A fluidic thrust vector control using the bypass flow in a dual throat nozzle.

The present study is to explore an active mass flow control technology for an emerging bypass dual throat nozzle. A new arc-shaped bypass system has been applied to replace the previous V-shaped bypass for the bypass dual throat nozzle, which can decrease the total pressure loss significantly. The bypass passage has a contraction part with a variable area ratio. The vector control effectiveness is discussed with different contraction area ratios of the bypass passage. The obtained results reveal that friction choking and geometry choking play crucial roles to affect the bypass mass flow, respectively. When the bypass passage is fully open, the choking location of the bypass flow occurs at the bypass exit, owing to the viscous boundary layer along the constant area passage. A contraction area ratio less than 0.5 does not change the choking position of the bypass flow, because the viscous boundary layer is larger than the geometry contraction height. While the contraction area ratio reaches or exceeds 0.5, the geometry choking takes place in the contraction section. The vectoring angle and bypass mass flow ratio decrease with an increase in the contraction area ratio, whereas thrust coefficient, thrust efficiency, and total pressure loss increase. [ABSTRACT FROM AUTHOR]