Variable Guide Vane Scheduling Method Based on the Kinematic Model and Dual Schedule Curves

Abstract

The variable guide vanes (VGV) of gas turbine engines are commonly utilized to expand operating range and to improve efficiency of the compressor. Guiding air flow using the VGVs in the compressor prevents aerodynamic instability by making proper incidence angle to the blades. In this study, we dealt with rig-type three-stages VGVs for developed engine tests. The three link mechanism of VGVs are linked to each other with two hydraulic actuators, and inevitably, induced hysteresis exists between vane rotations and actuators strokes, due to links with non-fully constrained degree of freedoms for easy installation and instrumentation, as well. Therefore, the adjustment of each VGVs link mechanism is required to satisfy vane angle demands. To adjust coupled three-stages VGVs link mechanism, an analytical VGV-link kinematic model was derived, and effects of two adjusting parameters (lengths of bell cranks and vertical links) were discovered. Lastly, we obtained two vane angle schedule curves from the experiments according to link moving directions, and applied them to the engine controller to minimize hysteresis of the variable inlet guide vane (VIGV). The proposed VGV adjusting and controlling method can be simply applied to the pre-designed or pre-manufactured VGVs system without mechanical compensation or additional cost.

Keywords

• gas turbine engine
• compressor
• variable guide vanes
• mechanical hysteresis
• link mechanism model
• VGV scheduling