scholarly journals Computational Simulation of Deposition in a Cooled High-Pressure Turbine Stage With Hot Streaks

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Robin Prenter ◽  
Ali Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
High Pressure ◽  
Particle Deposition ◽  
Particle Temperature ◽  
Computational Simulation ◽  
Stokes Number ◽  
Navier Stokes ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Tracking Model

Ash particle deposition in a high-pressure turbine stage was numerically investigated using steady Reynolds-averaged Navier-Stokes (RANS) and unsteady Reynolds-averaged Navie-Stokes (URANS) methods. An inlet temperature profile consisting of Gaussian nonuniformities (hot streaks) was imposed on the vanes, with vane cooling simulated using a constant vane wall temperature. The steady case utilized a mixing plane at the vane–rotor interface, while a sliding mesh was used for the unsteady case. Corrected speed and mass flow were matched to an experiment involving the same geometry, so that the flow solution could be validated against measurements. Particles ranging from 1 to 65 μm were introduced into the vane domain, and tracked using an Eulerian–Lagrangian tracking model. A novel particle rebound and deposition model was employed to determine particles' stick/bounce behavior upon impact with a surface. Predicted impact and capture distributions for different diameters were compared between the steady and unsteady methods, highlighting effects from the circumferential averaging of the mixing plane. The mixing plane simulation was found to generally under predict impact and capture efficiencies compared with the unsteady calculation, as well as under predict particle temperature upon impact with the blade surface. Quantitative impact and capture efficiency trends with the Stokes number are discussed for both the vane and blade, with companion qualitative distributions for the different Stokes regimes.

Computational Simulation of Deposition in a Cooled High-Pressure Turbine Stage With Hot Streaks

2016 ◽  
Author(s):  
Robin Prenter ◽  
Ali Ameri ◽  
Jeffrey P. Bons
Keyword(s):  
High Pressure ◽  
Particle Deposition ◽  
Particle Temperature ◽  
Computational Simulation ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Suction Surface ◽  
Pressure Surface ◽  
Tracking Model

Ash particle deposition in a high-pressure turbine stage was numerically investigated using steady (RANS) and unsteady (URANS) methods. An inlet temperature profile consisting of Gaussian non-uniformities (hot streaks) was imposed on the vanes, with vane cooling simulated using a constant vane wall temperature. The steady case utilized a mixing plane at the vane-rotor interface, while a sliding mesh was used for the unsteady case. Corrected speed and mass flow were matched to an experiment involving the same geometry, so that the flow solution could be validated against measurements. Particles ranging from 1 to 65 μm were introduced into the vane domain, and tracked using an Eulerian-Lagrangian tracking model. A novel particle rebound and deposition model was employed to determine particles’ stick/bounce behavior upon impact with a surface. Predicted impact and capture distributions for different diameters were compared between the steady and unsteady methods, highlighting effects from the circumferential averaging of the mixing plane. The mixing plane simulation was found to over predict impact and capture efficiencies compared with the unsteady calculation, as well as over predict particle temperature upon impact with the blade surface. Blade impact efficiencies increased with higher Stokes numbers in both simulations, with multiple rebounds occurring on the pressure surface in the mixing plane case, and on the suction surface in the unsteady case.

scholarly journals Effect of Inlet Temperature Non-Uniformity on High-Pressure Turbine Performance

2010 ◽  
Author(s):  
Craig I. Smith ◽  
Dongil Chang ◽  
Stavros Tavoularis
Keyword(s):  
High Pressure ◽  
Heat Load ◽  
Stokes Equations ◽  
Computation Time ◽  
Radial Pressure ◽  
Navier Stokes ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Navier Stokes Equations ◽  
Hot Streak

