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Şerban, Viorel Aurel - One of the best experts on this subject based on the ideXlab platform.
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Correlation between mass loss on the cavitation erosion and the fatigue stress level for a martensitic stainless steel
2019Co-Authors: Vodă Mircea, Pertuz Comas Alberto, Şerban, Viorel AurelAbstract:The effect of fatigue on the cavitation erosion was examined for a martensitic stainless steel used in manufacturing the blades for the Bulb Turbines of the “Iron Gates II” Power Plant Turbines. For the cavitation tests two kinds of specimens were manufactured: from the original material (which was not subjected to fatigue) and samples of material that were subjected to fatigue cycles with different amplitudes (from 170 to 255 MPa). It was observed that fatigue increases the tendency of cavitation erosion, therefore it appear a cumulative damage. The analysis of the cavitation erosion was done taking into account simultaneously the mass losses time dependence, the surface roughness and the modifications in the microstructure of the specimens. For the material subjected previously to fatigue cycles the final mass loss (after 150 minutes of cavitation exposure) increases with approximately 30% and the depth of penetration with 25%. In the microstructural analyses there were observed numerous cracks at grain boundaries. Finally, a mathematical model for the dependence of mass losses with the applied stress was developed.Se examinó el efecto de la fatiga en la erosión por cavitación para un acero inoxidable martensítico utilizado en la fabricación de palas para las turbinas Bulb de las turbinas de la Planta de Energía "Iron Gates II". Para las pruebas de cavitación se fabricaron dos tipos de especímenes: desde el material original (que no estaba sometido a fatiga) y muestras de material que se sometieron a ciclos de fatiga con diferentes amplitudes (de 170 a 255 MPa). Se observó que la fatiga aumenta la tendencia de la erosión por cavitación, por lo tanto, parece un daño acumulativo. El análisis de la erosión por cavitación se realizó teniendo en cuenta simultáneamente la pérdida de masa de la dependencia del tiempo, la rugosidad de la superficie y las modificaciones en la microestructura de las muestras. Para el material sometido previamente a ciclos de fatiga, la pérdida de masa final (después de 150 minutos de exposición a la cavitación) aumenta aproximadamente un 30% y la profundidad de penetración con un 25%. En los análisis microestructurales se observaron numerosas grietas en los límites de los granos. Finalmente, se desarrolló un modelo matemático para la dependencia de las pérdidas de masa con el estrés aplicado
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Correlation between mass loss on the cavitation erosion and the fatigue stress level for a martensitic stainless steel
'Universidad Industrial de Santander', 2019Co-Authors: Vodă Mircea, Pertuz Comas Alberto, Şerban, Viorel AurelAbstract:The effect of fatigue on the cavitation erosion was examined for a martensitic stainless steel used in the manufacture of the blades for the Bulb Turbines of the “Iron Gates II” Power Plant Turbines. For the cavitation tests, two kinds of specimens were manufactured: from the original material (which was not subjected to fatigue) and samples of materials that were subjected to fatigue cycles with different amplitudes (from 170 to 255 MPa). It was observed that fatigue increases the tendency of cavitation erosion and thus, seems like a cumulative damage. The analysis of the cavitation erosion was done considering simultaneously the mass loss of the time dependence, the surface roughness and the modifications to the microstructure of the specimens. For the material previously subjected to fatigue cycles, the final mass loss (after 150 minutes of cavitation exposure) increases approximately by 30% and the depth of penetration by 25%. In the microstructural analyses, numerous cracks at grain boundaries were observed. Finally, a mathematical model for the dependence of mass losses with the applied stress was developed.Se examinó el efecto de la fatiga en la erosión por cavitación para un acero inoxidable martensítico utilizado en la fabricación de palas para las turbinas Bulbo de las turbinas de la Planta de Energía "Iron Gates II." Para las pruebas de cavitación se fabricaron dos tipos de especímenes: tanto el material original (que no estaba sometido a fatiga) como muestras de material que se sometieron a ciclos de fatiga con diferentes amplitudes (de 170 a 255 MPa). Se observó que la fatiga aumenta la tendencia de la erosión por cavitación y por lo tanto, parece un daño acumulativo. El análisis de la erosión por cavitación se realizó teniendo en cuenta simultáneamente la pérdida de masa de la dependencia del tiempo, la rugosidad de la superficie y las modificaciones en la microestructura de las muestras. Para el material sometido previamente a ciclos de fatiga, la pérdida de masa final (después de 150 minutos de exposición a la cavitación) aumenta aproximadamente un 30 % y la profundidad de penetración con un 25 %. En los análisis microestructurales se observaron numerosas grietas en los límites de los granos. Finalmente, se desarrolló un modelo matemático para la dependencia de las pérdidas de masa con el estrés aplicado
Vodă Mircea - One of the best experts on this subject based on the ideXlab platform.
