Measurement and Prediction of the Influence of Catalytic and Dry Low NOx Combustor Turbulence on Vane Surface Heat Transfer

2003 ◽  
Vol 125 (2) ◽  
pp. 221-231 ◽  
Author(s):  
Forrest E. Ames ◽  
Chao Wang ◽  
Pierre A. Barbot

New combustion systems developed for low emissions have produced substantial changes to the characteristics of inlet turbulence entering nozzle guide vanes. This paper documents the characteristics of turbulence generated by mock combustion system configurations representative of recently developed catalytic and dry low NOx combustors. Additionally, heat transfer rates are determined on the surface of a vane subjected to inlet turbulence generated by these mock combustor configurations. Six different inlet turbulence conditions with levels ranging up to 14% are documented in this study and vane heat transfer rates are acquired at exit chord Reynolds numbers ranging from 500,000 to 2,000,000. Heat transfer distributions show the influence of turbulence level and scale on heat transfer augmentation and transition. Cascade aerodynamics are well documented and match pressure distributions predicted by a commercial CFD code for this large-scale low-speed facility. The vane pressure distribution could be characterized as a conventional or fully loaded distribution. This comprehensive data set is expected to represent an excellent test case for vane heat transfer predictive methods. Predictive comparisons are shown based on a two-dimensional boundary layer code using an algebraic turbulence model for augmentation as well as a transition model.

Author(s):  
Forrest E. Ames ◽  
Chao Wang ◽  
Pierre A. Barbot

New combustion systems developed for low emissions have produced substantial changes to the characteristics of inlet turbulence entering nozzle guide vanes. This paper documents the characteristics of turbulence generated by mock combustion system configurations representative of recently developed catalytic and dry low NOx combustors. Additionally, heat transfer rates are determined on the surface of a vane subjected to inlet turbulence generated by these mock combustor configurations. Six different inlet turbulence conditions with levels ranging up to 14 percent are documented in this study and vane heat transfer rates are acquired at vane exit chord Reynolds numbers ranging from 500,000 to 2,000,000. Heat transfer distributions show the influence of turbulence level and scale on heat transfer augmentation and transition. Cascade aerodynamics are well documented and match pressure distributions predicted by a commercial CFD code for this large scale low speed facility. The vane pressure distribution could be characterized as a conventional or fully loaded distribution. This comprehensive data set on vane heat transfer is expected to represent an excellent test case for vane heat transfer predictive methods. Predictive comparisons are shown based on a two-dimensional boundary layer code using an algebraic turbulence model for augmentation as well as a transition model.


2004 ◽  
Vol 126 (1) ◽  
pp. 139-149 ◽  
Author(s):  
F. E. Ames ◽  
M. Argenziano ◽  
C. Wang

Aft-loaded vane designs can have an impact on surface heat transfer distributions by accelerating boundary layers for a greater portion of the suction surface. New combustion systems developed for low emissions have produced substantial changes to the characteristics of inlet turbulence entering nozzle guide vanes. This paper documents heat transfer rates on an aft-loaded vane subject to turbulence generated by mock combustion configurations representative of recently developed catalytic and dry low NOx (DLN) combustors. Four different inlet turbulence conditions with levels ranging up to 21% are documented in this study and vane heat transfer rates are acquired at vane exit chord Reynolds numbers ranging from 500,000 to 2,000,000. Heat transfer distributions show the influence of the turbulence conditions on heat transfer augmentation and transition. Cascade aerodynamics are well documented and match pressure distributions predicted by a commercial computational fluid dynamics (CFD) code for this large-scale low-speed facility. The aft-loaded vane pressure distribution exhibits a minimum value at about 50% arc on the suction surface. This comprehensive vane heat transfer data set is expected to represent an excellent test case for vane heat transfer predictive methods. Predictive comparisons are shown based on a two-dimensional boundary layer code using an algebraic turbulence model for augmentation as well as a transition model.


