Research On Leakage Mechanism And Diffusion Law Of LNG Gas Cylinders Under Different Working Conditions

Due to the less pollutant emission,high economic efficiency and other characteristics,LNG is widely used as buses fuels in public transportation.Most of the LNG buses in Beijing are always parked under the overpass since the limited parking Spaces.Because of the structure and technology characteristics of LNG cylinders,there exists the gas leak risk during the buses parking.And then,a semi-closed space can be formed by accumulated natural gas and will cause a potential burning explosion hazard.In the previous papers,the leak and diffusion behaviors of chemical storage tanks and transport pipes were mostly studied,and which under urban complex space were rarely founded.Therefore,it is practical significance for the study of LNG leakage diffusion laws in this semi-closed space.This article mainly carries on the following work:(1)A simulation method based on the related theory of hazardous gas leak and CFD numerical method was firstly proposed,and the calculation method for the study object is designed by using the method,and then the designed experiment of the principle of similar small model is used to verify the calculation method.(2)On this basis,the effects of different parameters on the LNG leakage diffusion rules had been systematically analyzed,such as,wind speed,temperatures,the shape of overpass,number of buses,and so on.Based on the numerical results,an experienced model was established using least square method.(3)Lastly,according to the concentration and volume of natural gas leakage,the explosion effect and explosion shock wave were calculated by the TNT equivalent method,and then the influence of the explosion on the bridge,the bus and the pedestrian was analyzed.