Particle trajectories in turbine cascades

Dring, R. P.; Caspar, J. R.; Suo, M.

doi:10.2514/3.47996

Cited by 18 publications

(18 citation statements)

References 7 publications

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“…McCreath 67 integrated equations of motion for 15-micron particles in Tyne turbine stator vane and rotor-blade passages and found reasonable agreement with deposition buildup measured over their pressure surfaces in experiments. Dring et al 68 showed excellent agreement between calculated tra-jectories and photographs of trajectories over a range of particle diameters (Stokes numbers from ∼0.1 to 1.9) for experiments using a symmetric airfoil. At turbine flowpath conditions, integration of particle equations of motion considering only fluid drag forces typically applies to particles larger than a few microns in diameter (Stokes number on the order of 1 or larger), for which particles have sufficient inertia so that the other mechanisms already described have a relatively small effect on transport to airfoil nose and pressure (concave) surfaces.…”

Section: Models For Particle Delivery To Turbine Surfacesmentioning

confidence: 93%

Erosion and Deposition in Turbomachinery

Hamed

Tabakoff

Wenglarz³

2006

Journal of Propulsion and Power

287

135

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This paper presents a review of erosion and deposition research in turbomachines and the associated degradation in engine performance caused by particulate matter ingestion. Parameters affecting surface material losses as a result of erosion and development of experimental and analytical approaches to predict flowpath erosion and deposition are discussed. Tests results that quantify the effects of temperature, impact particle composition, impact velocity and angle, and surface material composition are reviewed along with particle restitution data (ratios of rebound to impact velocities and angles). Development and application of models using these data to calculate surface erosion in turbomachinery are described. These models predict particle trajectories in turbomachinery passages to determine impact rates, impact velocities, impact angles and uses the experimentally-obtained erosion data to calculate material losses. Literature on the effects of erosion on turbomachine performance and life is surveyed. Mechanisms of particle delivery and attachment upon arrival at turbomachine flowpath surfaces are also discussed along with experiential models that have been developed to predict surface deposit buildup. Delivery to turbine surfaces can occur as a result of inertial flight, as for erosion, but also through transport mechanisms involving turbulence, Brownian diffusion, and thermophoresis. The particle size range, where each of these mechanisms is dominant for delivery to surfaces, is described. The history and experience of developing models that use these mechanisms to quantify particle delivery rates to turbine flow path surfaces is discussed, along with the use of sticking fraction data to determine the amount of material retained on the surfaces after delivery and the resulting deposit buildup rates. Finally, factors that control whether extreme rates of deposition can occur in turbomachinery are described. . His early experience involved dynamics and control for gyroscopic systems and manned space stations. Later experience concerned developing and applying analytical and experimental methods to evaluate deposition, erosion, and corrosion (DEC) in advanced energy systems (e.g., gas turbines and fuel cells) operating with alternate fuels. Currently, Dr. Wenglarz is Manager of Research at SCIES for a DOE-sponsored program supporting university gas turbine research nationwide. Dr. Wenglarz has over 80 publications and presentations including invited presentations at the Von Karman

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Section: Models For Particle Delivery To Turbine Surfacesmentioning

confidence: 93%

Erosion and Deposition in Turbomachinery

Hamed

Tabakoff

Wenglarz³

2006

Journal of Propulsion and Power

287

135

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“…As discussed in Ref. 5, the agreement between the calculated and the measured trajectories was remarkably good. This agreement verified the assumption that the particles coming from the particle generator were of a given size.…”

Section: Cylindrical Lensmentioning

confidence: 59%

“…A procedure developed in Ref. 5 was then used to calculate the trajectories of particles of that diameter. This test was performed over a range of particle sizes.…”

Section: Cylindrical Lensmentioning

confidence: 99%

Particle trajectories near an airfoil with a film-cooled leading edge

1979

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Flow visualization techniques were developed and used to study particle trajectories near an airfoil with a filmcooled leading edge. The study was conducted to determine the size of particles which could be deflected by the cooling air jets. This is an important problem relevant to the development of high-temperature gas turbines which burn fuels which produce ash particles (e.g. coal). Experiments were performed on a large-scale airfoil in a low-speed wind tunnel utilizing uniformly sized DOP (Di-octyl phthalate) droplets and chopped streak photography to visualize particle trajectories. The results have been related to the flow in an engine through the use of Stokes parameter scaling. The results indicate that turbine airfoil leading-edge film cooling in a gas turbine engine may deflect particles up to at least 5.8 n in diameter when the cooling air velocity is at least 0.67 times the approach velocity.

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“…Its main range was 10-20 µm. According to the study conducted by Dring et al [30], the trajectory of the particles is dominated by the Stokes number. The Stokes number of particles in air flow can be defined as:…”

Section: Experimental Parametersmentioning

confidence: 99%

Experimental Study of Particle Deposition on Surface at Different Mainstream Velocity and Temperature

Zhang¹,

Liu²,

Liu³

et al. 2019

Energies

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The effect of mainstream velocity and mainstream temperature on the behavior of deposition on a flat plate surface has been investigated experimentally. Molten wax particles were injected to generate particle deposition in a two-phase flow wind tunnel. Tests indicated that deposition occurs mainly at the leading edge and the middle and backward portions of the windward side. The mass of deposition at the leading edge was far more than that on the windward and lee sides. For the windward and lee sides, deposition mass increased as the mainstream velocity was increased for a given particle concentration. Capture efficiency was found to increase initially until the mainstream velocity reaches a certain value, where it begins to drop with mainstream velocity increasing. For the leading edge, capture efficiency followed a similar trend due to deposition spallation and detachment induced by aerodynamic shear at high velocity. Deposition formation was also strongly affected by the mainstream temperature due to its control of particle phase (solid or liquid). Capture efficiency initially increased with increasing mainstream temperature until a certain threshold temperature (near the wax melting point). Subsequently, it began to decrease, for wax detaches from the model surface when subjected to the aerodynamic force at the surface temperature above the wax melting point.

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Particle trajectories in turbine cascades

Cited by 18 publications

References 7 publications

Erosion and Deposition in Turbomachinery

Erosion and Deposition in Turbomachinery

Particle trajectories near an airfoil with a film-cooled leading edge

Experimental Study of Particle Deposition on Surface at Different Mainstream Velocity and Temperature

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