Author(s):  
F. E. Ames ◽  
M. Argenziano ◽  
C. Wang

This paper documents heat transfer rates on an aft loaded vane subject to turbulence generated by mock combustion configurations representative of recently developed catalytic and dry low NOx (DLN) combustors. New combustion systems developed for low emissions have produced substantial changes to the characteristics of inlet turbulence entering nozzle guide vanes. Aft loaded vane designs can have an impact on surface heat transfer distributions by accelerating boundary layers for a greater portion of the suction surface. Four different inlet turbulence conditions with intensities ranging up to 21 percent are documented in this study and vane heat transfer rates are acquired at vane exit chord Reynolds numbers ranging from 500,000 to 2,000,000. Heat transfer distributions show the influence of the turbulence conditions on heat transfer augmentation and transition. Cascade aerodynamics are well documented and match pressure distributions predicted by a commercial CFD code for this large scale low speed facility. The aft loaded vane pressure distribution exhibits a minimum value at about 50 percent arc on the suction surface. Laminar heat transfer augmentation in the stagnation region and on the pressure surface have scaled well on theoretical parameters based on turbulence intensity, Reynolds number, and energy scale. Predictive comparisons are shown based on a two-dimensional boundary layer code using an algebraic turbulence model for augmentation as well as a transition model. This comprehensive vane heat transfer data set is expected to represent an excellent test case for vane heat transfer predictive methods.


1984 ◽  
Vol 106 (1) ◽  
pp. 149-158 ◽  
Author(s):  
D. A. Nealy ◽  
M. S. Mihelc ◽  
L. D. Hylton ◽  
H. J. Gladden

The results of an experimental study of aerodynamic (surface velocity) and heat transfer distributions over the surfaces of two different, highly loaded, low-solidity contemporary turbine vane designs are presented. The aerodynamic configurations of the two vanes were carefully selected to emphasize fundamental differences in the character of the suction surface pressure distributions and the consequent effect on surface heat transfer distributions. The experimental measurements were made in moderate-temperature, three-vane cascades under steady-state conditions. The principal independent parameters (Mach number, Reynolds number, turbulence intensity, and wall-to-gas temperature ratio) were varied over ranges consistent with actual engine operation, and the test matrix was structured to provide an assessment of the independent influence of each parameter. These measurements are intended to serve as verification data for a parallel analytical code development effort. The results of this parallel effort are briefly reviewed, and the principal conclusions to date are summarized.


1984 ◽  
Vol 106 (1) ◽  
pp. 222-228 ◽  
Author(s):  
M. L. Marziale ◽  
R. E. Mayle

An experimental investigation was conducted to examine the effect of a periodic variation in the angle of attack on heat transfer at the leading edge of a gas turbine blade. A circular cylinder was used as a large-scale model of the leading edge region. The cylinder was placed in a wind tunnel and was oscillated rotationally about its axis. The incident flow Reynolds number and the Strouhal number of oscillation were chosen to model an actual turbine condition. Incident turbulence levels up to 4.9 percent were produced by grids placed upstream of the cylinder. The transfer rate was measured using a mass transfer technique and heat transfer rates inferred from the results. A direct comparison of the unsteady and steady results indicate that the effect is dependent on the Strouhal number, turbulence level, and the turbulence length scale, but that the largest observed effect was only a 10 percent augmentation at the nominal stagnation position.


Author(s):  
Neil W. Harvey ◽  
Martin G. Rose ◽  
John Coupland ◽  
Terry Jones

A 3-D steady viscous finite volume pressure correction method for the solution of the Reynolds averaged Navier-Stokes equations has been used to calculate the heat transfer rates on the end walls of a modern High Pressure Turbine first stage stator. Surface heat transfer rates have been calculated at three conditions and compared with measurements made on a model of the vane tested in annular cascade in the Isentropic Light Piston Facility at DERA, Pyestock. The NGV Mach numbers, Reynolds numbers and geometry are fully representative of engine conditions. Design condition data has previously been presented by Harvey and Jones (1990). Off-design data is presented here for the first time. In the areas of highest heat transfer the calculated heat transfer rates are shown to be within 20% of the measured values at all three conditions. Particular emphasis is placed on the use of wall functions in the calculations with which relatively coarse grids (of around 140,000 nodes) can be used to keep computational run times sufficiently low for engine design purposes.


