A New Approach for Erosion Prediction Due To Fly Ash

1981 ◽  
Vol 103 (2) ◽  
pp. 265-270 ◽  
Author(s):  
R. Kotwal ◽  
W. Tabakoff
Keyword(s):  
Fly Ash ◽  
Gas Turbines ◽  
Precise Determination ◽  
Erosion Prediction ◽  
Industrial Gas Turbines ◽  
Series Of Experiments ◽  
A New Technique ◽  
Nickel Base ◽  
Semi Empirical

With increasing interest in the burning of coal in industrial gas turbines, there is also concern for the precise determination of the erosive effects on the turbine components. Series of experiments were conducted to determine the effects of fly ash constituents, particle size, particle velocity, angle of attack and target temperature on the erosion of iron and nickel base alloys. Based on the experimental results, a semi-empirical equation has been obtained for the prediction of the erosion losses. This equation provides a new technique for predicting the metal erosion due to the fly ash produced by the conventional burning of coal.

A New Approach for Erosion Prediction due to Fly Ash

1980 ◽  
Author(s):  
R. Kotwal ◽  
W. Tabakoff
Keyword(s):  
Fly Ash ◽  
Gas Turbines ◽  
Precise Determination ◽  
Erosion Prediction ◽  
Industrial Gas Turbines ◽  
Series Of Experiments ◽  
A New Technique ◽  
Nickel Base ◽  
Semi Empirical

With increasing interest in the burning of coal in industrial gas turbines, there is also concern for the precise determination of the erosive effects on the turbine components. Series of experiments were conducted to determine the effects of fly ash constituents, particle size, particle velocity, angle of attack and target temperature on the erosion of iron and nickel base alloys. Based on the experimental results, a semi-empirical equation has been obtained for the prediction of the erosion losses. This equation provides a new technique for predicting the metal erosion due to the fly ash produced by the conventional burning of coal.

Steady State Detection in Industrial Gas Turbines for Condition Monitoring and Diagnostics Applications

2014 ◽  
Author(s):  
Cesar Celis ◽  
Érica Xavier ◽  
Tairo Teixeira ◽  
Gustavo R. S. Pinto
Keyword(s):  
Steady State ◽  
Condition Monitoring ◽  
Gas Turbines ◽  
Signal Analysis ◽  
Operating Regime ◽  
State Detection ◽  
Industrial Gas Turbines ◽  
Monitoring And Diagnostics ◽  
Operating Regimes

This work describes the development and implementation of a signal analysis module which allows the reliable detection of operating regimes in industrial gas turbines. Its use is intended for steady state-based condition monitoring and diagnostics systems. This type of systems requires the determination of the operating regime of the equipment, in this particular case, of the industrial gas turbine. After a brief introduction the context in which the signal analysis module is developed is highlighted. Next the state of the art of the different methodologies used for steady state detection in equipment is summarized. A detailed description of the signal analysis module developed, including its different sub systems and the main hypotheses considered during its development, is shown to follow. Finally the main results obtained through the use of the module developed are presented and discussed. The results obtained emphasize the adequacy of this type of procedures for the determination of operating regimes in industrial gas turbines.

Investigation of Failures in Gas Turbines: Part 1 — Techniques and Principles of Failure Investigation

1993 ◽  
Author(s):  
Robert E. Dundas
Keyword(s):  
Gas Turbines ◽  
Heavy Duty ◽  
Case Histories ◽  
Logical Approach ◽  
Failure Investigation ◽  
Industrial Gas Turbines ◽  
The One ◽  
Aircraft Accident

This paper is Part 1 of a two-part paper on the principles and methods of failure investigation in gas turbines. The qualities of a successful failure investigator are presented, and the most efficacious approaches to an investigation are discussed. An example of an aircraft accident that might have been avoided is used to support the necessity for thorough and conclusive investigations into failures. Two case histories involving heavy-duty industrial gas turbines are described to demonstrate different aspects of the logical approach to construction of hypotheses and the determination of the essential cause of a failure — the one event without which the failure would not have occurred.

