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Turbulence Modelling and Parallel Solver Development Relevant for Investigation of Gas Turbine Cooling Processes

Jia, Rongguang LU (2004)
Abstract
To enhance the performance of gas turbine engines, high top-cycle temperatures are desired. However, the temperature is limited by current materials. To achieve the higher performance, and meanwhile maintain the metal temperatures of the combustors, vanes and blades below the allowable limits, sophisticated cooling techniques, such as impingement cooling, film cooling and convective internal cooling, are essential.



This thesis focuses on developing numerical tools for improved predictions of cooling processes of gas turbine blades and combustor walls. The cooling methods include impinging jets, rib roughness and film jets. An in-house Navier-Stokes solver was extended to multi-block and parallel computations, with... (More)
To enhance the performance of gas turbine engines, high top-cycle temperatures are desired. However, the temperature is limited by current materials. To achieve the higher performance, and meanwhile maintain the metal temperatures of the combustors, vanes and blades below the allowable limits, sophisticated cooling techniques, such as impingement cooling, film cooling and convective internal cooling, are essential.



This thesis focuses on developing numerical tools for improved predictions of cooling processes of gas turbine blades and combustor walls. The cooling methods include impinging jets, rib roughness and film jets. An in-house Navier-Stokes solver was extended to multi-block and parallel computations, with implementation of a range of turbulence models.



The evaluated turbulence models for the Reynolds stresses are: 1. Two-equation models: Shear Stress Transport model (SST model), Explicit Algebraic Stress Model (EASM model), and the Linear Eddy Viscosity Model (LEVM model); 2. Four-equation models: V2F model in three versions; 3. Seven-equation models (Reynolds Stress Transport Models (RSTM)): Standard RSTM, Stress-w model, and the Speziale-Sarkar-Gatski model (SSG model). In addition, a low-Re RSTM (combined SSG and SST), is developed, which solves the problem at reattachment points.



All the models mentioned above are based on the Reynolds averaged Navier-Stokes (RANS) equations. RANS methods, however, filter out many physical details of the underlying flow field. Consequently, the validity of the results is often questionable, especially for complex geometries, where the turbulence is very an-isotropic. Therefore, the large eddy simulation (LES) method was also considered, where large eddies are resolved and small scales are modelled.



A number of case studies are presented basically for the following three purposes: Validation of the parallel multi-block code; Validation and evaluation of turbulence models; Providing results for better understanding and enhancement of the cooling process relevant for gas turbine systems. (Less)
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author
opponent
  • Professor Ryo S. Amano, Ryo S. Amano, University of Wisconsin-Milwaukee, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Thermal engineering, applied thermodynamics, Termisk teknik, termodynamik, large eddy simulation, Reynolds stress transport model, turbulence modelling, multi-block, parallel computing, Impingement cooling, ribbed surface
pages
184 pages
publisher
Division of Heat Transfer, Lund Institute of Technology
defense location
Room M:A, M-building, Ole Römers Väg 1, Lund Institute of Technology
defense date
2004-02-20 13:15
external identifiers
  • other:ISRN:LUTMDN/TMHP-04/1020-SE
ISSN
0282-1990
ISBN
91-628-5963-3
language
English
LU publication?
yes
id
fc10f4e9-f8e5-4837-8469-69a5ed6cf997 (old id 466627)
date added to LUP
2007-09-10 10:43:46
date last changed
2016-09-19 08:44:52
@phdthesis{fc10f4e9-f8e5-4837-8469-69a5ed6cf997,
  abstract     = {To enhance the performance of gas turbine engines, high top-cycle temperatures are desired. However, the temperature is limited by current materials. To achieve the higher performance, and meanwhile maintain the metal temperatures of the combustors, vanes and blades below the allowable limits, sophisticated cooling techniques, such as impingement cooling, film cooling and convective internal cooling, are essential.<br/><br>
<br/><br>
This thesis focuses on developing numerical tools for improved predictions of cooling processes of gas turbine blades and combustor walls. The cooling methods include impinging jets, rib roughness and film jets. An in-house Navier-Stokes solver was extended to multi-block and parallel computations, with implementation of a range of turbulence models.<br/><br>
<br/><br>
The evaluated turbulence models for the Reynolds stresses are: 1. Two-equation models: Shear Stress Transport model (SST model), Explicit Algebraic Stress Model (EASM model), and the Linear Eddy Viscosity Model (LEVM model); 2. Four-equation models: V2F model in three versions; 3. Seven-equation models (Reynolds Stress Transport Models (RSTM)): Standard RSTM, Stress-w model, and the Speziale-Sarkar-Gatski model (SSG model). In addition, a low-Re RSTM (combined SSG and SST), is developed, which solves the problem at reattachment points.<br/><br>
<br/><br>
All the models mentioned above are based on the Reynolds averaged Navier-Stokes (RANS) equations. RANS methods, however, filter out many physical details of the underlying flow field. Consequently, the validity of the results is often questionable, especially for complex geometries, where the turbulence is very an-isotropic. Therefore, the large eddy simulation (LES) method was also considered, where large eddies are resolved and small scales are modelled.<br/><br>
<br/><br>
A number of case studies are presented basically for the following three purposes: Validation of the parallel multi-block code; Validation and evaluation of turbulence models; Providing results for better understanding and enhancement of the cooling process relevant for gas turbine systems.},
  author       = {Jia, Rongguang},
  isbn         = {91-628-5963-3},
  issn         = {0282-1990},
  keyword      = {Thermal engineering,applied thermodynamics,Termisk teknik,termodynamik,large eddy simulation,Reynolds stress transport model,turbulence modelling,multi-block,parallel computing,Impingement cooling,ribbed surface},
  language     = {eng},
  pages        = {184},
  publisher    = {Division of Heat Transfer, Lund Institute of Technology},
  school       = {Lund University},
  title        = {Turbulence Modelling and Parallel Solver Development Relevant for Investigation of Gas Turbine Cooling Processes},
  year         = {2004},
}