Research On The Distribution Of Gas Cloud Explosion Field In The Urban Utility Tunnel

The utility tunnel is the important infrastructure of the city and it’s the "artery" and"lifeline" of the city.It is the goal to ensure the safe operation under various circumstances.The integration of gas pipeline into utility tunnel has been advocated by relevant standards,which is likely to become a trend of development.When the gas leak occurs,the utility tunnel will be full of the combustible gas,which has the potential danger of forming the "strongly restrained、large volume、cylindrical gas explosion".So it is of special significance to study the explosion of gas cloud in the urban utility tunnel.This paper embarked from the theoretical analysis and numerical simulation methods,according to the experimental data published,calculated and adjusted the parameters used in the numerical simulation.Build 3D numerical models of closed utility tunnel and partial opening utility tunnel,use Fluent software to simulate the explosion of methane-air premixed gas,and research the distribution of gas explosion overpressure field and temperature field.Consider the premixed gas gathering length,tunnel section,ignition location and other factors,analyze and compare the influences of different factors on gas explosion overpressure field.The main conclusions of this paper are as follows:(1)The overpressure distribution and temperature distribution of the gas cloud explosion in the utility tunnel are obtained,discuss the distribution of gas cloud explosion field under the influence of premixed gas gathering length,cross section shape and ignition position.The results show that the influence of premixed gas gathering length on explosion intensity is the most significant,and the influence of cross section shape of the utility tunnel is minimal.(2)Build combustible gas model of partial opening utility tunnel,discuss the distribution of gas cloud explosion field under the influence of opening size,opening position and ignition position.The results show that the opening size affects the explosion intensity in the utility tunnel,and the pressure decreases with the increase of the opening size.The opening position and the ignition position have a little effect on the utility tunnel.(3)Analyse the overpressure time history curves of each point under the influence of various factors,the function expression of the arrival time of the peak overpressure and the function expression of the overpressure are obtained by data fitting.