Frequencies in the Vibration Induced by the Rotor Stator Interaction in a Centrifugal Pump Turbine

2007 ◽  
Vol 129 (11) ◽  
pp. 1428-1435 ◽  
Author(s):  
C. G. Rodriguez ◽  
E. Egusquiza ◽  
I. F. Santos
Keyword(s):  
Theoretical Analysis ◽  
Accurate Method ◽  
Corrective Action ◽  
Practical Case ◽  
Highly Qualified ◽  
Pump Turbine ◽  
Nonuniform Fluid ◽  
Rotor Stator Interaction ◽  
New Interpretation ◽  
Original Interpretation

The highest vibration levels in large pump turbines are, in general, originated in the rotor stator interaction (RSI). This vibration has specific characteristics that can be clearly observed in the frequency domain: harmonics of the moving blade passing frequency and a particular relationship among their amplitudes. It is valuable for the design and condition monitoring to count on these characteristics. A CFD model is an appropriate tool to determine the force and its characteristics. However, it is time consuming and needs highly qualified human resources while usually these results are needed immediately and in situ. Then, it is useful to determine these characteristics in a simple, quick, and accurate method. At present, the most suitable method indicates a large amount of possible harmonics to appear, without indicating the relative importance of them. This paper carries out a theoretical analysis to predict and explain in a qualitative way these frequencies and amplitudes. The theoretical analysis incorporates the number of blades, the number of guide vanes, the RSI nonuniform fluid force, and the sequence of interaction. This analysis is compared with the method currently in use, and both methods are applied to a practical case. The theoretical analysis gives a resulting force over the pump turbine, which corresponds well to the measured behavior of a pump turbine in terms of its frequencies and the relationship between their amplitudes. A corrective action is proposed as a result of the analysis and after it is carried out in one of the units, the vibration levels are reduced. The vibration induced by the RSI is predicted considering the sequence of interaction and different amplitudes in the interactions between the same moving blade and different stationary blades, giving a different and original interpretation about the source of the vibration characteristics. A successful corrective action is proposed as a consequence of this new interpretation.

scholarly journals THE DEVELOPMENT OF THE CONTENT OF VOCATIONAL TRAINING OF MASTER’S DEGREE STUDENTS TO MANAGEMENT IN PRESCHOOL EDUCATION

2020 ◽  
pp. 218-226
Author(s):  
Ирина Анатольевна Селиверстова ◽  
Марина Леонидовна Семенова
Keyword(s):  
Higher Education ◽  
Theoretical Analysis ◽  
Labour Market ◽  
Education Program ◽  
Vocational Training ◽  
Training Programs ◽  
Preschool Education ◽  
School Education ◽  
Highly Qualified ◽  
Education Standard

Рассматриваются вопросы подготовки будущих специалистов дошкольного образования к управленческой деятельности. Целью исследования является установление взаимосвязи между требованиями стандарта высшего образования, рынка труда и работодателя как основание отбора профессиональных компетенций при проектировании содержания образовательной программы магистратуры. Авторами использованы метод теоретического анализа, сопоставление реальных запросов практики в целом и задач подготовки будущих руководителей. В результате обозначены профессиональные компетенции и индикаторы их достижения, востребованные работодателем. Выводы и предложения авторов интересны в теоретическом и прикладном плане, могут быть применены при разработке и реализации программ подготовки высококвалифицированных социально активных кадров дошкольного образования. Discusses the preparation of future pre-school education specialists for management activities. The aim of the study is to establish a relationship between the requirements of the higher education standard, the labour market and the employer as a basis for selecting professional competencies in the design of the content of the master's education program. The authors used a method of theoretical analysis, comparing the actual requests of practice in general and the tasks of training future managers. As a result, the professional competences and indicators of their achievements, demanded by the employer, are marked. The authors' conclusions and proposals are interesting in theory and application, and can be applied in the development and implementation of training programs for highly qualified, socially active pre-school education.

scholarly journals On the Rotor Stator Interaction Effects of Low Specific Speed Francis Turbines

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Einar Agnalt ◽  
Igor Iliev ◽  
Bjørn W. Solemslie ◽  
Ole G. Dahlhaug
Keyword(s):  
Guide Vane ◽  
Pressure Fluctuations ◽  
Angular Position ◽  
Pressure Sensors ◽  
Pump Turbine ◽  
Blade Loading ◽  
Loading Case ◽  
Rotor Stator Interaction ◽  
Low Specific Speed ◽  
Specific Speed

The rotor stator interaction in a low specific speed Francis model turbine and a pump-turbine is analyzed utilizing pressure sensors in the vaneless space and in the guide vane cascade. The measurements are analyzed relative to the runner angular position by utilizing an absolute encoder mounted on the shaft end. From the literature, the pressure in the analyzed area is known to be a combination of two effects: the rotating runner pressure and the throttling of the guide vane channels. The measured pressure is fitted to a mathematical pressure model to separate the two effects for two different runners. One turbine with 15+15 splitter blades and full-length blades and one pump-turbine with six blades are investigated. The blade loading on the two runners is different, giving different input for the pressure model. The main findings show that the pressure fluctuations in the guide vane cascade are mainly controlled by throttling for the low blade loading case and the rotating runner pressure for the higher blade loading case.

