Dissertations / Theses on the topic 'Casing pipe'

Показано, що одними з основних параметрів COT, які відповідають за експлуатаційну надійність обсадної колони і можуть бути визначені методами неруйнівного контролю, є овальність та ексцентриситет. На основі проведених теоретичних досліджень розроблені способи та встановлені аналітичні залежності для визначення овальності та ексцентриситету COT. Експериментально досліджено характер залежності між основними параметри контролю та характеристиками дефектів. Розроблено та впроваджено у виробництво комплекс технічних засобів і технологій, які дозволяють проводити автоматизований вхідний контроль якості обсадних труб.
Обзор современных технических средств и технологий контроля качества элементов и соединений трубных колонн показывает, что, не смотря на широкое использование в нефтегазовой области методов неразрушающего контроля, вопрос комплексного контроля стальных обсадных труб (СОТ) остается нерешенным. По данным Американских нефтегазовых компаний в США на трубных базах после проверки обсадных труб на соответствие действующим стандартам отбраковывается до 20% общего количества проверенных труб. Учитывая то, что аварии с обсадными трубами составляют 7-8% всех аварий в бурении, на их ликвидации расходуется свыше 10% времени, которое приходится на ликвидацию аварий всех видов, задача разработки и внедрения методов и средств контроля СОТ является, безусловно, актуальной. Входной контроль СОТ с помощью разработанных технических средств и технологий обеспечит недопущение к эксплуатации труб с дефектами, а также позволит формировать обсадную колонну в соответствии с фактическим техническим состоянием СОТ. ель работы состоит в разработке методов, технических средств и технологий автоматизированного контроля стальных обсадных труб в условиях баз производственного обслуживания нефтегазодобывающего предприятия. Практическое значение полученных результатов состоит в том, что разработанные технические средства и технологии реализованы в комплексной установке контроля основных параметров СОТ, внедренные в производство. Разработанные методы и технические средства прошли промышленные испытания на базе производственного обслуживания Хрестищенского УБР ДК "Укргаздобыча" и в Научно-производственной фирме "Зонд".
Is shown, that some of basic parameters of casing pipes, which are responsible for operation reliability of casing string are ovality and eccentricity. These parameters can be defined by methods of non-destructive testing. On the basis of the carried out theoretical researches the designed ways also are established analytical dependences for definition of casing pipes ovality and eccentricity. Character of dependence between basic parameters of testing and defect characteristics was investigated experimentally. Is developed and entered into manufacture the complex of means and techniques which allow to carry out the automated entrance inspection of quality of casing pipes.