The temperature of the flow entering a high-pressure turbine stage is inherently non-uniform, as it is produced by several discrete, azimuthally-distributed combustors. In general, however, industrial simulations assume inlet temperature uniformity to simplify the preparation process and reduce computation time. The effects of a non-uniform inlet field on the performance of a commercial, transonic, single-stage, high-pressure, axial turbine with a curved inlet duct have been investigated numerically by performing URANS (Unsteady Reynolds-Averaged Navier-Stokes equations) simulations with the SST (Shear Stress Transport) turbulence model. By adjusting the alignment of the experimentally-based inlet temperature field with respect to the stator vanes, two clocking configurations were generated: an aligned case, in which each hot streak impinged on a vane and a misaligned case, in which each hot streak passed between two vanes. In the aligned configuration, the hot streaks produced higher time-averaged heat load on the vanes and lower heat load on the blades. As the aligned hot streaks impinged on the stator vanes, they also spread spanwise due to the actions of the casing passage vortices and the radial pressure gradient; this resulted in a stream entering the rotor with relatively low temperature variations. The misaligned hot streaks were convected undisturbed past the relatively cool vane section. Relatively high time-averaged enthalpy values were found to occur on the pressure side of the blades in the misaligned configuration. The non-uniformity of the time-averaged enthalpy on the blade surfaces was lower in the aligned configuration. The flow exiting the rotor section was much less non-uniform in the aligned case, but differences in calculated efficiency were not significant.

scholarly journals Calculation and Correlation of the Unsteady Flowfield in a High Pressure Turbine

2002 ◽  
Author(s):  
Milind A. Bakhle ◽  
Jong S. Liu ◽  
Josef Panovsky ◽  
Theo G. Keith ◽  
Oral Mehmed
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Forced Vibrations ◽  
Forced Response ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Turbine Stage ◽  
High Pressure Turbine

Forced vibrations in turbomachinery components can cause blades to crack or fail due to high-cycle fatigue. Such forced response problems will become more pronounced in newer engines with higher pressure ratios and smaller axial gap between blade rows. An accurate numerical prediction of the unsteady aerodynamics phenomena that cause resonant forced vibrations is increasingly important to designers. Validation of the computational fluid dynamics (CFD) codes used to model the unsteady aerodynamic excitations is necessary before these codes can be used with confidence. Recently published benchmark data, including unsteady pressures and vibratory strains, for a high-pressure turbine stage makes such code validation possible. In the present work, a three dimensional, unsteady, multi blade-row, Reynolds-Averaged Navier Stokes code is applied to a turbine stage that was recently tested in a short duration test facility. Two configurations with three operating conditions corresponding to modes 2, 3, and 4 crossings on the Campbell diagram are analyzed. Unsteady pressures on the rotor surface are compared with data.

CFD Heat Transfer Predictions for a High-Pressure Turbine Stage

2004 ◽  
Author(s):  
James A. Tallman
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Turbulence Modeling ◽  
Pressure Ratio ◽  
Numerical Procedure ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Computational Fluid Dynamics Cfd

Computational Fluid Dynamics (CFD) was used to predict the turbine airfoil heat transfer for the high-pressure vane and high-pressure blade of a modern, one and one half stage turbine at its correct scale. Airfoil pressure and heat transfer measurements were recently obtained for the turbine in a transient shock tunnel facility, which allows for the replication of the actual engine turbine’s design corrected speed, pressure ratio, and gas-to-metal temperature ratio. A 3-D, compressible, Reynolds-averaged Navier-Stokes CFD solver with k-ω turbulence modeling was used for the CFD predictions. The turbulence model’s implementation into the numerical procedure was modified slightly, in order to better capture the model’s intended near-wall behavior and resolve the heat transfer prediction. Both the high-pressure vane and high-pressure blade were computed as steady-state flows and for two different turbine Reynolds number settings. Overall, the predictions compare very favorably with the measurement for both pressure and heat transfer at the mid-span location. A discussion of the features of the airfoil heat transfer distribution is included.