Environmental Degradation of Heat-Resistant Alloys During Exposure to Simulated and Actual Gas Turbine Recuperator Environments

2008 ◽  
Author(s):  
James M. Rakowski ◽  
Charles P. Stinner ◽  
Mark Lipschutz ◽  
J. Preston Montague
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Austenitic Stainless Steels ◽  
Thin Foil ◽  
Test Program ◽  
Near Surface ◽  
Heat Resistant ◽  
Industrial Gas Turbines ◽  
Gas Turbine Exhaust ◽  
Nickel Base

Primary surface recuperators (PSR’s) for land-based industrial gas turbines are typically constructed from heat-resistant alloys such as nickel-base superalloys or highly-alloyed austenitic stainless steels. The water vapor present in gas turbine exhaust has been shown to increase the rate of chromium oxide volatility, which in turn can cause rapid oxidation of the underlying metal. As PSR’s are generally fabricated from thin foil materials, excessive degradation can cause perforation, leading to failure of components. The results of a field test program will be summarized, based on analysis of recuperator stand-in components which were exposed to a full-flow exhaust stream during gas turbine operation for times ranging from 500 hours to 21,500 hours. A significant effect of service on the materials of construction was observed, with near-surface chromium depletion and microstructural instability evident after the longest exposures. These results will be combined with those from an extensive laboratory test program to evaluate the performance of heat-resistant alloys during recuperator service, outlining the different modes of degradation and means for their mitigation.

CM 939 Weldable® Alloy

2004 ◽  
Author(s):  
Ken Harris ◽  
Jacqueline B. Wahl
Keyword(s):  
Mechanical Properties ◽  
Gas Turbines ◽  
Hot Tearing ◽  
Raw Material ◽  
Nickel Base Superalloy ◽  
Material Technology ◽  
Ultra High Purity ◽  
Industrial Gas Turbines ◽  
Nickel Base ◽  
Step Heat Treatment

IN 939 alloy, developed by the International Nickel Co. in the late 1960s, is a unique 22% Cr hot corrosion resistant γ′ strengthened, cast nickel-base superalloy. It is widely used in industrial gas turbines for equiaxed vanes, vane segments and burner nozzles and is of interest to the aero turbine industry for LP and PT integral nozzles (vane rings) and high temperature turbine casings. However, IN 939 is considered difficult to weld repair without parent metal microcracking and can exhibit marginal ductility in heavy section castings. Cannon-Muskegon has developed a proprietary chemistry modified version of IN 939 alloy designated CM 939 Weldable®. Emphasis has been directed on optimizing aim chemistry and ultra high purity manufacture using CM-developed single crystal superalloy melting and raw material technology and subsequently on obtaining superior casting microstructure for improved weldability and mechanical properties. Alloy purity and heat cleanliness will be discussed, along with a simplified two-step heat treatment cycle, resulting in attractive microstructure, mechanical properties and repair weldability. Significant market interest has resulted in extensive vacuum casting experience throughout the gas turbine industry. Excellent results in terms of fluidity, casting cleanliness and minimal microporosity have been obtained without any hot tearing or hot cracking problems.

scholarly journals Determination of the anisotropic elasticity tensor by mechanical spectroscopy

2021 ◽  
Author(s):  
Thomas Obermayer ◽  
Christian Krempaszky ◽  
Ewald Werner
Keyword(s):  
Base Alloy ◽  
Rectangular Cross Section ◽  
Optimization Method ◽  
Anisotropic Elasticity ◽  
Elasticity Tensor ◽  
Precise Determination ◽  
The Finite Element Method ◽  
Mechanical Spectroscopy ◽  
Nickel Base

AbstractA method is proposed to identify the fully anisotropic elasticity tensor by applying the impulse excitation technique. A specially designed batch of several differently oriented bar-shaped specimens with rectangular cross section is analyzed with respect to the eigenfrequencies of their fundamental flexural and torsional modes. Estimations based on the equations for the calculation of the isotropic Young’s modulus and the shear modulus from the ASTM standard allow a first approximation of the elasticity tensor from a selected subset of the measured eigenfrequencies. Subsequently, a more precise determination of the elasticity tensor is achieved by a numerical modal analysis using the finite element method. In this course, a Newton–Raphson optimization method is applied to solve the inverse problem. The proposed approach is demonstrated on a batch of specimen fabricated from the nickel-base alloy IN718 by selective laser melting.

