Effects of Aeroderivative Combustor Turbulence on Endwall Heat Transfer Distributions Acquired in a Linear Vane Cascade

2003 ◽  
Vol 125 (2) ◽  
pp. 210-220 ◽  
Author(s):  
Forrest E. Ames ◽  
Pierre A. Barbot ◽  
Chao Wang
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Combustion System ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
High Turbulence ◽  
Turbulence Condition ◽  
Vortex Systems

Vane endwall heat transfer distributions are documented for a mock aeroderivative combustion system and for a low turbulence condition in a large-scale low speed linear cascade facility. Inlet turbulence levels range from below 0.7% for the low turbulence condition to 14% for the mock combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Low turbulence endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the high turbulence cases. Turbulent scale has been documented for the high turbulence case. Inlet boundary layers are relatively thin for the low turbulence case, while inlet flow approximates a nonequilibrium or high turbulence channel flow for the mock combustor case. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the low turbulence and mock combustor inlet cases. Both midspan and 95% span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

Effects of Aeroderivative Combustor Turbulence on Endwall Heat Transfer Distributions Acquired in a Linear Vane Cascade

2002 ◽  
Author(s):  
Forrest E. Ames ◽  
Pierre A. Barbot ◽  
Chao Wang
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Combustion System ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
High Turbulence ◽  
Turbulence Condition ◽  
Vortex Systems

Vane endwall heat transfer distributions are documented for a mock aeroderivative combustion system and for a low turbulence condition in a large-scale low speed linear cascade facility. Inlet turbulence levels range from below 0.7 percent for the low turbulence condition to 14 percent for the mock combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Low turbulence endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the high turbulence cases. Turbulent scale has been documented for the high turbulence case. Inlet boundary layers are relatively thin for the low turbulence case while inlet flow approximates a nonequilibrium or high turbulence channel flow for the mock combustor case. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the low turbulence and mock combustor inlet cases. Both midspan and 95 percent span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

Effects of Catalytic and Dry Low NOx Combustor Turbulence on Endwall Heat Transfer Distributions

2005 ◽  
Vol 127 (4) ◽  
pp. 414-424 ◽  
Author(s):  
F. E. Ames ◽  
P. A. Barbot ◽  
C. Wang
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
Catalytic Combustor ◽  
Vortex Systems

Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0% for the mock catalytic combustor condition to 14% for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for both the mock catalytic and DLN combustor cases. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95% span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

Effects of Catalytic and Dry Low NOx Combustor Turbulence on Endwall Heat Transfer Distributions

2003 ◽  
Author(s):  
F. E. Ames ◽  
P. A. Barbot ◽  
C. Wang
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
Catalytic Combustor ◽  
Vortex Systems

Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0 percent for the mock catalytic combustor condition to 14 percent for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for both the mock catalytic and DLN combustor cases. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95 percent span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

The Influence of Aero-Derivative Combustor Turbulence and Reynolds Number on Vane Aerodynamics Losses, Secondary Flows, and Wake Growth

2006 ◽  
Author(s):  
F. E. Ames ◽  
J. D. Johnson ◽  
N. J. Fiala
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Loss ◽  
Total Pressure ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Total Pressure Loss ◽  
Surface Boundary ◽  
High Turbulence ◽  
Turbulence Condition

Exit surveys detailing total pressure loss, turning angle, and secondary velocities have been acquired for a fully loaded vane profile in a large scale low speed cascade facility. Exit surveys have been taken over a four-to-one range in Reynolds numbers based on exit conditions and for both a low turbulence condition and a high turbulence condition. The high turbulence condition was generated using a mock aero-derivative combustor. Exit loss, angle, and secondary velocity measurements were acquired in the facility using a five-hole cone probe at two stations representing axial chord spacings of 0.25 and 0.50. Substantial differences in the level of losses, distribution of losses, and secondary flow vectors are seen with the different turbulence conditions and at the different Reynolds numbers. The higher turbulence condition produces a significantly broader wake than the low turbulence case and shows a measurable total pressure loss in the region outside the wakes. Generally, total pressure losses are about 0.02 greater for the high turbulence case compared with the low turbulence case primarily due to the state of the suction surface boundary layers. Losses decrease moderately with increasing Reynolds number. Cascade inlet velocity distributions have been previously documented in an endwall heat transfer study of this same geometry. These exit survey measurements support our understanding of the endwall heat transfer distributions, the secondary flows in the passage, and the origin of losses.

