Adaptation of CFD to the Design of Centrifugal Pumps

2007 ◽  
Author(s):  
Shmariahu Yedidiah
Keyword(s):  
Case History ◽  
Mutual Understanding ◽  
Centrifugal Pumps ◽  
Case Histories ◽  
Science And Engineering ◽  
Actual Case ◽  
New Developments ◽  
Mathematical Equations ◽  
Logical Tool ◽  
State Of Affairs

The similarity between flow patterns predicted with the aid of CFD and those observed in practice indicates, that CFD might be capable to assist the pump -engineer in coming up with improved designs. Unfortunately, in practice, the results are rather elusive. This paper discusses some of the causes of this state of affairs and presents suggestions, how to eliminate them. It demonstrates that the main cause of these disappointing results is the existing gap between science and engineering. The present explosion of information makes it very difficult for an expert in any given field of engineering to follow all the new developments in his (her) own specialized area. The less can an engineer be distracted by attempts to master an additional field of expertise. The results arrived at with the aid of CFD demonstrate, that it is a very powerful and versatile logical tool. However, versatile also means that it can be used in many different ways. Consequently, in order to arrive at satisfactory results, it has to be applied in a manner specifically suitable for handling the problem, which is being worked on. This means, that it requires an in-depth familiarity with all its aspects. Something, a CFD expert cannot afford to study. The only solution is teamwork. However, for teamwork to be successful, each participant has to know and to understand, what the others are doing. This paper demonstrates, that a relevant interpretation of the physical meaning of mathematical equations is capable to provide logical explanations to some of the even most enigmatic events. This leads to the conclusion, that such interpretations may also be capable to establish the so badly needed mutual understanding between the pump-expert, and the specialist in CFD. The above conclusions are supported by actual case histories from practice, and/or by results of tests. In addition to the above, this paper discusses a case history, which demonstrates that even in cases, in which CFD is capable to provide the required results, its use is not always the best choice. In practice, it is often much simpler, faster and considerably less expensive to arrive at the required results by means, which can be hardly regarded as associated with fluids dynamics. Finally, this paper also presents an example of a problem, which only CFD may be capable to solve.

CPT-based liquefaction case histories compiled from three earthquakes in Canterbury, New Zealand

2021 ◽  
pp. 875529302199636
Author(s):  
Mertcan Geyin ◽  
Brett W Maurer ◽  
Brendon A Bradley ◽  
Russell A Green ◽  
Sjoerd van Ballegooy
Keyword(s):  
New Zealand ◽  
Case History ◽  
Prediction Models ◽  
Free Field ◽  
Case Histories ◽  
Cone Penetration ◽  
History Data ◽  
The Past ◽  
Surface Manifestation ◽  
The Many

Earthquakes occurring over the past decade in the Canterbury region of New Zealand have resulted in liquefaction case-history data of unprecedented quantity. This provides the profession with a unique opportunity to advance the prediction of liquefaction occurrence and consequences. Toward that end, this article presents a curated dataset containing ∼15,000 cone-penetration-test-based liquefaction case histories compiled from three earthquakes in Canterbury. The compiled, post-processed data are presented in a dense array structure, allowing researchers to easily access and analyze a wealth of information pertinent to free-field liquefaction response (i.e. triggering and surface manifestation). Research opportunities using these data include, but are not limited to, the training or testing of new and existing liquefaction-prediction models. The many methods used to obtain and process the case-history data are detailed herein, as is the structure of the compiled digital file. Finally, recommendations for analyzing the data are outlined, including nuances and limitations that users should carefully consider.

Different Failure Modes of Non-Metallic Pipelines at Connections

2014 ◽  
Author(s):  
Alex Tatarov ◽  
Frank Gareau
Keyword(s):  
Failure Modes ◽  
Root Cause Analysis ◽  
Case Histories ◽  
Actual Case ◽  
Cause Analysis ◽  
Root Cause ◽  
Pipeline Failures

The article provides an overview of different modes of failures in composite pipeline connections. Non-metallic spoolable (SCP) and reinforced thermoplastic pipelines (RTP) of different makes will be addressed. The article is based on actual case histories of pipeline failures (root cause analysis). Numerous factors contributing to failures and recommendations are discussed.

