Large Eddy Simulation of Externally Induced Ingress about an Axial Seal by Stator Vanes
Author:
Nketia Sabina1, Bryden Kenneth Mark2, Dalton Richard3, Shih Tom I-P.1
Affiliation:
1. School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907, USA 2. Ames National Laboratory, United States Department of Energy, Ames, IA 50011, USA 3. National Energy Technology Laboratory, United States Department of Energy, Morgantown, WV 26505, USA
Abstract
Turbine inlet temperatures in advanced gas turbines could be as high as 2000 °C. To prevent ingress of this hot gas into the wheelspace between the stator and rotor disks, whose metals can only handle temperatures up to 850 °C, rim seals and sealing flows are used. This study examines the abilities of large eddy simulation (LES) based on the WALE subgrid model and Reynolds-averaged Navier–Stokes (RANS) based on the SST model in predicting ingress in a rotor–stator configuration with vanes but no blades, a configuration with experimental data for validation. Results were obtained for an operating condition, where the ratio of the external Reynolds number to the rotational Reynolds number is 0.538. At this operating condition, both LES and RANS were found to correctly predict the coefficient of pressure, Cp, located downstream of the vanes and upstream of the seal, but only LES was able to correctly predict the sealing effectiveness. This shows Cp by itself is inadequate in quantifying externally induced ingress. RANS was unable to predict the sealing effectiveness because it significantly under predicted the pressure drop in the hot gas path along the axial direction, especially about the seal region. This affected the pressure difference across the seal in the radial direction, which ultimately drives ingress.
Funder
Ames National Laboratory and the National Energy Technology Laboratory (NETL) of the U.S. Department of Energy
Subject
Energy (miscellaneous),Energy Engineering and Power Technology,Renewable Energy, Sustainability and the Environment,Electrical and Electronic Engineering,Control and Optimization,Engineering (miscellaneous),Building and Construction
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