Paper 19: Conditions Producing Concentrated Erosion in Large Steam Turbines

1969 ◽  
Vol 184 (7) ◽  
pp. 45-56 ◽  
Author(s):  
M. J. Moore ◽  
P. Sculpher
Keyword(s):  
Uniform Distribution ◽  
Final Stage ◽  
Steam Turbines ◽  
Operating Life ◽  
Trailing Edge ◽  
Simple Modification ◽  
The Third

The paper presents the results of intrascope observations and instrument traverses in the final stages of three large steam turbines and describes the processes controlling the distribution of erosion on the moving blades. Concentrations of eroding water are shown to be produced by complex steam flows in the final stage which redistribute the water depositing on the surfaces of fixed blades. Of the three turbines considered, each has a different redistribution process, two leading to concentrated erosion, the third to a more uniform distribution of damage. In the former two turbines, it was found that the concentrations of water could be dispersed by small fences fitted to the fixed blade trailing edge, this simple modification promising to extend significantly the operating life of the moving blades.

Dewey and Higher Education

2018 ◽  
pp. 392-410
Author(s):  
Leonard J. Waks
Keyword(s):  
Higher Education ◽  
John Dewey ◽  
Final Stage ◽  
Logical Theory ◽  
Close Attention ◽  
The Third ◽  
The Moment ◽  
The University ◽  
Theory Of Inquiry

While John Dewey wrote relatively little about higher education, he had a well-developed and largely unexplored conception of the university, grounded in his three- stage account of thought or inquiry as developed in Studies in Logical Theory and further developed in Logic: Theory of Inquiry. The first stage is antecedent to inquiry proper, residing in the situations of living that evoke thought. The second is inquiry proper, where data or immediate materials are subjected to systematic thought to yield judgment. The third is the moment after thought has considered its data and reached its result and brought it forth in situations of living as transformed by this new element. This final stage, is the “objective of thought” but lies outside of the context of inquiry proper. This chapter, building on the Dewey corpus, explains that conception, with close attention to university-based research, teaching, and service.

A Study of Steam Turbine Droplet Formation, Shedding and Blade Impact

2008 ◽  
Author(s):  
Ahmad D. Vakili ◽  
Abraham J. Meganathan ◽  
Gary Golden
Keyword(s):  
Water Layer ◽  
Droplet Formation ◽  
Control Parameters ◽  
Steam Turbines ◽  
Trailing Edge ◽  
Measurement Results ◽  
Periodic Maintenance ◽  
Condensed Liquid ◽  
Fundamental Experiment ◽  
Made In

Blade erosion is a serious problem in steam turbines and reduces the life of turbine, requiring periodic maintenance. A fundamental experiment is being performed to evaluate effects of certain control parameters on the droplet formation process and distribution of the shed droplets sizes. Three blade coatings include Epoxy, Teflon®, Viton®, three trailing edge geometries and a new and innovative trailing edge effect are to be experimentally studied. Measurements are to be made in a simulated stationary cascade utilizing real turbine components. The condensed liquid film and the large droplets formed on the three coated blades and one original finish blade will be optically measured. A typical cascade is modeled using Volume of Fluid with different surface properties used to model the formation and breakup of a thin water layer into droplets. Droplet distributions for the various conditions will be compared and the best surface finish and configurations will be identified. Most importantly, the reason for a successful configuration will be given, based on the measurement results.

The Apocalypse of Adam and Pre-Christian Gnosticism

1990 ◽  
Vol 44 (3) ◽  
pp. 263-279
Author(s):  
Scott T. Carroll
Keyword(s):  
Final Stage ◽  
Evolutionary Stage ◽  
The Third ◽  
Stage Of Development ◽  
Third Stage ◽  
Ultimate Source ◽  
Ring Seal ◽  
Christian Literature ◽  
The Temple

AbstractSolomonic legend evolved through four clearly perceptible stages. The first stage found in the pre-Christian literature was marked by the most primitive notions about Solomon-as-exorcist. These legends about Solomon's abilities, however, were controlled by several qualifiers. Solomon controlled the demons by means of his God-given gift of wisdom along with the aid of some archaic talismans. The second evolutionary stage which spanned the first and second centuries A.D. expanded the theme of Solomon-as-exorcist. Solomon controlled the demons with talismans (his ring, seal, shield, magic roots, incantations, magic bottles ...), but God was still seen as the ultimate source of his power. Demons were used by the exorcist solely to help build the Temple in Jerusalem. The third stage, from the late second through the fourth centuries, was a watershed in the development of Solomonic legend. Solomon-the-magician extraordinaire was first attested at this date. Solomon's source of power was no longer readily identified with God. At this stage, demons were used by Solomon to accomplish manifold tasks. The final stage of development, dominated by Muslim adaptations, expanded the theme of Solomon-the-wizard and the idea of subservient demons, to imaginative heights.

scholarly journals Assessment of Residual Service Life of Cast Bodies of Control Valves of 220 MW Power Units

