To analyze the role of the flow structure downstream the swirl cup on the performance of aero gas turbine combustors

PIV (particle image velocimetry) was used to measure the non-reacting flow field downstream a dual-swirl cup under ambient pressure and temperature

and the effect of the inlet Reynolds number on the recirculation zone downstream a dual-swirl cup was studied. The experimental results indicate that the flow structure downstream is a converge-diverge type when the inlet Reynolds number is low. As the inlet Reynolds number increases to 25000

the flow structure turns to a diverge type.Then the flow structure of recirculation zone remains unchanged with increasing inlet Reynolds number

but the normalized velocities in the recirculation zone would increase accordingly.