Abstract:Based on solving Navier-Stokes equations, the numercial simulation on combination flow field for axisymmetric converge- divergengt nozzle of certain aeroengine in six real working conditions were carried out. Meanwhile, the flux coefficient and thrust coefficient were figured out. The results showed that at the state of ground, the supersonic jet was overexpanded, while it appeared to be underexpanded under other high altitude state, there were complex shock and expansion wave. At the state of underexpansion, with the increase of NPR (nozzle pressure ratio), the flux coefficient had no marked change, while the thrust coeffiecient dropped dramatically. In addition, aerodynamic performance parameters of the nozzle exit were obtained according to theoretical solution, and then the reliability of the numerical simulation results was verified by comparing with the theoretical solution results.