Engineering Design Studies Research Articles

Pipeline route selection and ground characterization, Algeria

Purpose of the study A terrain evaluation of a remote area of hyperarid desert in central Algeria was undertaken as part of the frontend engineering design (FEED) studies for a gas field development. The work was part of the identification of suitable route options for a large buried pipeline between the gas fields and the existing pipeline network, some 500 km to the north. The results of the study provided information to support construction costings and preliminary engineering design and construction evaluation of potential geohazards and geotechnical issues, notably trench excavatability and dune mobility, and to help subsequent selection of a specific alignment within the corridor. Techniques used The stages involved in the study are summarized in Figure 1, the work formed part of a broader programme of geological studies to characterize ground conditions along a preferred pipeline route. The basis for the preliminary terrain evaluation was a combination of a desk study review and interpretation of a 1:100 000 scale composite (SPOT and Landsat TM) satellite image of the route corridor (approximately 100 km either side of the proposed route). This evaluation was carried out in the UK and was used to identify locations for a limited number of boreholes and trenches. The results from the boreholes and trenches were used, along with a limited ‘ground truthing’ programme in Algeria, to refine the terrain evaluation and provide typical engineering geological and geomorphological characteristics for each terrain unit. The terrain evaluation involved the identification of generic terrain models (i.e. landscape types) each with a characteristic assemblage of terrain units .

Representations of strategic knowledge in design

This paper is concerned with the purpose and form of representations of strategic knowledge in design. A number of issues concerning the role of representations in design are considered. A distinction is made between representations for describing design and representations for guiding or prescribing design. Issues about the role and form of representations `of' and `for' design are considered in the light of experience from a case study of vehicle engineering design. The goals of the project from which this work arises were two-fold: first, to identify examples of strategic knowledge from a domain expert; and second, to inform the computer support design field about that issue. The approach adopted was to gather empirical information and model the results using different analysis frameworks. Three types of representations are described: a domain model of strategic knowledge for supporting interactive system design , a model for representing strategic knowledge computationally, and a design process model of strategic knowledge in engineering design.

95/06181 Wood cofiring experience in cyclone boilers

Wood waste has been cofired with coal in cyclone boilers at the Allen Fossil Plant of TVA, the King Station of Northern States Power Co., and other generating stations. This practice is sufficiently interesting that TVA plans long term testing of cofiring wood at Allen. This practice can be separate from, or combined with, cofiring tire-derived fuel (TDF) in cyclone boilers. Cofiring has been practiced with the wood waste being fed to the boilers simultaneously with the coal, and with the wood waste being introduced into the secondary air system of cyclone boilers, for separate feeding. The practice of cofiring wood waste with coal in cyclone boilers has been shown to reduce emissions of SO{sub 2} and NO{sub x}, while also reducing the cost of fuel in selected locations. Foster Wheeler Environmental Corporation has evaluated this practice both with engineering design studies and with field testing for the Electric Power Research Institute. This paper summarizes testing and experience in several locations, focusing upon the following issues: (1) the impact of cofiring on boiler performance and consequent airborne emissions, (2) the alternative designs to accomplish cofiring, and (3) the economics of cofiring under various conditions. The paper documents opportunities and constraintsmore » associated with firing waste fuels in cyclone boilers.« less

CFD predictions of lobed mixer performance

A finite volume calculation procedure has been used to predict the flow and temperature mixing in a multilobed mixer/nozzle geometry. The method adopts a non-aligned mesh to solve the steady-state three-dimensional elliptic equations describing the flow within the lobes. The calculation of the downstream mixing duct is then coupled with the lobe flow predictions to allow for the prediction of the complete lobed mixer/nozzle system. The calculation method and some initial predictions have been presented in [1]. The basic model and an improved version of the method obtained by implementing a higher-order finite-difference scheme are employed in the present computations to assess numerical accuracy. A series of numerical parametric studies are then undertaken to investigate performance variations brought about by changes in mixer inflow conditions. Attention is focussed on the prediction of overall performance parameters such as mixing effectiveness and total pressure losses which are essential in engineering design studies. It is demonstrated that the CFD method used, is capable of providing accurate and useful information for design purposes, and flowfield/temperature distributions which are otherwise difficult and expensive to obtain. It forms an important new tool for the evaluation and optimisation of internal lobed mixer configurations.

