Analysis Of Gas Explosion Effect Of Masonry Envelope Of Storefront

With the development of society and the improvement of people’s living standard,the demand for all kinds of energy is rising,including natural gas as a clean energy,plays an indispensable role in the new energy strategy layout of our country.Natural gas,as a high quality energy,has been hailed as "the chief energy of the 21 st century" because of the advantages of clean,efficient and so on.Expanding the scope and popularization of natural gas and promoting natural gas to become the main application energy is of great significance for our country to further adjust the energy structure,improve people’s quality of life,further reduce carbon emissions and achieve carbon neutralization.With the widespread use of urban gas,civil gas safety accidents occur frequently in recent years,resulting in serious consequences.Research on explosion of civil buildings has become particularly important.At present,unreinforced masonry filled walls are widely used in restaurants in streets and alleys as building space envelope structure.Because the restaurant has the characteristics of large flow of people,people are relatively dense,the surrounding environment is relatively complex,and the restaurant is mostly open kitchen design,if the explosion occurs in the kitchen,it will pose a threat to all personnel in the restaurant.Gas explosion effect analysis of masonry envelope structure involves key technologies such as indoor gas diffusion range analysis,dangerous zone prediction and mixed gas model calculation,which is an important link of dynamic response analysis of indoor building structure and has great significance for building structure layout and indoor renovation.In this paper,the dynamic response of natural gas diffusion,masonry parapet and glass structure under explosion is studied by theoretical analysis and numerical simulation.The main work includes:1.The causes and consequences of gas leakage and explosion are analyzed comprehensively,and the theory of gas diffusion and explosion is expounded.A small hole leakage model was established in the confined space of adjacent buildings.The second order upwind scheme was adopted for the spatial discrete algorithm of the pressure,momentum,turbulent kinetic energy,dissipation rate and energy of the model,and the SIMPLE method of the pressure based solver was used to solve the transient problems of the model.The diffusion of gas in a restaurant is simulated under different influencing factors.The general law of indoor gas leakage and diffusion and the dangerous area of explosion are studied in different time periods,different ventilation conditions and different ambient temperatures.The results show that indoor ventilation is beneficial to gas diffusion and can dilute gas concentration to a certain extent.After ventilation measures are carried out in different rooms and indoor gas concentration reaches stability,indoor deflation risk areas are mainly concentrated near the leakage port.By analyzing 10℃,20℃ and 30℃,it can be seen that with the increase of indoor temperature,the gas diffusion rate accelerates,and the indoor deflagration risk area shrinks.2.Considering the characteristics of Arbitrary lagrangian-Eulerian(ALE),an arbitrary Lagrangian-Eulerian(ALE)model is set up.The model is solved by LS-DYNA program.Linear polynomial equation is used to describe the gas state of air and mixed explosive gas clouds.Anisotropic brittle damage model is used to describe the constitutive relationship of masonry walls.The effects of gas mixture content,pressure relief port size,gas mixture volume and explosive gas location on the explosion response of building masonry envelope were studied.The results show that the more the mixture gas content is close to the concentration of the complete reaction,the smaller the indoor pressure relief port area,the larger the volume of the mixture gas,and the closer the location of the explosive gas,the more obvious the dynamic response generated during the indoor explosion.Finally,some safer suggestions are proposed for the layout of the restaurant.3.The CONWEP model of glass dynamic response of single-layer toughened glass under gas explosion was established.Johnson Holmauist ceramic model was used for constitutive equation and failure mode of glass.The failure effects of different detonation distance,different explosive content and different thickness of glass were studied,which provided reasonable suggestions for the transformation of shops.Through the above research work,the fluid-structure coupling model of three-dimensional adjacent masonry envelope is successfully established,which overcomes the shortcoming of large error of simulation results in the traditional empirical formula,realizes the dynamic response monitoring of adjacent buildings,and provides certain data and theoretical support for the design of construction projects such as new construction,expansion,reconstruction,decoration and partition of storefront shops.