Close-up photograph of the dual-throat nozzle assembly.
Schlieren photograph of the dual-throat nozzle at a pressure ratio of two with no secondary injection.
Schlieren photograph of the dual-throat nozzle at a pressure ratio of two with secondary injection from the top.
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Modern thrust vectoring in turbofan and rocket nozzles has traditionally been performed using mechanical actuation. However, recent research has identified fluidic thrust vectoring as a promising alternative, potentially lowering the overall system mass and complexity of a thrust vectoring system. One of the most promising configurations is a dual-throat nozzle in which an impinging secondary jet is used to deflect the core flow.

In an effort to better characterize the effect various dual-throat geometries and injection schemes have on vectoring efficiency, a small scale compressible flow wind tunnel was designed and built. This system provides a quasi-2D internal flow testing environment that is capable of delivering a nozzle pressure ratio of up to 5. Data is gathered through wall pressure transducers as well as schlieren photography, which provides a qualitative assessment of the flow field density gradients as well as the flow vector angle. 

The near-term objective of this project is to use experimental data to identify how key features such as injection mass flow rate and injection geometry can affect wall pressure profiles, thrust vector angle and vector efficiency.

This work has been internally supported at the University of Colorado Boulder by the Engineering Excellence Fund