Aerodynamics of a Letterbox Trailing Edge: Effects of Blowing Rate, Reynolds Number, and External Turbulence on Aerodynamic Losses and Pressure Distribution

2008 ◽  
Author(s):  
N. J. Fiala ◽  
J. D. Johnson ◽  
F. E. Ames
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Large Scale ◽  
Reynolds Numbers ◽  
Design Flow ◽  
Trailing Edge ◽  
Aerodynamic Loss ◽  
Secondary Velocity ◽  
Turbulence Condition ◽  
External Turbulence

A letterbox trailing edge configuration is formed by adding flow partitions to a gill slot or pressure side cutback. Letterbox partitions are a common trailing edge configuration for vanes and blades and the aerodynamics of these configurations are consequently of interest. Exit surveys detailing total pressure loss, turning angle, and secondary velocities have been acquired for a vane with letterbox partitions in a large scale low speed cascade facility. These measurements are compared with exit surveys of both the base (solid) and gill slot vane configurations. Exit surveys have been taken over a four to one range in chord Reynolds numbers (500,000, 1,000,000, and 2,000,000) based on exit conditions and for low (0.7%), grid (8.5%), and aero-combustor (13.5%) turbulence conditions with varying blowing rate (50%, 100%, 150%, and 200% design flow). Exit loss, angle, and secondary velocity measurements were acquired in the facility using a five-hole cone probe at a measuring station representing an axial chord spacing of 0.25 from the vane trailing edge plane. Differences between losses with the base vane, gill slot vane and letterbox vane for a given turbulence condition and Reynolds number are compared providing evidence of coolant ejection losses and losses due to the separation off the exit slot lip and partitions. Additionally, differences in the level of losses, distribution of losses, and secondary flow vectors are presented for the different turbulence conditions at the different Reynolds numbers. The letterbox configuration has been found to have slightly reduced losses at a given flow rate compared with the gill slot. However, the letterbox requires an increased pressure drop for the same ejection flow. The present paper together with a related paper [1], which documents letterbox heat transfer, is intended to provide designers with aerodynamic loss and heat transfer information needed for design evaluation and comparison with competing trailing edge designs.

The Influence of Large-Scale High-Intensity Turbulence on Vane Heat Transfer

1997 ◽  
Vol 119 (1) ◽  
pp. 23-30 ◽  
Author(s):  
F. E. Ames
Keyword(s):  
Heat Transfer ◽  
High Intensity ◽  
Large Scale ◽  
Reynolds Numbers ◽  
Surface Heat ◽  
Grid Turbulence ◽  
Stagnation Region ◽  
Linear Cascade ◽  
Pressure Surface ◽  
Scale Turbulence

An experimental research program was undertaken to examine the influence of large-scale high-intensity turbulence on vane heat transfer. The experiment was conducted in a four-vane linear cascade at exit Reynolds numbers of 500,000 and 800,000 based on chord length. Heat transfer measurements were made for four inlet turbulence conditions including a low turbulence case (Tu ≅ 1 percent), a grid turbulence case (Tu ≅ 7.5 percent), and two levels of large-scale turbulence generated with a mock combustor at two upstream locations (Tu ≅ 12 percent and 8 percent). The heat transfer data demonstrated that the length scale, Lu, has a significant effect on stagnation region and pressure surface heat transfer.

Heat Transfer Enhancement in Narrow Channels Using Two and Three-Dimensional Mixing Devices

1995 ◽  
Vol 117 (3) ◽  
pp. 590-596 ◽  
Author(s):  
S. V. Garimella ◽  
D. J. Schlitz
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Prandtl Number ◽  
Heat Transfer Enhancement ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Transitional Flow ◽  
Transfer Enhancement ◽  
Roughness Elements

The localized enhancement of forced convection heat transfer in a rectangular duct with very small ratio of height to width (0.017) was experimentally explored. The heat transfer from a discrete square section of the wall was enhanced by raising the heat source off the wall in the form of a protrusion. Further enhancement was effected through the use of large-scale, three-dimensional roughness elements installed in the duct upstream of the discrete heat source. Transverse ribs installed on the wall opposite the heat source provided even greater heat transfer enhancement. Heat transfer and pressure drop measurements were obtained for heat source length-based Reynolds numbers of 2600 to 40,000 with a perfluorinated organic liquid coolant, FC-77, of Prandtl number 25.3. Selected experiments were also performed in water (Prandtl number 6.97) for Reynolds numbers between 1300 and 83,000, primarily to determine the role of Prandtl number on the heat transfer process. Experimental uncertainties were carefully minimized and rigorously estimated. The greatest enhancement in heat transfer relative to the flush heat source was obtained when the roughness elements were used in combination with a single on the opposite wall. A peak enhancement of 100 percent was obtained at a Reynolds number of 11,000, which corresponds to a transitional flow regime. Predictive correlations valid over a range of Prandtl numbers are proposed.

