核心机驱动风扇级气动参数径向分布 对变循环发动机性能的影响

In order to take into account the effects of details of flow field on the engine performance, the iterative coupled approach is applied to establish the multi-level model for variable cycle engine (VCE). In the VCE multi-level model, the three-dimensional simulation result of the core driven fan stage (CDFS) are fed back to the VCE zero-dimensional simulation model in the form of correction factors of mass flow rate, pressure ratio and isentropic efficiency. All the three correction factors are used to modify the default map of CDFS. When the effects of radial distribution of CDFS aerodynamic parameters are under consideration, the mass flow rate, pressure ratio and isentropic efficiency of CDFS core and bypass flow are calculated respectively according to CDFS bypass ratio and the result of three-dimensional simulation. Meanwhile, CDFS bypass ratio is replaced by auxiliary variable β as an iterative variable in the zero-dimensional simulation model. The results indicate that the pressure ratio of bypass zone is lower than that of core zone when VIGV angle is 15°. However, the flow separation near the blade tip of VIGV is severer than middle and hub zone which leads to the increase of incidence angle for the rotor blade tip when VIGV angle is 40°. It means that the workload of the rotor blade tip increases and the pressure ratio of bypass zone are higher than that of core zone. And the radial distribution of CDFS aerodynamic parameters has a significant effect on the VCE performance. The higher pressure ratio of core flow and lower pressure ratio of bypass flow contribute to the increase of mass flow rate and total pressure ratio of core engine, and it causes the increase of engine thrust finally. The maximum change in engine thrust is 1.75%.