The Korsakov Syndrome in Spontaneous Subarachnoid Haemorrhage

1953 ◽  
Vol 99 (416) ◽  
pp. 521-530 ◽  
Author(s):  
John N. Walton
Keyword(s):  
Subarachnoid Haemorrhage ◽  
Neurological Disorders ◽  
Review Of The Literature ◽  
Case Histories ◽  
Actual Case ◽  
Mental Symptoms ◽  
Symptom Complex ◽  
Excellent Description ◽  
The Subject ◽  
Neurological Conditions

The amnestic-confabulatory symptom-complex to which the eponymous title of Korsakov's syndrome is usually given was probably first described by the Swedish physician Magnus Huss (1807–90), who spent the greater part of his lifetime in the study of alcoholism. There is, however, no doubt that Korsakov's (1890) paper on the subject gave an excellent description of the syndrome, and stressed the fact that whereas it often developed in patients with alcoholism and polyneuritis, numerous other metabolic and neurological disorders could be complicated by the characteristic mental changes. Indeed, in Korsakov's (1890) own series of cases alcoholics were in the minority. One of the neurological conditions in which the syndrome has been described significantly often is spontaneous subarachnoid haemorrhage. The first reports of the association were probably those of Flatau (1918 and 1921), and it was discussed in some detail by Goldflam (1923) and Herman (1925 and 1926). Each of these authors described the mental symptoms exhaustively but gave no actual case-histories; the first fully documented cases in the literature were the two reported by Hall (1929). Single cases have since been described by Cubitt (1930), Popow (1930) and Kulkow (1935), and in 1939 Tarachow gave an extensive review of the literature and reported an additional 3 cases. It is remarkable that since 1939 the association has received little attention, although it has been mentioned by Sands (1941) and Meadows (1951).

Empowering local food connections for resilient city-regions. Planning through foodsheds or terroir?

TERRITORIO ◽  
2012 ◽  
pp. 61-66
Author(s):  
Rositsa Todorova Ilieva
Keyword(s):  
Case History ◽  
Food Production ◽  
Intrinsic Value ◽  
Local Communities ◽  
Case Histories ◽  
Italian Case ◽  
City Regions ◽  
Effi Ciency ◽  
The Subject ◽  
Supply Systems

This essay explores two antonimic approaches adopted by planning to describe food production and supply systems deeply rooted in local communities. The fi rst is based on the concept of a ‘foodshed' and puts the accent on sustainability and ‘resilience', while the second refers to the notion of ‘terroir', with the emphasis on oneness and the intrinsic value of locally produced food. Through a reading of English and Italian case histories, the essay critically analyses the two approaches, their feasibility and the different results achieved in terms of effi ciency and effectiveness. The analysis is organised in two sections, each of which introduces the case history with a brief theoretical introduction. In the conclusions, the antynomy between the two approaches is re-examined and possible research developments on the subject are identifi ed.

Physical Interpretations of Mathematical Expressions, as a Potent Tool of Engineering

2011 ◽  
Author(s):  
Shmariahu Sam Yedidiah
Keyword(s):  
Common Sense ◽  
Past Experience ◽  
Case Histories ◽  
Actual Case ◽  
The Past ◽  
Mathematical Expressions

The presented study demonstrates the enormous potentials of translating mathematical expressions into their relevant physical meanings. In the past, such translations have proven capable of explaining the cause(s) of phenomena, which seemed to defy all principles of common sense. In other cases, they were able to rectify deeply rooted misconceptions, which haunted the engineers for many decades. Among others, they have revealed the need for revising everything what has been done in the last eight decades in relation to the head developed by an impeller. All the above conclusions are here supported by actual case histories from past experience. The discussions presented in this study relate directly to the design of centrifugal and other rotodynamic pumps. However, there exist strong indications, that such translations may prove equally useful also in other fields of engineering.

