bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Dynamics of the Temperature-Determined Stirling Cycle
Authors: Organ A. J. 
Published: February 2007

The Stirling cycle machine is modelled as a number of sections of duct in series, some tapered, some parallel. The working fluid assumes the temperature of the adjacent metal wall. Flow is defined by two conservation equations (mass and momentum) and the equation of state, p = ρRT. Friction is taken into account by using the steady-state correlation between friction factor, local instantaneous Reynolds number, and local hydraulic radius. The formulation permits frictional drag and frictional reheating to interact more or less as they do during operation of a Stirling cycle machine at high rotational speeds. The equations are converted to characteristic form and solved numerically with pressure, p, and velocity, u, as state variables rather than the more usual a (acoustic speed) and u. This formulation paves the way for a full characteristics solution incorporating the energy equation but avoiding the entropy gradient term ∂s/∂x which is inappropriate to conditions within the Stirling machine. The paper includes a Mach-line net plotted by computer for the first revolutions of the crankshaft after start-up. Indicator diagrams are presented corresponding to different angular speeds. It is found that the indicator diagram for the compression space is not greatly affected by angular speed, while that for the expansion space changes from positive, via figure-of-eight to negative over a relatively narrow speed range. An attempt is made to explain this unexpected finding in terms of the momentum equation for constant area flow with a severe temperature gradient. A comparison is included between the computed results and those predicted for the same operating conditions by the Schmidt isothermal analysis.
On the Thermal and Hydrodynamic Stability of a Fluid in a Vertical Slot
Authors: Sorour M. M. 
Published: February 2007

This investigation is devoted to studying the thermal and hydrodynamic stability of the conduction regime of natural convection of a fluid with a nonlinear density temperature relationship in a slender slot with different, but constant, temperature walls. Linear perturbation techniques are applied for the transverse two dimensional disturbances to derive a set of two coupled twelfth order partial differential equations; the Galerkin method was used to solve the eigenvalue problem. The results of this analysis indicate that this flow is much more susceptable to thermal stability than to hydrodynamic stability for Prandtl number, Pr > 3·2. On the other hand for Pr < 3·2 the reverse is true. Furthermore, both shear and bouyant mode characteristics are determined for a wide range of Pr.
Resonant Intake and Variable Geometry Turbocharging Systems for a V8 Diesel Engine
Authors: Watson N 
Published: February 2007

A mathematical model is used to analyse the performance of conventional and resonant (Cser type) intake systems on turbocharged six-cylinder and V8 engines. For the V8 the system is slightly less effective than for the six, but is more compact and easily installed within the V of the engine. An optimum system was designed and tested on a V8 engine, with maximum torque b.m.e.p. increasing from 12.0 bar at 1850 rev/min to 12.7 bar at a reduced speed of 1600 rev/min. Engine performance with the resonant system is compared to that with a simple variable-geometry turbocharger turbine, having only one major moving part. A mass-flowrate turndown of 42 per cent was achieved, but with a loss of turbine efficiency largely due to the constraints of adapting an existing turbocharger design. However a flat boost pressure curve was achieved from 1800–2600 rev/min. Maximum torque b.m.e.p. (with conventional inlet manifold) increased to 14 bar at 1600 rev/min. Engine performance at maximum speed (2600 rev/min) was unaffected with either system.
The Use of Photogrammetry in Piping Design
Authors: Bracewell P A , Klement U R 
Published: February 2007

Piping design for ‘revamp’ projects in the process industry requires the retrieval of large amounts of ‘as-built’ data from existing process plant installations. Positional data with a high degree of accuracy are required. Photogrammetry, the science of measurement from photographs, was identified in Imperial Chemical Industries plc (ICI) as a suitable tool for information retrieval. The mathematical formulation enabling the definition of three-dimensional positions from photographic information is described. The process of using ICI's photogrammetric system for the definition of complete objects such as structures and pipes is illustrated. The need for specialized photogrammetric software for design purposes is explained. A case study describing how the photogrammetric system has been applied is described and graphical outputs from this exercise are shown. It is concluded that this particular photogrammetric system has proved to be a cost effective and accurate tool for the retrieval of ‘as-built’ information.
Coal-Fired Stirling Engines for Railway Locomotive and Stationary Power Applications
Authors: Walker G , Kentfield J A C , Johnson E W , Fauvel R , Srinivasan V 
Published: February 2007

