分排式三股流喷管流动与噪声特性数值研究

The influences of the three-stream introduction and the tertiary bypass ratio on the flow and noise characteristics of the three-stream nozzle were studied by the numerical simulation method. The results showed that the three-stream introduction increased the length of the bypass potential core, shortened the axial distance of the direct mixing between the end of the primary potential core and the free stream, and reduced the peak value of the turbulent mixing between them by about 2.63%. However, due to the increase of the shear layer thickness, the low-speed three-stream had limited noise reduction effect in all directions. The increase of the tertiary bypass ratio was easy to achieve, at the cost of reducing fuel consumption, and it can increase the engine thrust and reduce the broadband noise of the exhaust system. The increase of tertiary bypass ratio to 2.52 weakened not only the turbulent mixing intensity at the end of the primary potential core, but also the mixing intensity of the strong shear layer between the three-stream and the free stream. Compared with the design condition, the mixing intensity at the end of the primary potential core decreased by 8.57%, and the overall sound pressure level decreased in all directions, with a peak value of about 2.37 dB.