Дисертація присвячена підвищенню герметичності та ремонтопридатності різьбових з’єднань обсадних труб шляхом удосконалення конструкції і програмування параметрів їх працездатності з урахуванням експлуатаційних навантажень. Програмна модель пружно-деформованого стану з’єднання муфти і труби з вузлом ущільнення розроблена на основі моментної теорії коротких циліндрів зі стінками змінної товщини, формул Ламе і знайденої формули контактного тиску. Аналітичні дослідження контактних тисків залежно від радіальних натягів, товщин стінок, внутрішніх і зовнішніх тисків, осьових сил дали змогу встановити нові закономірності впливу конструктивних та експлуатаційних чинників на герметичність і надійність різьбових з’єднань обсадних труб ОТТГ. Удосконалені конструкції різьбових з’єднань із вузлом ущільнення і спосіб підвищення їх герметичності захищені патентами України. Розроблені методики їх проектування і технологічного забезпечення. Дослідні випробування цих з’єднань підтвердили підвищення їх працездатності в обсадних колонах. Спосіб відновлення герметичності з’єднань ОТТГ розроблений на основі газопломеневого металопорошкового напилення герметизуючого шару.
Диссертация посвящена повышению герметичности и надежности муфтовых соединений обсадных колонн путем усовершенствования конструкции и программирования параметров работоспособности с учетом эксплуатационных нагрузок. В первом разделе проведен анализ причин усложнений с обсадными колоннами, способов повышения надежности их резьбовых соединений и методов рассвета упругих деформаций их элементов, обоснованы цель и задачи диссертации. Второй раздел посвящен теоретическим исследованиям формирования герметизирующей способности муфтовых соединений обсадных труб ОТТГ и разработке их упруго-деформационной модели с учетом натягов и эксплуатационных нагрузок. Программная аналитическая модель сложного напряженно-деформированного состояния соединений труб и муфт с уплотнительным узлом разработана на основе моментной теории коротких цилиндров со стенками переменной толщины с применением формул Ламе. Модель учитывает совместимость кольцевых, радиальных и изгибающих деформаций, которые возникают в их стенках при свинчивании с радиальным натягом, под действием контактных, внутренних и внешних давлений, осевых сил, и закономерности формирования контактных давлений на участках уплотнения и резьбы.В третьем разделе проведены аналитические исследования влияния конструктивных и эксплуатационных факторов на герметичность муфтовых соединений обсадных труб ОТТГ и зависимости контактных давлений в уплотнении и резьбе от радиальных натягов, толщин стенок, внутренних и внешних давлений, осевых нагрузок. Контактное давление больше при больших натягах, толщинах стенок и меньших диаметрах труб. Вследствие изгибов стенок трубы возникает спад контактного давления к торцу уплотнения, что определяет его герметичность. Величина и спад этого давления возрастают под действием внутреннего давления. Уменьшив в пределах допуска толщину стенок в узле уплотнения, увеличив их гибкость, можна уменьшить этот спад и взаимное влияние различных натягов в уплотнении и резьбе. Программный расчет толщин стенок и натягов обеспечивает большее и более равномерное контактное давление в уплотнении и повышение герметичности соединений ОТТГ при заданных эксплуатационных условиях. В четвертом разделе описаны усовершенствованные муфтовые соединения обсадных труб типа ОТТГ повышенной надежности, представлена методика, оборудование и результаты экспериментальных исследований их герметичности, а также разработаны методики проектирования и технологического обеспечения этих соединений для заданных условий эксплуатации. Опытные испытания усовершенствованных соединений подтвердили закономерности повышения их герметичности в зависимости от натягов в уплотнении и резьбе, толщин и диаметров труб, возможность уменьшения толщины стенки в уплотнении при необходимости увеличения натяга. Испытания позволили установить параметры надежной герметизации таких соединений и их пригодность для использования в эксплуатационных колоннах. Экспериментально установлено, что для соединений ОТТГ 146 увеличение радиального натяга на 0,01 мм повышает их герметичность на 9... 10 МПа, а натяг, больший 0,08 мм, обеспечивает их герметичность при максимальных давлениях опрессовки согласно стандарта. В пятом разделе разработаны ремонтопригодная конструкция муфтовых соединений обсадных труб ОТТГ и способ восстановления их герметичности, представлены результаты их внедрения, обосновано технологическое обеспечение ремонта соединений в производственных условиях. Опытная апробация этого способа проведена на установке газопламенного металлопорошкового напыления путем напыления герметизирующего слоя на уплотнительные поверхности соединения ОТТГ. Апробация подтвердила возрастание герметичности восстановленных соединений при максимальных опрессовочных давлениях по стандарту (до 57,9 МПа для ОПТ 146 х 9,5 Е і до 62,8 МПа для ОПТ 146 х 10,6 Е) и эффективность его применения в промышленных условиях. На основе разработанной методики проектирования и технологического обеспечения усовершенствованных соединений типа ОТТГ разработан руководящий документ для повышения надежности соединений обсадных колонн нефтяных и газовых скважин. Он принят для внедрения на буровых предприятиях ВАТ "Укрнефть".
The dissertation deals with the enhancement of impermeability of threaded joints of casing pipes by means of construction improvement of seal assembly and programming of their working capacity parameters taking into account operational loadings. The computer-generated model of the elastic-deformed state of pipe and coupling joint with seal assembly is designed on the basis of the moment theory of short cylinders with variable thickness of their walls, Lame's formulas and the formula of contact pressure found by the author. Analytical studies of contact pressures dependence from radial tension, thicknesses of walls, internal and external pressures, thrust load have allowed to determine new influencing patterns of constructional and operational factors on leakproofness of threaded joints of casing pipes with seal assembly. Advanced constructions of casing pipes joints with seal assembly and the increase technique of their impermeability are patented. The author has elaborated their design technique and procedures of their technological support. Experimental trials of these joints have confirmed the increase of their working capacity in casing strings. The restoration technique of impermeability of joints with seal assembly is designed on the basis of gas-flame powder spraying of pressurizing metallic layer.

