Potential of a novel variable inlet guide vane for high-efficiency core driven fan stage

The variable cycle engine (VCE) adapts its component geometries dynamically to meet the demands of multi-mode flight. The core driven fan stage (CDFS) has emerged as a critical component of the VCE due to its unique flow regulation capabilities, with a variable inlet guide vane playing a key role in facilitating the mode transitions of the CDFS. This research innovatively introduces a three-segment variable inlet guide vane (TVIGV), which reduces aerodynamic losses and enhances the overall performance of the CDFS by decoupling the airflow turning tasks. An orthogonal simulation experiment is conducted to investigate the impact of critical design parameters on the aerodynamic performance and flow behavior of the CDFS. The results demonstrate that the turning position of the rear segment blade has the most significant effect on the peak efficiency of the CDFS, while the turning angle of the middle segment blade notably influences the total pressure loss of the guide vane. The optimal design case is identified using the comprehensive evaluation method coupled with the objective weighting approach. Subsequently, flow field visualization analysis is conducted to validate the flow optimization mechanism of the TVIGV. The optimal configuration successfully mitigated significant flow separation regions within the guide vane, reduced secondary flows and blockage losses, resulting in a total dissipation loss reduction of 60.37%. The findings indicate that the application of the TVIGV significantly enhances the performance of the CDFS, providing new theoretical foundations and technical support for the future development of high-performance VCE.