Endwall Heat Transfer and Aerodynamic Measurements in an Annular Cascade of Nozzle Guide Vanes

Spencer, M. C.; Lock, Gary; Jones, T. V.; Harvey, N. W.

doi:10.1115/95-gt-356

Cited by 3 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Generally the heat transfer coefficient contours reflect those of Mach number. An interpretation of these contours based on flow visualisation experiments is discussed by Spencer et al (1995Spencer et al ( , 1996. One point worthy of note here is that the casing contours illustrate an enhanced region of heat transfer on the suction surface side near the leading edge.…”

Section: Comparing Cfds With Experimentsmentioning

confidence: 93%

“…At engine design conditions the exit Mach number is 0.96 and the Reynolds number (based on an axial chord of 66.4 mm) is 2 x 106 . The free-stream turbulence intensity and length scale at the NGV inlet plane was measured to be 13% and 21 mm respectively (Spencer et al 1995). The facility has a run-time of -5 seconds and transient experimental techniques are employed to measure heat transfer using liquid crystals (Martinez-Botas et al 1995 or thin film gauges (Guo et al 1995).…”

Section: Experimental Conditionsmentioning

confidence: 99%

“…Figures 8a and 8b illustrate experimentally determined contours of the heat transfer coefficient (W/m 2 K) for the pressure and suction aerofoil surfaces with 25 pm roughness (Martinez-Botas et al 1995, Spencer 1996. These were obtained using the transient liquid crystal technique which has the advantage of providing global measurements of heat transfer.…”

Section: Comparing Cfds With Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Computational Prediction of Heat Transfer to Gas Turbine Nozzle Guide Vanes With Roughened Surfaces

Guo

Jones

Lock

et al. 1996

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

Self Cite

View full text Add to dashboard Cite

The local Mach number and heat transfer coefficient over the aerofoil surfaces and endwalls of a transonic gas turbine nozzle guide vane have been calculated. The computations were performed by solving the time averaged Navier-Stokes equations using a fully three-dimensional computational code (CFDS) which is well established at Rolls-Royce. A model to predict the effects of roughness has been incorporated into CFDS and heat transfer levels have been calculated for both hydraulically smooth and transitionally rough surfaces. The roughness influences the calculations in two ways; firstly the mixing length at a certain height above the surface is increased; secondly the wall function used to reconcile the wall condition with the first grid point above the wall is also altered. The first involves a relatively straightforward shift of the origin in the van Driest damping function description, the second requires an integration of the momentum equation across the wall layer. A similar treatment applies to the energy equation. The calculations are compared with experimental contours of heat transfer coefficient obtained using both thin film gauges and the transient liquid crystal technique. Measurements were performed using both hydraulically smooth and roughened surfaces, and at engine-representative Mach and Reynolds numbers. The heat transfer results are discussed and interpreted in terms of surface-shear flow visualisation using oil and dye techniques.

show abstract

Section: Comparing Cfds With Experimentsmentioning

confidence: 93%

Section: Experimental Conditionsmentioning

confidence: 99%

Section: Comparing Cfds With Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Computational Prediction of Heat Transfer to Gas Turbine Nozzle Guide Vanes With Roughened Surfaces

Guo

Jones

Lock

et al. 1996

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

Self Cite

View full text Add to dashboard Cite

show abstract

Convective Heat Transfer and Aerodynamics in Axial Flow Turbines

Dunn

2001

Journal of Turbomachinery

110

View full text Add to dashboard Cite

The primary focus of this paper is convective heat transfer in axial flow turbines. Research activity involving heat transfer generally separates into two related areas: predictions and measurements. The problems associated with predicting heat transfer are coupled with turbine aerodynamics because proper prediction of vane and blade surface-pressure distribution is essential for predicting the corresponding heat transfer distribution. The experimental community has advanced to the point where time-averaged and time-resolved three-dimensional heat transfer data for the vanes and blades are obtained routinely by those operating full-stage rotating turbines. However, there are relatively few CFD codes capable of generating three-dimensional predictions of the heat transfer distribution, and where these codes have been applied the results suggest that additional work is required. This paper outlines the progression of work done by the heat transfer community over the last several decades as both the measurements and the predictions have improved to current levels. To frame the problem properly, the paper reviews the influence of turbine aerodynamics on heat transfer predictions. This includes a discussion of time-resolved surface-pressure measurements with predictions and the data involved in forcing function measurements. The ability of existing two-dimensional and three-dimensional Navier–Stokes codes to predict the proper trends of the time-averaged and unsteady pressure field for full-stage rotating turbines is demonstrated. Most of the codes do a reasonably good job of predicting the surface-pressure data at vane and blade midspan, but not as well near the hub or the tip region for the blade. In addition, the ability of the codes to predict surface-pressure distribution is significantly better than the corresponding heat transfer distributions. Heat transfer codes are validated against measurements of one type or another. Sometimes the measurements are performed using full rotating rigs, and other times a much simpler geometry is used. In either case, it is important to review the measurement techniques currently used. Heat transfer predictions for engine turbines are very difficult because the boundary conditions are not well known. The conditions at the exit of the combustor are generally not well known and a section of this paper discusses that problem. The majority of the discussion is devoted to external heat transfer with and without cooling, turbulence effects, and internal cooling. As the design community increases the thrust-to-weight ratio and the turbine inlet temperature, there remain many turbine-related heat transfer issues. Included are film cooling modeling, definition of combustor exit conditions, understanding of blade tip distress, definition of hot streak migration, component fatigue, loss mechanisms in the low turbine, and many others. Several suggestions are given herein for research and development areas for which there is potentially high payoff to the industry with relatively small risk.

show abstract

Computational Prediction of Heat Transfer to Gas Turbine Nozzle Guide Vanes With Roughened Surfaces

Guo

Jones

Lock

et al. 1998

Journal of Turbomachinery

View full text Add to dashboard Cite

The local Mach number and heat transfer coefficient over the aerofoil surfaces and endwalls of a transonic gas turbine nozzle guide vane have been calculated. The computations were performed by solving the time-averaged Navier–Stokes equations using a fully three-dimensional computational code (CFDS), which is well established at Rolls-Royce. A model to predict the effects of roughness has been incorporated into CFDS and heat transfer levels have been calculated for both hydraulically smooth and transitionally rough surfaces. The roughness influences the calculations in two ways; first the mixing length at a certain height above the surface is increased; second the wall function used to reconcile the wall condition with the first grid point above the wall is also altered. The first involves a relatively straightforward shift of the origin in the van Driest damping function description, the second requires an integration of the momentum equation across the wall layer. A similar treatment applies to the energy equation. The calculations are compared with experimental contours of heat transfer coefficient obtained using both thin-film gages and the transient liquid crystal technique. Measurements were performed using both hydraulically smooth and roughened surfaces, and at engine-representative Mach and Reynolds numbers. The heat transfer results are discussed and interpreted in terms of surface-shear flow visualization using oil and dye techniques.

show abstract

Endwall Heat Transfer and Aerodynamic Measurements in an Annular Cascade of Nozzle Guide Vanes

Cited by 3 publications

References 13 publications

Computational Prediction of Heat Transfer to Gas Turbine Nozzle Guide Vanes With Roughened Surfaces

Computational Prediction of Heat Transfer to Gas Turbine Nozzle Guide Vanes With Roughened Surfaces

Convective Heat Transfer and Aerodynamics in Axial Flow Turbines

Computational Prediction of Heat Transfer to Gas Turbine Nozzle Guide Vanes With Roughened Surfaces

Contact Info

Product

Resources

About