scholarly journals Leakage and Power Loss Test Results for Competing Turbine Engine Seals

2004 ◽  
Author(s):  
Margaret P. Proctor ◽  
Irebert R. Delgado
Keyword(s):  
High Temperature ◽  
Power Loss ◽  
High Speed ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
Test Rig ◽  
Labyrinth Seals ◽  
Turbine Engine

Advanced brush and finger seal technologies offer reduced leakage rates over conventional labyrinth seals used in gas turbine engines. To address engine manufactures’ concerns about the heat generation and power loss from these contacting seals, brush, finger, and labyrinth seals were tested in the NASA High Speed, High Temperature Turbine Seal Test Rig. Leakage and power loss test results are compared for these competing seals for operating conditions up to 922 K (1200 °F) inlet air temperature, 517 KPa (75 psid) across the seal, and surface velocities up to 366 m/s (1200 ft/s).

Angular Contact Ball Bearings: Track Position at High Speeds

1969 ◽  
Vol 184 (1) ◽  
pp. 351-370
Author(s):  
K. C. Falcon ◽  
C. Andrew
Keyword(s):  
High Speed ◽  
Contact Angles ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Rig ◽  
Outer Race ◽  
High Speeds ◽  
Surface Displacements ◽  
Lubricant Flow

The track position of the balls on the outer race of an angular contact bearing of the series and size used on the main shaft of aero gas turbine engines was measured in a test rig. The test rig was capable of simulating the operating conditions of the bearing with respect to axial load, inner race speed and high lubricant flow rates. The contact angle, defined by the track position, was deduced from the measurement of sub-surface displacements in the race using a number of small transducers embedded therein. The resulting contact angles were compared with values predicted from a number of unconfirmed theories in current use. At conditions of high speed and low load the correlation is poor; an over-estimation of the cage speed, arising from the false assumption that gross ball slip does not occur, gives rise to an over-estimation of the changes of contact angles from their nominal values.

Ultra-High Temperature Compliant Foil Bearings: The Journey to 870°C and Application in Gas Turbine Engines — Experiment

2018 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton ◽  
Brian D. Nicholson
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Foil Bearings ◽  
Wide Range ◽  
The U.S ◽  
Ultra High Temperature

In this paper, the authors present the results of recent developments demonstrating that ultra-high temperature compliant foil bearings are suitable for application in a wide range of high temperature turbomachinery including gas turbine engines, supercritical CO2 power turbines and automotive turbochargers as supported by test data showing operation of foil bearings at temperatures to 870°C (1600°F). This work represents the culmination of efforts begun in 1987, when the U.S. Air Force established and led the government and industry collaborative Integrated High Performance Turbine Engine Technology (IHPTET) program. The stated goal of IHPTET was to deliver twice the propulsion capability of turbine engines in existence at that time. Following IHPTET, the Versatile Affordable Advanced Turbine Engines (VAATE) program further expanded on the original goals by including both versatility and affordability as key elements in advancing turbine engine technology. Achieving the stated performance goals would require significantly more extreme operating conditions including higher temperatures, pressures and speeds, which in turn would require bearings capable of sustaining temperatures in excess of 815°C (1500°F). Similarly, demands for more efficient automotive engines and power plants are subjecting the bearings in turbochargers and turbogenerators to more severe environments. Through the IHPTET and VAATE programs, the U.S. has made considerable research investments to advancing bearing technology, including active magnetic bearings, solid and vapor phase lubricated rolling element bearings, ceramic/hybrid ceramic bearings, powder lubricated bearings and compliant foil gas bearings. Thirty years after the IHPTET component goal of developing a bearing capable of sustained operation at temperatures above 540°C and potentially as high as 815°C (1500°F) recent testing has demonstrated achievement of this goal with an advanced, ultra-high temperature compliant foilgas bearing. Achieving this goal required a combination of high temperature foil material, a unique elastic-tribo-thermal barrier coating (KOROLON 2250) and a self-adapting compliant configuration. The authors describe the experimental hardware designs and design considerations of the two differently sized test rigs used to demonstrate foil bearings operating above 815°C (1500°F). Finally, the authors present and discuss the results of testing at temperatures to 870°C (1600°F).