Increase in the price of oil has stimulated interest in coal-burning engines including the Stirling engines. Applications for large (> 1 MW) coal-burning Stirling engines are foreseen for marine propulsion, stationary power, railway locomotive and the heavy off-highway rubber-tyred equipment used in mining, agriculture, construction and forestry. This paper is directed principally to speculations about large coal-fired Stirling air engines with water lubrication for railway locomotive application, but similar philosophy is applicable in the other applications for large slow running engines. A brief discussion is included about mechanical arrangements and the use of air as a working fluid with water as the lubricant in Stirling engines combined with fluidized bed coal combustors and sodium vapour heat transport systems. The possibilities for railway locomotive application are explored in terms of a large unit designed from the start to utilize Stirling engines and the conversion of existing steam locomotives. Related studies have considered the conversion of diesel-electric locomotives and the designing of a free-piston Stirling engine hydrostatic drive yard locomotive.
The Evaluation of Load and Torque in Hot Flat Rolling from Slip Line Fields
Authors: Sparling L G M 
Published: February 2007

This paper presents a computer evaluation of slip line fields for rolling with medium arc of contact to thickness ratios for conditions of sticking throughout the arc of contact. The results of load and torque evaluations using a computer version of the Prager geometrical method are combined with the results obtained by Dewhurst, Collins and Johnson for the classes of slip line fields with shorter arc of contact to thickness ratios. The two methods of slip line field evaluation by the Prager and the matrix methods are shown to give load and torque functions which give a smooth transition over the boundary. The load and torque functions are presented in the form suitable for use with the yield stress functions of Cook and McCrum (BISRA method). The computer evaluation of slip line fields by the Prager method lacks elegance by comparison with the matrix method, but is the only method at present available for the evaluation of slip line fields for rolling where two rigid metal zones occur on the surface of the rolls. It is also believed that the computerized Prager method for slip line field evaluation is more readily adapted to the evaluation of slip line fields for conditions of mixed sticking and sliding friction.
The Ford Cargo
Authors: Marshall P H 
Published: February 2007

During 1981 and 1982 the fifteen year old Ford ‘D’ Series was replaced by the distinctively designed Cargo range. This is intended to meet road transport needs in the 1980s and beyond for vehicles from 6 to 32.5 tonnes gross mass and up to 150 kW. This segment covers about 50 per cent of the total Western European market for commercial vehicles above 3.5 tonnes. This paper gives a glimpse of how the objectives for such a programme were defined and how they were met by careful attention to planning, initial design, development and testing with the close co-operation of manufacturing engineers at all stages.
Driving Axles into the Eighties
Authors: Davies A J , Harrop S , Rufus D , Thompson J M 
Published: February 2007

GKN Axles Limited, Heavy Division manufactures a range of forgings and heavy axles for domestic and international markets. It constitutes approximately 50 per cent of GKN Axles Limited, who employ 2800 employees, contributing in 1981 £60 million turnover to the automotive sector of GK N. This paper shows how the Company, formally Kirkstall Forge Engineering Limited, revised its marketing, product engineering and investment strategies in order to implement a coordinated programme to ensure realization of progressive product and financial objectives.
An Experimental Investigation into the Effect of Changes in the Geometry of a Slot Nozzle on the Heat Transfer Characteristics of an Impinging Air Jet
Authors: Hardisty H , Can M 
Published: February 2007

High velocity, impinging, air jets are commonly used for heating, cooling, drying etc., because of the high heat transfer coefficients which occur in the impingement region. To provide data for design, a variety of slot nozzles has been tested to determine the effect on heat transfer of both nozzle shape and slot width. A small heat flux meter was used to measure local values of the heat transfer coefficient in the impingement zone, and these local values were integrated to yield space average values. As a necessary preliminary to the heat transfer investigation, the discharge coefficients of the nozzles were measured. From the first test series it was found that heat transfer results from differently shaped nozzles could be satisfactorily correlated provided that the effective slot width was used to characterize nozzle shape. From the second test series it was found that for geometrically similar arrangements, narrower slots gave higher heat transfer coefficients.
Structural High Temperature Materials—A View with a Future
Authors: Alexander J D 
Published: February 2007

High temperature structural materials are used to contain or extract power from furnaces—the jet engine being considered as one of these. To improve efficiency of operation and life, materials have been strengthened by various metallurgical mechanisms and each has required a better production control. The parameters of casting have been understood and developed to the extent where the orientation of single crystal turbine blades is now controlled on a semi-automated production basis. High strength disc materials are made to precise structures and defect levels to optimize properties. In the future this understanding will lead to more novel melting techniques, for cleaner material and even more precise and automated production control. The detailed material understanding gained from metallic materials gives an immediate opportunity to review the traditional approach to ceramics and to take a major and physics-based step to their more general acceptance. This understanding and precision of manufacture with its associated automation gives an opportunity for the wider use of these high temperature materials in other areas such as modern diesels.
Modernization of Control Systems to Maintain Plant Reliability and Economy in a Flexible Operating Regime
Authors: Wronski G , Wilson R G 
Published: February 2007