The issue of mold cooling is one, which presents a foundry with a dilemma. On the one hand; the use of air for cooling is safe and practical, however, it is not very effective and high cost. On the other hand, water-cooling can be very effective but it raises serious concerns about safety, especially with a metal such as magnesium. An alternative option that is being developed at McGill University uses heat pipe technology to carry out the cooling.
The experimental program consisted of designing a permanent mold to produce AZ91E magnesium alloy and A356 aluminum alloy castings with shrinkage defects. Heat pipes were then used to reduce these defects. The heat pipes used in this work are novel and are patent pending. They are referred to as McGill Heat Pipes.
Computer modeling was used extensively in designing the mold and the heat pipes. Final designs for the mold and the heat pipes were chosen based on the modeling results.
Laboratory tests of the heat pipe were performed before conducting the actual experimental plan. The laboratory testing results verified the excellent performance of the heat pipes as anticipated by the model.
An industrial mold made of H13 tool steel was constructed to cast nonferrous alloys. The heat pipes were installed and initial testing and actual industrial trials were conducted. This is the first time where a McGill heat pipe was used in an industrial permanent mold casting process for nonferrous alloys.
The effects of cooling using heat pipes on AZ91E and A356 were evaluated using computer modeling and experimental trials. Microstructural analyses were conducted to measure the secondary dendrite arm spacing, SDAS, and the grain size to evaluate the cooling effects on the castings. The modeling and the experimental results agreed quite well. The metallurgical differences between AZ91E and A356 were investigated using modeling and experimental results. Selected results from modeling, laboratory and industrial trials are presented. The results show a promising future for heat pipe technology in cooling permanent molds for the casting of nonferrous alloys.

Thesis (MScEng)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: The use of cylindrical heat pipes for the thermal control and management of casting moulds have been investigated. Heat pipes are tubes that possess a high capability to transfer heat, up to a thousand times or more than an equivalent solid copper rod. The heat pipes used in this thesis are copper tubed, use water as working fluid and have (phosphor-bronze) screen mesh wicks. Experiments relating to practical casting situations in industry were designed and performed, using pure tin as the casting metal. Three cases pertaining to the requirements of an industrial casting mould were considered. The first case considered heating of a mould through heat pipes, in order to keep it at a specific temperature. The second case relates to the situation where metal is cast around a core, and the core is cooled by a heat pipe connected to a heat sink. The heat sink in this case was an air cooled fin. The third case is representative of the situation where molten metal is cast into an external mould and the mould heats up due to the energy flowing in from the casting. In order to cool the mould, heat pipes are used to transport the heat to a water cooled heat sink. These three cases were modeled theoretically, which included using a standard finite element method (FEM) computer package, NASTRAN 2.0 for Windows. For the FEM simulations, the heat pipes are modeled using an equivalent conductivity approach. Theoretical and experimental results are to within ± 30% of each other, but better results could possibly be achieved using a better finite element model for the heat pipes. A simulation case was performed to compare the use of an uncooled mould with a heat pipe cooled mould, and a two and a half time improvement of production rate was achieved. In support of the above mentioned casting related experiments, experiments have also been performed on a specially designed cylindrical heat pipe to determine the evaporator and condenser heat transfer coefficients. It was found that the heat pipe can transfer more than 500 W for vertical operation and around 160 W for horizontal operation. The heat transfer coefficients of the condenser and evaporator ends are in the order of 1800 to 2000 W/mK. Experiments were also performed on the fins used as the heat sink in the experiment where core cooling is investigated, to compare the experimentally determined fin heat transfer coefficient with the theoretically predicted coefficient. A theoretical study was also performed for an inclined ammonia thermosyphon in order to compare the theory to a set of previously determined experimental results. The theory produced accurate results for vertical operation, but it is clearly limited for inclined operation, and can lead to inaccurate results. A special correlation factor, the splashing factor, was defined to analyse the deviation between the theoretical and experimental results. The splashing factor can be used in two ways. Firstly, it can be used as a design correction factor and secondly, it can be processed to indicate which operational variables have the highest impact on the discrepancy between the theory and the experimental data. It is recommended that further research into the use of heat pipes for the thermal control of moulds be considered, based on the results achieved in this thesis. Furthermore, a finite element model for a heat pipe can also be considered. It is also recommended that the use of the splashing factor be considered for the analysis of thermosyphons.
AFRIKAANSE OPSOMMING: Die moontlikheid om hittepype te gebruik in die termiese beheer van gietvorms is ondersoek. Hittepype is buise wat oor 'n baie goeie warmte-oordragsvermoë beskik, 'n duisend maal of beter as 'n ekwivalente soliede koper staaf. Die hittepype wat gebruik is in die tesis is gesëelde koperbuise, wat water gebruik as werksvloeier en ook 'n (fosfor-brons) sifdraad pitmateriaal bevat. Eksperimente wat verband hou met industriële gietprosesse is ontwerp en uitgevoer. Suiwer tin is gebruik as die gietmateriaal. Drie giet gevalle is ondersoek. Die eerste geval het die verhitting van 'n gietvorm met hittepype behels. Die tweede geval hou verband met die situasie waar metaalom 'n kern gegiet word en die kern word afgekoel deur middle van 'n hittepyp wat gekoppel is aan 'n hitteput, wat in die geval 'n lugverkoelde fin is. Die derde geval hou verband met die situasie waar gesmelte metal gegiet word in 'n eksterne gietvorm en die gietvorm verhit as gevolg van die energie wat vanaf die gietstuk invloei. Hierdie drie gevalle is teoreties gemodelleer, wat die gebruik van 'n eindige element analise (EEA) rekenaarpakket insluit (NASTRAN 2.0 for Windows). Tydens die EEA simulasies is die hittepype gemodelleer met behulp van die ekwivalente geleidingskoëffisiënt metode. Teoretiese en eksperimentele resultate is binne .± 30% van mekaar. Beter resultate kan moontlik verkry word as 'n verbeterde eindige element model vir die hittepype ontwikkel kan word. 'n Simulasie geval is uitgevoer om die produksietempo van 'n onverkoelde gietvorm te vergelyk met 'n hittepyp-verkoelde gietvorm, en 'n verbetering van twee en 'n half maal is gevind vir die verkoelde gietvorm. Ter ondersteuning van die bogenoemde gietverwante eksperimente en teoretiese modelle, is eksperimente ook op 'n spesiaalontwerpte silindriese hittepyp uitgevoer om die kondeser en verdamper hitte-oordragskoëffisiënte te bepaal. Daar is bevind dat die hittepyp meer as 500 W kan oordra tydens vertikale gebruik en ongeveer 160W tydens horisontale gebruik. Die hitte-oordragskoëffisiënte vir die kondenser en verdamper is in die orde van 1800 tot 2000 W/m2K. Eksperimente is ook uitgevoer op die finne wat gebruik is as die hitteput in die geval waar die kern verkoeling ondersoek is, om die eksperimenteel bepaalde fin hitteoordragskoëffisiënte te vergelyk met die teoretiese koëffisiënt. 'n Teoretiese studie is ook uitgevoer vir 'n skuins termoheuwel sodat die teorie vergelyk kan word met In stel bestaande resultate. Die teorie gee akkurate voorspellings vir vertikale gebruik, maar is duidelik beperk en kan lei tot onakkurate resultate vir skuins gebruik. 'n Spesiale faktor (splashing factor) is gedefiniëer om die verskil tussen die teoretiese en eksperimentele resultate mee te analiseer. Hierdie factor kan op twee maniere gebruik word. Eerstens kan dit gebruik word as 'n korreksiefaktor en tweedens kan dit geprosesseer word om aan te dui watter veranderlikes die hoogste impak het op die verskil in eksperimentele en teoretiese resultate. Dit word aanbeveel dat verdere navorsing gedoen word op die gebruik van hittepype vir die termiese beheer van gietvorms, gebasseer op die resultate wat verkry is uit die tesis. Verder kan 'n eindige element model vir 'n hittepyp ontwikkel word. Dit word ook aanbeveel dat die "splashing factor" oorweeg word in die analise van termohewels.

