CFD Simulation Of Dispersion In LPG Spherical Tank Area And Simplified Calculation Model Of Vapor Cloud Explosion Load

Petrochemical production involves the storage and processing of a large amount of flammable and explosive products such as liquefied hydrocarbons and combustible gases.Once the gas leaks,it will easily mix with air to form a flammable gas cloud mixture.If it encounters electric sparks,open flames,lightning strikes,etc.The ignition source is very prone to vapor cloud explosion(VCE),resulting in a very dangerous and serious accident.In recent years,related accidents have occurred frequently at home and abroad.The explosion in the factory area will cause serious damage to a large number of storage tanks,pipelines,equipment,structures,etc.,threatening people’s lives and property safety,and has become a prominent problem in the field of production safety.The central control room is the control core of the petrochemical industry.Once damaged,it will trigger a chain reaction,which will affect the production operation and safety status of the entire plant area.It is the focus of the anti-blast design of the building.This paper takes a typical spherical storage tank area as an example to study the leakage and explosion environment of spherical storage tanks.Based on ANSYS/Fluent software and computational fluid dynamics(CFD)methods,the process of leakage diffusion,vapor cloud explosion and shock wave propagation.The turbulence,component transport,chemical reaction,heat transfer and other physical and chemical processes are simulated.This method has been proved to be quite reliable in recent studies,and it avoids the difficult problems of large-scale explosion tests.The main step is to first simulate the leakage diffusion process to obtain the non-uniform combustible gas concentration field under the influence of various factors,and then ignite on the basis of the obtained non-uniform concentration field to simulate the gas cloud explosion,thereby obtaining the spherical tank area opening The characteristics of the explosion flow field of the vapor cloud in the open space,and finally the law of the load change on the surface of the control room during the propagation of the shock wave is analyzed,and the corresponding simplified calculation formula is proposed.The research results show that the liquefied petroleum gas is a typical heavy gas diffusion after a leakage accident,and it is easy to spread along the ground.In a short period of time,it can form a large-scale combustible gas concentration field,which can be triggered by a smaller energy ignition.The vapor cloud exploded in open space,and the overpressure could reach 37 k Pa at a distance of 3m from the explosion source.In addition,the obstacles in the environment affect the diffusion and explosion process at the same time,which will significantly increase the risk of explosion.The distribution of the load on each wall of the control room in space and time has significant non-uniformity.This paper proposes a simplified calculation formula of a binary quadratic polynomial for the uneven distribution of the load in the control room.The research in this paper provides a simulation method of using computational fluid dynamics to carry out leakage and explosion accidents in actual petrochemical tank farms,which can be used for related safety consulting and design load determination.At the same time,different walls of control rooms can be quickly obtained through simplified calculation formulas The load distribution of the surface has important reference significance for the anti-blast design and damage mechanism of the control room and other buildings.