Liquid Atomization in Rotary Slinger Injectors: Role of Liquid Delivery Manifold

Abstract

In rotary injectors, the method of liquid delivery can play an important role in the quality of liquid atomization. In slingers, which are employed in small gas turbine engines, the liquid delivery manifold is a key component in the atomizer assembly, which not only delivers the liquid to the atomizer but also acts as a fuel metering device. In the present work, we investigate the liquid atomization in a slinger atomizer with a focus on the effect of the number of liquid delivery ports and port size in the static manifold. Different optical diagnostics are employed to visualize primary liquid breakup and measure droplet size. The results showed that, at a low liquid feed rate, a smaller number of injection ports or port size promotes supercritical breakup (annular liquid exit and disintegration) at an orifice exit such that the breakup length and droplet size are smaller. Also, hole-to-hole variation in the liquid breakup mode is noticed, which refers to different breakup mechanisms in adjacent slinger orifices. On the other hand, Coriolis-induced film breakup is promoted when the liquid feed rate increases. The present study highlights that the design of the delivery manifold can potentially influence spray performance in slinger injectors.