Abstract: A combustion apparatus comprises a combustion chamber disposed about a central longitudinal axis and means to separately introduce oxidant and fuel into the combustion chamber such that when ignited, the resulting diffusion flame swirls about the central axis and exhibits characteristics of a premixed flame. The asymmetric nature of the flame components introduction allows the combustion to be conducted stably at a fuel rich or fuel lean condition and if desired, to extinguish the flame. The fuel oxidant ratio can be reduced such that nitrogen oxide emissions are reduced. Great combustion stability obtained at low equivalence ratios and elimination of possibility of flashback are achieved in the new process and due to the spinning flame, combustion is completed in very short distances.