Effect of flame surface area of downward propagating flames induced by single and double laser irradiation on transition to parametric instability

The single laser irradiation ( SLI ) method was adopted to develop a double DLI investigate the effects of laser-induced structures downward-propagating flames in tube on transition from primary acoustic instability parametric . Previously, effectively used study interaction between oscillation and flame structure by controlling shape front. deformed cellular (either concave or convex) -induced can under certain conditions. We conducted experiments same combustion with C 2 H 4 /O /CO mixtures using both for comparison. forms structures, while only flames. It found that more effective than generating total power. Furthermore, linear relationship area (irrespective its dimension) corresponding growth rate pressure fluctuation during propagation flame. - having surface demonstrate thermo-acoustic regardless difference ak , where is amplitude k wavenumber respectively. This factor described velocity coupling mechanism important reveal due variation area. results revealed actual area, rather structure, determines presence nonhomogeneous cell distribution induced comprehensive criterion instability.