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Correlation between mass loss on the cavitation erosion and the fatigue stress level for a martensitic stainless steel
2019Co-Authors: Vodă Mircea, Pertuz Comas Alberto, Şerban, Viorel AurelAbstract:The effect of fatigue on the cavitation erosion was examined for a martensitic stainless steel used in manufacturing the blades for the Bulb Turbines of the “Iron Gates II” Power Plant Turbines. For the cavitation tests two kinds of specimens were manufactured: from the original material (which was not subjected to fatigue) and samples of material that were subjected to fatigue cycles with different amplitudes (from 170 to 255 MPa). It was observed that fatigue increases the tendency of cavitation erosion, therefore it appear a cumulative damage. The analysis of the cavitation erosion was done taking into account simultaneously the mass losses time dependence, the surface roughness and the modifications in the microstructure of the specimens. For the material subjected previously to fatigue cycles the final mass loss (after 150 minutes of cavitation exposure) increases with approximately 30% and the depth of penetration with 25%. In the microstructural analyses there were observed numerous cracks at grain boundaries. Finally, a mathematical model for the dependence of mass losses with the applied stress was developed.Se examinó el efecto de la fatiga en la erosión por cavitación para un acero inoxidable martensítico utilizado en la fabricación de palas para las turbinas Bulb de las turbinas de la Planta de Energía "Iron Gates II". Para las pruebas de cavitación se fabricaron dos tipos de especímenes: desde el material original (que no estaba sometido a fatiga) y muestras de material que se sometieron a ciclos de fatiga con diferentes amplitudes (de 170 a 255 MPa). Se observó que la fatiga aumenta la tendencia de la erosión por cavitación, por lo tanto, parece un daño acumulativo. El análisis de la erosión por cavitación se realizó teniendo en cuenta simultáneamente la pérdida de masa de la dependencia del tiempo, la rugosidad de la superficie y las modificaciones en la microestructura de las muestras. Para el material sometido previamente a ciclos de fatiga, la pérdida de masa final (después de 150 minutos de exposición a la cavitación) aumenta aproximadamente un 30% y la profundidad de penetración con un 25%. En los análisis microestructurales se observaron numerosas grietas en los límites de los granos. Finalmente, se desarrolló un modelo matemático para la dependencia de las pérdidas de masa con el estrés aplicado
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Correlation between mass loss on the cavitation erosion and the fatigue stress level for a martensitic stainless steel
'Universidad Industrial de Santander', 2019Co-Authors: Vodă Mircea, Pertuz Comas Alberto, Şerban, Viorel AurelAbstract:The effect of fatigue on the cavitation erosion was examined for a martensitic stainless steel used in the manufacture of the blades for the Bulb Turbines of the “Iron Gates II” Power Plant Turbines. For the cavitation tests, two kinds of specimens were manufactured: from the original material (which was not subjected to fatigue) and samples of materials that were subjected to fatigue cycles with different amplitudes (from 170 to 255 MPa). It was observed that fatigue increases the tendency of cavitation erosion and thus, seems like a cumulative damage. The analysis of the cavitation erosion was done considering simultaneously the mass loss of the time dependence, the surface roughness and the modifications to the microstructure of the specimens. For the material previously subjected to fatigue cycles, the final mass loss (after 150 minutes of cavitation exposure) increases approximately by 30% and the depth of penetration by 25%. In the microstructural analyses, numerous cracks at grain boundaries were observed. Finally, a mathematical model for the dependence of mass losses with the applied stress was developed.Se examinó el efecto de la fatiga en la erosión por cavitación para un acero inoxidable martensítico utilizado en la fabricación de palas para las turbinas Bulbo de las turbinas de la Planta de Energía "Iron Gates II." Para las pruebas de cavitación se fabricaron dos tipos de especímenes: tanto el material original (que no estaba sometido a fatiga) como muestras de material que se sometieron a ciclos de fatiga con diferentes amplitudes (de 170 a 255 MPa). Se observó que la fatiga aumenta la tendencia de la erosión por cavitación y por lo tanto, parece un daño acumulativo. El análisis de la erosión por cavitación se realizó teniendo en cuenta simultáneamente la pérdida de masa de la dependencia del tiempo, la rugosidad de la superficie y las modificaciones en la microestructura de las muestras. Para el material sometido previamente a ciclos de fatiga, la pérdida de masa final (después de 150 minutos de exposición a la cavitación) aumenta aproximadamente un 30 % y la profundidad de penetración con un 25 %. En los análisis microestructurales se observaron numerosas grietas en los límites de los granos. Finalmente, se desarrolló un modelo matemático para la dependencia de las pérdidas de masa con el estrés aplicado
Ivan Božić - One of the best experts on this subject based on the ideXlab platform.
