Numerical Simulation Of Premixed Gas Flame Propagation In Open Space

Based on the advantages of high calorific value,easy storage and little pollution,natural gas is expected to replace gasoline as a new generation of automobile fuel.Ho wever,during its transportation,storage and usage,it may cause explosion when it accidentally leaks and explodes.In this paper,the background is the open space,it is based on the fact that the gas leaks and burns easily in the gas filling station.Fluent will be used to solve such problems.This paper will research on the process of detonation flame propagation on the hemispherical premixed gas cloud,in a hemispherical open space with a radius of 5m,the gas cloud radius is 0.3m~0.9m,the gas cloud density is 9.5%.Firstly,The 2D and 3D cases are calculated respectively.It is found that the temperature and pressure in the propagation process is almost the same in two cases,so the 2D case is selected for the further study.The combustion model and the turbulence model are validated by comparison with the experiments in the literature.The eddy-dissipation combustion model and the RNG turbulence model are selected.Secondly,the influence of ignition pressure,gas cloud radius and ignition temperature in the flame propagation process was studied.When the gas cloud radius is less than 0.6m but more than 0.3m,the flame propagation process is the same,When the radius of the gas cloud is larger than 0.7m but less than 0.9m,The higher the gas cloud radius,the higher the peak temperature and the peak pressure,the earlier the pressure began to rise,the faster the temperature and pressure propagated and the wider the range.The ignition temperature had little effect on the flame propagation process.Finally,I studied the influence of ambient temperature,obstacles and environmental wind speed on the flame propagation process.As the ambient temperature increases,the peak pressure decreases,the peak of temperature increases,the pressure rises earlier,however the pressure and temperature's trends is not effected;If there are more obstacles,the peak of pressure and temperature ishigher.The change of the external wind speed has almost no effect on the temperature field,pressure and velocity of the flame propagation process.