Combination of Fluidic Thrust Modulation and Vectoring in a 2D Nozzle

Methods of vectoring and modulating exhaust thrust in a converging-diverging nozzle by secondary fluidic injection were investigated. The application of fluidic thrust control (FTC) offers potentially significant gains in performance and manoeuvrability without the cost of heavy mechanical systems. FTC nozzles also have significant advantages in relation to reducing observability and are particularly suited to low-cost, lightweight, highly manoeuvrable missiles and uninhabited combat air vehicles. The throat shifting thrust modulation (TSTM) and the shock vector control (SVC) FTC methods, and the combination of the TSTM and the SVC systems to achieve both modulation and vectoring simultaneously, were investigated to determine the level of flow interaction and any resulting influence on thrust. In the SVC method, shocks were induced in the supersonic flow by secondary injection in the diverging section of the nozzle. In the TSTM method secondary fluid was injected near the nozzle throat. A design of experiments (DOE) approach was used to study the effects of different factors on the fluidic thrust control. In the TSTM method study, relative injector size (Aratio), injector angle (θinj) and relative injection pressure (Prratio) and the interaction of the latter two factors were found to be significant to the effectiveness of the thrust modulation. In the SVC method the maximum thrust vectoring angle was achieved for the case where the induced oblique shock was just impinging at the opposite side wall at the nozzle exit. The throat modulation efficiency reduced for the combined method due to the additional SVC injection mass flow. The same amount of vectoring was achieved with a lower injection mass flow for the combination method compared to the standalone SVC method.