Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks

In gas turbines, the hot gas exiting the combustor can have temperatures as high as 2000 °C, and some of this hot gas enter into the space between the stator and rotor disks (wheelspace). Since the entering hot gas could damage the disks, its ingestion must be minimized. This is carried out by rim s...

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Main Authors: Sabina Nketia, Tom I-P. Shih, Kenneth Bryden, Richard Dalton, Richard A. Dennis
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/16/11/4354
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author Sabina Nketia
Tom I-P. Shih
Kenneth Bryden
Richard Dalton
Richard A. Dennis
author_facet Sabina Nketia
Tom I-P. Shih
Kenneth Bryden
Richard Dalton
Richard A. Dennis
author_sort Sabina Nketia
collection DOAJ
description In gas turbines, the hot gas exiting the combustor can have temperatures as high as 2000 °C, and some of this hot gas enter into the space between the stator and rotor disks (wheelspace). Since the entering hot gas could damage the disks, its ingestion must be minimized. This is carried out by rim seals and by introducing a cooler flow from the compressor (sealing flow) into the wheelspace. Ingress and egress into rim seals are driven by the stator vanes, the rotor and its rotation, and the rotor blades. This study focuses on the ingress and egress driven by the rotor and its rotation. This is carried out by performing wall-resolved large eddy simulation (LES) around an axial seal in a rotor–stator configuration without vanes and blades. Results obtained show the mechanisms by which the rotor and its rotation induce ingress, egress, and flow trajectories. Kelvin–Helmholtz instability was found to create a wavy shear layer and displacement thickness that produces alternating regions of high and low pressures around the rotor side of the seal. Vortex shedding on the backward-facing side of the seal and its impingement on the rotor side of the seal also produces alternating regions of high and low pressures. The locations of the alternating regions of high and low pressures were found to be statistically stationary and to cause ingress to start on the rotor side of the seal. Vortex shedding and recirculating flow in the seal clearance also cause ingress by entrainment. With the effects of the rotor and its rotation on ingress and egress isolated, this study enables the effects of stator vanes and rotor blades to be assessed.
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spelling doaj.art-fcea410b61bb44f8addc0cde17317c852023-11-18T07:47:43ZengMDPI AGEnergies1996-10732023-05-011611435410.3390/en16114354Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator DisksSabina Nketia0Tom I-P. Shih1Kenneth Bryden2Richard Dalton3Richard A. Dennis4School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907, USASchool of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907, USAAmes National Laboratory, U.S. Department of Energy, Ames, IA 50011, USANational Energy Technology Laboratory, U.S. Department of Energy, Morgantown, WV 26505, USANational Energy Technology Laboratory, U.S. Department of Energy, Morgantown, WV 26505, USAIn gas turbines, the hot gas exiting the combustor can have temperatures as high as 2000 °C, and some of this hot gas enter into the space between the stator and rotor disks (wheelspace). Since the entering hot gas could damage the disks, its ingestion must be minimized. This is carried out by rim seals and by introducing a cooler flow from the compressor (sealing flow) into the wheelspace. Ingress and egress into rim seals are driven by the stator vanes, the rotor and its rotation, and the rotor blades. This study focuses on the ingress and egress driven by the rotor and its rotation. This is carried out by performing wall-resolved large eddy simulation (LES) around an axial seal in a rotor–stator configuration without vanes and blades. Results obtained show the mechanisms by which the rotor and its rotation induce ingress, egress, and flow trajectories. Kelvin–Helmholtz instability was found to create a wavy shear layer and displacement thickness that produces alternating regions of high and low pressures around the rotor side of the seal. Vortex shedding on the backward-facing side of the seal and its impingement on the rotor side of the seal also produces alternating regions of high and low pressures. The locations of the alternating regions of high and low pressures were found to be statistically stationary and to cause ingress to start on the rotor side of the seal. Vortex shedding and recirculating flow in the seal clearance also cause ingress by entrainment. With the effects of the rotor and its rotation on ingress and egress isolated, this study enables the effects of stator vanes and rotor blades to be assessed.https://www.mdpi.com/1996-1073/16/11/4354gas turbinesrim sealsrotationally induced ingress
spellingShingle Sabina Nketia
Tom I-P. Shih
Kenneth Bryden
Richard Dalton
Richard A. Dennis
Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks
Energies
gas turbines
rim seals
rotationally induced ingress
title Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks
title_full Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks
title_fullStr Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks
title_full_unstemmed Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks
title_short Large Eddy Simulation of Rotationally Induced Ingress and Egress around an Axial Seal between Rotor and Stator Disks
title_sort large eddy simulation of rotationally induced ingress and egress around an axial seal between rotor and stator disks
topic gas turbines
rim seals
rotationally induced ingress
url https://www.mdpi.com/1996-1073/16/11/4354
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AT kennethbryden largeeddysimulationofrotationallyinducedingressandegressaroundanaxialsealbetweenrotorandstatordisks
AT richarddalton largeeddysimulationofrotationallyinducedingressandegressaroundanaxialsealbetweenrotorandstatordisks
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