Дисертація присвячена підвищенню герметичності муфтових різьбових з’єднань обсадних колон за рахунок герметизуючого зузла із вставним тонкостінним герметизуючим елементом із іншого матеріалу, ніж муфта і труба. Удосконалено методи розрахунку вигинів стінок муфти, труби і герметизуючого елемента, з’єднаних з натягом, з врахуванням їх взаємного впливу і крайових умов опирання при дії осесиметричних навантажень. Виведені формули радіальних деформацій стінок для усіх ділянок удосконаленого з’єднання. На основі системи рівнянь балансу деформацій і натягів визначені контактні тиски у різьбі і в ущільненні. Програмно реалізована аналітична модель пружно-деформовано-го стану з’єднання враховує дію тисків, осьового навантаження і температури. Аналітичні дослідження впливу експлуатаційних чинників на з’єднання виявили закономірності розподілу та зміни деформацій герметизуючого елемента і контактного тиску в ущільненні залежно від жорсткості елементів з’єднання, натягів різьби і ущільнення, величин внутрішнього і зовнішнього тисків, осьового зусилля і температури. Виявлено причини порушення герметичності з’єднання та встановлено умови, за яких пружний тонкостінний елемент забезпечує її при гідравлічних випробуваннях, щільність прилягання його стінок (підвищений контактний тиск) в ущільненні та їх допустимі деформації під час експлуатації. Експериментальні дослідження герметичності нового з’єднання при дії внутрішнього тиску, осьової сили і температури підтвердили, що додатні натяги ущільнення витримують тиски, які більші від випробувальних та експлуатаційних. Температурне розширення герметизуючого елемента компенсує зазор в ущільненні, що дозволяє зменшити крутний момент при згвинчуванні. Розроблено методику проектування нового герметизуючого вузла муфтових з’єднань обсадних труб для заданих експлуатаційних умов (діючих у свердловині внутрішнього і зовнішнього тисків, температури, осьового навантаження).
Диссертация посвящена усовершенствованию конструкции и повышению герметичности муфтовых резьбовых соединений безупорного типа обсадных колонн за счет герметизирующего узла со вставным тонкостенным елементом. В первом разделе проведен анализ способов обеспечения герметичности муфтовых резьбовых соединений обсадных колонн, методов расчета деформаций этих соединений, обоснованы актуальность диссертации, ее цель и задачи. Во втором разделе разработаны методы расчета деформаций участков муфты, трубы и герметизирующего елемента, соединенных с натягами, с учетом их взаимного влияния и краевых условий при действии осесимметричных нагрузок. Стенки элементов получают изгибы при опирании на смежные участки с разной жесткостью и деформациями, учитывая влияние и несмежных участков. Выведены формулы изгибов стенок всех участков нового соединения. Из системы уравнений баланса радиальных деформаций и натягов определены контактные давления в резьбе и уплотнении. Модель упруго-деформированного состояния соединения реализована программно и учитывает осевую нагрузку и температуру. В третьем разделе аналитические исследования влияния эксплуатационных факторов на соединение и герметизирующий узел выявили закономерности распределения и изменения деформаций герметизирующего елемента и контактного давления в уплотнении в зависимости от жесткости элементов соединения, натягов в резьбе и в уплотнении, отдельного и совместного действия внутреннего и внешнего давлений, осевой нагрузки и температуры. Неравномерность распределения (особенно давления) зависит от жесткости (толщины) стенок герметизирующего елемента и трубы на контактном участке. Выявлены причины нарушения герметичности и условия, при которых упругий герметизирующий елемент обеспечивает герметичность соединения при гидравлических испытаниях, плотность прилягання его стенок (повышенное контактное давление) в уплотнении и их допустимые деформации при эксплуатации. Осевая нагрузка соединения и температурное расширение герметизирующего елемента вызывают его деформации сжатия и увеличение контактного давления в уплотнении. В четвертом разделе описаны методика, оборудование и результаты экспериментальных исследований герметичности нового соединения при действии внутреннего давления, осевой силы и повышенной температуры при заданных натягах в резьбе и уплотнении. Они подтвердили, что минимальные натяги в уплотнении выдерживают давления, больше испытательных и эксплуатационных давлений. Температурное расширение герметизирующего елемента компенсирует зазор в уплотнении, что уменьшает крутящий момент свинчивания. Допустимое давление линейно зависит от натягов в резьбе и уплотнении, а при малом увеличении натяга в уплотнении выдерживаемое давление резко возрастает. В пятом разделе разработана методика проектирования герметизирующего узла муфтовых соединений обсадных труб для заданных условий эксплуатации (действующих в скважине перепада давлений, температуры, осевой нагрузки).
There have been improved the calculation methods of insulation element, pipe and plug divisions deformation joined with the standoff taking into account their cross-effect and boundary conditions under axisymmetric loading. There have been derived the formulas of walls turns of all divisions of a new joint. On the basis of equation system of radial deformations and standoff balance there have been determined the contact pressure in the thread and obturator. The model of elastic-deformed joint has been applied programmatically and considers the axial load and temperature. The analytical research of exploitation factor influence on the joints - has determined the regularities of allocation and change of deformation of insulation element and contact pressure in the obturator depending on rigidity of joining elements, axial load, and temperature. There have been revealed the reasons of proofness abnormality and established the conditions due to which the elastic thin-walled socket provides the joints proofness at hydraulic testing, conformity thickness in sealing (increased contact pressure) and its admissible deformations while exploiting. The experimental research of a new joint proofness under internal pressure, axial force and temperature vindicated that the minimum standoffs in the sealing stand the pressure which is more than testing and operating pressure in the wells. Temperature extension of insulation element compensates the gap in the standoff which reduces the rotational moment of torsion. There has been developed the methodology of design of insulation element of casing socket joints for the predetermined working conditions (operating in the well of pressure difference, temperature, and axial load).

