Material Type  

 학위논문

 

0016935124

Date and Time of Latest Transaction  

20240214101855

ISBN  

9798380485104

DDC  

500

Author  

Nketia, Sabina Boatemah Afum.

Title/Author  

Large-Eddy Simulation of Rotationally- And Externally-Induced Ingress in an Axial Rim Seal of a Stator-Rotor Configuration - [electronic resource]

Publish Info  

[S.l.] : Purdue University., 2023

Publish Info  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Material Info  

1 online resource(109 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-04, Section: B.

General Note  

Advisor: Shih, Tom I-P.

학위논문주기  

Thesis (Ph.D.)--Purdue University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Abstracts/Etc  

요약In gas turbines, the hot gas exiting the combustor can be as high as 2000 oC, and some of this hot gas enter into the space between the stator and rotor disks (wheelspace). Since the hot gas entering with its high temperatures could damage the disks, hot-gas ingestion must be minimized. This is done by using rim seals and by introducing a flow of cooler air from the compressor (sealing flow) into the wheelspaceIngress 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 first-stage turbine, where ingress could cause the most damage and has two parts. The first part focuses on understanding ingress and egress driven by the rotor and its rotation, known as rotationally-induced ingress, by studying ingress about an axial seal in a stator-rotor configuration without vanes and without blades. The second part focuses on understanding ingress and egress driven by stator vanes, known as externally-induced ingress, by studying a stator-rotor configuration with vanes but no blades, where the ratio of the external Reynolds number to the rotational Reynolds number is 0.538. For both parts, solutions were generated by wall-resolved large-eddy simulation (LES) based on the WALE subgrid model and by Reynolds-averaged Navier-Stokes (RANS) based on the SST model. For both stator-rotor configurations, the grid-independent solutions obtained were compared with available experimental data.Results obtained for the configuration without vanes and blades show Kelvin-Helmholtz instability (KHI) to form even without swirl from the hot-gas flow and to create a wavy shear layer on the rotor. Also, Vortex shedding (VS) occurs on the backward-facing side of the seal and impinges on the rotor side of the seal. The KHI and VS produce alternating regions of high and low pressures about the rotor-side of the axial seal, which cause ingress to start on the rotor side of the seal. Results obtained for the configuration with vanes but no blades show both LES and RANS to correctly predict the coefficient of pressure, Cp, upstream of the axial seal. However, only LES was able to correctly predict the sealing effectiveness. This shows Cp by itself maybe is inadequate in quantifying externally-induced ingress. One reason why RANS was unable to predict sealing effectiveness is significantly under predicting the pressure drop on the rotor surface, which affected the pressure variation along the hot-gas path and hence the pressure difference across the axial seal, which ultimately drives ingress.

Subject Added Entry-Topical Term  

Kinematics.

Subject Added Entry-Topical Term  

Pressure distribution.

Subject Added Entry-Topical Term  

Viscosity.

Subject Added Entry-Topical Term  

Turbulence models.

Subject Added Entry-Topical Term  

Gas turbine engines.

Subject Added Entry-Topical Term  

Gas flow.

Subject Added Entry-Topical Term  

Reynolds number.

Subject Added Entry-Topical Term  

Energy consumption.

Subject Added Entry-Topical Term  

Shear stress.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Fluid mechanics.

Subject Added Entry-Topical Term  

Mechanics.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 85-04B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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소장사항  

202402 2024

Control Number  

joongbu:640822