THE INFLUENCE OF PURGE FLOW PARAMETERS ON HEAT TRANSFER AND FILM COOLING IN TURBINE CENTER FRAMES

2021 ◽  
pp. 1-26
Author(s):  
Patrick René Jagerhofer ◽  
Marios Patinios ◽  
Tobias Glasenapp ◽  
Emil Goettlich ◽  
Federica Farisco
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Density Ratio ◽  
Constant Heat Flux ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Turbofan Engines ◽  
Blowing Ratio ◽  
Purge Flow

Abstract The imperative improvement in the efficiency of turbofan engines is commonly facilitated by increasing the turbine inlet temperature. This development has reached a point where also components downstream of the high-pressure turbine have to be adequately cooled. Such a component is the turbine center frame (TCF), known for a complex aerodynamic flow highly influenced by purge-mainstream interactions. The purge air, being injected through the wheelspace cavities of the upstream high-pressure turbine, bears a significant cooling potential for the TCF. Despite this, fundamental knowledge of the influencing parameters on heat transfer and film cooling in the TCF is still missing. This paper examines the influence of purge-to-mainstream blowing ratio, density ratio and purge swirl angle on heat transfer and film cooling in the TCF. The experiments are conducted in a sector-cascade test rig specifically designed for such heat transfer studies using infrared thermography and tailor-made flexible heating foils with constant heat flux. Three purge-to-mainstream blowing ratios and an additional no purge case are investigated. The purge flow is injected without swirl and also with engine-similar swirl angles. The purge swirl and blowing ratio significantly impact the magnitude and the spread of film cooling in the TCF. Increasing blowing ratios lead to an intensification of heat transfer. By cooling the purge flow, a moderate variation in purge-to-mainstream density ratio is investigated, and the influence is found to be negligible.

Using CFD to Reduce Resonant Stresses on a Single-Stage, High-Pressure Turbine Blade

2002 ◽  
Author(s):  
J. P. Clark ◽  
A. S. Aggarwala ◽  
M. A. Velonis ◽  
R. E. Gacek ◽  
S. S. Magge ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Guide Vane ◽  
Turbine Blades ◽  
Suction Side ◽  
Lessons Learned ◽  
Single Stage ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Time Resolved

The ability to predict levels of unsteady forcing on high-pressure turbine blades is critical to avoid high-cycle fatigue failures. In this study, 3D time-resolved computational fluid dynamics is used within the design cycle to predict accurately the levels of unsteady forcing on a single-stage high-pressure turbine blade. Further, nozzle-guide-vane geometry changes including asymmetric circumferential spacing and suction-side modification are considered and rigorously analyzed to reduce levels of unsteady blade forcing. The latter is ultimately implemented in a development engine, and it is shown successfully to reduce resonant stresses on the blade. This investigation builds upon data that was recently obtained in a full-scale, transonic turbine rig to validate a Reynolds-Averaged Navier-Stokes (RANS) flow solver for the prediction of both the magnitude and phase of unsteady forcing in a single-stage HPT and the lessons learned in that study.

Assessment of the Indirect Combustion Noise Generated in a Transonic High-Pressure Turbine Stage

2015 ◽  
Author(s):  
Dimitrios Papadogiannis ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Gaofeng Wang ◽  
Stéphane Moreau ◽  
...  
Keyword(s):  
High Pressure ◽  
Acoustic Waves ◽  
Gas Turbines ◽  
Guide Vane ◽  
Combustion Noise ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Noise Generation ◽  
Turbine Stage ◽  
High Pressure Turbine

Indirect combustion noise, generated by the acceleration and distortion of entropy waves through the turbine stages, has been shown to be the dominant noise source of gas turbines at low-frequencies and to impact the thermoacoustic behavior of the combustor. In the present work, indirect combustion noise generation is evaluated in the realistic, fully 3D transonic high-pressure turbine stage MT1 using Large-Eddy Simulations (LES). An analysis of the basic flow and the different turbine noise generation mechanisms is performed for two configurations: one with a steady inflow and a second with a pulsed inlet, where a plane entropy wave train at a given frequency is injected before propagating across the stage generating indirect noise. The noise is evaluated through the Dynamic Mode Decomposition of the flow field. It is compared with previous 2D simulations of a similar stator/rotor configuration, as well as with the compact theory of Cumpsty and Marble. Results show that the upstream propagating entropy noise is reduced due to the choked turbine nozzle guide vane. Downstream acoustic waves are found to be of similar strength to the 2D case, highlighting the potential impact of indirect combustion noise on the overall noise signature of the engine.

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