Experimental Investigation on Pilot Spray Characteristic of Internally-Staged Combustor

In order to investigate the pilot spray characteristic, a series of experiment was taken. Phase doppler particle analyzer (PDA) was used to measure size and velocity of droplets. The photos of spray were captured with a light sheet. The results are as conclusion: spray corn angle ranged from 50° to 70°, it seemed quite small due to the restriction of sleeve. With increasing fuel mass flow rate or air pressure drop, spray corn angle became larger, and the spray ranged broader. The quantity of droplet increased and drop diameter decreased. The width of the center recirculation zone was merely 20mm, and the maximal recirculate velocity was about 10m/s. Changes of fuel mass flow rate hardly influenced the air flow field while increasing air pressure drop lead to obvious enhance of flow velocity and circulation. However, the position of circulation zone and the structure of flow field did not charge with the variation of the operating conditions. The increase of air pressure drop as well as the decrease of fuel mass flow contributed to the decrease of Sauter mean diameter (SMD), but the changes of air pressure drop mattered more. At a certain air pressure drop, the average SMD decreased with the rising of air-liquid ratio (ALR), however the curve flattened out as the increase of ALR. © 2020, Editorial Department of Journal of Propulsion Technology. All right reserved.