bluuebunny/crossref_metadata_2025 huggingface dataset:
Wave Propagation in Mixtures of Solids and Liquids
Authors: Thorley A. R. D.
Published: February 2007

The differential equations for conservation of mass and linear momentum in unsteady flows of slurries are developed to the point where they can be solved using the numerical method of characteristics. An approximation is introduced which permits the flow velocities of the two components to vary at different rates. Comparisons are made with new experimental data for the amplitude and speed of propagation of transient pressure waves in slurries containing up to 40 per cent by volume of solid matter.
Time-Domain Finite-Element Solutions for Single-Degree-of-Freedom Systems with Time-Dependent Parameters
Authors: Penny J. E. T. , Howard G. F.
Published: February 2007

The motion of systems in which mass, damping, and stiffness properties are known functions of time is described in terms of time-domain finite elements. The response of such systems to external forces is determined by generating matrices, the coefficients of which are functions of the varying parameters. The original differential equations are then replaced by sets of linear algebraic equations which are solved numerically. Examples of the use of the method are given.
Stress and Displacement in Internally Pressurized Thin Prismatic Ducts
Authors: Holland M.
Published: February 2007

An elastic analysis is presented which provides formulae for the prediction of stress and displacement in an internally pressurized thin prismatic duct having three or more flat sides of equal size. Maximum stress in square and haxagonal ducts (of particulor significance in industrial designs) is compared with maximum stress in a circular tube having the same wall thickness and a mean radius equal in length to the maximum radius vector of the mean line in the flat-sided duct.
Thermal and Inertia Effects in Turulent-Flow Thrust Bearings
Authors: Safar Z. S.
Published: February 2007

This paper presents a semi-analytical study of the influence of inertia terms on the thermohydrodynamic analysis of infinitely-wide thrust bearings operating under conditions of laminar and turbulent flow. The momentum and energy equations are not seriously affected by the presence of inertia forces. Results show that the inclusion of inertia terms causes an increase in the fluid film pressure and load-carrying capacity. Thermal effects exert a pronounced influence on bearing performance.
Normal Approach of a Cylinder towards an Elastic Layer
Authors: Cudworth C. J. , Mykura J. F.
Published: February 2007

This paper considers the squeeze film lubrication process of a cylinder approaching a plane rigid surface covered in a thin elastic layer. A simplified lubrication theory is presented, which makes the assumption that the shapes of the solids are the same as the elastically deformed surfaces under dry conditions. The lubrication equations are solved using alternative pressure boundary conditions derived from the dry contact pressure curve. In the experiments, lubricant film thickness is measured using optical interference methods. Curves of film thickness against time are plotted, and the effects on these curves of variations in load and layer thickness are shown to agree with the predictions of the theory.
An Experimental Study of Hydrodynamic Film Rupture in a Steadily-Loaded, Non-Conformal Contact
Authors: Dowson D. , Smith E. H. , Taylor C. M.
Published: February 2007

A study of ventilated gaseous cavitation in a steadily-loaded, non-conformal contact has been undertaken. The work is particularly appropriate to what can be called ‘lightly loaded’ situations such as those occurring in radial race seals and certain industrial coating processes. A wide-ranging experimental programme has been carried out and measurements of film rupture location and pressure distributions compared to computer predictions obtained using the cavitation boundary conditions of Coyne and Elrod. Photographic studies are also reported. The boundary conditions due to Coyne and Elrod have been confirmed as appropriate for the experimental conditions studied.
Turbulent Heat Transfer in a Revolving Square-Sectioned Tube
Authors: Morris W. D. , Dias F. M.
Published: February 2007

An investigation of turbulent heat transfer in a revolving square-sectioned tube is reported in this paper. It is demonstrated that rotation about a parallel axis enhances the customary forced convection heat transfer, and a correlating equation for assessing this effect is proposed. The range of parameters covered in the experiments permit the results to have application for the assessment of heat transfer in certain gas-cooled electrical machine rotors.
An Investigation of the Transient Effects during Variable Speed Cutting
Authors: Sexton J. S. , Stone B. J.
Published: February 2007

