Numerical Study of Mass Flow and Septum Position Effects on Thrust Vectoring and Flow Structure of an ACHEON Nozzle

ACHEON nozzle is a thrust vectoring control device in which interaction of two jet flows under the influence of Coanda effects is implemented. The effects of inlet mass flow rate and the position of septum (relative to nozzle outlet) on flow structure, thrust vectoring, and shock formation have not been paid enough attention in previous studies. However, in this study, different mass flow rates and various positions of the septum were investigated. Flow was considered turbulent, two-dimensional, stationary, and compressible and RANS approach with standard k-ε model was implemented. The equations were solved using a pressure-based finite volume method on a structured computational grid. Using different Mach and Reynolds numbers and also various positions of the septum, thrust vectoring angle, flow structure, and nozzle shock position were studied. Our results show that with increasing inlet mass flow rate, thrust vectoring angle increases. It is noted that at a certain mass flow rate, a normal shock wave is formed in the nozzle. Also, except at this special mass flow rate (with shock wave), increasing inlet mass flow rate leads to increasing thrust vectoring angle. In addition, reducing the distance between the septum tip and the nozzle outlet increases thrust vectoring angle.