A computational investigation was conducted to optimize the fluidic injection angle effects on Thrust vectoring. Numerical simulation of fluidic injection for shock vector control, with a convergent-divergent nozzle concept was performed, using URANS approach with Spalart-Allmaras turbulence model. The fluidic injection angles from 60º to 120º were investigated at different aerodynamic and geometric conditions. The current investigation demonstrated that secondary injection angle is an essential parameter in fluidic Thrust vectoring. Computational results indicated that, optimizing secondary injection angle would have positive impact on Thrust vectoring performance. Furthermore, in most cases, decreasing expansion ratio of the nozzle with increasing NPR has negative impact on pitch Thrust vector angle and Thrust vectoring efficiency. That is, the highest pitch Thrust vector angle is obtained by decreasing nozzle expansion ratio with increasing SPR in smaller fluidic injection angles. In addition, the current investigation attempted to initiate a database of optimized injection angles with different essential parameter effects on Thrust vectoring, in order to guide the design and development of an efficient propulsion system.

Dual-throat Nozzle (DTN) is known as one of the most effective approaches of fluidic Thrust-vectoring. It is gradually flourishing into a promising technology to implement supersonic and hypersonic Thrust-vector control in aircrafts. The main objective of the present study is numerical investigation of the effects of secondary injection geometry on the performance of a fuel-injected planar dual throat Thrust-vectoring nozzle. The main contributions of the study is to consider slot and circular geometries as injector cross-sections for injecting four different fuels, moreover, the impact of center-to-center distance of injection holes for circular injector is examined. Three-dimensional compressible reacting simulations have been conducted in order to resolve the flowfield in a dual throat nozzle with pressure ratio of 4. 0. Favre-averaged momentum, energy and species equations are solved along with the standard k-ε model for the turbulence closure, and the eddy dissipation model (EDM) for the combustion modelling. Second-order upwind numerical scheme is employed to discretize and solve governing equations. Different assessment parameters such as discharge coefficient, Thrust ratio, Thrust-vector angle and Thrust-vectoring efficiency are invoked to analyze the nozzle performance. Computationally predicted data are agreed well with experimental measurements of previous studies. Results reveal that a maximum vector angle of 17. 1 degrees is achieved via slot injection of methane fuel at a secondary injection rate equal to 9% of primary flow rate. Slot injection is performing better in terms of discharge coefficient, Thrust-vector angle and Thrust-vectoring efficiency, whereas circular injection provides higher Thrust ratio. At 2% secondary injection for methane fuel, vector angle and vectoring efficiency obtained by slot injector is 8% and 34% higher than the circular injector, respectively. Findings suggest that light fuels offer higher Thrust ratio, vector angle and vectoring efficiency, while heavy fuels have better discharge coefficient. Increasing center-to-center distance of injector holes improves Thrust ratio, while having a negative effect on discharge coefficient, vector angle and vectoring efficiency. A comparison between fuel injectant of current study and inert injectant in the previous studies indicates that fuel reaction could exhibit substantial positive effects on vectoring performance. Secondary-to-primary momentum flux ratio is found to play a crucial role in nozzle performance.

In the realm of aviation, jet propulsion systems serve to provide enhanced maneuverability and to make sure that the aircraft Thrust is accurately and precisely regulated during take-off and landing operations. The movement of aerodynamic control surfaces (flaps, slats, elevators, ailerons, spoilers, wing attachments) determines the mobility of practically all aircraft types. Recognized as dependable components in the aviation world for take-off and landing tasks, these control surfaces are being replaced by fluidic Thrust vectoring (FTV) systems, especially in small unmanned aerial vehicles (UAVs) and short or vertical take-off and landing aircraft. The FTV system is capable of directing Thrust in any preferred direction without the need for any movable components. This paper numerically examines the FTV system by utilizing computational fluid dynamics (CFD) and an optimization technique based on gradients of the system components to understand the physics of the Coanda effect in FTV systems. This research employs gradient-based optimization for nozzle design in order to optimize the parameter space for different velocity ratios (VR) by calculating the moment around the upper Coanda surface, which is used to represent the jet deflection angle. In that context, four different Coanda surface-pintle pair designs for four different VRs are produced. The parameter space shows significant improvement in all four configurations, and results reveal that all output parameters successfully delay separation on the Thrust vectoring system's upper Coanda surface. Finally, four optimum design suggestions are tested at various VRs, and the most efficient and proper design is recommended based on output parameters.

The feasibility of using a stand alone Fluidic Thrust- vectoring (FTV) system for the purpose of longitudinal trim of an unmanned aerial vehicle is the focus of the research presented in this paper. Since the fluidic Thrust vectoring requires high pressure secondary air to deflect the engine exhaust gases, this research also provides an analytical toolset for the preliminary sizing of a suitable secondary air supply. The study is based on a conceptual model of a Vertical Take-Off and Landing (VTOL) Tail-sitter type unmanned aerial vehicle in three common phases of flight named as Hovering, Transition and Cruise. A relationship is finally presented between the Thrust-vectoring angle and the required secondary mass flow rate.It is found that, just by use of FTV system the aircraft trim is possible. In addition, the mathematical model developed in this study can be used as a preliminary tool for overall performance evaluation of such a conceptual aircraft, especially for sensitivity analysis of Thrust-vectoring control and finding the optimum values of the parameters like centre of gravity and engine location.

One of the modern concept of Fluidic Thrust vectoring (FTV) is the Bypass Dual Throat Nozzle (BDTN). In the present work this nozzle with a circular cross-section which is called ABDTN has been studied numerically. In this method a bypass channel separates the main nozzle flow into two parts as a primary and secondary flow from upstream of the nozzle throat. The results of the interaction between the main nozzle flow and the bypass channel flow are investigated as a secondary injection. The present work discusses about the performance parameters of the ABDTN, including Thrust deflection angle, resultant Thrust ratio, discharge coefficient, and Thrust vectoring efficiency over a range of nozzle pressure ratios (NPR) to obtain the effects of different circumferential angles (α, ) of the bypass channel. The results of increasing α,show that the maximum deflection angle will decrease from 24º,to 21º,at the nozzle pressure ratio of 1. 5.