Effect of Near Melting Temperatures on Microparticle Sand Rebound Characteristics at Constant Impact Velocity

2014 ◽  
Author(s):  
J. M. Delimont ◽  
M. K. Murdock ◽  
W. F. Ng ◽  
S. V. Ekkad
Keyword(s):  
Melting Temperature ◽  
Particle Deposition ◽  
Road Dust ◽  
Turbine Engines ◽  
Glass Transition Point ◽  
Range Data ◽  
Gas Turbine Engines ◽  
Hastelloy X ◽  
Melting Temperatures ◽  
Impact Characteristics

When gas turbine engines operate in environments where the intake air has some concentration of particles, the engine will experience degradation. Very few studies of microparticles at temperatures approaching the melting temperature of the particles are available in open literature. Coefficient of Restitution (COR), a measure of the particles’ impact characteristics, was measured for microparticles using a particle tracking technique. This study presents data taken using the Virginia Tech Aerothermal Rig and Arizona Road Dust (ARD) of 20–40μm size range. Data was taken at temperatures up to and including 1323 K, where significant deposition of the sand particles was observed. The velocity at which the particles impact the surface was held at a constant 70m/s for all of the temperature cases. The target on which the particles impacted was made of a nickel alloy, Hastelloy X. The particle angle of impact was also varied between 30° and 80°. The COR of the particles decreases slightly as some of the particles approach their glass transition point and start to become molten. Other particles, which do not become molten due to different particle composition, rebound and maintain a relatively high COR. Images were taken using a microscope to examine the particle deposition that occurs at various angles. A rebound ratio is formulated to give a measure of the number of particles which deposit on the surface. The results show an increase in deposition as the temperature approaches the melting temperature of sand.

Effect of Temperature on Microparticle Rebound Characteristics at Constant Impact Velocity—Part II

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
J. M. Delimont ◽  
M. K. Murdock ◽  
W. F. Ng ◽  
S. V. Ekkad
Keyword(s):  
Particle Deposition ◽  
Road Dust ◽  
Effect Of Temperature ◽  
Turbine Engines ◽  
Glass Transition Point ◽  
Range Data ◽  
Gas Turbine Engines ◽  
Hastelloy X ◽  
Melting Temperatures ◽  
Impact Characteristics

When gas turbine engines operate in environments where the intake air has some concentration of particles, the engine will experience degradation. Very few studies of such microparticles approaching their melting temperatures are available in open literature. The coefficient of restitution (COR), a measure of the particles' impact characteristics, was measured in this study of microparticles using a particle tracking technique. Part II of this study presents data taken using the Virginia Tech Aerothermal Rig and Arizona road dust (ARD) of 20–40 μm size range. Data were taken at temperatures up to and including 1323 K, where significant deposition of the sand particles was observed. The velocity at which the particles impact the surface was held at a constant 70 m/s for all of the temperature cases. The target on which the particles impacted was made of a nickel alloy, Hastelloy X. The particle angle of impact was also varied between 30 deg and 80 deg. Deposition of particles was observed as some particles approach their glass transition point and became molten. Other particles, which do not become molten due to different particle composition, rebounded and maintained a relatively high COR. Images were taken using a microscope to examine the particle deposition that occurs at various angles. A rebound ratio was formulated to give a measure of the number of particles which deposited on the surface. The results show an increase in deposition as the temperature approaches the melting temperature of sand.

scholarly journals Measurement Drift in 3-Hole Yaw Pressure Probes From 5 Micron Sand Fouling at 1050° C

2019 ◽  
Author(s):  
Edward J. Turner ◽  
Matthew F. Bogdan ◽  
Tyler M. O’Connell ◽  
Wing F. Ng ◽  
Kevin T. Lowe ◽  
...  
Keyword(s):  
Flow Direction ◽  
Significant Risk ◽  
Road Dust ◽  
Maximum Error ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Flow Angle ◽  
Cylindrical Probe ◽  
Flow Characterization ◽  
Yaw Angle

