The thrust-vectoring in particular “Fluid” type is of increasing interest for the maneuverability and the agility of combat and fighter aircraft. This has been employed for different nozzles mainly axisymmetric and 2-dimensional. For the latter, the aspect ratio, i.e. the ratio of the long-to-short side of the nozzle has significant influence upon the exhaust and thrust-vectoring performance. The effectiveness of a high aspect-ratio nozzle in order to deflect the jet engine’s thrust has been demonstrated {Hiley, 1975} but, such large aspect ratios often causes increasing of the structure weight and internal pressure losses. Here, the design of a two-dimensional nozzle with respect to the thrust-loss factor of a small jet-engine is presented. Computational Fluid Dynamics (CFD) techniques were used in order to simulate the nozzle’s flow characteristics under various engine’s operating settings as well as different aspect-ratio designs. Computations results were obtained from the “Fluent” program. All developed models are 3-D and meshed by using “Gridgen” code. Moreover, the boundary conditions were obtained by using of the engine’s performance model developed in TURBOMATCH program. Also, the paper describes an experiment in order to predict the engine’s performance for a test case that has aspect ratio of 8.5. The CFD results were compared with experimental measurements. The results showed that nozzle with higher aspect-ratio results in larger pressure losses, while, its thrust discharge coefficient is not far from the moderate aspect-ratio nozzle.

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