scholarly journals Discussion: “Heat Transfer and Flowfield Measurements in the Leading Edge Region of a Stator Vane Endwall” (Kang, M. B., Kohli, A., and Thole, K. A., 1999, ASME J. Turbomach., 121, pp. 558–568)

1999 ◽  
Vol 121 (3) ◽  
pp. 568-568
Author(s):  
L. S. Langston
Keyword(s):  
Heat Transfer ◽  
Leading Edge ◽  
Edge Region ◽  
Stator Vane

Heat Transfer and Flowfield Measurements in the Leading Edge Region of a Stator Vane Endwall

1999 ◽  
Vol 121 (3) ◽  
pp. 558-568 ◽  
Author(s):  
M. B. Kang ◽  
A. Kohli ◽  
K. A. Thole
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Edge Region ◽  
Leading Edge Vortex ◽  
Stator Vane ◽  
Edge Vortex ◽  
The Mean

The leading edge region of a first-stage stator vane experiences high heat transfer rates, especially near the endwall, making it very important to get a better understanding of the formation of the leading edge vortex. In order to improve numerical predictions of the complex endwall flow, benchmark quality experimental data are required. To this purpose, this study documents the endwall heat transfer and static pressure coefficient distribution of a modern stator vane for two different exit Reynolds numbers (Reex = 6 × 105 and 1.2 × 106). In addition, laser-Doppler velocimeter measurements of all three components of the mean and fluctuating velocities are presented for a plane in the leading edge region. Results indicate that the endwall heat transfer, pressure distribution, and flowfield characteristics change with Reynolds number. The endwall pressure distributions show that lower pressure coefficients occur at higher Reynolds numbers due to secondary flows. The stronger secondary flows cause enhanced heat transfer near the trailing edge of the vane at the higher Reynolds number. On the other hand, the mean velocity, turbulent kinetic energy, and vorticity results indicate that leading edge vortex is stronger and more turbulent at the lower Reynolds number. The Reynolds number also has an effect on the location of the separation point, which moves closer to the stator vane at lower Reynolds numbers.

Heat Transfer and Flowfield Measurements in the Leading Edge Region of a Stator Vane Endwall

1998 ◽  
Author(s):  
M. B. Kang ◽  
A. Kohli ◽  
K. A. Thole
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Leading Edge ◽  
Secondary Flows ◽  
Edge Region ◽  
Leading Edge Vortex ◽  
Lower Reynolds Number ◽  
Stator Vane ◽  
Edge Vortex ◽  
The Mean

The leading edge region of a first stage stator vane experiences high heat transfer rates especially near the end wall making it very important to get a better understanding of the formation of the leading edge vortex. In order to improve numerical predictions of the complex endwall flow, benchmark quality experimental data are required. To this purpose, this study documents the endwall heat transfer and static pressure coefficient distribution of a modern stator vane for two different exit Reynolds numbers (Reex = 6 × 105 and 1.2 × 106). In addition, laser Doppler velocimeter measurements of all three components of the mean and fluctuating velocities are presented for the stagnation plane in the leading edge region. Results indicate that the endwall heat transfer, pressure distribution and flowfield characteristics change with Reynolds number. The endwall pressure distributions show that lower pressure coefficients occur at the higher Reynolds number due to secondary flows. The stronger secondary flows cause enhanced heat transfer near the trailing edge of the vane at the higher Reynolds number. On the other hand the mean velocity, turbulent kinetic energy and vorticity results indicate that leading edge vortex is stronger and more turbulent at the lower Reynolds number. The Reynolds number also has an effect on the location of the separation point which moves closer to the stator vane at the lower Reynolds number.