Preload Effects of a Guide Bearing on the Metal Temperature and the Shaft Vibration

2000 ◽  
Vol 123 (1) ◽  
pp. 144-150 ◽  
Author(s):  
Hyun Cheon Ha
Keyword(s):  
Theoretical Analysis ◽  
Metal Temperature ◽  
Hydraulic Pump ◽  
Pump Turbine ◽  
Rotating Machine ◽  
Maximum Value ◽  
Bearing Stiffness ◽  
Shaft Vibration ◽  
Very High

Segment type vertical guide bearings are widely used for vertical rotating machinery; nevertheless, bearing problems, such as excessive vibration and temperature rise, frequently take place in the actual rotating machine. The purpose of the present work is to investigate the influence of preload effects of a segment type vertical guide bearing on the bearing metal temperature and the shaft vibration, in a hydraulic pump-turbine. Investigations have been performed not only by in-situ measurement but also by theoretical analysis. A guide bearing consists of eight pads and runs bi-directionally. Both the shaft vibration and the bearing metal temperature are very high in the non-preloaded bearing but are slight in the preloaded bearing, comparatively. Bearing metal temperature is decreased by the increase of cooling effect of the lubricant due to the preload effect. Shaft vibration is also decreased by the increase of bearing stiffness. Theoretical analysis shows that the segment type vertical guide bearing has an optimum preload ratio at which the bearing stiffness reaches a maximum value while the bearing metal temperature is minimized. Furthermore, it is found that the characteristics of shaft vibration of a Francis type hydraulic pump-turbine highly depend on the generating power.

scholarly journals The Influence of Flow Rates on Pressure Fluctuation in the Pump Mode of Pump-Turbine with Splitter Blades

2020 ◽  
Vol 10 (19) ◽  
pp. 6752
Author(s):  
Ping Huang ◽  
Yajing Xiao ◽  
Jinfeng Zhang ◽  
Haikun Cai ◽  
Haiqin Song
Keyword(s):  
Pressure Fluctuation ◽  
Draft Tube ◽  
Guide Vane ◽  
Pump Mode ◽  
Pump Turbine ◽  
Flow Rates ◽  
Guide Vanes ◽  
Rotor Stator Interaction ◽  
Computational Fluid Dynamics Cfd ◽  
The Stability

This paper takes a pump-turbine as the research subject and, based on the Computational Fluid Dynamics (CFD) numerical method and combined with test data, investigates the pressure fluctuation characteristics in the pump mode and analyzes the pressure fluctuation characteristics at 0.75 Qd, 1.0 Qd and 1.25 Qd when the guide vane opening is 17.5°. The results showed that the protruding frequencies of pressure fluctuation in the bladeless region were mainly 5 fn, 10 fn and 20 fn, and the main frequencies in the runner area and near the outlet wall of the draft tube were 16 fn and 5 fn, respectively. At different heights for the guide vanes, the pressure fluctuation in the bladeless region had significant differences, and the pressure fluctuation near the bottom ring was the most intense. The amplitude of the rotor–stator interaction frequency continuously attenuates from the bladeless region to the outlet of the stay vanes, and the amplitude attenuation of each frequency is mainly concentrated in the area of the guide vanes. In this paper, the influence of different flow rates on the pressure fluctuation in the pump mode is analyzed, which provides a theoretical reference for the stability and further study of pump-turbines.

Numerical Simulation of the Unsteady Flow in a High-Head Pump Turbine and the Runner Improvement

2008 ◽  
Author(s):  
Hongjuan Ran ◽  
Xianwu Luo ◽  
Yao Zhang ◽  
Baotang Zhuang ◽  
Hongyuan Xu
Keyword(s):  
Numerical Simulation ◽  
Unsteady Flow ◽  
Guide Vane ◽  
Positive Slope ◽  
Pump Turbine ◽  
Operation Conditions ◽  
Partial Load ◽  
Discharge Curve ◽  
Rotor Stator Interaction ◽  
High Head

The unsteady flow in a high-head pump-turbine whose head-discharge curve has the positive slopes at high-partial-load operation condition was investigated. It is noted that the numerical methods is very important for predicting this kind of head-discharge curve with positive slopes, and better agreement between calculation results and experimental data was achieved by using Spalart-Allmaras turbulence model and mesh strategy with y+ controlling for numerical simulation. From the analysis of hydraulic losses at different parts in the pump turbine, it is found that the head loss at the flow passage of the guide vane and stay vane was not small at pump mode. In order to make clear the reason why the positive slopes at head-discharge curve occur, the flow between the impeller exit and the inlet of spiral casing was checked carefully. Much intensive vortex was observed near the impeller shroud, and there was strong rotor stator interaction for those operation conditions with positive slope. It is suspected the instability such as positive slope at head-discharge curve was resulted from the vortex formation near the flow channel wall. Based on the flow analysis, the runner optimization was conducted so as to mitigate the intensive rotor stator interaction. It is noted that the pressure fluctuation as well as the flow pattern was improved by applying the optimized impeller.

