Turbulent structures and mixing enhancement with lobed mixers in a supersonic mixing layer

摘要

Experiments are conducted on a supersonic mixing layer with two lobed mixers, which are designed following the concept of a shock-eliminating combustor. Instantaneous images were obtained to examine the evolution process of large-scale vortices downstream of the lobed mixers. The results show that no streamwise vortices appeared downstream of the lobed mixer with a penetration angle of approximately 6.7 degrees owing to the smaller pressure difference between the peak and trough regions of the lobed mixer compared with the rectangular lobed mixer (RLM). However, it provides a similar mixing enhancement as an RLM. Streamwise vortices appear downstream of the lobed mixer with a higher penetration angle of approximately 9.7 degrees. Greater mixing enhancement is observed in the lobed mixer with a larger penetration angle. The lobed mixers have potential applications for mixing enhancement in air-breathing propulsion systems, such as scramjet engines. Published under license by AIP Publishing.