Computational Study Of A Vector-enhanced Dual-throat Thrust-vectoring Nozzle And Experimental Validation

A design concept of vector-enhanced thrust-vectoring nozzle is advanced based on dual-throat thrust-vectoring nozzle. In the newly designed nozzle two expansion ramps are added after the second throat of the nozzle to employ the Coanda effect to achieve greater vector angle. Using CFD an optimization study for the design law and the internal flow pattern of the vector-enhanced thrust-vectoring nozzle is performed, then an improved design that placing slots on the concave expansion ramps is proved to suppress the overexpansion of the exhaust flow . Furthermore, the NHW is altered to be a fluidic nozzle experiment rig and the primary experiments are accomplished.Results show: Length of primary nozzle cavity, divergent cavity ramp angle, convergent cavity ramp angle, expansion angle, expansion length and expansion contour all affect the performance and the internal flow pattern of the nozzle obviously. The concave expansion ramps obtaining a vector angle of 24.96°and a thrust ratio of 0.900 at a secondary flow consumption of 2.8 percent. placing slots on the concave expansion ramps can suppress the overexpansion of the exhaust flow effectively, obtaining a vector angle of 23.02°and a thrust ratio of 0.935 whit 3 slots of 30°.The difference of pressure on the up and down ectotheca affect the performance of the nozzle obviously in the high-altitude flight conditions , obtaining a vector angle of 23.92°and a thrust ratio of 0.945 whit 3 slots of 30°.The experimental resuilts have good consistency with the simulation resuilts, therefore, the means of the numerical simulation is of a very high degree of accuracy, while the results of the study are credible.