Influence of oxygen addition in multi-swirl pilot zone on atmospheric pressure ignition characteristics

The ignition experiments were conducted on atmospheric pressure and normal temperature. The experimental research object was a model combustor with multi-swirl air atomizing nozzle. The systematic parameters for study consist of atmospheric pressure, normal temperature, pressure drop of chamber of 1%-6%, ignition energy of 20 J and 12 J, mass flow ratios of oxygen and air in pilot zone of 0-0.04. The change rule of ignition fuel-air ratio of multi-swirl air atomizing nozzle. The results indicate that when ignition fuel-air ratio is small enough, maximum ignition air flow velocity at combustor inlet increases with the rising oxygen addition mass flow in pilot zone. On the condition of the same ignition energy and pressure drop of chamber, while the mass flow ratio of oxygen and air in pilot zone increases, the ignition fuel-air ratio reduces. When the mass flow ratio of oxygen and air in pilot zone increases to a threshold value (20 J-0.01, 12 J-0.015), the trend of ignition fuel-air ratio of curve changes. When it continues rising to another threshold value (20 J-0.025, 12 J-0.03), the ignition fuel-air ratio will not change.