Turbine Blade Leading Edge Cooling With One Row of Normal or Tangential Impinging Jets

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Nian Wang ◽  
Andrew F. Chen ◽  
Mingjie Zhang ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbine Blade ◽  
Leading Edge ◽  
Jet Impingement ◽  
Test Surface ◽  
Test Model ◽  
Edge Region ◽  
Target Plate ◽  
Blade Leading Edge

Jet impingement cooling has been extensively used in the leading edge region of a gas turbine blade. This study focuses on the effect of jet impinging position on leading edge heat transfer. The test model is composed of a semicylindrical target plate, side exit slots, and an impingement jet plate. A row of cylindrical injection holes is located along the axis (normal jet) or the edge (tangential jet) of the semicylinder, on the jet plate. The jet-to-target-plate distance to jet diameter ratio (z/d) is 5 and the ratio of jet-to-jet spacing to jet diameter (s/d) is 4. The jet Reynolds number is varied from 10,000 to 30,000. Detailed impingement heat transfer coefficient distributions were experimentally measured by using the transient liquid crystal (TLC) technique. To understand the thermal flow physics, numerical simulations were performed using Reynolds-averaged Navier–Stokes (RANS) with two turbulence models: realizable k–ε (RKE) and shear stress transport k–ω model (SST). Comparisons between the experimental and the numerical results are presented. The results indicate that the local Nusselt numbers on the test surface increase with the increasing jet Reynolds number. The tangential jets provide more uniform heat transfer distributions as compared with the normal jets. For the normal jet impingement and the tangential jet impingement, the RKE model provides better prediction than the SST model. The results can be useful for selecting a jet impinging position in order to provide the proper cooling distribution inside a turbine blade leading edge region.

Flowfield Measurements for a Highly Turbulent Flow in a Stator Vane Passage

1999 ◽  
Author(s):  
R. W. Radomsky ◽  
K. A. Thole
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Reynolds Shear Stress ◽  
Correlation Coefficients ◽  
Leading Edge ◽  
Surface Heat ◽  
Laser Doppler Velocimeter ◽  
Surface Heat Transfer ◽  
Turbine Vanes ◽  
Stator Vane

Turbine vanes experience high convective surface heat transfer as a consequence of the turbulent flow exiting the combustor. Before improvements to vane heat transfer predictions through boundary layer calculations can be made, we need to understand how the turbulent flow in the inviscid region of the passage reacts as it passes between two adjacent turbine vanes. In this study, a scaled-up turbine vane geometry was used in a low-speed wind tunnel simulation. The test section included a central airfoil with two adjacent vanes. To generate the 20% turbulence levels at the entrance to the cascade, which simulates levels exiting the combustor, an active grid was used. Three-component laser Doppler velocimeter measurements of the mean and fluctuating quantities were measured in a plane at the vane mid-span. Coincident velocity measurements were made to quantify Reynolds shear stress and correlation coefficients. The energy spectra and length scales were also measured to give a complete set of inlet boundary conditions that can be used for numerical simulations. The results show that the turbulent kinetic energy throughout the inviscid region remained relatively high. The surface heat transfer measurements indicated high augmentation near the leading edge as well as the pressure side of the vane as a result of the elevated turbulence levels.

Turbine Blade Leading Edge Cooling With One Row of Normal or Tangential Impinging Jets

2017 ◽  
Author(s):  
Nian Wang ◽  
Andrew F. Chen ◽  
Mingjie Zhang ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbine Blade ◽  
Leading Edge ◽  
Jet Impingement ◽  
Test Surface ◽  
Test Model ◽  
Edge Region ◽  
Target Plate ◽  
Blade Leading Edge

Jet impingement cooling has been extensively used in the leading edge region of a gas turbine blade. This study focuses on the effect of jet impinging position on leading edge heat transfer. The test model is composed of a semi-cylindrical target plate, side exit slots, and an impingement jet plate. A row of cylindrical injection holes is located along the axis (normal jet) or the edge (tangential jet) of the semi-cylinder, on the jet plate. The jet-to-target-plate distance to jet diameter ratio (z/d) is 5 and the ratio of jet-to-jet spacing to jet diameter (s/d) is 4. The jet Reynolds number is varied from 10,000 to 30,000. Detailed impingement heat transfer coefficient distributions were experimentally measured by using the transient liquid crystal technique. To understand the thermal flow physics, numerical simulations were performed using RANS with two turbulence models: realizable k-ε (RKE) and shears stress transport k-ω model (SST). Comparisons between the experimental and the numerical results are presented. The results indicate that the local Nusselt numbers on the test surface increase with the increasing jet Reynolds number. The tangential jets provide more uniform heat transfer distributions as compared with the normal jets in the stream-wise direction. For the normal jet impingement and the tangential jet impingement, the RKE model provides better prediction than the SST model. The results can be useful for selecting a jet impinging position in order to provide the proper cooling distribution inside a turbine blade leading edge region.

