Numerical Investigation on Aerodynamic Vector Performance of a Axisymmetric Bypass Dual Throat Nozzle

The bypass dual throat nozzle (BDTN) is capable of achieving thrust vectoring by introducing secondary flow from upstream through the bypass channel. In order to investigate the aerodynamic vectoring characteristics of the axisymmetric BDTN, numerical simulations are performed to analyze the internal flow field of the nozzle at different nozzle pressure ratios (ratio of total inlet pressure to ambient pressure, NPR) in three dimensions. The results show that the influence of the bypass secondary flow causes a significant asymmetry in the parameter distribution of the flow field of the axisymmetric nozzle, and the flow also undergoes lateral expansion in the axial direction. As the total inlet pressure increases, the internal flow velocity and temperature are more stable, while the pressure and density gradually increase. Compared with the 2D configuration, the lateral expansion within the nozzle cavity reduces the degree of asymmetric difference in the internal flow field structure, resulting in a vector deflection effect. The thrust vector angle decreases as the NPR increases, and the thrust coefficient increases slightly and then decreases.