Experimental study on the explosion characteristics of hydrogen-methane premixed gas in complex pipe networks

To explore the overpressure evolution laws and flame propagation characteristics in complex pipe networks after the addition of hydrogen to methane, we experimentally studied the explosive pressure wave and flame wave propagation laws for three different premixed gas mixtures with hydrogen-methane concentrations of 0, 10% and 20% when the equivalence ratio was 1. Experimental results indicate that the maximum explosion overpressure of the premixed gas increases with increasing distance from the explosion source, and it shows a gradually decreasing trend. In the complex pipe network, an overpressure zone is formed in the B–E–H and D–E sections of the network. The flame temperature is superimposed with the superimposition of the pressure, showing a trend of first increasing, then decreasing, then increasing, and finally decreasing in the complex pipe network. The flame arrival time increases with increasing distance, and the maximum flame speed shows a decreasing trend. The peak overpressure and maximum flame velocity of the premixed gas under a hydrogen volume fraction of 20% are 1.266 MPa and 168 m/s. The experimental research results could provide important theoretical guidelines for the prevention and control of fuel gas explosions in urban pipe networks.