In this study, the aim is to investigate the stiffness, longitudinal tensile strength and circumferential tensile strength of short fiber reinforced polyester composite pipes produced by centrifugal casting production method. To achieve this aim, theoretical calculation of modulus of elasticity of pipes was done and then test program was carried out on pipe samples produced with three different resin types which were orthophthalic, isophthalic and vinyl ester resin and three different fiber types which were E glass fiber, ECR glass fiber and basalt fiber. The tests were performed according to ISO (International Organization for Standardization) standards. When resin type and fiber type effect on the fiber reinforced polyester pipe samples were evaluated, calculated elastic modulus values were in accordance with the test results. According to the experimental test data, which were used to evaluate the effect of resin type on fiber reinforced polyester pipe properties, there is not a significant difference was observed in the stiffness, longitudinal and circumferential tensile strength test results of pipes having different resin types. In other words, there was not a significant effect of resin type on the stiffness, longitudinal tensile strength and circumferential tensile strength of short fiber reinforced pipes produced by centrifugal casting method. According to the experimental test data, which were used to evaluate the effect of fiber type on the properties of fiber reinforced polyester pipe, basalt fiber reinforced pipe samples showed higher mechanical performance over E glass fiber and ECR glass fiber reinforced pipes. However, the test results of basalt reinforced polyester pipe were not as good as the individual properties of basalt fiber. Finally, by comparing the basalt fiber reinforced pipe samples having almost the same stiffness and tensile test results as E glass fiber reinforced pipe samples, the gain in fiber and resin amount were investigated. Basalt fiber reinforced pipes were slightly lighter and thinner than E glass fiber reinforced pipes. However, the decrease in the amount of the fiber and resin in basalt reinforced pipe did not result in an overall cost reduction.

