Flame propagation of premixed liquefied petroleum gas explosion in a tube

Flame propagation in premixed liquefied petroleum gas (LPG) explosion was studied experimentally in a tube of diameter 2.6 m and length 25 m. Experiments on LPG explosion were conducted in a single zone first in this large explosion tube. The explosion tube was then divided into two zones with different mixing ratios of LPG and air. A thin polyvinyl chloride (PVC) film sheet was used to adjust the length of each zone. A total of three single-zone experiments and five two-zone experiments were carried out. Explosion phenomena and flame propagation in the tube were studied analytically using experimental results and theoretical analysis. A simple model for the flame propagation was proposed and tested using the experimental data in the present study and some literature results. Flame propagation characteristics were found with a general trend to vary with time as an exponential function for adequate fuel with uniform concentrations within a certain distance of the tube. The flame propagation speed at a point in explosion depends on the turbulent burning speed and expansion ratio. Experimental data deviated more from the empirical exponential function for larger variations of fuel concentrations.