Indoor Gas Fire Gaseous Flashover Mechanism And Its Relation With Detonation

The paper is supported by the National Basic Research Program of China (973). The study aims at the fatalness, spread and the mechanism of indoor gas fire.The paper researches it through the experiment and the numerical simulation and abstracts the physical model from the actual room through analogous theoretic. In the experiment, the flame accelerates suddenly and fills the entire compartment in the combustion process, which the paper defines it gaseous flashover. In former research, through the experiment and the simulations result, we obtain the symbolic parameter which the flashover occurs is the pressure increases suddenly, and define the second peak value for the flashover time in the combustion process.On the basic of former research, the paper will design new experiment and simulation conditions and summarize the former experiment and the numerical simulation data to compare flame's spread mechanism of premix combustion and partial premix situations. The paper tries to post the mechanism of gaseous flashover and whether is detonation in this phenomenon.Through analyzing the numerical simulation result, the study obtains the following conclusion:1.the bigger boxes make the gaseous flashover easier. The bigger is flux, the bigger is pressure. The gaseous flashover is easy. Big open window causes the fuel accumulation to be slow and simultaneously the pressure variation is small. It is not easy to make flashover. The ignition position approaching the window is easier to ignite fuel gas. The pressure changes grate. It is easy to make flashover.2. The fuel gas volume and box body volume's ratio between 0.024-0.043 has the high probability to make flashover.3. Through the simulation premix combustion's situation, we know that there are two peak values similarly in the compartment. The process of twice pressure elevating has the same reaction mechanism, which is the fuel's participation chemical reaction. Through analyzing the progress variable chart, the vorticity chart, the streamlines pattern in the partial premix combustion's situation, we know that, the fuel gas, the intermediary product burn after the first pressure peak value drops as a result of the eddy current function in the later period. It causes the pressure to elevate again. The flame entire the compartment then gaseous flashover occurs.4. Through contrasting the literature's result, summarizing the paper data, for example the pressure variation, the flame propagation velocity, we know that the fuel gas leaked causes the fire, as well as the gaseous flashover phenomenon have nothing to do with the detonation. It has not transformed as detonation.