le-Duan Chen; Rui Zhou

Addresses: Beijing Jiaotong University, Beijing 100044, China; State Key Laboratory of Building Safety and Built Environment, Beijing 100013, China ' Beijing University of Civil Engineering and Architecture, Beijing 100044, China ' University of Science & Technology Beijing, Beijing 100083, China; China Academy of Building Research, Beijing 100013, China ' Department of Engineering Physics, Institute for Public Safety Research, Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing 100084, China

Abstract: According to the structural features of utility tunnels, the origin and development process of combustion and explosion of premixed natural gas with the volume fraction of 5%, 7%, 9%, 11%, 13% and 15% was simulated by fluid dynamics software ANSYS-Fluent. The results showed that the evolution rules of the overpressure and overtemperature produced by the flame front were basically the same within the critical concentration range of methane explosion. Local pressure and temperature jumps in right of bottom edges were formed appearing at the maximum overpressure, which was affected by the combustion front and pressure waves together with reflected wave pressure. The combustion process in utility tunnels can be divided into four stages: rapid growth of combustion, steady development of combustion, combustion jump, and pressure and temperature oscillating retrenchment after burning. The simulated maximum overpressure is around 1.7 MPa and it is obtained under the conditions when the premixed gas concentration is 9% and 7%.

Keywords: numerical stimulation; utility tunnels; explosion; overpressure.

DOI: 10.1504/IJWMC.2019.097414

International Journal of Wireless and Mobile Computing, 2019 Vol.16 No.1, pp.1 - 6

Received: 21 May 2018
Accepted: 10 Aug 2018
Published online: 21 Jan 2019 *

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