Experimental study on self-excitations in nitrogen-diluted laminar lifted butane flames

► A new extremely low frequency self-excitation (< 0.1 Hz) and a newly observed flame blow-out are caused by conductive heat loss from premixed wings to the trailing diffusion flame. ► A self-excitation prior to flame blow-out is shown to be due to buoyancy effects. ► Buoyancy-induced self-excitation frequencies increase in triple-flame propagation and decrease in flame-front propagation modes.