Study on flame propagation and acceleration mechanism of city coal gas

An experimental study on acceleration mechanism of flame propagation of city coal gas-air mixture was conducted in a closed obstructed duct with 80 mm diameter and 21 mm length, and acceleration mechanism of flame with or without obstructions is researched. Acceleration mechanism of flame propagation owes mainly to the positive feedback of unburned gas heated and compressed by the leading compression wave and the turbulence region induced by obstacles for combustion process. The experimental results indicate that the maximum explosion pressure can increase by 20% when the obstacles are present, and the maximum explosion pressure of theoretical computation results agree with the experimental data. The flame propagation characteristics with the variation of equivalence ration of city coal gas-air mixtures are described. The circular plates number and blockage ratio have some effects on the flame velocity and overpressure.