Author(s):  
R. F. Martinez-Botas ◽  
A. J. Main ◽  
G. D. Lock ◽  
T. V. Jones

The Oxford University Blowdown Tunnel has been substantially modified to test a large annular cascade of high pressure nozzle guide vanes (mean blade diameter of 1.11 m and axial chord of 0.0673 m). The new transonic facility has been constructed to obtain complete contours of heat transfer coefficient for both the end walls and blade surfaces using the transient liquid crystal technique, to measure pressure distributions and losses, and to study fundamental aspects of boundary layers and secondary flows. The facility allows an independent variation of Reynolds and Mach numbers, providing aerodynamic and heat transfer measurements in the region of interest for gas turbine design. The mass flow rate through the cascade at NGV design conditions (exit Mach number 0.96 and Reynolds number 2.0 × 106) is 38 kg/s and the pressure-regulated test duration exceeds 7 seconds.


2002 ◽  
Vol 124 (3) ◽  
pp. 508-516 ◽  
Author(s):  
M. D. Barringer ◽  
O. T. Richard ◽  
J. P. Walter ◽  
S. M. Stitzel ◽  
K. A. Thole

The flow field exiting the combustor in a gas turbine engine is quite complex considering the presence of large dilution jets and complicated cooling schemes for the combustor liner. For the most part, however, there has been a disconnect between the combustor and turbine when simulating the flow field that enters the nozzle guide vanes. To determine the effects of a representative combustor flow field on the nozzle guide vane, a large-scale wind tunnel section has been developed to simulate the flow conditions of a prototypical combustor. This paper presents experimental results of a combustor simulation with no downstream turbine section as a baseline for comparison to the case with a turbine vane. Results indicate that the dilution jets generate turbulence levels of 15–18% at the exit of the combustor with a length scale that closely matches that of the dilution hole diameter. The total pressure exiting the combustor in the near-wall region neither resembles a turbulent boundary layer nor is it completely uniform putting both of these commonly made assumptions into question.


Author(s):  
Zixiang Sun ◽  
Alistair Kifoil ◽  
John W. Chew ◽  
Nicholas J. Hills

In compressor inter-disc cavities with a central axial throughflow it is known that the flow and heat transfer is strongly affected by buoyancy in the centrifugal force field. As a step towards developing CFD methods for such flows, buoyancy-driven flows under gravity in a closed cube and under centrifugal force in a sealed rotating annulus have been studied. Numerical simulations are compared with the experimental results of Kirkpatrick and Bohn (1986) and Bohn et al (1993). Two different CFD codes have been used and are shown to agree for the stationary cube problem. Unsteady simulations for the stationary cube show good agreement with measurements of heat transfer, temperature fluctuations, and velocity fluctuations for Rayleigh numbers up to 2 × 1010. Similar simulations for the rotating annulus also show good agreement with measured heat transfer rates. The CFD results confirm Bohn et al’s results, showing reduced heat transfer and a different Rayleigh number dependency compared to gravity-driven flow. Large scale flow structures are found to occur, at all Rayleigh numbers considered.


1984 ◽  
Vol 106 (3) ◽  
pp. 619-627 ◽  
Author(s):  
J. C. Simonich ◽  
R. J. Moffat

An experimental heat transfer study on a concavely curved turbulent boundary layer has been performed. A new, instantaneous heat transfer measurement technique utilizing liquid crystals was used to provide a vivid picture of the local distribution of surface heat transfer coefficient. Large scale wall traces, composed of streak patterns on the surface, were observed to appear and disappear at random, but there was no evidence of a spanwise stationary heat transfer distribution, nor any evidence of large scale structures resembling Taylor-Gortler vortices. The use of a two-dimensional computation scheme to predict heat transfer rates in concave curvature regions seems justifiable.


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