CELERITY AND FLAME LENGTH OF BURNING NATURAL GAS PUFFS

An experimental study of combustion in natural gas puffs has been conducted. The present work concentrated on the effects of duty-cycle and puff volume on the flame length. Individual puffs which are widely separated, have considerably shorter flame lengths, by as much as a factor of four, when compared to a steady jet flame. Furthermore, the flame length of individual puffs scales with the initial puff volume, in agreement with the previous studies of buoyant puffs in aqueous media. For any puff volume, as the duty-cycle is increased beyond a given value, the flame length tends to rise rapidly due to the interaction among neighboring puffs. Measurements of the puff celerity indicate that the puffs are buoyancy-driven.