Environmental Degradation of Heat-Resistant Alloys During Exposure to Simulated and Actual Gas Turbine Recuperator Environments

2007 ◽  
Author(s):  
James M. Rakowski ◽  
Charles P. Stinner ◽  
Mark Lipschutz ◽  
J. Preston Montague
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Austenitic Stainless Steels ◽  
Thin Foil ◽  
Heat Resistant ◽  
Industrial Gas Turbines ◽  
Exhaust Stream ◽  
Gas Turbine Exhaust ◽  
Nickel Base ◽  
One Year

Primary surface recuperators (PSR’s) for land-based industrial gas turbines are typically constructed from heat-resistant alloys such as austenitic stainless steels or nickel-base superalloys. The water vapor present in gas turbine exhaust has been shown to increase the rate of chromium oxide volatility, which in turn can cause rapid oxidation of the underlying metal. As PSR’s are generally fabricated from thin foil materials, excessive degradation can cause perforation, leading to failure of components. The results of an extensive laboratory test program to characterize the performance of heat-resistant alloys will be summarized, outlining the different modes of attack and means for their mitigation. These results will be compared to an investigation carried out using sub-size recuperator components which were exposed to a full-flow exhaust stream during gas turbine operation for times ranging from a few weeks to over one year.

The Effect of Stress and Warfarin on the Adrenal Gland in Relation to Spontaneous Hemorrhage, as Judged by Measurement of Adrenal Ascorbic Acid and Serum Corticosterone

1971 ◽  
Vol 26 (02) ◽  
pp. 275-288 ◽  
Author(s):  
S Chattopadhyay ◽  
D. D Johnson ◽  
G. J Millar ◽  
L. B Jaques
Keyword(s):  
Ascorbic Acid ◽  
Acid Concentration ◽  
Ascorbic Acid Concentration ◽  
Corticosterone Concentration ◽  
Serum Corticosterone ◽  
Spontaneous Hemorrhage ◽  
Combined Action ◽  
Series Of Experiments ◽  
Pituitary Adrenal Axis

SummaryRats were subjected to the following procedures: No treatment, Stressor (10% NaCl i.p.), Warfarin for 7 days, Stressor followed by Warfarin; and groups were sacrificed at intervals for assessment of spontaneous hemorrhage and of adrenal ascorbic acid concentration. There was no hemorrhage in the no treatment and stressor groups; some hemorrhage in the warfarin group; profound hemorrhage with Warfarin + Stressor. The adrenal ascorbic acid concentration was found to be lower, 8 h and again 5 days after stress, and remained lower in the warfarin + stress animals. Warfarin had no effect on adrenal ascorbic acid level.In another series of experiments in which the stress consisted of an electric current to the cage floor for 6 sec over 15 min, rats were sacrificed daily for determination of serum corticosterone concentration and occurrence of spontaneous hemorrhage. There was a statistically significant increase of serum corticosterone concentration with stress, warfarin and combined warfarin and stress treatments (P< 0.001 for all three variables). There was a significant correlation (r = 0.96 and 0.89, P< 0.01) for serum corticosterone concentration with hemorrhage score and incidence of hemorrhage in stressed rats receiving warfarin, but not in those receiving only warfarin. The results indicate an activation, rather than an exhaustion, of the pituitary-adrenal axis during the combined action of anticoagulant and stress, which results in the development of spontaneous hemorrhage.

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