Design and flow control mechanism of a novel dual-body variable geometry turbine vane

The variable geometry turbine (VGT), as a core component of next-generation aero-engines, plays a significant role in enhancing flight range and reducing emissions. Conventional VGTs suffer from severe leakage losses due to their pivot structure, and this causes an efficiency loss exceeding 2%. To address this issue, this paper proposes a novel Dual-Body Sliding Vane (DBSV) based on a sliding blade structure and investigates its design methodology and aerodynamic analysis. In terms of design, this structure reduces the leakage area through a dual-body structure consisting of a fixed blade and a circumferential sliding blade. Compared to spherical endwall structures, this design provides a certain degree of meridional expansion capability. Furthermore, this paper presents a rapid method for determining the rotation center of sliding blade, thereby simplifying structural design. In terms of analysis, numerical simulations demonstrate that the DBSV exhibits significant advantages over conventional VGTs in leakage control, achieving a 10% reduction in total pressure loss coefficient at a 0° rotation angle. It outperforms conventional VGTs by retaining geometry variability while minimizing design-point inefficiencies. Further studies elucidate the flow control mechanism of DBSV: The high-speed flow generated by the slot suppressed the scale of the tip leakage vortex. Proper arrangement of front and rear blade rows enhances leakage vortex suppression. Effective suppression is achieved at 0° and positive rotation angles, while this effect diminishes under large negative rotation angles.