| 1. |
- Eriksson, Robert, et al.
(författare)
-
INTERSPLAT OXIDATION OF ATMOSPHERIC PLASMA SPRAYED MCRALY COATINGS
- 2014
-
Ingår i: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2014, VOL 6. - : AMER SOC MECHANICAL ENGINEERS. - 9780791845752
-
Konferensbidrag (refereegranskat)abstract
- MCrAlY coatings and thermal barrier coatings (TBC) are commonly used in gas turbines to prolong the life of structural parts. The atmospheric plasma spray (APS) process yields coatings with a typical splat-on-splat structure which oxidizes at intersplat boundaries during high-temperature exposure. A study was performed to establish the influence of intersplat oxidation on Al depletion. It was found that the P -depletion based life may be overestimated by a factor of 1.8-18 if intersplat oxidation is not considered. Two different mechanisms of intersplat oxidation were observed: At high temperature (1050 degrees C), a fraction of the intersplat boundaries remained in contact with the coating surface and oxidized with the same kinetics as the surface oxides. At lower temperature (900 degrees C), intersplat oxidation occurred by considerable slower growth rates than surface oxidation. The mechanisms behind intersplat oxide growth was further studied by O diffusion calculations.
|
|
| 2. |
- Monaco, Lucio, et al.
(författare)
-
A remotely operated aeroelastically unstable LPT cascade for turbomachinery aeromechanics education and training : Remote flutter lab
- 2014
-
Ingår i: Proceedings of the ASME Turbo Expo. - 9780791845752
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of advanced pedagogical methodologies in connection with advanced use of modern information technology (ICT) for delivery enables new ways of communicating, of exchanging knowledge, and of learning that are gaining increasing relevance in our society. Remote laboratory exercises offer the possibility to enhance learning for students in different technical areas, especially to the ones not having physical access to laboratory facilities and thus spreading knowledge in a world-wide perspective. A new "Remote Flutter Laboratory" has been developed to introduce aeromechanics engineering students and professionals to aeroelastic phenomena in turbomachinery. The laboratory is world-wide unique in the sense that it allows global access for learners anywhere and anytime to a facility dedicated to what is both a complex and relevant area for gas turbine design and operation. The core of the system consists of an aeroelastically unstable turbine blade row that exhibits self-excited and self-sustained flutter at specific operating conditions. Steady and unsteady blade loading and motion data are simultaneously acquired on five neighboring suspended blades and the whole system allows for a distant-based operation and monitoring of the rig as well as for automatic data-retrieval. This paper focuses on the development of the "Remote Flutter Laboratory" exercise as a hands-on learning platform for online and distant-based education and training in turbomachinery aeromechanics enabling familiarization with the concept of critical reduced frequency and of flutter phenomena. This laboratory set-up can easily be used "as is" directly by any turbomachinery teacher in the world, free of charge and independent upon time and location with the intended learning outcomes as specified in the lab, but it can also very easily be adapted to other intended learning outcomes that a teacher might want to highlight in a specific course. As such it is also a base for a turbomachinery repository of advanced remote laboratories of global uniqueness and access. The present work documents also the pioneer implementation of the LabSocket System for the remote operation of a wind tunnel test facility from any Internet-enabled computer, tablet or smartphone with no end-user software or plug-in installation.
|
|
| 3. |
- Ranasinghe, C., et al.
(författare)
-
A simplified method for determining gas turbine performance parameters based upon available catalogue data
- 2014
-
Ingår i: Proceedings of the ASME Turbo Expo. - 9780791845752
-
Konferensbidrag (refereegranskat)abstract
- Overall theoretical performance analysis of gas turbines can be conducted by applying design parameters into several thermodynamic theories and equations. However, limited availability of the design parameters will not provide sufficient room for a detailed analysis. Ga s turbine manufacturers publish only a limited amount of design/performance data, while important parameters remained hidden and the available information is not sufficiently enough for obtaining a complete gas turbine performance dataset. Five main parameters commonly provided by a gas turbine manufacturer's catalogues; pressure ratio of the compressor, exhaust mass flow rate, exhaust temperature of flue gas, overall efficiency, and electrical output. A theoretical model developed based on Mathcad software as documented in literature is used to reveal other hidden gas turbine parameters. A similar theoretical model using another solver was developed to obtain a complete dataset by using the available catalogue data with additional assumptions, which correspond to the commercial state of the art. The engineering equation solver (EES) software has been used as a platform to rebuild the theoretical model. As the main development, a graphical user interphase (GUI) has been introduced to the new program with the aim to make it more user friendly. Furthermore on top of obtaining the hidden thermodynamic parameters for the gas turbine, performing flue gas analysis and an exergy analysis has now become possible through this program. The developed EES program is expected to be run in the learning laboratory at the Division of Heat and Power Technology, Department of Energy Technology, Royal Institute of Technology (KTH), Stockholm and finally it is going to be incorporated into CompEdu Learning Platform of the same division.
|
|
| 4. |
- Yuan, Kang, et al.
(författare)
-
Influence of Ru, Mo and IR on the behavior of Ni-based MCrAlY coatings in high temperature oxidation
- 2014
-
Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791845752
-
Konferensbidrag (refereegranskat)abstract
- To improve the oxidation/corrosion resistance of MCrAlY coatings (M for Ni and/or Co), elements like Y, Si and Ta have been added into the coatings in past decades. In this study the oxidation performance of a Ni-based MCrAlY coating with small proportion of Ru, Mo and/or Ir were investigated after high-temperature exposure. The oxidation tests were carried out at 900C 1000C or 1100C The microstructure study showed that the addition of Ru, Mo and/or Ir had significant influence on the oxidation behavior at the coating surface and the microstructural evolution in the material. The microstructural evolution was quantitatively evaluated by measuring the phase degradation of β-NiAl in the coating and γ′-Ni3Al in the substrate of superalloy. Since no oxides of Ru, Mo and Ir were found on the coating surface, it was believed that the effects by those elements were mainly due to their dissolution in the metallic phases in the coatings.
|
|