Flowfield Measurements for a Highly Turbulent Flow in a Stator Vane Passage

1999 ◽  
Vol 122 (2) ◽  
pp. 255-262 ◽  
Author(s):  
R. W. Radomsky ◽  
K. A. Thole
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Reynolds Shear Stress ◽  
Correlation Coefficients ◽  
Leading Edge ◽  
Surface Heat ◽  
Laser Doppler Velocimeter ◽  
Surface Heat Transfer ◽  
Turbine Vanes ◽  
Stator Vane

Turbine vanes experience high convective surface heat transfer as a consequence of the turbulent flow exiting the combustor. Before improvements to vane heat transfer predictions through boundary layer calculations can be made, we need to understand how the turbulent flow in the inviscid region of the passage reacts as it passes between two adjacent turbine vanes. In this study, a scaled-up turbine vane geometry was used in a low-speed wind tunnel simulation. The test section included a central airfoil with two adjacent vanes. To generate the 20 percent turbulence levels at the entrance to the cascade, which simulates levels exiting the combustor, an active grid was used. Three-component laser-Doppler velocimeter measurements of the mean and fluctuating quantities were measured in a plane at the vane midspan. Coincident velocity measurements were made to quantify Reynolds shear stress and correlation coefficients. The energy spectra and length scales were also measured to give a complete set of inlet boundary conditions that can be used for numerical simulations. The results show that the turbulent kinetic energy throughout the inviscid region remained relatively high. The surface heat transfer measurements indicated high augmentation near the leading edge as well as the pressure side of the vane as a result of the elevated turbulence levels. [S0889-504X(00)02302-3]

Turbine blade heat transfer calculations using two-equation turbulence models

1997 ◽  
Vol 211 (3) ◽  
pp. 253-262 ◽  
Author(s):  
J Larsson
Keyword(s):  
Heat Transfer ◽  
Turbulence Models ◽  
Leading Edge ◽  
Suction Side ◽  
External Heat ◽  
Navier Stokes ◽  
Edge Region ◽  
Turbine Cascades ◽  
Good Agreement

A full Navier-Stokes solver is used to calculate external heat transfer in two linear two-dimensional turbine cascades, one subsonic and one transonic. Heat transfer results obtained with two low-Reynolds k-∊ models (Chien and Launder-Sharma) and two k-ω models (Wilcox standard and transition) are compared with measurements. Good agreement is found in some regions, but the suction side transition and the leading edge are not predicted correctly. Problems with turbulence levels that are too high in the leading edge region are investigated. The numerical quality of the results is investigated and a few general guidelines about the numerics are given. Grid and scheme independence is also demonstrated.

scholarly journals Infrared Low-Temperature Turbine Vane Rough Surface Heat Transfer Measurements

2000 ◽  
Vol 123 (1) ◽  
pp. 168-177 ◽  
Author(s):  
R. J. Boyle ◽  
C. M. Spuckler ◽  
B. L. Lucci ◽  
W. P. Camperchioli
Keyword(s):  
Heat Transfer ◽  
Infrared Camera ◽  
Leading Edge ◽  
Suction Side ◽  
Surface Heat ◽  
Test Facility ◽  
Edge Region ◽  
Linear Cascade ◽  
Test Conditions ◽  
Turbine Vane

Turbine vane heat transfer distributions obtained using an infrared camera technique are described. Infrared thermography was used because noncontact surface temperature measurements were desired. Surface temperatures were 80°C or less. Tests were conducted in a three-vane linear cascade, with inlet pressures between 0.14 and 1.02 atm, and exit Mach numbers of 0.3, 0.7, and 0.9, for turbulence intensities of approximately 1 and 10 percent. Measurements were taken on the vane suction side, and on the pressure side leading edge region. The designs for both the vane and test facility are discussed. The approach used to account for conduction within the vane is described. Midspan heat transfer distributions are given for the range of test conditions.

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