Evaluation of Mechanical Reliability of Silicon Nitride Vanes After Field Tests in an Industrial Gas Turbine

2002 ◽  
Author(s):  
H.-T. Lin ◽  
M. K. Ferber ◽  
W. Westphal ◽  
F. Macri
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Field Tests ◽  
Coordinate Measuring Machine ◽  
Biaxial Test ◽  
Silica Layer ◽  
Secondary Phases ◽  
Surface Strength ◽  
Measuring Machine ◽  
Industrial Gas Turbine

This paper provides a review of recent studies undertaken to examine the mechanical and thermal stability of silicon nitride ceramic vanes with and without an oxide-based environmental barrier coating (EBC) after field tests in an industrial gas turbine. Two commercially available silicon nitride vanes (i.e., AS800 and SN282) were evaluated, where the AS800 vanes had an EBC and the SN282 vanes did not. The average temperature and pressure of gas impinging upon the vanes were approximately 1066°C and 8.9 atm, respectively. Both silicon nitride vanes were subjected to exposure time up to 1818h. Scanning electron microscopy was used to provide an insight into the changes in the microstructures of silicon nitrides and EBC arising from the environmental effects. The recession of the airfoils resulting from the volatilization of the normally protective silica layer, and /or EBC, was also measured using a coordinate measuring machine. The long-term chemical as well as structural stability of the secondary phases as well as EBC were characterized using x-ray diffraction. The surface strength of exposed airfoils was evaluated using a miniature biaxial test specimen, which was prepared by a diamond core drilling.

Degradation of Silicon Nitrides in High Pressure, Moisture Rich Environments

2000 ◽  
Author(s):  
M. K. Ferber ◽  
H. T. Lin ◽  
V. Parthasarathy ◽  
R. A. Wenglarz
Keyword(s):  
Biaxial Test ◽  
Silica Layer ◽  
X Ray Diffraction ◽  
Surface Strength ◽  
Silicon Nitride Ceramic ◽  
Average Temperature ◽  
Total Exposure Time ◽  
The Stability ◽  
Industrial Gas Turbine ◽  
Thermal Stability Of

This paper provides a review of a recent study undertaken to examine the mechanical and thermal stability of silicon nitride ceramic nozzles exposed in an industrial gas turbine. The average temperature and pressure of gas entering the vanes were approximately 1066°C and 8.9 atm, respectively. The total exposure time was 815 h including a 22 h shakedown test. Scanning electron microscopy was used to elucidate the changes in the microstructures arising from the oxidation process. The recession of the airfoils arising from the volatilization of the normally protective silica layer was also measured. The stability of the intergranular phases was evaluated using x-ray diffraction. The surface strength was measured using a miniature biaxial test specimen which was prepared by diamond core drilling.

Characterization of Ceramic Components Exposed in Industrial Gas Turbines

2001 ◽  
Author(s):  
M. K. Ferber ◽  
H.-T. Lin
Keyword(s):  
Gas Turbines ◽  
Field Tests ◽  
Biaxial Test ◽  
Silica Layer ◽  
X Ray Diffraction ◽  
Surface Strength ◽  
Ceramic Components ◽  
Industrial Gas Turbines ◽  
The Stability

Abstract This paper provides a review of recent studies undertaken to examine the mechanical and thermal stability of silicon nitride ceramic components that are currently being considered for use in gas turbine applications. Specific components examined included a bowed ceramic nozzle evaluated in an engine test stand, ceramic vanes exposed in two field tests, and an air-cooled vane that is currently under development. Scanning electron microscopy was used to elucidate the changes in the microstructures arising from the environmental effects. The recession of the airfoils resulting from the volatilization of the normally protective silica layer was also measured. The stability of the intergranular phases was evaluated using x-ray diffraction. The surface strength was measured using a miniature biaxial test specimen, which was prepared by diamond core drilling.

