Numerical Simulation Of Gas Explosion In Confined Space

The explosion process of flammable gases cause great economic losses and casualty every year, as a result of the restriction on experimental fields, testing methods and the experimental founds, numerical simulation became one of an important method of investigating flammable gas explosion.On the basis of theoretical analysis and the results of previous studies, a numerical model of gas explosion in the confined vessels was formed by using k-∈turbulence model,zimont turbulence combustion model and the probability density method in the FLUENT,a UDF program was programed to revise the zimont model. The contrast between literature of the carbon monoxide, methane, ethylene, acetylene’s burning temperature and the prePDF calculated result with error less than5%,The conclusion was drawn that the in build thermodynamic database can be used to generate the thermodynamic parameters. Some simulation with carbon monoxide was done in different concentration and initial temperature, it showed the maximum overpressure of the simulation was higher than the experimental result and they were within20%error. The model was more suitable in the equivalent concentration and higher temperature at the mean time.In order to verify the model can be used in different constructions, methane/air explosion simulation was made in the straight pipeline, opening pipeline and closed pipeline. Comparing the dynamic pressure and the progress variable contour map at50ms, it proved the existence of "two waves and three zones" and the flame progress was deflagration; It also showed the formation, development and distinguish of the flame by intercepting the temperature contour map at different times. As there was no pressure gathering condition in the opening pipeline, the propagation was faster and the overpressure was smaller; The flame speed rise in front of the obstacle which caused a sudden pressure jump rise, but the final maximum overpressure was not rise.All the above numerical simulation proved the model can be used in practical engineering, and the model was helpful in finding the explosion law of combustible gases and reducing the losses in accident caused by explosion.