Investigation of the effect of a pylon and a wing with flaps on the flow within an exhaust jet of a double-flow turbojet engine by a simulation method for large eddies

The effect of a pylon and a wing with deflected flaps on the flow and turbulence characteristics in the exhaust jet of a double-flow turbojet engine (TJE) is investigated with the use of the combined Reynolds Averaged Navier-Stokes/Implicit Large Eddy Simulation (RANS/ILES) method with high resolution. In addition to assessment of the accuracy of the method and comparability, the flow in an axisymmetric nozzle with the same geometry and in its exhaust jet is calculated. All computations are carried out for the flow mode corresponding to the take-off. In the case of the axisymmetric nozzle, good agreement between the computation and the experiment on the distribution of the averaged longitudinal velocity and the turbulence energy in jet cross sections is observed. It is shown that the flap angle and the gap between their internal tips, which the exhaust jet of the TJE passes through, significantly affect the flow and the turbulence level in the jet. Because of the interaction between the jet and tip eddies coming out from the flaps, jet deformation occurs, and a heterogeneous azimuth appears in the distribution of the flow parameters in jet cross sections. The peak turbulence energy increases by a factor of $1.5$–$2$ in comparison with the basic axisymmetric variant. Computations are carried out with meshes containing $2.224\times 10^6$ cells in the case of the axisymmetric nozzle and $3.34\times 10^6$ cells in the case of the nozzle with the pylon and the wing.