A Comparison between 3D Scanning and CMM Dimensional Inspection of Small Size Gas Turbine

2015 ◽  
Vol 1128 ◽  
pp. 347-352
Author(s):  
Gheorghe Matache ◽  
Valeriu Dragan ◽  
Cristian Puscasu ◽  
Valeriu Vilag ◽  
Alexandru Paraschiv
Keyword(s):  
Gas Turbine ◽  
White Light ◽  
Coordinate Measuring Machine ◽  
3D Scanning ◽  
Cad Model ◽  
Dimensional Inspection ◽  
Scanning Method ◽  
Thin Walls ◽  
Sharp Edges ◽  
Measuring Machine

The paper presents a comparison between Coordinate Measuring Machine and 3D white light scanning technologies as applied to the dimensional inspection of turbo-machinery parts such as turbine blade. The results were compared with the CAD model and each other. The results indicate that, even both methods are enough accurate with a slightly better accuracy for CMM, the operational speed and the variety of scanable surfaces give significant advantages to the 3D scanning method when prototypes require dimensional inspection by an alternative rapid route especially when dealing with objects with thin walls or sharp edges.

Characterization of First-Stage Silicon Nitride Components After Exposure to an Industrial Gas Turbine

2006 ◽  
Vol 89 (1) ◽  
pp. 258-265 ◽  
Author(s):  
H.-T. Lin ◽  
M. K. Ferber ◽  
P. F. Becher ◽  
J. R. Price ◽  
M. van Roode ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Industrial Gas Turbine

Study and Field Tests of the Novel Low Pressure Fogger System for Industrial Gas Turbine

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Y. Levy ◽  
V. Sherbaum ◽  
V. Ovcharenko ◽  
Y. Sotsenko ◽  
I. Zlochin
Keyword(s):  
Gas Turbine ◽  
Closed Loop ◽  
Field Tests ◽  
Low Pressure ◽  
The Novel ◽  
Test Results ◽  
Sauter Mean Diameter ◽  
Jet Engine ◽  
Compressor Inlet ◽  
Industrial Gas Turbine

Based on three patented innovations (air-assist atomizer, wetness sensor, and closed loop programmable logic controller (PLC)), a new low-pressure power gas turbine augmentation system was developed. Two modifications of air-assist atomizer were tested in the Jet Engine Laboratory of the Technion. The tests were performed to investigate influence of thermodynamic parameters on spray characteristics, as droplet size and velocity distribution of the spray. The system as a whole has passed field test in a gas turbine of a power station. Droplet characteristics, conceptual design aspects, and test results are described. It was found that the droplet sauter mean diameter was 20μm. The field tests demonstrated that the power augmentation system operates safely and reliably. Wetness sensors and closed loop PLC proved to be a safe method for power augmentation, which prevents droplet penetration into the compressor inlet.

scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

Development of L1-norm sliding mode observer for sensor fault diagnosis of an industrial gas turbine

2021 ◽  
pp. 095965182199617
Author(s):  
Mahyar Akbari ◽  
Abdol Majid Khoshnood ◽  
Saied Irani
Keyword(s):  
Fault Detection ◽  
State Space ◽  
Gas Turbine ◽  
Sliding Mode ◽  
State Space Model ◽  
Sensor Fault ◽  
Space Model ◽  
Decision Logic ◽  
Sensor Fault Detection ◽  
Industrial Gas Turbine

In this article, a novel approach for model-based sensor fault detection and estimation of gas turbine is presented. The proposed method includes driving a state-space model of gas turbine, designing a novel L1-norm Lyapunov-based observer, and a decision logic which is based on bank of observers. The novel observer is designed using multiple Lyapunov functions based on L1-norm, reducing the estimation noise while increasing the accuracy. The L1-norm observer is similar to sliding mode observer in switching time. The proposed observer also acts as a low-pass filter, subsequently reducing estimation chattering. Since a bank of observers is required in model-based sensor fault detection, a bank of L1-norm observers is designed in this article. Corresponding to the use of the bank of observers, a two-step fault detection decision logic is developed. Furthermore, the proposed state-space model is a hybrid data-driven model which is divided into two models for steady-state and transient conditions, according to the nature of the gas turbine. The model is developed by applying a subspace algorithm to the real field data of SGT-600 (an industrial gas turbine). The proposed model was validated by applying to two other similar gas turbines with different ambient and operational conditions. The results of the proposed approach implementation demonstrate precise gas turbine sensor fault detection and estimation.

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