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Influence of Working Fluid on Gas Turbine Cooling Modeling

Sammak, Majed LU ; Thern, Marcus LU and Genrup, Magnus LU (2013) ASME Turbo Expo 2013: Turbine Technical Conference and Exposition In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition 2.
Abstract
Cooling is essential in all modern high-temperature gas turbines. Turbine cooling is mainly a function of gas entry temperature, which plays the key role in overall gas turbine performance. High turbine entry temperatures can be achieved through appropriate selection of blade cooling method and blade material. The semi-closed oxy-fuel combustion combined cycle (SCOC-CC) operates at the same high entry gas temperature, hence blade cooling is necessary. The aim of this paper was to calculate the required turbine cooling in oxy-fuel gas turbines and compare it to the required turbine cooling in conventional gas turbines. The approach of the paper was to evaluate the thermodynamic and aerodynamic factors affecting turbine cooling with using... (More)
Cooling is essential in all modern high-temperature gas turbines. Turbine cooling is mainly a function of gas entry temperature, which plays the key role in overall gas turbine performance. High turbine entry temperatures can be achieved through appropriate selection of blade cooling method and blade material. The semi-closed oxy-fuel combustion combined cycle (SCOC-CC) operates at the same high entry gas temperature, hence blade cooling is necessary. The aim of this paper was to calculate the required turbine cooling in oxy-fuel gas turbines and compare it to the required turbine cooling in conventional gas turbines. The approach of the paper was to evaluate the thermodynamic and aerodynamic factors affecting turbine cooling with using the m*-model. The results presented in the paper concerned a single turbine stage at a reference diameter. The study showed greater cooling effectiveness in conventional gas turbines, but a greater total cooled area in oxy-fuel gas turbines. Consequently, the calculated total required cooling mass flow was close in the both single stage turbines. The cooling requirement and cooled area for a conventional and oxy-fuel twin-shaft gas turbine was also examined. The gas turbine was designed with five turbine stages. The analysis involved various turbine power and combustion outlet temperatures (COT). The results showed that the total required cooling mass flow was proportional to turbine power because of increasing gas turbine inlet mass flow. The required cooling mass flow was proportional to COT as the blade metal temperature is maintained at acceptable limit. The analysis revealed that required cooling for oxy-fuel gas turbines was higher than for conventional gas turbines at a specific power or specific COT. This is due to the greater cooled area in oxy-fuel gas turbines. The cooling effectiveness of conventional gas turbines was greater, which indicated higher required cooling. However, the difference in cooling effectiveness between conventional and oxy-fuel gas turbines was less in rear stages. The cooling mass flow as percentage of gas turbine inlet mass was slightly higher in conventional gas turbines than in oxy-fuel gas turbines. The required cooling per square meter of cooled area was used as a parameter to compare the required cooling for oxy-fuel and conventional gas turbines. The study showed that the required cooling per cooled area was close in both studied turbines. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
SCOC-CC, oxy-fuel, conventional gas turbine, blade cooling, thermodynamic analysis, aerodynamic analysis, wetted area, m*-model.
in
ASME Turbo Expo 2013: Turbine Technical Conference and Exposition
volume
2
pages
12 pages
publisher
American Society Of Mechanical Engineers (ASME)
conference name
ASME Turbo Expo 2013: Turbine Technical Conference and Exposition
external identifiers
  • Scopus:84890217627
DOI
10.1115/GT2013-95457
language
English
LU publication?
yes
id
aa60ef8c-1c62-4f69-9567-f811f2712b7c (old id 4276325)
date added to LUP
2014-01-30 11:10:16
date last changed
2016-10-13 04:49:44
@misc{aa60ef8c-1c62-4f69-9567-f811f2712b7c,
  abstract     = {Cooling is essential in all modern high-temperature gas turbines. Turbine cooling is mainly a function of gas entry temperature, which plays the key role in overall gas turbine performance. High turbine entry temperatures can be achieved through appropriate selection of blade cooling method and blade material. The semi-closed oxy-fuel combustion combined cycle (SCOC-CC) operates at the same high entry gas temperature, hence blade cooling is necessary. The aim of this paper was to calculate the required turbine cooling in oxy-fuel gas turbines and compare it to the required turbine cooling in conventional gas turbines. The approach of the paper was to evaluate the thermodynamic and aerodynamic factors affecting turbine cooling with using the m*-model. The results presented in the paper concerned a single turbine stage at a reference diameter. The study showed greater cooling effectiveness in conventional gas turbines, but a greater total cooled area in oxy-fuel gas turbines. Consequently, the calculated total required cooling mass flow was close in the both single stage turbines. The cooling requirement and cooled area for a conventional and oxy-fuel twin-shaft gas turbine was also examined. The gas turbine was designed with five turbine stages. The analysis involved various turbine power and combustion outlet temperatures (COT). The results showed that the total required cooling mass flow was proportional to turbine power because of increasing gas turbine inlet mass flow. The required cooling mass flow was proportional to COT as the blade metal temperature is maintained at acceptable limit. The analysis revealed that required cooling for oxy-fuel gas turbines was higher than for conventional gas turbines at a specific power or specific COT. This is due to the greater cooled area in oxy-fuel gas turbines. The cooling effectiveness of conventional gas turbines was greater, which indicated higher required cooling. However, the difference in cooling effectiveness between conventional and oxy-fuel gas turbines was less in rear stages. The cooling mass flow as percentage of gas turbine inlet mass was slightly higher in conventional gas turbines than in oxy-fuel gas turbines. The required cooling per square meter of cooled area was used as a parameter to compare the required cooling for oxy-fuel and conventional gas turbines. The study showed that the required cooling per cooled area was close in both studied turbines.},
  author       = {Sammak, Majed and Thern, Marcus and Genrup, Magnus},
  keyword      = {SCOC-CC,oxy-fuel,conventional gas turbine,blade cooling,thermodynamic analysis,aerodynamic analysis,wetted area,m*-model.},
  language     = {eng},
  pages        = {12},
  publisher    = {ARRAY(0x81a90d0)},
  series       = {ASME Turbo Expo 2013: Turbine Technical Conference and Exposition},
  title        = {Influence of Working Fluid on Gas Turbine Cooling Modeling},
  url          = {http://dx.doi.org/10.1115/GT2013-95457},
  volume       = {2},
  year         = {2013},
}