Experimental study on endwall film cooling performance of an adjustable guide vane

Variable-geometry turbines are a crucial technology in advanced variable cycle engines, with the inevitable endwall clearance caused by blade rotation being a key concern. While current research primarily focuses on its influence on aerodynamics performance, there is a notable dearth of studies on endwall cooling behaviors. To this end, this article establishes an experimental platform to assess the endwall film cooling characteristics of adjustable guide vanes. Firstly, the film cooling characteristics were compared between traditional fixed guide vanes and adjustable guide vanes with a 0° turning angle under different MFRs (0.5 %, 1.0 %, 1.5 %). Results demonstrate that the adjustable guide vane configuration expands the film coverage on the endwall near the leading and trailing edges under the MFR investigated. This is because the leakage flow caused by clearances transports some coolant into these gaps, effectively suppressing them on the endwall surface, thereby creating a beneficial cooling coverage effect. Subsequently, the influence of turning angles (0°, −1.5°, −3°) on the film cooling characteristics of adjustable guide vanes was further investigated. Results indicate that turning angle exerts minor influences on cooling effectiveness near the LE clearance. However, a slight enhancement in cooling effectiveness near the TE clearance is observed with decreasing turning angles.