| Gas explosion in coal mine is a instant and serious accident with severe destruction and prone to secondary explosions, causing many casualties. So except for the further study of accident prevention measures, rescue technology for the emergency of coal mine should become the focus of attention, including emergency safety system and its installation technology. Because of the high mobility, short starting time and convenient installation characteristics, mobile refuge chamber for mine is taken as the object of emergency actions system.Mobile refuge chamber is a kind of important equipment for escaping the disasters. Its structural strength and sealing reliability, thermal shock resistance directly affects the miners’ safety. But powerful shock waves generated in the gas explosion can lead to some plastic deformation, dumping and distortion of the chamber, at the same time, the thermal shock of the explosion will make internal temperature rising sharply and instantly. So in order to ensure the protection function of refuge chamber, it must avoid damaging and leaking of structure under explosion, and have the ability of resisting instantaneous high temperature shock. In order to study the safety and reliability of the refuge chamber, it is necessary to investigate the shock wave amplitude and regulation, and analysis the coupling effect of chamber and air shock wave based on the actual conditions in the gas explosion.In this thesis, the three-dimensional finite element models of explosive source, air in roadway and chamber are established By the nonlinear explicit dynamic analysis software LS-DYNA. In this simulation, ALE elements were adopted for explosive source and air elements, Lagrange elements were adopted for chamber structure, ensure the overpressure of 100m away meet the demand loading of chamber, and considering the effect of chamber on the shock wave propagation. One point ALE multi-material coupling method was adopted for the simulation process, and the shock wave propagation process in the explosion, TNT equivalent of explosion source and the pressure-time curves around chamber were obtained.Took a sectional rigid refuge chamber as the research object, the above-mentioned real explosion load curves were loaded on the different surfaces of chamber to investigate the stress and deformation of its structure, gained the equivalent stress-time and plastic strain-time curves, deformation distribution contours, and the maximum stress as well as maximum deformation position according to the Mises criterion. This kind of chamber’s safety and reliability under explosive loading was checked and judged according to the safety criteria. The results show that the front door system of the chamber, and its explosion-proof glass of observation window, hinges and frame all meet the safety standards. There is stress concentration leading to plastic deformation on the flanges of structure. Strong elastic oscillations occurs during the whole process on the outer steel sheet, its equivalent stress is less than material yield strength but the maximum elastic deformation is out of the safety criterion, so its rigidity is insufficient. Though there is no failure for the back door system, its deformation is too large to seal of the escape door, so the rigidity is also insufficient.Finally, a section structure of chamber was taken as the object to analyze the performance of transient high temperature resistance in thermal analysis module of ABAQUS.900℃heat flux was loaded on the outside surface of the chamber and load time is2min. Temperature history curves on the external surface, the thermal insulation layer and the internal surface of chamber were obtained, the temperature distribution contours and the thermal stress were also concluded. At last, the properties of transient high temperature resistance of chamber were assessed according to the safety evaluation criteria. All these results will provide some reference for the design and optimization of mobile refuge chamber. |
PDF Full Text Request