泄爆口强度对管内天然气爆炸流场的影响仿真

When a natural gas line pipe is in a leaking combustion state, gas explosion inside the pipe will easily occur, and the flow field of which is directly affected by the strength of the pipe vent port. To elucidate this incident, a small-size rectangular pipe (80 mm×80 mm×600 mm) as the simulated object was chosen, then based upon the FLAC, analyzed the flame spread properties of methane explosion under such working conditions as vent opening, vent sealing, vent bearing-blast (vent bearing 0.1, 0.3, 0.5 MPa respectively). The laws of explosion pressure, explosion temperature, and flame spreading-speed varying with time under the above working conditions were obtained. In the explosion of the mixed methane and air in the pipe, pressure and temperature show no apparent descending trend after climbing to the peak value under the working condition of vent sealing, but pressure presents a sudden drop and temperature is slowly decreasing after the peak values under the working condition of vent opening. Under the working condition of vent bearing-blast, the trend of pressure and temperature change in the pipe was the same, rising first up to the peak values and then descending afterwards, but along with the rise of bearing-blast pressure, both the peaks and the climbing time of pressure and temperature in the pipe will increase. The pressure peaks under various working conditions are from large to small, showing that the strength of vent port has an obvious impact on the explosion pressure and flame propagation speed but little effect on the temperature in the pipe.