Effect of premixed LPG/Air mixture fractions on flame front propagation in a cylindrical combustion chamber: experimental and numerical study

The present study investigates flame propagation of LPG/air fuel in a cylindrical combustion chamber. All behaviors of flame growth are included within this study starting from its earlier stages till tulip shape collapse. In addition, the impact of changing the flow conditions on the flame through each stage is investigated numerically. Additionally, the study delves into the underlying physical mechanisms that are responsible for the tulip flame phenomenon and any subsequent flame inversions. OpenFOAM software is used to conduct the numerical models and assess the capability to accurately simulate the propagation of flame within the chamber. The study's findings show that hydrodynamic factors are primarily responsible for tulip shape formation. This happens because of the competition between the moving forward of unburned gases in the finger-shaped flame region and the moving backward of deflected burned gases that expand from the sides of the flame. The highest flame speed for LPG/Air mixture was found to be at (ER =1) while the highest flame temperature was recorded for pure Propane fuel. Landau-Darrieus instabilities, pressure waves, and vortex motion have no significant contribution in flame tulip reformation while Rayleigh-Taylor instability rarely affects flame distortion initiation. Error between numerical and experimental values of laminar flame speed does not pass 10.7%. On the other hand, the current experimental and numerical results were validated with corresponding data form literature where the errors between both studies are acceptable.