Abstract The present paper focuses on the resilience of 3-hole pressure probes to hot sand fouling in turbomachinery environments. These probes are utilized inside jet engine hot sections for diagnostics and flow characterization. Ingestion of sand and other particulates pose a significant risk to hot section components and measurement devices in gas turbine engines. In this study, wedge, cylindrical, and trapezoidal probes were exposed to hot section turbine aerothermal conditions of 1050°C and 65–70 m/s flow velocity and fouled with 0–5 μm Arizona Road Dust (ARD). Sand accumulated more rapidly on the surface of the trapezoidal and cylindrical probe geometries than on the surface of the wedge probe geometry. Probe calibrations following sand fouling were performed in an ambient temperature, open air, calibration jet at Mach 0.3 and 0.5. Calibration curves using non-dimensional coefficients were used to assess probe error in yaw angle due to sand fouling. Probe error was based on each probe’s ability to accurately measure flow direction over a flow angle range of [−10°, 10°]. On average, the probes displayed greater error at Mach 0.5 than Mach 0.3. The wedge probe performed the best after sand fouling and displayed a maximum error of less than ±2° in yaw angle. In contrast, the cylindrical probe performed the worst after sand fouling and displayed maximum errors of more than ±8° in yaw angle. Transient response did not change notably with sand fouling.

The Increasing Complexity of Corrosion in Gas Turbines

2019 ◽  
Author(s):  
David A. Shifler
Keyword(s):  
Hot Corrosion ◽  
Gas Turbines ◽  
Solution Chemistry ◽  
Unburned Carbon ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Metallic Materials ◽  
Sulfate Salt ◽  
Melting Temperatures ◽  
Air Intake

Abstract Removal of fuel sulfur assumes that hot corrosion events will subsequently end in shipboard and aero gas turbine engines. Most papers in the literature since the 1970s consider Na2SO4 and SO3 as the primary reactants causing hot corrosion. However, several geographical sites around the world have relatively high pollutant levels (particulate matter, SO2, etc.) that have the potential to initiate high-temperature corrosion. The deposit chemistry influencing hot corrosion is more complex consisting of multiple sulfates and silicates with the addition of chlorides in a marine environment. Sulfur species may still enter a ship combustion chamber as contaminants via air intake or with seawater entrained in air entering through the ship air intake. High levels of impurities (SO2) above 2 ppm can lead to hot corrosion attack. Research is needed to determine how sulfate salt mixtures and air impurities influence hot corrosion in marine and non-marine conditions. Other impurities such as phosphorus, lead, chlorides, sand, and unburned carbon may lower salt melting temperatures, alter the sulfate activity, or change the solution chemistry and acidity/basicity that leads to accelerating hot corrosion. Other issues need to be considered in non-metallic materials system.

A Simple Physics-Based Model for Particle Rebound and Deposition in Turbomachinery

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
J. P. Bons ◽  
R. Prenter ◽  
S. Whitaker
Keyword(s):  
Gas Turbine ◽  
Particle Deposition ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Cfd Simulations ◽  
Model Predictions ◽  
Computational Fluid Dynamics Cfd ◽  
Parametric Dependencies ◽  
Key Aspects ◽  
Physical Phenomena

A new model is proposed for predicting particle rebound and deposition in environments relevant to gas turbine engines. The model includes the following physical phenomena: elastic deformation, plastic deformation, adhesion, and shear removal. It also incorporates material property sensitivity to temperature and tangential-normal rebound velocity cross-dependencies observed in experiments. The model is well-suited for incorporation in computational fluid dynamics (CFD) simulations of complex gas turbine flows due to its algebraic (explicit) formulation. Model predictions are compared to coefficient of restitution data available in the open literature as well as deposition results from two different high-temperature turbine deposition facilities. While the model comparisons with experiments are in many cases promising, several key aspects of particle deposition remain elusive. The simple phenomenological nature of the model allows for parametric dependencies to be evaluated in a straightforward manner. It is hoped that this feature of the model will aid in identifying and resolving the remaining stubborn holdouts that prevent a universal model for particle deposition.

