Numerical Investigation on the Effect of Slot Leakage on a NGV With 2D Contoured Endwall: Adiabatic Effectiveness and Aerodynamic Loss

Abstract

Endwall 2D contouring is a typical design to reduce the strength of secondary flows within the passage. Such contouring can lead to significant changes in the passage flow. A leakage slot at the combustor-turbine interface is a typical turbine endwall design. The leakage flow can be used to cool the endwall and vane surface. Moreover, the leakage flow interacts with the main flow and results in the change of aerodynamic loss. A 3D numerical method was used to investigate endwall adiabatic effectiveness and passage total pressure loss coefficient (TPLC) on a NGV with 2D contoured endwall under a series of mass flow ratios (MFRs). The numerical method was validated by comparision with the experiment data. The results indicate that under the condition of this study, When MFR<0.625%, there is ingestion, and when 0.625%<MFR<1.0%, the TPLC is high. When 0.875%<MFR<1.0%, the area averaged adiabatic effectiveness (AAAE) decreases and the TPLC stays high as the MFR increases. When 1.0%<MFR<1.5%, the adiabatic effectiveness is high and the TPLC is low. To accomplish high adiabatic effectiveness, low aerodynamic loss and slight ingestion, the recommended range of MFR is 1.0%<MFR<1.5%.