78 / 2023-06-09 15:17:46

Investigating the impact of shock wave reflection on the pressure of premixed methane/air explosions in a triple T-opening branch pipeline network

Three T-shaped tube,Gas explosion,premixed combustion,Pressure propagation,Shock wave motion process

Pipeline branching conditions in the process industry can significantly affect gas explosion pressures in gas pipelines, pipe networks, or underground coal mine tunnels. Previous studies have mainly focused on double right angle and bifurcated pipe networks when studying gas explosion propagation. In this paper, we employ both experimental and simulation methods to study the effect of triple-T pipe network structure on premixed methane/air explosion pressure. Our results show that the triple-T branching structure in the pipe network has a pressure relief function. Specifically, the explosion overpressure reduces by 15% in the main network and 39% in the branch after passing through the T-shaped branch. When explosive overpressure propagates through a network of T-shaped branch, it initially enters the main network before subsequently disseminating to the branch network. There is a positive correlation between the time of flame appearance and the time of peak pressure appearance. The propagation of the three-T structure pipe network causes a secondary boost phenomenon in the pressure of the main network between the first pipe and the second branch pipe. This is due to the reverse propagation pressure caused by the shock wave reflection, which opposes the positive propagation of the explosion overpressure. As a result, a pressure strengthening channel is formed between the first and second branch pipes, and the strengthened positive propagation pressure tends to propagate along the pipe wall in the main network, ultimately impacting the end wall of the pipeline. The reflection of the shock wave prevents the overpressure from entering branches 2 and 3. In this structure, the pressure in the main network is higher than in the first branch, and the pressure in branch 1 is significantly greater than in branches 2 and 3. Our study provides guidance for pipeline protection in natural gas pipelines and emergency personnel evacuation measures in the event of an explosion in a triple-branch network structure.