Fluidic Thrust Vectoring on an Altitude-Adaptive Double-Divergent Nozzle Using a Bypass Passage

Shock vector control (SVC) is one of the most researched topics in the field of fluidic thrust vectoring (FTV). In SVC, a secondary fluid flows through an injector to deflect the primary flow through the nozzle. However, the losses associated with the secondary injection is significantly high due to engine bleed. Modern research on SVC focuses on the use of bypass passage in order to mitigate this loss. The present study deals with this so-called bypass-SVC on altitude-adaptive double-divergent nozzles (DDNs), which have two diverging sections separated by an inflection point. The inflection Mach number is set to be 1.5. Three different DDN configurations have been studied in this work by varying the lengths of the diverging sections. The steady-state flow-field has been numerically solved using ANSYS Fluent software over a range of nozzle pressure ratios (NPRs), and results have been compared to a single-divergent nozzle (SDN) of the same nozzle area expansion ratio (ε). The results indicate higher pitch thrust vector angle (δp) for the DDNs as compared to the SDN at certain NPRs. Also, the thrust losses (ω) have been observed to be less for the DDNs as compared to the SDN at higher NPRs. In the non-vectored state, the coefficient of thrust (CF) of the DDNs is comparable with that of the SDN.