Experimental Study On Influence Of Vacuum Degree And Thickness Of Weak Panel Material On Effect Of Vacuum Cavity Explosion Suppression

Gas explosion is the largest disaster in coal mine safety production of China, which will not only cause a lot of casualties, but also seriously destroy each system of the mine, and even lead to some secondary disasters. Therefore, the study of the gas explosion suppression technology is particularly important. Vacuum cavity explosion suppression technology is a new explosion isolation technology and it has a great significance on preventing gas explosion. Under the premise of previous research results of our research team, this thesis choose experimental research as the main means and take the scientific research method of "theory to guide practice, practice to prove theory" to further study the mechanism of vacuum cavity explosion suppression and the influence of vacuum degree and thickness of weak panel material on effect of vacuum cavity explosion suppression.Firstly, starting from the gas explosion propagation theory, combining dynamics and thermodynamics principle of gas explosion propagation, the mechanism of vacuum cavity explosion suppression is analyzed and elaborated in detail using thermal theory, mass transfer theory, chain reaction theory, fire triangle theory and energy attenuation theory.In order to study the influence of vacuum degree on the effect of vacuum cavity explosion suppression, the vacuum cavity explosion suppression experiments under different vacuum degree are designed and completed in this thesis. The experimental data is processed and analyzed from three aspects of explosion flame, explosion overpressure and impulse of shockwave. The experimental results indicate that the vacuum cavity has a relatively good effect of explosion suppression under different vacuum degree. For each measuring point, the maximum flame signal strength is reduced to 0.5V below, the maximum overpressure is attenuated to 0.2MPa below and the impulse is reduced to 5.5 k Pa?s below. And the relationship between vacuum degree and effect of vacuum cavity explosion suppression is concluded that beginning from normal pressure, the effect of explosion suppression gradually becomes excellent with the increase of vacuum degree, while the increase of vacuum degree has little influence on the effect of vacuum cavity explosion suppression after the vacuum degree reaches-0.04 MPa.Polytetrafluoroethylene film is selected as a new wake panel material of vacuum cavity in the experiments, its compressive strength is determined by the thickness. During the experiments, comparative experimental research is carried out by changing the thickness of wake panel material under the conditions of a fixed vacuum degree of-0.05 MPa. The experimental results show that the smaller the thickness of wake panel material of vacuum cavity is, the shorter the propagation distance of flame front is when Polytetrafluoroethylene film breaks, and also the better the effect of vacuum cavity explosion suppression is.