Aerothermal Performance of Slashface Leakage With Double Surface Angle Under Realistic Swirling Inflow

Abstract

The turbine vanes being manufactured and assembled piece by piece leads to an unavoidable gap on the vane endwall called slashface. Usually, the coolant leakage introduced from the slashface with a single surface angle aims to prevent hot gas ingression and protect the vane endwall. However, the cooling effectiveness is greatly reduced when considering the swirling flow from the combustor. In the current work, against strong swirling inflow, a new solution to improve endwall film cooling performance through applying the slashface leakage with the double surface angle is carried out. Through numerical method, the effects of the location of the angle transition region (D/L = 0%, 25%, 50%, 75%, 100%) and mass flow ratio (MFR = 0.5%, 1.0%, 1.5%) of the leakage on the turbine vane endwall aerothermal and film cooling performance are investigated. The results indicated that the coverage area of the coolant on the endwall was obviously enlarged when the slashface leakage with the double surface angle was employed. The film cooling level on both the endwall and suction side surface of the vane increased with increasing MFR. Moreover, the endwall thermal load was reduced. The designs of D/L = 25% and 50% are recommended for their high endwall film cooling level and low endwall thermal load. This paper provides turbine designers with a new idea to increase endwall film cooling performance by the slashface leakage with the double surface angle when considering aggressive swirling inflow.