关键词: 蓄水高度, 受限空间, 油气爆燃, 自由基, 数值模拟

Abstract:

To prevent and control gas deflagration accidents in confined spaces, a numerical model of a horizontal pipeline was established. The pipeline was set to be closed on the left and open on the right. Through this model, the effects of different water storage levels on the oil and gas deflagration features inside the confined space were investigated. The results show that under conditions without water storage, the overpressure time history at each measurement point in the horizontal pipeline first increases and then decreases, followed by Helmholtz oscillations and eventual stabilization. As the water storage height is increased, the main peak of the overpressure time history is shifted from a single-peak structure to a double-peak or multi-peak structure similar to the state without water storage. Furthermore, after the maximum overpressure peak is reached, irregular oscillations are generated, whereby the Helmholtz oscillation observed in the absence of water storage is disrupted, and the overpressure peak is caused to decay significantly. The heat generated by the deflagration is absorbed, contact with the flame is increased, and the concentration of key free radicals that drive temperature rise is suppressed by the presence of water storage. Thereby, the decline in deflagration characteristics related to temperature within the pipeline is accelerated. Flame propagation is inhibited by water storage. As the reaction proceeds, heat is absorbed by the water storage, and large amounts of water vapor are produced through evaporation. The unreacted hydrocarbons and oxygen are diluted by the increased water vapor content. Consequently, the reaction rate is further reduced, and a significant decrease in flame propagation speed during the oil and gas deflagration is caused.

Key words: water storage height, confined space, oil and gas deflagration, free radicals, numerical simulation