2020 ◽  
Vol 23 (4) ◽  
pp. 22-28
Author(s):  
Olha Yu. Chernousenko ◽  
◽  
Dmytro V. Ryndiuk ◽  
Vitalii A. Peshko ◽  
◽  
...  
Keyword(s):  
Service Life ◽  
Control Valve ◽  
Steam Turbines ◽  
Operating Life ◽  
Control Valves ◽  
Intermediate Pressure ◽  
Operating Modes ◽  
Residual Operating Life ◽  
Start Ups ◽  
Total Damage

In the regulatory documents of the Ministry of Energy and Coal Industry of Ukraine, the beyond-design operating life of the high-energy equipment of 220 MW power units is limited to the operating life of 220 thousand hours and 800 start-ups. To date, the high-temperature cast bodies of the control valves for the high- and intermediate-pressure cylinders of the K-200-130 200 MW steam turbines of DTEK Lugansk TPP have operated about 305–330 thousand hours with the total number of start-ups from 1438 to 1704, which exceeded the beyond-design service life characteristics. Therefore, it is necessary to assess the residual operating life of the control valve bodies of the high- and intermediate-pressure cylinders of K-200-130 steam turbines in order to determine the possibility of their further operation. These calculations were carried out on the basis of our earlier studies of the thermal and stress-strain states of cast turbine equipment. This paper establishes the values of stress intensity amplitudes, the values having been reduced to a symmetric loading cycle for the most typical variable operating modes. Using the experimental low-cycle fatigue curves for the 15Kh1M1FL steel, we established the values of the permissible number of start-ups and the cyclic damage accumulated in the base metal. We also determined the value of the static damage accumulated in the course of stationary operating modes according to our previously obtained experimental data on the long-term strength of the 15Kh1M1FL steel. The calculations showed that the total damage to the control valve bodies of the K-200-130 steam turbine of power unit 15 of DTEK Lugansk TPP is 97 and 98%. The residual operating life of the metal of the control valves of high-pressure cylinders is practically exhausted, being equal to 10 thousand hours. The residual life of the control valves of intermediate- pressure cylinders is 7 thousand hours, i.e. it is also practically exhausted, with safety factors for the number of cycles and strains at the level of 5 and 1.5, as well as the permissible 370,000 operating hours of the metal. With an increase in the permissible operating life of the metal to 470 thousand hours, according to experimental studies of Igor Sikorsky KPI, the total damage to the metal of cast valve bodies is reduced to 80%, and the residual metal life increases to 79,000 h and 75,000 h for the control valves of the high- and intermediate-pressure cylinders, respectively.

scholarly journals About the features of hypersonic flow past a yawed plate

2019 ◽  
Vol 487 (1) ◽  
pp. 24-27
Author(s):  
G. N. Dudin ◽  
V. Ya. Neyland
Keyword(s):  
Hypersonic Flow ◽  
Strong Interaction ◽  
Leading Edge ◽  
Transverse Coordinate ◽  
Trailing Edge ◽  
The Third ◽  
Flow Past ◽  
Flow Functions

The flow around the yawed plate in the regime of strong interaction is considered in the case when the pressure at its trailing edge is not constant, but changes along the transverse coordinate. It is shown that in the case of large transverse gradients of the induced pressure, the type of expansions of flow functions in the vicinity of the leading edge changes significantly and the third term of the expansions should be taken into account.

scholarly journals KUDETA REDAKSIONAL DALAM PROSES LEGISLASI NASIONAL

2020 ◽  
Vol 5 (2) ◽  
pp. 162-181
Author(s):  
Ni Ketut Wiratny ◽  
Ni Luh Putu Geney Sri Kusuma Dewi
Keyword(s):  
Final Stage ◽  
Plenary Session ◽  
Secondary Data ◽  
Legislative Process ◽  
Constitutional Court ◽  
Special Committee ◽  
Material Defects ◽  
The Third ◽  
The Government ◽  
The Right

It is undeniable that there are problems in the legislative process in Indonesia, one of which is tampering with articles or editorial coups. In fact, this illegal practice can occur in three conditions. First, it occurs in the draft produced by a special committee or commission before it is brought to the plenary session of the DPR. The second occurred after the DPR plenary session. The third is the most difficult to control, if an editorial coup is carried out by the government before it is passed by the president, then it is promulgated in the State Gazette. At this stage, when the bill is in the hands of the government, the DPR finds it difficult to check. Given that this is the final stage, the possibility of a new editorial coup has been traced after it was implemented. As a product that is agreed upon in the highest forum (plenary session) and is the result of joint legislative-executive agreement, the slightest change made is haram. This research is a normative juridical research by conducting literature studies and analyzing secondary data. The results of this study indicate that if it is true that there is an editorial coup in the legislative process, the legal product has formal and material defects which can be canceled through the right to test exercised by the Constitutional Court.