Genetic algorithm optimization of multi-peak problems: studies in convergence and robustness

Engineering design studies can often be cast in terms of optimization problems. However, for such an approach to be worthwhile, designers must be content that the optimization techniques employed are fast, accurate and robust. This paper describes recent studies of convergence and robustness problems found when applying genetic algorithms (GAs) to the constrained, multi-peak optimization problems often found in design. It poses a two-dimensional test problem which exhibits a number of features designed to cause difficulties with standard GAs and other optimizers. The application of the GA to this problem is then posed as a further, essentially recursive problem, where the control parameters of the GA must be chosen to give good performance on the test problem over a number of optimization attempts. This overarching problem is dealt with both by the GA and also by the technique of simulated annealing. It is shown that, with the appropriate choice of control parameters, sophisticated niche forming techniques can significantly improve the speed and performance of the GA for the original problem when combined with the simple rejection strategy commonly employed for handling constraints. More importantly, however, it also shows that more sophisticated multi-pass, constraint penalty functions, culled from the literature of classical optimization theory, can render such methods redundant, yielding good performance with traditional GA methods.

Microelectrode Study of the Lithium/Propylene Carbonate Interface: Temperature and Concentration Dependence of Physicochemical Parameters

Selected physicochemical parameters useful for characterizing the metallic lithium electrode exposed to a lithium perchlorate salt in a propylene carbonate solvent are reported as functions of temperature and salt composition. The advantages of using microelectrodes for the measurements are elucidated. Transport parameters governing the electrolyte‐phase limiting current density are found to be independent of salt composition over a concentration range of interest for lithium batteries. The Li‐Li+ reaction is shown to correspond to classic electron‐transfer theory, with a symmetry factor of one‐half, as would be expected for a strongly solvated ionic reactant. Simplified equations are derived that allow one to focus on specific aspects of a lithium thin‐film battery, demonstrating the utility of the measured parameters for engineering design studies.

Physics and engineering design studies on the Large Helical Device

The construction of the Large Helical Device (LHD) is progressing as a seven year project in Japan, which began in 1990. This year, necessary research and development programs are nearly reaching the final goal of the original schedule and we have started the construction of the basic parts of LHD. We report on the results of the physics and engineering design studies, and the recent status of the construction of LHD.

Opportunities for U.S. Industry in the ITER project

The author discusses the role of industry in the ITER project. In particular, emphasis is placed on preparing US industry to play a role in this program, and to prepare it to bid on construction contracts for either ITER systems, or parts of other development efforts which result from the engineering design study phase of the ITER project which is just about to commence. Fusion is on the verge of moving from the research lab into the commercial sector, and US business has to be brought into the project now in order to be prepared to bid on eventual construction projects. The objective is to involve industry in the design of the ITER reactor. The opportunity for industry to participate in identifying the requirements of the site for the ITER facility exists. In the area of technology development, industry must have a leading role in the design, construction, and testing of hardware prototypes. The objective is to prepare US industry to bid successfully on the construction of ITER or any other large fusion facilities to be built anywhere in the world.

An engineering design study of a hermetic liquid argon calorimeter for the SSC

Abstract The goal of our study is to evaluate the physics performance of a large liquid argon calorimeter for the SSC engineered to include a realistic support system, cryogenic vessels, signals, and services. The physics performance is dependent on the effect of the dead material on the hermeticity. An integrated design, modeling analysis, and simulation approach is used to allow rapid iteration of the three-dimensional model as well as to provide the ability to trace rays through the design. The results show that a liquid argon calorimeter for the SSC can be designed from a mechanical engineering standpoint and that such a device would achieve excellent physics performance.