Conventionally the stability analysis of machine tools is restricted to determining if a particular operation will become unstable. The transient behaviour is not examined in any further detail. However, under certain conditions larger transient vibrations occur even though the process may ultimately be stable. A method of prediction of transient behaviour is presented and applied to variable speed cutting on a lathe where such transients are significant.
The Rolling Contact of Misaligned Elastic Cylinders
Authors: Barber J. R.
Published: February 2007

A solution is given for the tangential tractions developed between two rolling cylinders of identical elastic materials, whose axes are slightly misaligned. A critical misalignment angle is found, above which slip occurs throughout the contact area. For smaller angles, the contact area contains regions of adhesion and microslip. Results are given for the extent of these regions and for the axial force generated due to the misalignment.
Dynamics of the Dynatune Gyroscope
Authors: Bulman D. N. , Maunder L.
Published: February 2007

The paper describes a new form of tuned gyroscope capable of achieving the high precision required for inertial navigation. The essential features of the arrangement consist of a rotor, driven and supported by a set of transverse flexible spokes to which tuning masses are added. The principle of operation is described briefly and confirmed by reference to experimental results.
Wear Out Failure Patterns and Their Interpretation
Authors: Carter A. D. S.
Published: February 2007

It is shown theoretically that fatigue of a component will result in a failure pattern which consists of an initial period of intrinsic reliability, or near zero failures, followed by a rapid increase in failure rate when loss of fatigue strength becomes operative, to be followed in turn by a period during which the failure rate decreases with time or maybe remains constant. By contrast other wear-out modes involving a continuous loss of strength give rise to a steadily increasing failure rate after the period of intrinsic reliability has expired. Practical examples of each type are quoted to substantiate the theoretical deductions. The interpretation of wear out characteristics by Weibull distributions is discussed.
Measurement of Sodium Vapour Pressure Using Sodium as Manometer Fluid
Authors: Erens P. J. , Kröger D. G.
Published: February 2007

The pressure of saturated sodium vapour in the range 1114–47 500N/m2 is measured using a sodium manometer developed for this purpose. Commercially obtainable reactor grade sodium is used and is found to follow the equation log P= 9.36037-(5048–74/r), where P is in N/m2 and T in Kelvin.
Choking Effects in the Blade Rows of Turbomachines
Authors: Horlock J. H.
Published: February 2007

Three-dimensional flows through cascades of blades are studied, the blading being fully choked internally. Initially the two-dimensional flow through a ‘zero stagger, zero camber’ blade row, with subsonic entry and exit flow, is described. The radial flows are produced by radial variations in throat area, or by a variety of entry shear flows. Subsequently, the analysis is developed to describe similar fully choked flows through staggered blade rows, particularly the first rotating row of a transonic compressor.
The Steady Performance of Externally Pressurized Porous Rectangular Pad Gas Bearings Incorporating Viscous and Inertia Dominated Flow
Authors: Naaum A. G. , Lewis G. K.
Published: February 2007

A general analysis of three-dimensional flow through a porous rectangular thrust bearing which incorporates both viscous and inertia permeabilities of the porous media is presented. Solutions for load capacity and flow rate are obtained using standard numerical procedure but introducing a new term ‘the effective permeability’. It is shown that inertia flow reduces the load capacity and increases the flow rate through the bearing.
Interaction and Wall Corrections for the Slow Motion of Two Fluid or Solid Particles Parallel to the Axis of a Circular Cylinder through a Viscous Fluid
Authors: Greenstein T.
Published: February 2007

Numerical values are provided which enable the drag force on the reference spherical fluid or solid particle, and the torque on the reference spherical solid particle, to be computed for the particular case when two spherical particles move in a direction parallel to their line of centres parallel to the axis of a circular cylinder. Results for this motion are also expressed in terms of the ratio of drag forces experienced by (1) the particle of arbitrary shape in a bounded, two particle system, and the particle in an unbounded, two particle system, and (2) the particle in a bounded, two particle system, and the particle moving alone with the same speed and orientation in the same, but unbounded, fluid. The computation furnishes the interaction and wall corrections correctly to the first-order in the ratios of characteristic particle dimension to characteristic distance of the particle from both another particle and from the cylinder wall.