This thesis presents a method for optimizing cable configuration inside a large magnetic cylindrical steel casing, from the total ampacity point of view. The method is comprised of two main parts, namely: 1) analytically calculating the electromagnetic losses in the steel casing and sheathed cables, for an arbitrary cables configuration, and 2) implementing an algorithm for determining the optimal cables configuration to obtain the best total ampacity. The first part involves approximating the eddy current and hysteresis losses in the casing and cables. The calculation is based on the theory of images, which this thesis expands to apply to casings having both high magnetic permeability and high electric conductivity at the same time. The method of images, in combination with approximating the cable conductors and sheaths as multiple physical filaments, is used to compute the final current distributions in the cables and pipe and thus the associated losses. The accuracy of this computation is assessed against numerical solutions obtained using the Maxwell finite element program by Ansoft. Next, the optimal cable configuration is determined by applying a proposed two-level optimization algorithm. At the outer level, a combinatorial optimization based on a genetic algorithm explores the different possible configurations. The performance of every configuration is evaluated according to its total ampacity, which is calculated using a convex optimization algorithm. The convex optimization algorithm, which forms the inner level of the overall optimization procedure, is based on the barrier method. This proposed optimization procedure is tested for a duct bank installation containing twelve cables and fifteen ducts, comprising two circuits and two cables per phase, and compared with a brute force method of considering all possible configurations. The optimization process is also applied to an installation consisting of a single circuit inside a large magnetic steel casing.

碩士
中華大學
土木工程學系
106
In recent years, with the construction of large-scale public infrastructures, such as construction of traffic bridges, high-rise buildings, factories, etc., the frequency of use of piles has become more and more frequent, especially the full-casing piles have been widely used. Therefore, it is necessary to further study the characteristics of the construction of the whole casing pile. This study will focus on the full-casing construction to explore its engineering characteristics in different situations. In order to obtain the relevant problems in the practice of the whole casing pile construction technology, this study carried out a series of related cases and possible problems in practical problems. The research results show that the full casing pile has many advantages, because the drilling process has the steel casing prevents the soil from collapsing, so that the pile quality is good, and it can be applied to various geological and topography with different drilling equipment and excavation facilities, and has considerable experience in different geology and topography for practical use. For quite mature work methods. In addition, through the special case study in practice, due to the advantages of small construction space, simple tools, flexible movement, etc., the special casing geology and the lack of base space can be used to make semi-circular retaining piles. The section of the soil facility is halved, and the available area of the basement is increased. The construction speed can shorten the construction period, reduce the project cost, increase the land and project expenditure to achieve the maximum benefit.

碩士
朝陽科技大學
營建工程系碩士班
91
ABSTRACT Many transportation construction projects are performed in Taiwan. Bridge structure is often used in those projects. The critical activity for construction a bridge is the foundation construction. In foundation construction, pile casing is usually the first activity to be performed. Among different type of pile casing, all-casing pile is quite common used. The operations of all-casing pile include position, driving piles, as well as concrete placing that form the cyclic operations. Discrete event simulation technique is suitable in the analysis of system performance for the cyclic operations. This research takes WH33 viaduct foundation construction project as example to analyze the production rate and unit cost for all-casing pile operations. The computer simulation software COST developed based on CYCLONE discrete simulation methodology is used for facilitating the analysis. Several resource combinations are examined for replacing the original resource allocation. Simulation analysis shows one type of resource allocation that can conduct a better system performance, i.e., lower unit cost and higher production rate.

