Abstract: In order to improve the explosion release efficiency and protection level of combustible mixed gas in a narrow and long space, the methane explosion discharge test in square pipes with pipe wall conduits was carried out, and the influence of pipe wall conduit diameter and position factors on the gas flame propagation process and explosion overpressure in the pipeline was explored by changing the length diameter ratio and position of the pipe wall conduit. The results show that there is a slight lag in the time of the release effect of the pipe wall conduit on the flame. Compared with the working condition of conduit without pipe wall, when the pipe diameter of catheter is 60, 80 and 100 mm, the flame propagation time is extended by 15.4%, 35.8% and 61.0%, and the peak peak explosion overpressure is reduced by 24.5%, 30.5% and 40.4%, respectively. The same pipe diameter pipe wall conduit placed at the front end of the square pipe can effectively discharge part of the flame and pressure, reduce the lateral propagation power of explosion energy, and the explosion discharge effect is obviously better than that of the pipe wall conduit placed in the middle and back end of the pipeline. When the conduit was placed at the front end, middle and rear end, the flame propagation time was extended by 85.4%, 15.4% and 4.5%, and the peak peak explosion overpressure decreased by 40.6%, 24.5% and 18.6%, respectively. Therefore, the installation of pipe wall conduit can effectively reduce the speed of flame propagation and vent explosion overpressure.

Key words: tube wall catheter, explosion venting, flame propagation speed, explosive overpressure, methane flame