scholarly journals Internal Passage Heat Transfer Prediction Using Multiblock Grids and a k-ω Turbulence Model

1996 ◽  
Author(s):  
David L. Rigby ◽  
A. A. Ameri ◽  
E. Steinthorsson
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Flow And Heat Transfer ◽  
Aspect Ratios ◽  
Single Block ◽  
Multiblock Grid ◽  
Good Agreement

Numerical simulations of the three-dimensional flow and heat transfer in a rectangular duct with a 180° bend were performed. Results are presented for Reynolds numbers of 17,000 and 37,000 and for aspect ratios of 0.5 and 1.0. A k-ω turbulence model with no reference to distance to a wall is used. Direct comparison between single block and multiblock grid calculations are made. Heat transfer and velocity distributions are compared to available literature with good agreement. The multi-block grid system is seen to produce more accurate results compared to a single-block grid with the same number of cells.

Onset of Transition in the Flow Over a Three-Dimensional Array of Rectangular Obstacles

1992 ◽  
Vol 114 (2) ◽  
pp. 251-255 ◽  
Author(s):  
S. V. Garimella ◽  
P. A. Eibeck
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Water Channel ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Channel Height ◽  
Circuit Boards ◽  
Three Dimensional Flow ◽  
Transfer Data ◽  
Array Geometry

Onset of transition is investigated in the flow over an array of protruding elements mounted on the bottom wall of a rectangular water channel simulating flow passages between adjacent circuit boards in computers. The element dimensions are held constant while the channel height and the element spacing are varied. Flow visualization and turbulence measurements are used to determine transition Reynolds numbers, which compare well with previous results obtained from heat transfer data. The complicated, three-dimensional flow field causes transition to be a function not only of flow rate and array geometry but also of location in the array. Transition occurs in the fully developed region of the array at a channel height-based Reynolds number of 700 for a channel height of 1.2 element heights, increasing to 1900 for a channel height of 3.6 element heights. However, when Reynolds number is defined based on element height, transition occurs at the same Reynolds number of 550 for all channel heights. Increasing the stream wise spacing between elements causes transition to occur at lower Reynolds numbers.

Gill Slot Trailing Edge Aerodynamics: Effects of Blowing Rate, Reynolds Number, and External Turbulence on Aerodynamic Losses and Pressure Distribution

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
J. D. Johnson ◽  
N. J. Fiala ◽  
F. E. Ames
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Large Scale ◽  
Reynolds Numbers ◽  
Companion Paper ◽  
Trailing Edge ◽  
Film Cooling Effectiveness ◽  
Turbulence Condition ◽  
External Turbulence

Gill slots (also called cutbacks) are a common method to cool the trailing edge of vanes and blades and to eject spent cooling air. Exit surveys detailing total pressure loss, turning angle, and secondary velocities have been acquired for a gill slot vane in a large-scale, low speed cascade facility. These measurements are compared with exit surveys of the base (solid) vane configuration. Exit surveys have been taken over a four to one range in chord Reynolds numbers (500,000, 1,000,000, and 2,000,000) based on exit conditions and for low (0.7%), grid (8.5%), and aerocombustor (13.5%) turbulence conditions with varying blowing rate (50%, 100%, 150%, and 200% design flows). Exit loss, angle, and secondary velocity measurements were acquired in the facility using a five-hole cone probe at two stations representing axial chord spacings of 0.25 and 0.50. Differences between losses with and without the gill slot for a given turbulence condition and Reynolds number are compared providing evidence of coolant ejection losses and losses due to the separation off the gill slot lip. Additionally, differences in the level of losses, distribution of losses, and secondary flow vectors are presented for the different turbulence conditions and at the different Reynolds numbers. The turbulence condition has been found to have only a small effect on the increase in losses due to the gill slot. However, decreasing Reynolds number has been found to produce an increasing increment in losses. The present paper, together with a companion paper (2007, “Gill Slot Trailing Edge Heat Transfer—Effects of Blowing Rate, Reynolds Number, and External Turbulence on Heat Transfer and Film Cooling Effectiveness,” ASME Paper No. GT2007-27397), which documents gill slot heat transfer, is intended to provide designers with the heat transfer and aerodynamic loss information needed to compare competing trailing edge designs.

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