The bulk of the electricity generated within the Central Electricity Generating Board (CEGB) is produced from units with a capacity of 500 MW and above. A further 10.2 GW of generation is due to be commissioned in the next few years. Hence those 500 MW units with the highest generating costs now need to develop a flexible operating capability. An attempt is made to define the effect on plant performance of improving the plant automatic controls systems and enhancing the amount and presentation of information to operating staff. The consequences on plant performance of providing minute to minute regulation against grid frequency are given. The economic consequences of running at off design conditions are evaluated and related to the benefits of modernizing the control and display systems on the 500 MW units. Examples are given of the improvements being made in instrumentation and data handling systems.
The Effect of Large-Scale Structures on the Stability of Coal-Face Steering
Authors: Edwards J B 
Published: February 2007

Simplified models of piecewise rigid support structures for power-loaders operating on longwall coal-faces are shown to be amenable to analysis by z-transform methods. Such analysis predicts that increasing sufficiently the length of the sub-sections of the structure (compared to the inherent delay within the vertical steering system of the machine) should stabilize the vertical steering of the entire coalface. Increasing the width of the structure to embrace more than two consecutive cut floors is shown analytically to eliminate the need for electronic tilt-feedback in control systems. In general terms, these analytical predictions are shown to hold good in detailed simulations of the system that eliminate the simplifications demanded by the analytical method. The general conclusion of the work is therefore that an increase in the size of support structure segments can potentially reduce the complexity of steering control systems. The size-increase must be substantial, e.g. to four to five times the size of conventional structures.
The Design, Construction and Installation of a Continuous Casting Plant for the Production of Special Steel Billets at Stocksbridge Works
Authors: Murray J D 
Published: February 2007

The decision to install a continuous casting plant for the production of special steels was taken by the British Steel Corporation in January 1979. In October 1983, the plant installed at their Stocksbridge Works operated for the full month at rated capacity. In this paper an attempt has been made to give an appreciation of the project from concept to customer acceptance of the product produced. Increasing economic pressures demanded that new technological processes be adopted to reduce the conversion costs from raw materials to sold billet products, and maintain or improve the product quality. Early in the modern history of steel-making it was realized that the continuous casting process would reduce costs by the considerable energy savings and improved yields which could be achieved. However, it was not until recent years that certain aspects of the process were developed such that continuous casting could be considered acceptable for the high demands of special steels. The metallurgical parameters for the machine and the translation to machine hardware have been discussed, together with some of the problems encountered in the construction and commissioning. The finished plant introduces contemporary technology to the steel-making process and Stocksbridge are justifiably proud of the enviable position now occupied with a plant which places it at the forefront of continuous casting technology, producing a product which is at least as good as that produced by the conventional ingot route but with enhanced productivity and profitability. All metallurgical requirements have been satisfied and the course is set for developing the route for steels used in even more demanding applications and markets.
Computer Aided Design of Split Power Hydrostatic Transmission Systems
Authors: Dorey R E , Vaughan N D 
Published: February 2007

Split power hydrostatic transmission systems have been proposed in applications ranging from machine tool drives to military tanks. So far only quite simple arrangements have been considered and the full potential of the transmission remains to be exploited. This paper investigates the design of the split power transmission for a vehicle drive and shows how the transmission characteristics can be matched to the particular requirements of the vehicle duty. The number of design alternatives makes a computer investigation an ideal approach to assess the most appropriate solution in a given application. To enable computer programs describing behaviour of complex transmissions to be easily constructed and altered requires a unified approach to the modelling procedure. The paper describes how such an approach can be used for the evaluation of transmission performance and emphasizes the importance of the computer model in determining the efficiency and fuel economy of the vehicle transmission system.
On Machine Perception of the Relative Position of Two Objects Using Bilateral Tactile Sensing Systems
Authors: McCallion H , Pham D T 
Published: February 2007

>New systems for measuring the relative location of two contacting bodies using tactile signals generated by the contacts are presented and discussed. Kinematic models of the systems are given to aid their visualization, and the Kutzbach formula is used to test the uniqueness of the relative location vector inferred from the tactile signals. Using the Kutzbach formula it has been shown that, in general, bilateral systems involve measurements of more than one state of contact, that is they are multinary in character. In the Appendix mathematical procedures have been described for evaluating the relative location from the tactile signals.
Preparing the Offer
Authors: Warby D J 
Published: February 2007

