Experimental Analysis of Clearance Leakage Characteristics at Blade Edge Plates of a Gas Turbine Engine

Abstract

The loss of cold air from the blade edge plates of the turbine has a negative impact on engine performance and safety. Using an experimental method, this paper investigates the effect of geometric and aerodynamic parameters on cold air leakage through pressure and mass flow measurements. Based on the results, it can be concluded that, with a change in sheet spacing, the proportion of bypass leakage and clearance leakage changes. At the same sheet spacing, the edge plate clearance is increased from 1 mm to 1.1 mm, resulting in a 30% increase of total leakage and a 25.7% increase of leakage equivalent mass flow. The edge plate clearance was increased from 1.1 mm to 1.2 mm, the total leakage increased by 19.2%, and the equivalent mass flow of leakage was 19%. The proportion of clearance leakage in the total leakage increased gradually for a given edge plate clearance. When the sheet spacing was 1 mm, bypass leakage accounted for 68% of the total leakage and was the primary source of leakage. The clearance leakage accounted for 83% of the total leakage with a plate spacing of 10 mm. When the sheet spacing is small, bypass leakage dominates; when it is large, clearance leakage dominates. The variation law of leakage with pressure, structural parameters and the ratio of sheet spacing to sealing slot length play an important role in the design of sealing structures.