The axisymmetric problem was extended to the more general case where the two particles may be placed eccentrically within the cylinder and the torque was also computed. Furthermore, the two particles may be fluid droplets as well as solid particles.
Pressure Distribution between Closely Contacting Surfaces
Authors: Mostofi A. , Gohar R.
Published: February 2007

The pressure distribution, contact arc extent, and deflection are determined for the elastic contact of a long roller and a cylindrical hole in an infinite body. It is shown that these variables depend on the degree of conformity of the two bodies and that Hertz's theory should not be used when the arc dimensions are of the same order as the radii of curvature, as its assumptions are violated. When the hole circumference available is reduced, pressure discontinuities can occur where the arc terminates. The results of the analysis have application in the design of some engineering components, such as complete and partial arc bearings and Novikov gears, where a knowledge of the magnitude and distribution of the contact stress is important.
Optimization of a Follower Train for a Two Degree of Freedom Cam
Authors: Jaini C. K. C. , Rao A. C.
Published: February 2007

Contributions intended for publication as Research Notes should preferably be limited in length to 1000 words and two illustrations, and should be addressed to the Manuscript Section, The Institution of Mechanical Engineers, 1 Birdcage Walk, Westminster, London SW1H 9JJ
Dynamics of Gyropendulum for Small Angles
Authors: Krishnan V.
Published: February 2007

It was shown in (1)‡ that at a given angle of inclination, the gyropendulum may perform steady precession Ω1 or Ω2 and any small disturbance will result in the subsequent motion consisting of precession and nutation, the corresponding nutational frequency being Ω1 or Ω2 respectively. For small angles, Ω1 and Ω2 represent the natural frequencies of the system.
Prediction of Turbulent Cavity Flow Driven by Buoyancy and Shear
Authors: Ideriah F. J. K.
Published: February 2007

A finite-difference numerical procedure, incorporating a buoyant version of the k-ε turbulence model, is employed to compute turbulent, mixed convection in a square cavity for Reynolds number Re =104 to 2 × 105, and Archimedes number Ar=0 to 0.4. For Ar>0–04 stable advancement of the solution procedure is obtained only through the use of an ‘inertial relaxation’ method. The calculated flow, temperature, and turbulence fields are presented and compared with available experimental data. At high Re and low Ar the predicted heat transfer agrees with the correlation Nu = 1.16 Re0.5. When buoyancy is pronounced the computed Nu is some 15 per cent higher than the data; this is suspected to be due to the turbulence model, and possible improvements to the model are suggested.
Thermal Bending of Thick Rectangular Plates of Bimodulus Composite Materials
Authors: Reddy J. N. , Ber C. W. , Hsu Y. S. , Reddy V. S.
Published: February 2007

Closed-form and finite-element solutions are presented for thermal bending and stretching of laminated composite plates. The material of each layer is assumed to be elastically and thermoelastically orthotropic and bimodular, i.e., having different properties depending upon whether the fibre-direction normal strain is tensile or compressive. The formulations are based on the thermoelastic version of the Whitney-Pagano laminated plate theory, which includes thickness shear deformations. Numerical results are obtained for deflections and neutral-surface positions associated with normal strains in both of the in-plane coordinates. The closed-form and finite-element results are found to be in good agreement.
Effect of Swirl on Pressure Recovery in Annular Diffusers
Authors: Kumar D. S. , Kumar K. L.
Published: February 2007

Annular diffusers are likely to operate with varying amounts of swirl at the inlet. The work described in this paper is concerned mainly with an experimental investigation of subsonic turbulent swirling flows through annular diffusers having diverging hub and casing boundaries. The test facility was designed SO as to peImit different levels of inlet swirl. The static pressure distributions and the axial and tangential velocity profiles were measured with the help of a three-hole cobra probe suitably mounted at different cross sections along the diffuser length. The diffuser performance parameters such as static-pressure recovery, effectiveness, and the total pressure loss coefficient were then computed from the experimental observations. The behaviour of these parameters has been discussed to establish the effect of swirl. The presence of inlet swirl was found to increase the overall static-pressure recovery. A substantial increase in the pressure recovery occurred over the initial stages of diffusion and the gain was maintained thereafter. Improvement in effectiveness was more significant for otherwise stalled diffusers. Introduction of swirl was found to substantially reduce the chances of separation at the casing and to shift the stall from the casing to the hub for the stalled diffusers.
Design of Planetary Cams for Short Period Events
Authors: Turnbull S. R.
Published: February 2007