A Simple Physics-Based Model for Particle Rebound and Deposition in Turbomachinery

2016 ◽  
Author(s):  
J. P. Bons ◽  
R. Prenter ◽  
S. Whitaker
Keyword(s):  
Gas Turbine ◽  
Particle Deposition ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Cfd Simulations ◽  
Straightforward Manner ◽  
Model Predictions ◽  
Parametric Dependencies ◽  
Key Aspects ◽  
Physical Phenomena

A new model is proposed for predicting particle rebound and deposition in environments relevant for gas turbine engines. The model includes the following physical phenomena: elastic deformation, plastic deformation, adhesion, and shear removal. It also incorporates material property sensitivity to temperature and tangential-normal rebound velocity cross-dependencies observed in experiments. The model is well-suited for incorporation in CFD simulations of complex gas turbine flows due to its algebraic (explicit) formulation. Model predictions are compared to coefficient of restitution data available in the open literature as well as deposition results from two different high temperature turbine deposition facilities. While the model comparisons with experiments are in many cases promising, several key aspects of particle deposition remain elusive. The simple phenomenological nature of the model allows for parametric dependencies to be evaluated in a straightforward manner. It is hoped that this feature of the model will aid in identifying and resolving the remaining stubborn holdouts that prevent a universal model for particle deposition.

Measurement Drift in 3-Hole Yaw Pressure Probes From 5 µm Sand Fouling at 1050 °C

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Edward J. Turner ◽  
Matthew F. Bogdan ◽  
Tyler M. O’Connell ◽  
Wing F. Ng ◽  
Kevin T. Lowe ◽  
...  
Keyword(s):  
Flow Direction ◽  
Significant Risk ◽  
Road Dust ◽  
Maximum Error ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Flow Angle ◽  
Cylindrical Probe ◽  
Flow Characterization ◽  
Yaw Angle

Abstract The present paper focuses on the resilience of 3-hole pressure probes to hot sand fouling in turbomachinery environments. These probes are utilized inside jet engine hot sections for diagnostics and flow characterization. Ingestion of sand and other particulates pose a significant risk to hot section components and measurement devices in gas turbine engines. In this study, wedge, cylindrical, and trapezoidal probes were exposed to hot section turbine aerothermal conditions of 1050 °C and 65–70 m/s flow velocity and fouled with 0–5 µm Arizona Road Dust (ARD). Sand accumulated more rapidly on the surface of the trapezoidal and cylindrical probe geometries than on the surface of the wedge probe geometry. Probe calibrations following sand fouling were performed in an ambient temperature, open air, calibration jet at Mach 0.3 and 0.5. Calibration curves using nondimensional coefficients were used to assess probe error in yaw angle due to sand fouling. Probe error was based on each probe’s ability to accurately measure flow direction over a flow angle range of [−10 deg, 10 deg]. On average, the probes displayed greater error at Mach 0.5 than Mach 0.3. The wedge probe performed the best after sand fouling and displayed a maximum error of less than ±2 deg in yaw angle. In contrast, the cylindrical probe performed the worst after sand fouling and displayed maximum errors of more than ±8 deg in yaw angle. Transient response did not change notably with sand fouling.

Gas Screen in Components of Gas Turbine Engines

1997 ◽  
Vol 28 (7-8) ◽  
pp. 536-542
Author(s):  
A. A. Khalatov ◽  
I. S. Varganov
Keyword(s):  
Gas Turbine ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Screen

Potential Application of Composite Materials to Future Gas Turbine Engines

1988 ◽  
Author(s):  
James C. Birdsall ◽  
William J. Davies ◽  
Richard Dixon ◽  
Matthew J. Ivary ◽  
Gary A. Wigell
Keyword(s):  
Composite Materials ◽  
Gas Turbine ◽  
Potential Application ◽  
Turbine Engines ◽  
Gas Turbine Engines

PYROMET ALLOY CTX-1

Alloy Digest ◽  
1997 ◽  
Vol 46 (5) ◽  
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
High Strength ◽  
Heat Treating ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Thermal Fatigue Resistance ◽  
Temperature Performance ◽  
Hot Work Die ◽  
Pressure Hydrogen ◽  
Hot Hardness

Abstract Pyromet CTX-1 is a high-strength, precipitation-hardenable superalloy exhibiting a low coefficient of thermal expansion and high strength up to about 1200 deg F. The alloy possesses high hot hardness and good thermal fatigue resistance. Its applications include components for gas turbine engines, hot-work die applications and high-pressure hydrogen environments. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: FE-56. Producer or source: Carpenter. Originally published February 1976, revised May 1997.

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