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DESIGN OF SMALL Bulb Turbines WITH UNEQUAL SPECIFIC WORK DISTRIBUTION OF THE RUNNER'S ELEMENTARY STAGES
2015Co-Authors: Jasmina Bogdanović-jovanović, Božidar Bogdanović, Ivan BožićAbstract:Abstract. Regarding the present state of knowledge in the field of the turbomachinery design, the method for designing small Bulb Turbines with unequal specific work distribution of the turbine runner's elementary stages near the hub is presented in the paper. The distribution function of specific work of all the elementary stages is obtained, according to which the averaged axisymmetric flow surfaces of the turbine runner have a negligibly small deviation from the cylindrical flow surfaces. The specific work of the near-the-hub elementary stages, in the given distribution function, can be reduced up to 60 % of the required (design) specific work, still achieving nearly cylindrical flow surfaces
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DESIGN OF SMALL Bulb Turbines WITH UNEQUAL SPECIFIC WORK DISTRIBUTION OF THE RUNNER’S ELEMENTARY STAGES
2014Co-Authors: Jasmina Bogdanović-jovanović, Božidar Bogdanović, Ivan BožićAbstract:Regarding the present state of knowledge in the field of the turbomachinery design, the method for designing small Bulb Turbines with unequal specific work distribution of the turbine runner’s elementary stages near the hub is presented in the paper. The distribution function of specific work of all the elementary stages is obtained, according to which the averaged axisymmetric flow surfaces of the turbine runner have a negligibly small deviation from the cylindrical flow surfaces. The specific work of the near-the-hub elementary stages, in the given distribution function, can be reduced up to 60% of the required (design) specific work, still achieving nearly cylindrical flow surfaces.
Luo Yuan-hong - One of the best experts on this subject based on the ideXlab platform.
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Structure Design of 57 MW Bulb Turbine for Qiaogong Power Station
Dongfang Electric Review, 2010Co-Authors: Luo Yuan-hongAbstract:The Bulb type hydraulic generating units of Qiaogong hydroelectric power station, with the maximum output of each single unit upto presently in China, have been designed and manufactured by DFEM successfully. This paper introduces the main parameters and structure characteristics of the Bulb Turbines for the said units.
Arash Emdadi - One of the best experts on this subject based on the ideXlab platform.
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Electricity Generation by the Tidal Barrages
Energy Procedia, 2011Co-Authors: Ahmad Etemadi, Yunus Emami, Orang Asefafshar, Arash EmdadiAbstract:Abstract Concern over global climate change has led policy makers to accept the importance of reducing Greenhouse gas emissions. A tidal barrage utilizes the potential energy of the tide and has proven to be very successful, despite opposition from environmental groups. Tidal barrages make use of the potential energy of the tides. A tidal barrage is typically a dam, built across a bay or estuary that experiences a tidal range in excess of 5 m. Electricity generation from tidal barrages employs the same principles as hydroelectric generation, except that tidal currents flow in both directions. A typical tidal barrage consists of Turbines, sluice gates, embankments and ship locks. The Turbines that are used in tidal barrages are either unidirectional or bi-directional, and include Bulb Turbines, straflo or rim Turbines and tubular Turbines. Tidal barrages can be broken into two types: single-basin systems and double-basin systems. This paper discussed about the tidal barrage, wave energy, environmental impacts and special conditions in there process
