Structure of a Swirl-stabilized, Combusting Spray

Measurements of the structure of a swirl-stabilized, reacting spray are presented. The configuration consisted of a research air-assist atomizer located in the center surrounded by a coflowing air stream. Both the air assist and coflow streams had swirl imparted to them in the same direction with 45 degree angle swirlers. The fuel and air entered the combustor at ambient temperature and the combustor was operated in an unconfined environment. The gas phase was seeded with aluminum oxide particles in order to obtain velocity measurements. Velocity measurements for the gas phase are reported for both an isothermal, single-phase case without drops and a reacting spray case at axial distances from 2.5 to 350 mm downstream of the nozzle. Both mean and fluctuating values are reported. Heptane fuel was used for all the experiments. Drop size and velocity, and drop number flux are also reported for five axial distances downstream. Both mean and fluctuating values are reported for the drops. The measurements were performed using a two-component phase/Doppler particle analyzer. Profiles across the entire flowfield where velocities were significant are presented. Mean gas phase temperatures were also measured intrusively using a single pt/pt-13 percent rh thermocouple and are reported at axial distances from 2.5 to 200 mm downstream of the nozzle.