Paper 7: Field Experiences with Combustion Equipment for Boilers, with Particular Reference to Safety Measures

1966 ◽  
Vol 181 (14) ◽  
pp. 61-67
Author(s):  
W. Grant
Keyword(s):  
Solid Fuel ◽  
Fuel Oil ◽  
Oil Refining ◽  
Air Distribution ◽  
Case Histories ◽  
Close Collaboration ◽  
Actual Case ◽  
Safety Measures ◽  
Gas Fuel ◽  
Flame Shape

The paper is set in a background of boiler commissioning for customers in power generating, industrial, marine, petro-chemical and oil-refining companies in Britain and overseas. Some of the problems encountered during the commissioning of a diversity of units employing solid fuel, oil fuels, naphtha, gas fuel firing, either singly or in combination, are discussed, and actual case histories detailed. The paper embraces difficulties experienced with the ignition of fuels, the control of flame shape, air distribution to burners, layout of fuel supply lines, safety circuits, and the necessity for close collaboration between the customer and the designer during the tender and contract stages, in order to avoid loss of availability, resulting from delays in commissioning or subsequent damage to equipment.

PROBLEMS AND PERSPECTIVES IN RECOVERY OF OIL POLLUTION REMOVAL COSTS1

1977 ◽  
Vol 1977 (1) ◽  
pp. 35-38 ◽  
Author(s):  
William H. Norris ◽  
Hugh N. Johnston
Keyword(s):  
Pollution Control ◽  
Reporting System ◽  
Oil Pollution ◽  
Case Law ◽  
Third Party ◽  
Case Histories ◽  
Actual Case ◽  
Federal Water Pollution Control ◽  
The Government ◽  
Pollution Removal

ABSTRACT The paper examines Sections 311(f), and (i) of the Federal Water Pollution Control Act (FWPCA) and discusses the statutory scheme for the recovery of clean-up costs by both the government and private persons. Legislative intent then is compared with actual practice and experience as reflected in statistics developed from the Coast Guard's Pollution Incident Reporting System (PIRS) data and the records used in administering the revolving fund. Actual case histories are used as a means of discussing the legal problems involved in administering sections 311(f) and (i). Government practice and case law are examined wherever appropriate, including recovery under 311(f) when government liability is at issue; recovery when both an owner/operator and a third-party are involved; recovery by the government from CRISTAL and TOVALOP; and practice in the Court of Claims under section 311(i). The paper concludes with a brief comment concerning the comprehensive oil spill liability bill (H.R. 14862), introduced in the 94th Congress, which would provide for an unlimited, readily accessible cleanup fund by imposing a per-barrel fee on oil as it is received at the refinery or transport terminal.

Introduction to Special Issue on Engineering and Groundwater

Geophysics ◽  
1986 ◽  
Vol 51 (2) ◽  
pp. 221-222 ◽  
Author(s):  
P. R. Romig
Keyword(s):  
State Of The Art ◽  
The State ◽  
Special Issue ◽  
Case Histories ◽  
New Developments ◽  
Future Developments ◽  
Seismic Methods ◽  
Anniversary Issue

This section of the issue of Geophysics is draw from a collection of papers originally submitted for a monograph on engineering and groundwater geophysics. It is a mixture of tutorial, new developments, and case histories focused on seismic methods. This introduction will review the evolution of this section and introduce each of the papers. These papers complement the overview presented by Dobecki and Romig (1985) in the Golden Anniversary Issue of Geophysics. That paper reviews the history, summarizes the state of the art, and attempts to predict possible future developments.

The Potential of Using CFD in Order to Design Better Centrifugal Pumps

2008 ◽  
Author(s):  
S. Yedidiah
Keyword(s):  
Flow Patterns ◽  
Centrifugal Pumps ◽  
Recent Advances ◽  
To Come ◽  
State Of Affairs

Recent advances in CFD made it capable of producing fairly realistic predictions of the flow-patterns within the passages of centrifugal pumps. This raises the possibility that CFD might also be capable of assisting the pump engineer to come up with better designs. Success, however, is still very elusive. This paper discusses the reason for that state of affairs, and how to cope with it. As such, this paper can be regarded as a supplement to the discussions presented in References [1] and [2]. It has been demonstrated in Refs. [1] and [2], that the main cause for that lack of success is due to the present explosion of information. It prevents the CFD specialist from acquiring the necessary in-depth knowledge of the practical aspects of a problem, which a pump engineer has to solve. At the same time, this explosion of information makes it impossible for the pump specialist to become adequately familiar with the potentials and with the limitations of CFD. It has been demonstrated in Ref.[2] that certain problems related to centrifugal pumps can be solved easier, faster and more successfully with the aid of more conventional logical tools, than with the aid of CFD. This paper will discuss, among others, problems, which only CFD might be capable to solve.

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