碩士
國立中央大學
土木工程學系碩士在職專班
94
Taiwan land resources are limited. With a view to expanding industry and the promotion of life quality, we have to invest in public projects earnestly and boost them. The land prices in urban areas are especially high, which leads to the construction of skyscrapers. Therefore, to increase the stability of the structures, pile foundation is of more use. Traditionally, all-casing pile foundation is designed by the procedure of trial and error. Though it can answer to the satisfaction of requirements and safety consideration, its building cost is not the lowest, nor is its effectiveness. At the present time, because the grit’s price runs high, and the sizable demands, it will have tremendous effect on the project cost. The purpose of this study is to solve this problem and to develop a fast, simple and convenient model of primary optimization in order to offer a reference to designers making decisions. This study utilizes non-linear mathematics to plan the theory, using LINGO software and finding out the diameter pile, length of pile, distance between piles and the number of piles through the known parameter and confided conditions, for the best solution to low costs. During the course of resolution, geology, load or the unit price changes, we can adjust the parameter to the latest condition at anytime and re-plan the model. With sensitivity analysis, we can understand the influence on the engineering project cost by the parameter change. Then, further the specification of the designs and sizes of the piles for the purpose of saving costs. After this study is tested with the case, comparing the performance differences between this study model and traditional method, the result shows well. The contents of this study can be applied to each pile designing flexibly, so will they show effectiveness and practicality.

碩士
明新科技大學
電機工程研究所
98
The purpose of this article is to probe into the harmonic abnormal amplification problems and its related improvement effort results happened in an iron-pipe casting factory. Firstly, it presents the power system and harmonic abnormalities data; amid, to maintain a balanced power supply from the 3-phase currents for the single phase holding furnace, the capacitors and inductors were installed unequally onto the 3-phase circuits inside the furnace body. Such installation comes up with an effect of series resonance with the system and causes a large number of harmonic current injecting into the holding furnace to make the furnace operate improperly. Therefore, it is suggested to use the solution to make a series connection with an impedance isolation transformer between the holding furnace transformer and MOF. Secondly, it mentions that in order to promote production output for the casting factory, there is a set of 3-phase 4,000kW with 12-Pulse medium frequency melting furnace additionally set up. As it uses 12-Pulse converter for this installation, it then produces many 11th and 13rd order harmonic currents (12k 1, k=1, 2, 3…). Besides, as it requires 24 hours operations for the medium frequency melting furnace, it causes frequent abnormalities or damages to the capacitive load equipment from 0:00 a.m. midnight to 08:00 a.m. morning during off peak load hours and successive holidays. To avoid such events happened again, there are 11th and 13rd level filters planned and installed achieved by the casting factory. In the end, there is an on-site measurement evaluation report and proposal finished with reference to the improvement effects brought by the filters to be provided to the casting factory for further reference.

碩士
國立成功大學
材料科學及工程學系
87
Abstract In this study, a series of hypereutectic Al-Si alloy pipe were manufactured by centrifugl casting technique. Rotational speed ( 1000rpm, 1500rpm, 2000rpm, 2500rpm ), pouring temperature ( 670℃, 730℃, 790℃ ) and silicon content ( 15wt%, 20wt%, 25wt%, 30wt% ) were the experimental parameters. To explore the effects of above mentioned experimental parameters on the solidification structure, the volume percentage of primary silicon and the hardness were measured in this study. Except for two extremely condition include 20 wt%Si with the rotational speed of 1000 rpm and the pouring temperature of 790℃, the centrifugal solidification structure of the specimens could be divided into the four specific zones from the outer peripheral zone to the inner peripheral zone. Those are (1) hypereutectic solidification structure zone is composed of the coarse primary silicon, the eutectic silicon ( which is coarse and acicular )and the primary a-aluminium, (2) eutectic solidification structure zone is composed of the eutectic silicon ( which is finer and acicular ) and the primary a-aluminium. The spacing of the eutectic silicon is the most close here, (3) hypoeutectic solidification structure zone is composed of the eutectic silicon ( which is also coarse and acicular ) and the dendritic a-aluminium. The dendritic a-aluminium grown directionally from the outer peripheral zone to the middle peripheral zone, (4) mixed solidification structure zone is composed of hypereutectic solidification structure zone, eutectic solidification structure zone and hypoeutectic solidification structure zone. A comparison was made between the specimens cast by different rotational speed , pouring temperature and silicon content. Experiment data shows a significant difference in volume percentage of primary silicon particle that increases as increased the rotational speed, but the width of primary silicon distribution is tend to decrease in the outer peripheral zone. And experiment data also shows a significant difference in volume percentage of primary silicon particle that increases as increased the silicon content, and the width of primary silicon distribution is tend to increase. But experiment data does not shows a significant difference in volume percentage of primary silicon particle and the width of primary silicon distribution as increased pouring temperature. The morpholopies of primary silicon were observed under all specimens investigated, though the silicon particle could be affected by centrifugal force , but commonly were found to form as a star-like, dendrite-like, rod-like and massive in the outer peripheral zone. On the other hand, a rod-like and massive primary silicon are mainly in the inner peripheral zone. It also can be seen that there are acicular eutectic silicon as a fethear-like, net-like, radiating-like and angular-like within the pipe. The resulting similarity in the hardness explains the evidence in the distribution of primary silicon corresponding to different volume percentage.