scholarly journals The Formation of High Temperature Minerals From an Evaporite-Rich Dust in Gas Turbine Engine Ingestion Tests

2020 ◽  
Author(s):  
Jacob Elms ◽  
Alison Pawley ◽  
Nicholas Bojdo ◽  
Merren Jones ◽  
Rory Clarkson
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Bed ◽  
Turbine Engine ◽  
Mineral Assemblages ◽  
Mineral Dusts ◽  
Engine Components

Abstract The ingestion of multi-mineral dusts by gas turbine engines during routine operations is a significant problem for engine manufacturers because of the damage caused to engine components and their protective thermal barrier coatings. A complete understanding of the reactions forming these deposits is limited by a lack of knowledge of compositions of ingested dusts and unknown engine conditions. Test bed engines can be dosed with dusts of known composition under controlled operating conditions, but past engine tests have used standardised test dusts that do not resemble the composition of the background dust in the operating regions. A new evaporiterich test dust was developed and used in a full engine ingestion test, designed to simulate operation in regions with evaporiterich geology, such as Doha or Dubai. Analysis of the engine deposits showed that mineral fractionation was present in the cooler, upstream sections of the engine. In the hotter, downstream sections, deposits contained new, high temperature phases formed by reaction of minerals in the test dust. The mineral assemblages in these deposits are similar to those found from previous analysis of service returns. Segregation of anhydrite from other high temperature phases in a deposit sample taken from a High Pressure Turbine blade suggests a relationship between temperature and sulfur content. This study highlights the potential for manipulating deposit chemistry to mitigate the damage caused in the downstream sections of gas turbine engines. The results of this study also suggest that the concentration of ingested dust in the inlet air may not be a significant contributing factor to deposit chemistry.

CFD Assessment of Rotordynamic Coefficients in Labyrinth Seals

2014 ◽  
Author(s):  
Sai S. Sreedharan ◽  
Giuseppe Vannini ◽  
Hiteshkumar Mistry
Keyword(s):  
High Speed ◽  
Test Results ◽  
Active Magnetic Bearings ◽  
Test Rig ◽  
Labyrinth Seals ◽  
Cfd Simulations ◽  
Flow Solver ◽  
Rotordynamic Coefficients ◽  
Pressure Test ◽  
Dynamic Seal

Seals used in high speed centrifugal compressors are prone to generate rotordynamic (RD) instabilities. To further understand their influence, a CFD based approach is developed. The objective of the current study is to numerically investigate and characterize the RD coefficients, representative of the dynamic seal forces. Experiments were carried out at high pressure test rig (up to 200 bar seal inlet pressure) which runs at 10000 RPM and has a high pre-swirl (about 0.9) along the same direction of rotor rotation. The rotor shaft in the experiment was instrumented with active magnetic bearings (AMBs) to linearly excite the rotor at three different frequencies: 28 Hz, 70 Hz and 126 Hz. Each frequency is characterized by amplitude of vibration and a phase. CFD simulations were carried out using commercial flow solver, using similar boundary conditions as that of experiments. The paper describes details of CFD model and its comparison against experiments. Numerical results show reasonable agreement of RD coefficients with test results. This job has to be considered as a first approach to CFD methodology applied to annular seals for the authors.

scholarly journals The Basics of Powder Lubrication in High-Temperature Powder-Lubricated Dampers

1991 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Basic Mechanism ◽  
Test Facility ◽  
Experimental Program ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Powder Lubrication ◽  
Basic Features ◽  
Selection Of

The objective of this investigation is to develop a novel powder-lubricated rotor bearing system damper concept for use in high-temperature, high-speed rotating machinery such as advanced aircraft gas turbine engines. The approach discussed herein consists of replacing a conventional oil lubrication or frictional damper system with a powder lubrication system that uses the process particulates or externally-fed powder lubricant. Unlike previous work in this field, this approach is based on the postulate of the quasi-hydrodynamic nature of powder lubrication. This postulate is deduced from past observation and present verification that there are a number of basic features of powder flow in narrow interfaces that have the characteristic behavior of fluid film lubrication. In addition to corroborating the basic mechanism of powder lubrication, the conceptual and experimental work performed in this program provides guidelines for selection of the proper geometries, materials and powders suitable for this tribological process. The present investigation describes the fundamentals of quasi-hydrodynamic powder lubrication and defines the rationale underlying the design of the test facility. The performance and the results of the experimental program present conclusions reached regarding design requirements as well as the formulation of a proper model of quasi-hydrodynamic powder lubrication.