Transitions in Engineering: Guillaume Henri Dufour and the Early 19th Century Cable Suspension Bridges by Tom F. Peters

TECHNOLOGY AND CULTURE 530 Book Reviews Chaussade’s firm and that of the Crowleys in England “deserve detailed examination” (p. 239). Should that work arrive, it will, like this one, provide comprehensive and multilayered treatment and, perhaps, offer further explanation for the French failure to exploit the energies of its entrepreneurs. Reed Benhamou Ms. Benhamou is associate professor of interior design at Indiana University. She is writing a dissertation on the preparation of the artist in 18th-century France. Transitions in Engineering: Guillaume Henri Dufour and the Early 19th Century Cable Suspension Bridges. By Tom F. Peters. Basel: Birkhauser Verlag (P.O. Box 133, CH-4010), 1987. Pp. 244; illustrations, notes, bibliography, index. SFr 80.00. Tom Peters’s new book deals with an aspect of the evolution of an engineering design technique using an interesting blend of biogra­ phy, contextual material, and a discussion of technical issues in a very accessible manner. The book is well written and lavishly illustrated. The opening chapter, “Some Basic Facts,” is an essay on the nature of scientific and technical thought and eloquently introduces what follows. It stresses the essentially hybrid nature of engineering—that rich mixture of intuition, experience, scientific method, and empiri­ cism. This short essay stands on its own, although the questions it poses make the reader wish to proceed. This introduction places engineering history firmly in the realm ofthe history ofideas and contributes to the philosophy of technology. Chapter 2 deals with the prehistory of sus­ pension bridges and ranges widely both in time and location—notably in China. The third chapter provides a background to the main theme and discusses the importance of Geneva in the dissemination of en­ gineering knowledge to the French-speaking world from 1789 to 1815 and the development of engineering education in France. It is at this point that Peters introduces the Swiss engineer Guil­ laume Henri Dufour (1787—1875), who was an important figure in various aspects of modern Swiss history. But this is no conventional piece of engineering biography. Indeed, the author’s view is that “Biography tends drastically to impoverish the image of complex events and historical figures. All incertitude, dilemma, conflict and contradiction disappear and leave behind the mere husk of fact, a fallacious determinism, a caricature of persons and events” (p. 57). It is easy to see why Peters was drawn to Dufour as a central figure around which to weave the threads of a historical engineering design study. The Dufour archives in Geneva contain a collection of his drawings, letters, manuscript proposals for various projects, and published reports. It is clear that Dufour was both articulate and an acute observer and reporter. He also exchanged information with TECHNOLOGY AND CULTURE Book Reviews 531 others working in the field, and Peters draws on this interaction to gain an engrossing insight into a crucial period in the evolution of the wire suspension bridge. The largest section of the book deals with the genesis of the wire cable bridge, beginning with the Seguin brothers in France. One theme explored is the fascination of the properties of the catenary curve for mathematicians and engineers and its role in engineering research. A proposal to build the Saint Antoine Bridge in Geneva in the 1820s brought Marc Seguin and Dufour (then state engineer) into discussions. The bridge was completed to Dufour’s design and opened in August 1823. This was the world’s first permanent wire cable suspension bridge, and the design techniques, wire tests, and test loading of the completed structure are discussed. Dufour’s sketches, drawings, manuscript reports, and subsequent archival photographs illustrate this section. The remaining two chapters deal with French developments up to 1850, and an undeveloped design where the cable was beneath the bridge deck. Peters’s exploration of engineering design clearly shows decision making to be multidisciplinary, involving social, military, economic, and political issues. Moreover, Dufour’s design style is the product of his personality and of the culture in which he worked. The author believes that “some familiarity with engineering history is a pre­ requisite of modern education, for engineering is one of the basic constituents of modern civilization and culture” (p. 9). If only this...

Climate change in fact and in theory: Are we collecting the facts?

