Design Rules Of Dual-throat Fluidic Thrust-vectoring Nozzle And Its Integration With The Afterbody Of Aircraft

Using CFD and DOE an optimization study for a 2-D dual-throat fluidic thrust-vectoring nozzle is performed. Based on the optimization results an optimal three-dimensional nozzle is designed and then the effects of the aircraft afterbody on the performance of the nozzle are obtained in this paper. In order to improve the poor performance of the nozzle with the afterdeck caused by the integration with the afterbody, one method by placing slots on the afterdeck is brought forward and numerically studied. In addition, with the aim of the high resolutions of the experiment, an improved design for the test facility is conducted and the reliabilities is proved by uncertainty analysis.Results show: Length of primary nozzle cavity, divergent cavity ramp angle, convergent cavity ramp angle, height of primary nozzle upstream throat and secondary flow injection angle affect the performance and internal flow patterns of the nozzle obviously. The optimal design can achieve a pitch thrust vector angle of 14.34odegrees at a mass consumption of 2.55% and a corresponding thrust ratio of 0.967. Furthermore, due to the integration with the afterbody, obvious bad influences are brought on the performance of the nozzle with the afterdeck and swept angle. Thereore, one method that places the slots on the afterdeck is brought forward to improve the poor performance of the nozzle with the afterdeck. The CFD results indicate that, using this method, at the cruise condition the thrust coefficient can be raised to 0.95 and the corresponding vector angle is reduced to 2o without the injection. Additionally, an improved design for the baseline test facility is conducted and the system uncertainty is lowered from 2% to 0.5%.