Numerical Simulation Of Gas Leakage Diffusion And Explosion Effect In Chemical Industry Park

Natural gas as one of the common low-carbon energy has widely used in industrial production and life at present.It has the advantages of cleanliness and high efficiency.In addition,many chemical industrial use natural gas as clean fuel in production.If the natural gas leakage accident occurs in the chemical industry park,it will lead to a series of accidents.At first,according to relevant theories.,this paper simulates the experimental scene through the gas diffusion wind tunnel experiment and open space gas explosion experiment conducted by Beijing Institute of Technology.And relative error method and statistical parameters were used to evaluate the effectiveness of the numerical simulation.Then,takes a chemical industry park as the research object.Through the CASD module of the FLACS,the geometric model of the chemical industry park is established.The influence of gas concentration variation and sensitive factors on gas cloud diffusion is studied.Secondly,analyzed the explosion scenario of the leaking gas cloud,explored the change of pressure and temperature field in explosion scene.Finally,studied the influence of sensitive factors,such as gas cloud concentration,size and ignition position.The results are as follows:(1)Using FLACS software to simulate the natural gas leakage and diffusion,the process can be divided into five stages: jet phase,deflection phase,rapid propagation phase,stable propagation phase,and dissipation stage.Secondly,the equivalent gas cloud is closely related to the subsequent explosion scene,and the volume of the equivalent gas cloud accounts for about 44% of the real gas cloud volume.(2)Gas leakage will be affected by different factors.This paper studies the influence of three factors on the gas leakage diffusion process,including the leakage aperture,wind speed and temperature,(1)The size of the leakage aperture is directly proportional to the gas leakage rate,the area of the gas cloud and the regional risk(2)Wind speed will directly affect the concentration distribution and deflecting direction.When the wind speed is small,the distribution range of the gas cloud is relatively limited after diffusion;When the wind speed is increased,the distribution range of the leakage gas cloud is wider(3)Temperature mainly affects the shape,height and diffusion distance of the gas cloud.When the ambient temperature is low,the concentration of gas cloud is high and the distance of diffusion is short;When the ambient temperature increases,the concentration of gas cloud decreases and the diffusion distance increases correspondingly.(3)On the basis of gas leakage and diffusion,the equivalent gas cloud of combustible gas is extracted,and the gas explosion scenario is further simulated by FLACS software.In the process of gas explosion,the pressure will rise sharply and then decrease after reaching the peak value.The high temperature region in the temperature field coincides with the peak time of explosion pressure.Then,the high temperature region transfers to the surrounding,and the peak temperature shows a downward trend.(4)Gas explosion will be affected by a variety of factors.This paper analyzes the gas concentration,equivalent gas cloud size and ignition position:(1)The pressure peak value produced by gas explosion with different concentration is quite different.If the concentration of gas cloud is too large or too small,the explosion overpressure peak value will be relatively small.(2)As the volume of the gas cloud increases,the maximum explosion pressure also increases.There is an exponential relationship between the equivalent gas cloud size and the gas explosion pressure.(3)The change of explosion pressure caused by ignition position.The reason is that the degree of congestion in the building congestion is different.The congestion degree of buildings is large,and the cyclic excitation effect of explosion increases.