For the past 100 years, a mostly volunteer group of observers has formed the backbone of the U.S. National Weather Service (NWS) Cooperative (CO-OP) network. These stations have provided most of the observations used to satisfy the Department of Commerce's statutory mandate of 1890... “to establish and record the climatic conditions of the United States” (15 USCA 313). Originally, this network was intended primarily for agriculture, but many other uses of the data have since emerged, such as the climatic planning of weather sensitive activities, input to engineering design studies, and input and verification for weather and river forecasts. In recent years, heightened awareness regarding climatic change and variability has challenged this network with yet another mission: the monitoring and detection of climate change. While not designed for that mission, the CO-OP network has proved useful in this respect. However, with some changes in operation, it could become even more valuable in monitoring for climatic change, and could do so in a most economical way. Similar practices instituted worldwide will be necessary for comprehensive study of climate change to the degrees of detail necessary to address specific policy issues and practical local-scale decision making.

High temperature properties of hot-rolled, structural steels for use in fire engineering design studies

An extensive programme of small-scale tensile tests has been carried out under both steady-state and transient heating conditions to provide elevated temperature data on the behaviour of hot-rolled, structural steels for use in fire engineering design studies. It has been demonstrated that predictions on the behaviour of structural steels at small strains from data derived under steady-state conditions are optimistic and information should preferably be used from transient tests. However, when temperatures and stresses corresponding to strains approaching ‘runaway’ or the ‘limit of deflection’ are compared, then there is negligible difference between the minimum properties derived from either type of test. Tables of data are provided in a form suitable for use in fire engineering calculations.

Network Performance Evaluation Model for HOV Facilities

A model to assess the impacts of major high-occupancy vehicle (HOV) facilities on regional levels of energy consumption and vehicle air pollution emissions in urban areas is developed and applied. This model can be used to forecast and compare the impacts of alternative HOV facility design and operation plans on traffic patterns, travel costs, mode choice, travel demand, energy consumption, and vehicle emissions. The model is designed to show differences in the overall impacts of alternative HOV facility types, locations, and operation plans, rather than to serve as a tool for detailed engineering design and traffic planning studies. The Network Performance Evaluation Model (NETPREM) combines several urban transportation planning models into a multimodal network equilibrium framework, including a module with which to define the type, location, and operation of the HOV facility to be tested, and an evaluation module with which to assess the impacts of this facility. As an example application, potential impacts of three different HOV lane/ramp facilities, when added to a major expressway in the Pittsburgh metropolitan area, are forecasted. The results of these example runs and potential improvements to the model are discussed.

LASER IGNITION OF OIL SPILLS

ABSTRACT A major oil spill in the Arctic, whether from a tanker or an oil rig, could result in large concentrations of oil among broken ice and/or thousands of oiled melt pools. The remoteness of the area and the inadequacy of other countermeasures make in-situ burning the only possible response. Helicopter-deployable igniters have been developed to ignite the oil, but studies have shown that use of these devices has severe logistical constraints. The use of a helicopter-borne laser system as an alternative to, or in conjunction with, the igniters has been pursued from conceptual development to completion of the engineering design phase. The concept was examined by theoretical analysis combined with laboratory studies. This work indicated that a dual-laser system would ignite both fresh and weathered crude oils at temperatures representative of an arctic spring or fall day. A series of outdoor experiments was carried out in Kanata, Ontario, Canada, in March 1985. These experiments, under climatic conditions very similar to those in the Canadian Arctic in June, demonstrated that a two-laser system would ignite both fresh and weathered crudes. An engineering feasibility and design study was undertaken. The study confirmed that a system having the required performance can be assembled from existing, proven hardware and operated effectively from a helicopter. The development of the laser ignition of oil spills from concept through engineering design is described.

Geotechnical Investigations Offshore Hong Kong

A comprehensive site investigation was performed offshore the island of Chek Lap Kok as part of the civil engineering design studies for the proposed replacement airport at Hong Kong, The program included conventional drilling and sampling carried out from floating craft, as well as extensive in situ testing, including piezocone penetration, field vane shear, and permeability tests. The laboratory testing program incorporated Ko‐consolidated, undrained, triaxial compression, extension, and direct simple shear tests, as well as numerous more conventional tests. The thrust of the investigation was the determination of engineering characteristics for two extensive marine clay deposits that are considered critical to the performance of the proposed airport reclamation. One of these deposits, referred to as the upper marine clay, covers the entire offshore portion of the site. It is extremely soft and sensitive, with undrained shear strengths ranging from 3–12 kPa and sensitivities of about 10. The other deposit, referred to as lower marine clay, is medium stiff and overconsolidated, with in situ shear strengths in the range of 40–90 kPa. The results of the field and laboratory tests are synthesized to develop engineering properties appropriate for reclamation design. Correlations between the piezocone data and field vane shear tests are presented, as well as correlations of compressibility parameters with index properties. Normalized strength parameters for the two marine clays are also presented.