Evaluation of Alternate High Temperature Coatings to Improve Hot Corrosion Resistance in a Shipboard Environment

2009 ◽  
Author(s):  
David A. Shifler ◽  
Dennis M. Russom ◽  
Bruce E. Rodman
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Corrosion Fatigue ◽  
Hot Corrosion ◽  
Turbine Engines ◽  
Type I ◽  
Gas Turbine Engines ◽  
Type Ii ◽  
Turbine Engine ◽  
Type Ii Hot Corrosion

501-K34 marine gas turbine engines serve as auxiliary power sources for the U.S. Navy’s DDG-51 Class. It is desired that 501-K34 marine gas turbine engines have a mean time between removal of 20K hours. While some engines have approached this goal, others have fallen significantly short. A primary reason for this shortfall is hot corrosion (Type I and Type II) damage in the turbine area (more specifically the first row turbine hardware) due to both intrusion of salts from the marine air and from sulfur in the gas turbine combustion fuel. The Navy’s technical community recognizes that engine corrosion problems are complex in nature and are often tied to the design of the overall system. For this reason, two working groups were formed. One group focuses on the overall ship system design and operation, including the inlet and fuel systems. The second, the corrosion issues working group, will review the design and performance of the turbine itself and develop sound, practical, economical, and executable changes to engine design that will make it more robust and durable in the shipboard operating environment. Metallographic examination of unfailed blades removed from a marine gas turbine engine with 18000 operating hours showed that the coating thickness under the platform and in the curved area of transition between the platform to the blade stem was either very thin, or in a few cases, non-existent on each unfailed blade. Type II hot corrosion was evident at these locations under the platform. It was also observed that this corrosion under the platform led to corrosion fatigue cracking of first stage turbine blades due to poor coating quality (high porosity and variable thickness). Corrosion fatigue cracks initiated at several hot corrosion sites and had advanced through the stems to varying degrees. Cracking in a few blades had advanced to the point that would have led to premature blade failure. Low velocity, atmospheric-pressure burner-rig (LVBR) tests were conducted for 1000 hours to evaluate several alternative high-temperature coatings in both Type I and Type II hot corrosion environments. The objectives of this paper are to: (1) report the results of the hot corrosion performance of alternative high temperature coating systems for under the platform of the 1st stage blade of 501-K34 gas turbine engine, (2) compare the performance of these alternative coating systems to the current baseline 1st stage blade coating, and (3) down select the best performing coating systems (in terms of their LVBR hot corrosion and thermal cycling resistance) to implement on future 501-K34 first stage blades for the Fleet.

Windage Heating of Air Passing Through Labyrinth Seals

1994 ◽  
Author(s):  
J. A. Millward ◽  
M. F. Edwards
Keyword(s):  
High Speed ◽  
Cooling System ◽  
Momentum Balance ◽  
Viscous Drag ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Secondary Cooling ◽  
Labyrinth Seals ◽  
Accurate Temperature ◽  
Cooling Air

The viscous drag on rotating components in gas turbine engines represents both a direct loss of power from the cycle and an input of heat into the secondary (cooling) air system. Hotter cooling air in turn means increased flow requirements. The effects of windage on performance are therefore compounded. To facilitate accurate temperature predictions of highly stressed components, information is needed on windage characteristics of all elements in the secondary cooling system. Much information is available in the literature for discs, cones, cylinders, bolts etc but little has been published on windage heating in high speed seals. Results are presented for experiments carried out (at representative non-dimensional conditions) on different designs of labyrinth seals. The results are compared with values calculated from the simple momentum balance theory suggested by McGreeham and Ko (1989) and with several values determined from CFD analysis.

