| 1. |
- Engdar, Ulf, et al.
(författare)
-
Investigation of the two-phase flow field of the GTX100 compressor inlet during off-line washing
- 2004
-
Ingår i: ASME Turbo Expo 2004: Power for Land, Sea, and Air. - 0791841693 ; 4, s. 509-518
-
Konferensbidrag (refereegranskat)abstract
- A modern gas turbine compressor, with its highly aerodynamically loaded blades, is sensitive to changes in profile shape and to surface roughness. Fouling is inevitable, despite highly efficient filtration systems. The remedy to this problem is washing. There are two different approaches, online or off-line washing. The off-line wash is the most effective one, whilst on-line washing only prolongs the interval between off-line washes. Most findings in this field are highly empirical, being based on some 50 years of industrial gas turbine operation. This paper is an investigation of the two-phase flow in the bellmouth of the compressor during off-line washing conditions. The unit under study was the GTX100 turbo-set. Computational fluid dynamics (CFD) is used in this paper to perform a detailed study of the flow field. The main emphasis has been on studying the characteristics of the injected spray used for cleaning of the compressor. The benefit of heating this fluid is of special interest, since if this heating can be avoided, the outage time for the off-line compressor wash can be shortened. To provide the CFD computations with accurate boundary conditions for the spray, laser-based measurements of a spray, originating from an authentic wash nozzle, have been conducted. The commercial CFD program Star-Cd has been used for all computations. The computations show that the water injected, regardless of its inlet temperature, is cooled down to ambient air temperature well before the spray reaches the inlet guide vanes. This indicates that heating of the wash fluid can be abolished. The airflow seems not to be to influenced by the injected fluid to any great extend.
|
|
| 2. |
- Li, Xin-Hai, et al.
(författare)
-
The use of acoustic emission technology in coating ductility testing at various temperatures
- 2004
-
Ingår i: Proceedings of the ASME Turbo Expo 2004 [Volume 4: Turbo Expo 2004]. - : ASME. - 0791841693 ; , s. 753-761
-
Konferensbidrag (refereegranskat)abstract
- In this study, tests of ductility and ductile to brittle transition temperature DBTT of both PtAl RT22 and MCrAlY Amdry 997 coatings on both single crystal and polycrystalline substrates (CMSX-4, SCB, and In792) have been carried out. An acoustic emission detection technique that makes the detection of coating failures (micro cracking and delamination) possible has been employed during the tensile tests. The acoustic emission AE detection has been calibrated on the uncoated substrates and on some coated specimens at various testing temperatures and at different strain rate, together with metallurgical examination. A correlation between AE signals and failure types is established. It has been found that the substrate materials generate also some AE signals during plastic deformation. The amplitude of the AE signals depends strongly on the type of substrate material and the testing temperature but slightly on the strain rate. The substrate emissions may disturb the detection of coating failure. However, except for the disturbance from the substrate materials, the AE is still a sensitive, reliable, and useful technique to detect coating failures at various temperatures. The ductility results determined in this study have shown that the overlay coating Amdry 997 has a lower DBTT ∼550°C and higher ductilities than the diffusion coating RT22. Both of these differences indicate that Amdry 997 is much more ductile than RT22.
|
|