The activities connected with the preparation of an engineering tender are considered in the context of a notional entrepreneurial company, Entaprize Limited, which does not have a rigid product base. Commencing with the corporate plan, which identifies the basic decision to seek an area of business, the succeeding steps are followed through to the preparation and submission of a tender. The treatment of the process is in the context of the type of inquiry specification customary for purpose made goods for a major purchasing organization. The emphasis is on the relationship of Entaprize Limited as supplier to their purchaser clients, but of course, Entaprize are also purchasers from their own suppliers and subcontractors.
The Dynamical Behaviour of Externally Pressurized Gas-Lubricated Unloaded Porous Journal Bearings
Authors: Malik M , Rodkiewicz C M 
Published: February 2007

In many practical applications, such as with vertical rotors, journal bearings operate with nearly zero eccentricities. In such situations the externally pressurized gas-lubricated porous bearings can offer a viable alternative to the self-acting gas and oil bearings which are generally prone to film induced instabilities under lightly loaded conditions. This paper presents a thorough investigation of the dynamical behaviour of unloaded externally pressurized gas porous bearings. Expensive computations and a large number of design variables involved with the overall performance analysis make it difficult to carry out a comprehensive study of these bearings. However, an attempt has been made to bring out clearly the effect of the more important design variables on the dynamic performance of the bearings.
Estimation of Flash Temperatures in Dry Sliding
Authors: Lingard S 
Published: February 2007

The paper develops expressions for the flash temperatures experienced by contacting surface asperities during dry sliding. The analysis is based on the heat transfer equations of the Jaeger—Archard theory but additional terms are introduced to allow for the effects of junction growth and cold work in plastic conjunctions. Results of direct measurements of surface temperature in metallic contacts are also given which are in approximate accord with the theory.
Axisymmetric Elastic-Plastic Buckling of Axial and Pressure Loaded Cylinders
Authors: Croll J G A 
Published: February 2007

An analytical approach to the axisymmetric elastic buckling of isotropic cylinders, under arbitrary combinations of radial pressure and axial loading, is used as the basis of a first surface yield and a first full plasticity criterion of plastic collapse. Bending disturbances caused by the boundary constraint of both Poisson bulging under axial loading and the effects of arbitrary radial pressure loading are combined with any prescribed initial geometric errors to provide total ‘equivalent imperfection parameters’ on an otherwise perfectly cylindrical prebuckling state. Elasto-plastic collapse loads are then summarized in terms of just three parameters: the total equivalent membrane and bending imperfections parameters and the ratio of the minimum elastic classical critical axial stress to the material yield stress. The ease with which shells of arbitrary end conditions or internal ring stiffener supports can be treated, the consideration that the results so closely reproduce and extend the more elaborate numerical solutions, and the possible simplifications of the method, make it an ideal basis for design against axisymmetric collapse.
Aerodynamic Influences on the Performance of the Grand Prix Racing Car
Authors: BSc J A Dominy , Dominy R G 
Published: February 2007

The remarkable cornering power of the modern Formula 1 Grand Prix car is almost entirely due to its aerodynamic characteristics. As aerodynamic research generates much more data than can be track tested, it has been found necessary to develop an analytical model to investigate the effect of downforce, drag and centre of pressure on lap times round a sample circuit thus sifting the experimental results. This paper presents such an analysis and applies it to an investigation of the performance of a Formula 1 car round a typical circuit.
Control of Warship Machinery
Authors: Neumann J 
Published: February 2007

The paper traces the evolution of remote and automatic control of warships' machinery. It refers to various incidents and developments which have stimulated the application of centralized control rooms outside the machinery spaces and the evolution of new concepts of presentation of data to the operators. Experience is drawn from the Royal Navy when looking at the historical development of control systems and account is also taken of designs for several other Western navies. The influence of the rapid advances in control technology is reviewed drawing upon experience of pneumatic systems. analogue electronic designs, and the present concepts for distributed digital installations. The paper also takes a speculative look at future designs particularly with respect to presentation of information to the operator. Lessons learnt along the way are highlighted in relation to manning levels and training requirements which must be borne in mind by the control system designer (and/or specifier) prior to the introduction of new system technologies into the fleet.
Measurement of the Aerodynamic and Rolling Resistances of Road Tanker Vehicles from Coast-Down Tests
Authors: Evans E M , Zemroch P J 
Published: February 2007

The aerodynamic and rolling resistances of three articulated road tankers have been measured in a statistically planned series of coast-down tests. Pairs of deceleration and velocity measurements were obtained by applying digital filters to the recorded times at which the vehicle crossed special reflective strips anchored to the road surface. A statistical error analysis showed that the resistances to motion then could be validly estimated by fitting a two-parameter regression model to these measurements. The aerodynamic drag coefficient, CD, was found to be similar for all three vehicles and CD, did not depend on their loading conditions. The rolling resistance, R, approximately doubled when the vehicle was loaded to three times its unladen weight. Significant reductions in R were obtained by changing from twin tyres to single wide tyres on the trailer.