碩士
國立成功大學
工程科學系專班
92
This paper is to study (1) the casting method of the connection between heat sink and heat pipe, (2) the thermal response and the thermal resistance for the heat sinks with heat pipe of casting and insert types, (3) the thermal response of self-made and commercial heat pipes. In the study, a simple experimental method of thermal response is built and it can be used to inspect the efficiency of a heat pipe. An improved method is developed to cast the heat sink with heat pipe, which can prevent the heat pipe from burning out and then lose its function. The thermal response and the thermal resistance of casting-type heat sink with heat pipe are superior to those of insert one. In the process of heat-pipe fabrication, there exists a critical relation between the temperature and the vacuum pressure of a heat pipe, which can be applied as an important index for making a heat pipe. However, the self-made heat pipe in this research is inferior to the commercial one. Finally, the package FIDAP is used in simulating the heat conduction of the heat sink and heat pipe. The equivalent heat conduction coefficient of heat pipe can be obtained with the trial and error method by comparing the computing temperatures with experimentally measured ones.

碩士
國立臺灣科技大學
營建工程系
94
The application of pile foundation is getting popular in Taiwan. For these structures like high-rise buildings, elevated bridges, etc., which require their foundations with high bearing capacity and strict control on the settlement, the design for pile foundation is normally adopted. Particularly, the all-casing pile construction, during the placement of underwater concrete, always results in a contaminated concrete layer mixed with the mud and bentonite slurry at the top portion of pile foundation. This study investigates the ranges of strength variation of those contaminated top layer concrete with different pile diameters and collect their possible influencing factors such as diameter, length, amount of concrete, etc. With these information, the grey relational analysis of grey system is used, together with the grey prediction adopted as the tool for the model establishment, to assess the major factors that affect the distribution range of top contaminated concrete layer. Finally, a statistical regression analysis was utilized to build up a simply prediction model to estimate the distribution depth of top contaminated concrete layer. The experimental results and the corresponding numerical analysis indicate that the dominating factor that influences the depth of top contaminated concrete layer is the size of pile diameter. As a whole, the depth of top contaminated concrete layer is less than 1 m for the pile with diameter of 1.2 m, and the depth is about equal to the diameter of the pile with diameters between 1.5 and 3 m. The depth of such top contaminated concrete layer can reach 3.3 m for the pile with diameter larger than 3 m. Keywords: all-casing pile, contaminated concrete, grey relational analysis, grey prediction, regression analysis

Lost Foam Casting (LFC) is a metal casting technology that facilitates fabrication of near-net shape metal castings using expanded polystyrene (EPS) foam patterns that are coated with refractory slurry and is effective for producing aluminum or iron castings of complicated geometry. However, the LFC process can produce considerable amount of scrap due to casting defects. Removing the EPS thermal decomposition products through the ceramic coating ahead of the advancing metal front during the liquid metal pour is a key factor in obtaining a defect free casting. Developing a fundamental understanding of foam degradation mechanism is essential in improving LFC process. Modeling of the LFC process till date has completely neglected the effect of styrene on the overall thermal degradation of EPS foam. The dissolution effect of styrene is investigated by presenting the thermodynamic principles of polymer solution theory along with experiments to verify its impact on polystyrene degradation. By subjecting EPS Foam samples directly either to thermal radiation or to styrene vapor, it is demonstrated that styrene’s solubility of polystyrene significantly alters the degradation mechanism of EPS foam in LFC process and thus can control the metal fill process leading to reduction of defects in castings. LFC process uses expanded polystyrene foam patterns in which isomers of pentane are used as blowing agents to achieve the expansion. In order to expand polystyrene, steam is used as a heat source and the expansion process takes place via conduction of heat from the surface of unexpanded polystyrene beads into the bulk. Pentane isomers are volatile organic compounds and green house gases that are either liberated directly into the atmosphere or combusted using expensive setup. The environmental impact of the current process using pentane as an expansion agent has been considered and a new method for manufacturing of EPS foam has been developed with benign expansion agent. Laboratory experiments are demonstrated where PS pellets are successfully expanded into foam. Novel heating technology using microwave radiation is proposed and implemented in order to achieve efficient volumetric heating for the manufacturing of foam with target density.