Rock engineering for construction of Science North, Sudbury, Ontario

This paper presents a case study of rock engineering investigations, design, and construction work for the new Science North museum in Sudbury, Ontario. While the rock work is not particularly innovative, the building construction involved singular geotechnical requirements and problems.The building sits astride a major regional fault, which has a mapped length of 56 km, a throw of over 600 m, and a shear zone 30 m wide. Inclined drilling was used to locate and characterize the shears within this zone. The paper describes the site investigation and assesses the fault's history of movement and the potential for future fault activity.Architectural requirements included excavation of a "cavern" and entrance tunnel with exposed rock faces that were to appear rough yet remain stable. Given the sheared rock, the excavation required careful blasting. No shotcrete, mesh, or other visible forms of support were permitted. Instead, the rock was stabilized by "invisible" fully resin-bonded dowels. Anchors with a working load of 500 kN each were used to pretension the piers to the rock and stabilize the rock faces beneath pier foundations. The paper describes the methods used to assess foundation bearing capacity and rock cut stability, to design the anchoring system, and to inspect and scale the footings, the tunnel, and the open-cut rock faces. Key words: rocks, foundations, blasting, site investigation, anchoring, bolting, slope stability, scaling, faults.

Simulation of a Major Oilfield Gas-Gathering Pipeline System

An engineering design study was performed on a gas-gathering system in a major offshore oilfield in Saudi Arabia. The dew point gas from separators will undergo retrograde condensation in the pipelines with reduction of pressure and temperature. Calculations presented for sizing the pipelines include phase behavior, pressure drop, temperature profiles, liquid volumes, flow pattern predictions, liquid flow rates and the minimum gas velocity required to continuously remove liquid from the risers.

Poloidal Divertor Systems for Impurity and Particle Control in Ignition Tokamaks

Poloidal divertors and pumped limiters are the leading candidates for impurity and particle control systems for ignited tokamaks. Such systems must be able to provide heat removal and He pumping while satisfying the requirements for (1) minimum plasma contamination by impurities, (2) reasonable component lifetime (∼ 1 year), and (3) minimum size and cost and maximum simplicity. The advantage of poloidal divertor systems is that they offer the possibility of low sputtering rates for the first wall components and modest pumping requirements due to the formation of a cool, dense plasma near the collector plates. Estimates made as part of the INTOR study indicate that the sputtering rates for pumped limiters could be unacceptably large. A engineering design study of a poloidal divertor system for an ignited tokamak indicates that such a system offers a reasonable solution to the impurity and particle control problem at only a modest increase in total reactor cost (∼7%) and complexity compared to a pumped limiter system.

Elementary External SGEMP Model for System Engineering Design

Elementary algebraic models for maximum external SGEMP response current are presented. Models predict body current on an isolated cylindrical object in partial atmosphere. Models have been validated by comparison to test data, and are useful for system engineering design studies to estimate external SGEMP response.

Wind waves: a review of research during the last twenty-five years

Summary. Surface gravity waves generated by the wind have been studied extensively over the last twenty-five years. Advances in the theories of wave generation together with field measurements have now clarified the principal means by which waves grow. Weak non-linear wave-wave interactions have been found to have an important role in controlling the evolution of the wind-wave spectrum, as shown in the Joint North Sea Wave Project. However, a major area of future research is in the study of breaking waves. This highly non-linear phenomenon still defies detailed analysis and is very difficult to observe quantitatively. Wave prediction methods based on the energy balance equation are discussed together with a short review on their application to engineering design studies.