Endwall 2D-contouring is a presently-employed design feature for reducing the strength of secondary flows within gas turbine passages. Such contouring can lead to significant changes of passage flow, making the flow field different from that of the widely-studied flat-endwall passage. Also, there is an interface, or leakage slot, on the endwall between the combustor and the turbine affecting the passage flow. Though introduced for eliminating ingression of passage gas into the cavity, leakage flow through it, which has bypassed the combustor, can be used to cool the endwall and vane surfaces. Moreover, this leakage flow interacts with the main flow resulting in a change of aerodynamic losses. In this study, a 3D RANS method using an SST γ-θ transition model was employed to investigate endwall adiabatic cooling effectiveness values, η, and passage total pressure loss coefficients, TPLC, in a nozzle guide vane passage with a 2D-contoured endwall. Cases of differing mass flow ratios, MFRs, for flow through the slot were evaluated and compared. The numerical method employed was validated by comparing its computed results with experimental data. The results show how cooling effectiveness, aerodynamic performance and vortex structures near the endwall are significantly affected by passage flows of various MFR values. An appropriate range of MFR was found for gaining high adiabatic cooling effectiveness values and low aerodynamic losses while avoiding hot gas ingression into the slot.
|Original language||English (US)|
|Number of pages||14|
|Journal||International Journal of Thermal Sciences|
|State||Published - Aug 2019|
Bibliographical noteFunding Information:
The authors would like to acknowledge the financial support by the National Natural Science Foundation of China (Project 51706116 and Project 51576110 ) and the support provided by China Scholarship Council (No. 201706210252 ) for Pingting Chen to visit University of Minnesota.
- Aerodynamic loss
- Contoured endwall
- Film cooling