A cam mechanism is described in which a planetary cam operates in sequence a number of equally spaced radial translating followers, the lift and return of the followers taking place during a small angular rotation of the arm which carries the planetary cam.

Equations for the synthesis of the planetary cam are developed, along with those for the sliding velocity between cam and follower.

A method for allowing small variations in timing is described and some experimental results are given for a number of cams operating two different types of translating follower.
Large Deflection Cylindrical Bending Analysis of Cross-Ply Laminated Strips
Authors: Turvey G. J.
Published: February 2007

A finite-difference implementation of the dynamic relaxation (DR) method is used to solve the equations for antisymmetrically laminated, cross-ply strips. Comprehensive dimensionless results are presented for uniformly loaded simply supported and clamped GFRP (glass fibre reinforced plastic) and CFRP (carbon fibre reinforced plastic) strips in order to establish the influence of extensional-flexural coupling on the strip response in the large deflection regime.
Dynamic Loading of Micropolar Fluid Lubricated Short Journal Bearings
Authors: Singh C. , Sinha P.
Published: February 2007

Dynamically loaded bearings in which the load alternates or rotates are studied in this paper. The Reynolds equation for the general case of a dynamically loaded infinitely short bearing is derived, where the lubricant is assumed to be micropolar. Detailed consideration is given to the dynamic behaviour of squeeze films in a short journal bearing under a sinusoidal load with no journal rotation. Various bearing characteristics are calculated, assuming a full film to exist. The micropolarity of the fluid results in more resistance to journal motion, thereby allowing smaller eccentricities for a constant load. The overall conclusion of this study is an increase in the effective viscosity due to the micropolarity of the lubricant. This theory may find application in lubrication when additives are used.
Flow of Compressible Two-Phase Mixtures through Sharp-Edged Orifices
Authors: Chisholm D.
Published: February 2007

It is demonstrated that equations for the velocity ratio during the flow of two-phase gas/liquid mixtures through sharp-edged orifice plates, developed under incompressible flow conditions, are applicable to compressible flow conditions. Pressure ratios down to 0.1, and choked and unchoked flow conditions, are examined.
A Theoretical Analysis of the Twin-Land Type of Oil-Control Piston Ring
Authors: Ruddy B. L. , Dowson D. , Economou P. N.
Published: February 2007

Cyclic variations of the important operating characteristics of the twin-land type of oil-control ring have been analysed by considering radial and torsional equilibrium of the ring cross-section. The assumed form of the face profiles of the lands are related to measurements of worn oil-control rings and the analysis includes the effect of surface roughness in the mixed lubrication regime.

The results show that oil-control rings may operate with fluid film, mixed, or boundary lubrication, depending upon the land profiles, the attitude of the ring, and the surface roughnesses on liners and rings. A small height difference between the lands is shown to have a significant effect upon the calculated volume of lubricant passing the ring and the analysis has provided the basis for further rational design of this important machine element.
Drain Discharge Characteristics of Horizontal Drums
Authors: Cranfield R. R.
Published: February 2007

An investigation is made of the normal steady drainage of water from horizontal drums freely discharging in a steam atmosphere via vertical drains.