scholarly journals Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera

2020 ◽  
Author(s):  
Giambattista BELLO
Keyword(s):  
Complex Structure ◽  
Copulatory Organ ◽  
Morphological Characters ◽  
Distal Portion ◽  
Nominal Species ◽  
New Genera ◽  
Simple Modification ◽  
The Third ◽  
Copulatory Apparatus ◽  
Light Organs

The subfamily Sepiolinae (Mollusca: Cephalopoda: Sepiolidae), currently containing the genera Sepiola Leach, 1817, Euprymna Steenstrup, 1887, Inioteuthis Verrill, 1881, Rondeletiola Naef, 1921 and Sepietta Naef, 1912, is characterized by the hectocotylization of the left dorsal arm, i.e., its transformation into a copulatory organ thanks to modifications of sucker/pedicel elements. The hectocotylus morphology varies to a great extent across genera and species. In particular, one to several pedicels in its proximal third lose their sucker and become highly and diversely modified in shape to constitute a copulatory apparatus. An evolutionary gradient was observed in the copulatory apparatus morphology, from the simple modification into a papilla of just one pedicel from the third element of the ventral sucker row (some nominal species of Euprymna) to a quite complex structure involving several variously modified pedicels from both the ventral and dorsal sucker rows (Inioteuthis). In some species, elements in the distal portion of the hectocotylus may also be highly modified, such as the columnar suckers in Euprymna. The hectocotylian diversity allows to distinguish nine groups of species that do not match the current generic subdivision of Sepiolinae. Additional morphological characters (number of sucker rows on arms, female bursa copulatrix, occurrence and shape of visceral light organs, etc.) corroborate the subdivision of Sepiolinae into nine subtaxa, i.e., genera. Accordingly, a cladogram is drawn to describe the possible phylogenetic relationships among the nine clades. To comply with these results, all current genera are redefined and four new genera are described, namely Adinaefiola gen. nov., Boletzkyola gen. nov., Eumandya gen. nov. and Lusepiola gen. nov.

Vegetation recovery of old-arable lands by vegetation in the Forecarpathian Upland

2018 ◽  
pp. 81-86
Author(s):  
Pozynych I.
Keyword(s):  
Rare Species ◽  
Final Stage ◽  
Vegetation Recovery ◽  
Oak Forests ◽  
Quantitative Indices ◽  
The Third ◽  
Third Stage ◽  
Galanthus Nivalis ◽  
Epipactis Helleborine

In the process of forming succession on abandoned arable lands, the quantitative indices relative to the permanent cоenopopulations are quite similar, although in the third stage they decrease almost twofold, and at the final stage of light oak forests the representation of cоenopopulations of rare species increases: Epipactis helleborine, Leucojum vernum, Galanthus nivalis.

Experimental and Numerical Analyses of Relaxation Processes in LP Steam Turbines

2005 ◽  
Vol 219 (12) ◽  
pp. 1411-1436 ◽  
Author(s):  
F Kreitmeier ◽  
R Greim ◽  
F Congiu ◽  
J Faelling
Keyword(s):  
Flow Field ◽  
Homogeneous Nucleation ◽  
Saturation Line ◽  
Relaxation Processes ◽  
Steam Turbines ◽  
The Third ◽  
Two Generations ◽  
Loaded Part ◽  
Lp Turbine ◽  
The One

Flow fields in low-pressure (LP) steam turbines, starting expansion well above the saturation line, show four pronounced non-equilibrium processes (called relaxation processes). The first one above the saturation line is centred around heterogeneous nucleation/condensation, the second one around subcooling and the subsequent homogeneous nucleation/condensation (‘Wilson point’), and the third and the fourth ones are characterized by thermodynamic and mechanical effects in the established droplet-loaded part of the flow field. All these relaxation processes are interacting downwards in the progressive expansion in the turbine. In a multistage LP turbine, the most important ones are the second - because it is mainly responsible for the number of droplets (sizes) - and the third - because it creates most of the dissipation. In addition, the first and the fourth ones can damage the flow guiding geometry by corrosion and erosion, respectively. More than 40 years ago, Gyarmathy formulated the first strictly physical basis for these processes. Subsequently, many researchers have contributed to increase the physical understanding using both experimental and numerical methods. The intuition that the one-dimensional treatment of the flow field in multistage turbines cannot explain the measured droplet sizes behind the blading has been particularly relevant. It became clear that especially the temperature fluctuation within the blading has to be included in homogeneous nucleation/condensation considerations. Also of some importance has been the improved understanding of the first relaxation process, which was initially underestimated. This article highlights the current situation seen by a turbomachinery company that has been contributing to and supporting this discipline for many decades. A wide literature survey and a critical appraisal of published Baumann factors are included. High quality experimental tools and procedures are introduced on the basis of two generations of split-shaft model LP turbines and Damköhler numbers. Further, an overview of the in-house numerical tools and processes developed for wet steam applications is given. More recent experimental results on the influence of impurities and conditioning agents in the relaxation processes and newer numerical results on the influence of phase transition in the flow field around a blade row are presented.

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