scholarly journals THEORETICAL ASPECTS OF THE STUDY OF BIOETHICAL CONSCIOUSNESS

2021 ◽  
Vol 31 (1) ◽  
pp. 39-44
Author(s):  
L.O. Puzyreva ◽  
S.Yu. Zhdanova
Keyword(s):  
Theoretical Analysis ◽  
Modern World ◽  
Highly Qualified ◽  
Present Stage ◽  
The Social ◽  
History Of ◽  
Bioethical Issues ◽  
Definition Of ◽  
Key Events ◽  
Scientific Life

This article presents a theoretical analysis of the history of the formation and existence of a relatively new branch of scientific knowledge - bioethics - at the present stage of its development. Different approaches to the definition of the causes and prerequisites for the emergence of bioethics are analyzed. The key events of the social, moral, ethical and scientific life of society that have influenced the emergence and identification of the direction of bioethics are indicated. The relevance and importance of bioethics in the modern world is demonstrated. The authors of the article have analyzed existing materials on this problem and identified a number of significant problems, the solution of which is currently being addressed by researchers of bioethical issues of our time. Moreover, the article presents a theoretical analysis of such important concepts of bioethics as bioethical consciousness, bioethical upbringing and education. The main and most important functions of bioethical consciousness are highlighted. It is shown that bioethical upbringing and education is becoming extremely important today for the training of highly qualified specialists of any profile.

scholarly journals Cognitive investigations in Kantian perspective: towards new synthesis

2020 ◽  
Vol 24 (4) ◽  
pp. 730-737
Author(s):  
Nikolay L. Arkhiereev ◽  
Marina L. Ivleva ◽  
. Baldo Dagtcmaa
Keyword(s):  
Social Sciences ◽  
Philosophy Of Science ◽  
Cultural Revolution ◽  
Cognitive Activity ◽  
Research Perspective ◽  
New Synthesis ◽  
New Interpretation ◽  
Naturalistic Interpretation ◽  
Religious Systems ◽  
Original Interpretation

This is a review of the book Mozg - kultura - socium. Kantianskaya programma v cognitivnykh issledovaniyakh by Bazhanov V.A. The author`s main aim is a reconsideration of some fundamental principles of epistemology and philosophy of science in the light of state-of-the-art advancements of neurosciences. According to the author of the book, social and cultural revolution in neurosciences has been crucially modifying the initial Kantian program of consciousness research and the modes of linguistic representation of its results. In particular, in epistemology the universal concept of transcendental subject has been altered with regard to neurobiological and social data, which concern some preconditions of cognitive activity. In philosophy of science such a shift of research perspective allows to implement a naturalistic interpretation of natural sciences, clarifies the problem of empirical foundations of mathematics and sheds a new light on the problem of apriori elements of mathematical thought. The analysis of evolutionary and neurobiological preconditions of logical thought leads to the sort of revival of psychologism program in logic, which enables author to put forward an original interpretation of the problem of plurality of logical systems. Finally, some topics of social sciences as well as problems of genesis of art, ethical and religious systems, can acquire new interpretation with respect to modern investigations in cognitive science.

scholarly journals Analysis of Rotor-Stator Interaction of a Pump-Turbine with Splitter Blades in a Pump Mode

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1465 ◽  
Author(s):  
Haiqin Song ◽  
Jinfeng Zhang ◽  
Ping Huang ◽  
Haikun Cai ◽  
Puyu Cao ◽  
...  
Keyword(s):  
Radial Force ◽  
Stable Operation ◽  
Power Station ◽  
Pump Turbine ◽  
Main Frequency ◽  
Pulsation Amplitude ◽  
Depth Analysis ◽  
Rotor Stator Interaction ◽  
Guide Blade ◽  
Pumped Storage

The pump-turbine is the core component of a pumped storage power station. This paper considers an in-depth analysis of the rotor-stator interaction characteristics under computational fluid dynamics (CFD) and experimental measurements of pump-turbine with splitter blades used in a domestic pumped storage power station. The results show that as the guide blade opening increases, the rotor-stator interaction of the pump-turbine intensifies and the magnitude of the runner radial force and its pulsation amplitude as well as the magnitude of the guide blade water moment and its pulsation amplitude also increase. In addition, when the opening degree increases from 9.8° to 17.5°, the influence on the main frequency is mainly reflected in the phase change. While the opening degree increases from 17.5° to 24.8°, the influence on the main frequency is mainly reflected in the amplitude change. Moreover, the amplitude of 5fn at opening 9.8° and opening 24.8° is greater than the optimal opening 17.5°, indicating that deviation from the optimal opening will aggravate the difference of rotor-stator interaction between splitter blades and guide blades. In the paper, the influence of guide blade openings on the rotor-stator interaction between the splitter guide blade is studied, which provides a theoretical reference for the stable operation of the pump-turbine.

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