Study on explosion characteristics of natural gas with concentration gradient in residence

In order to improve the accuracy of the investigation of natural gas explosion accidents. The effects of different concentration gradients on the explosion characteristics of natural gas are studied. It is found that the concentration gradient can significantly change the evolution path of flame shape and induce the formation of asymmetric tulip flame and stretched tulip flame. The generation of vortex is the key factor to induce the flame to take on an asymmetric tulip shape. Compared with uniform concentration, when there is a concentration gradient, it is more conducive to the generation of vortex, and the reverse flow appears later. With the increase of concentration gradient, the explosion overpressure and the rate of pressure rise decrease significantly. Spatial location has a significant impact on the distribution of overpressure; the overpressure in the kitchen oscillates violently, showing four peaks, while the overpressure in the living room only shows two peaks.