Fail Safe, High Temperature Magnetic Bearing for High Efficiency Gas Turbine Engine Applications

2001 ◽  
Author(s):  
Alan Palazzolo ◽  
Gerald T. Montague ◽  
Yeonkyu Kim ◽  
Andrew Kenny ◽  
Randall Tucker ◽  
...  
Keyword(s):  
High Temperature ◽  
Test Performance ◽  
High Speed ◽  
High Efficiency ◽  
Magnetic Bearing ◽  
Test Results ◽  
Turbine Engine ◽  
Significant Extension ◽  
Actuator Control ◽  
Fail Safe

This paper contributes to the magnetic bearing literature in two distinct areas: high temperature and redundant actuation. Design considerations test results are given for the first published combined 538°C (1000°F)-high speed rotating test performance of a magnetic bearing. Secondly, a significant extension of the flux isolation based, redundant actuator control algorithm is proposed to eliminate the prior deficiency of changing position stiffness after failure.

Advanced Seal Test Rig Validation and Operation

2006 ◽  
Author(s):  
Gerrit A. Kool ◽  
Arjen B. Kloosterman ◽  
Edward R. Rademaker ◽  
Bambang I. Soemarwoto ◽  
Fons M. G. Bingen ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
High Speed ◽  
High Surface ◽  
Weight Ratio ◽  
Labyrinth Seal ◽  
Test Rig ◽  
Turbine Engine ◽  
System A ◽  
Collaborative Program

Advanced seals have been identified as critical in meeting engine goals for specific fuel consumption, thrust-to-weight ratio, emissions, durability, and operating costs. In a direct effort to reduce the parasitic leakage, a high-temperature, high-speed seal test rig with Active Clearance Control (ACC) has been designed, built and validated by the National Aerospace Laboratory (NLR) in the Netherlands within a collaborative program with Sulzer Metco Turbine Components (SMTC) and Pratt & Whitney (P&W). NLR’s new seal test rig is capable to evaluate seals for the next generation gas turbine engines. It will test air seals (i.e., labyrinth, brush, and new seal concepts) in near gas turbine engine environment conditions of high temperature to 815 °C (1500 °F), high pressure to 2400 kPa (335 psid), high surface speeds to 365 m/s (1200 ft/s). Seal flows for typical engine seal clearances between 0.12 mm (0.005 inch) and 0.65 mm (0.025 inch) can be measured without changing test articles but by using the ACC system. A compressed air facility at the German-Dutch Windtunnel, located at the NLR site, delivers the required compressed clean and dry air. This paper describes the design, the instrumentation, the control system and the validation of the test rig. The rig certification was achieved by validating test measurements using a known three knife-edges stepped labyrinth seal. This paper also addresses the NLR’s CFD and engineering tool development to predict the seal performance.

Performance Evaluation of High Temperature Coatings for Hot Section Turbine Components

2005 ◽  
Author(s):  
David A. Shifler ◽  
Dennis M. Russom ◽  
Bruce E. Rodman
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Hot Corrosion ◽  
Gas Turbine Engine ◽  
Turbine Engines ◽  
Type I ◽  
Gas Turbine Engines ◽  
Type Ii ◽  
Power Sources ◽  
Turbine Engine

501-K34 marine gas turbine engines serve as auxiliary power sources for the U.S. Navy’s DDG-51 Class ships. It is desired that 501-K34 marine gas turbine engines have a mean time between removal of 20K hours. While some engines have approached this goal, others have fallen significantly short. A primary reason for this shortfall is hot corrosion (Type I and Type II) damage in the hot section turbine area due to both intrusion of salts from the marine air and from sulfur in the gas turbine combustion fuels. Previous metallographic examination of several unfailed blades removed from a marine gas turbine engine after 18000 operating hours showed that the coating thickness under the platform and in the curved area of transition between the platform to the blade stem was either very thin, porous, and in a few cases, non-existent on each unfailed blade. Type II hot corrosion was evident at these locations under the platform. Corrosion fatigue cracks initiated at several hot corrosion sites and had advanced through the blade stems to varying degrees. Cracking in a few blades had advanced to the point that blade failure was imminent. The objectives of this paper are to: (1) report the hot corrosion results of alternative high temperature coating systems on Alloy M247 and Alloy 792 for hot section components of the 501-K34 gas turbine engine using a low velocity, atmospheric-pressure burner-rig (LVBR), (2) compare and rank hot corrosion performance of these coatings systems to the baseline coating/substrate system (2) down select the best performing coating systems (in terms of LVBR hot corrosion and thermal cycling resistance) to implement on future hot section components in the 501-K34 engine for the Fleet.

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