Abstract: When a gas pipeline leaks and comes into contact with an external fire source, it may lead to the formation of jet fire, which poses a huge risk to nearby workers and equipment. Therefore, it is particularly crucial to conduct in-depth research on the combustion behavior of jet flames in gas pipelines. Six types of pore sizes were selected, including 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mm, with pressures of 0.5, 0.8, 1.0, 1.2, and 1.5 MPa, respectively, to conduct jet fire experiments on gas pipelines under different operating conditions. The results show that when natural gas combustion reaches stability, the flame height and thermal radiation gradually increase with the increase of injection pressure and nozzle diameter; At a 3 mm aperture, the flame reaches a maximum length of 4.32 m, and the maximum thermal radiation reaches 552 W/m2 at a horizontal position of 1m from the leakage hole; When the aperture is 1.5 mm and the pressure is 1.2 MPa, the flame begins to rise. As the pressure and aperture increase, the rise phenomenon becomes more pronounced. When the leakage aperture is 3 mm and the pressure is 1.5 MPa, the maximum lift is 0.4 m. The experimental values provide guidance for dealing with the situation of jet fire caused by natural gas pipeline leakage.

Key words: natural gas pipelines, jet fire, flame morphology, thermal radiation