The flow to the drain orifice in a horizontal drum is asymmetric. At the drain the discharge flow may have several forms; however, there are two basic regimes. At low discharge rates it resembles flow over a weir, whereas with increasing flow there is a transition to a form of orifice flow when discharge is as a jet. In both cases the discharging water is free from entrained steam and vortex formation. Correlations are given to determine the regime and, hence, the applicable head/discharge relationship for drain/drum radius ratios from 0–08 to 0–25.
Theoretical Analysis of the Electroforming Process
Authors: McGeough J. A. , Rasmussen H.
Published: February 2007

A theoretical model is developed for electroforming with a shaped, soluble anode-electrode. Cases are considered for which the electrode is either flat or conforms initially to the shape of the cathode-mandrel. The model is first analysed by a perturbation procedure for a case where the amplitude and slope of the surfaces of sinusoidally-shaped electrodes are small compared with the inter-electrode gap width. The analysis shows that for d.c. electroforming, when the soluble anode is initially flat, the upper surface of the electroformed metal can become fiat at some stage. After that stage has been passed, the amplitude of the metal layer increases indefinitely with time of electroforming. A uniform thickness for the electroformed metal layer cannot, therefore, be achieved, unlike the case for insoluble plane anodes. When a soluble anode which conforms initially to the cathode-mandrel is used, a fiat upper surface for the metal layer can be obtained.

When periodic reversal of polarity is used with soluble anodes, a uniform thickness for the electroformed layer cannot be achieved.

A numerical method of analysis of electroforming is proposed which removes the restrictions on the size of shape treated by the perturbation method. The latter method is then applied to the practical case of electroforming of a mould for a rubber ‘O’ ring.

Conditions are investigated where the anode is (i) plane and insoluble, (ii) plane and soluble, (iii) and (iv) conforming initially to the mandrel-shape and either insoluble or soluble. The numerical method has revealed that a variation in the metal layer thickness occurs for all these types of anode, and that little marked improvement arises if the simplest type of anode—plane and insoluble—is replaced by any one of the others.
Analogue Computer Simulation of a Robot-Manipulator
Authors: Backhouse C. , Jones J. Rees
Published: February 2007

This paper describes a dynamic simulation of a robot-manipulator implemented on an analogue computer and under position control of a microcomputer. A method of dynamics based on constraints is developed which enables the simulation to be implemented on a computer of limited capacity. Hydraulic motors, controlled by electrohydraulic servo-valves are modelled at each joint. Results of displacement, velocity and motor load pressures are shown for example motions, and the interdependence of link motion is discussed. The potential uses of the analogue simulation in research and development of manipulators and their control algorithms are described.
The Rolling-Pad Journal Bearing: A Promising Antiwhirl Configuration
Authors: Malik M. , Sinhasan R. , Singh D. V.
Published: February 2007

The rolling-pad journal bearing is a kinematic variation of the well-known tilting-pad journal bearing. In rolling-pad bearings, the pads, instead of tilting about fixed pivots, roll at their back surfaces on the inside surface of a common sleeve to accommodate changes in the operating conditions of the bearing. This paper presents a comparison of the theoretical performance characteristics of rolling-pad journal bearings with those of tilting-pad journal bearings. The comparative study indicates that the dynamic performance characteristics of the rolling-pad bearing configuration are superior to those of the tilting-pad bearing.
Analysis of a Centrally Loaded 120 Degree Partial Porous Journal Bearing Taking Tangential Velocity Slip into Account
Authors: Malik M. , Chandra M. , Sinhasan R.
Published: February 2007

This paper presents the analysis of a partial porous journal bearing for its static and dynamic characteristics. Tangential velocity slip at the interface of the fluid film and the porous medium has been taken into account. The analysis is general and can be easily adapted to plane journal and non-circular bearing configurations.

The results reported in the paper are for centrally loaded 120 degree partial bearings of aspect ratio equal to unity. These results include static as well as dynamic characteristics of the bearing. A wide range of permeability parameter and R/C ratio has been covered making the data quite comprehensive for design purposes.
A Theoretical and Experimental Evaluation of the Multigimbal Hooke's Joint Gyroscope
Authors: Burdess J. S. , Fox C. H. J.
Published: February 2007

The paper considers the response of a multigimbal Hooke's joint gyroscope to constant and harmonic rates of turn. The resonant behaviour of the gyro is examined in some detail and it is shown that the suspension may be designed to make the device insensitive to harmonic inputs at twice rotor frequency. The predictions of the theory are tested experimentally.
Unfolding a Curved Elastic Sheet
Authors: Wang C.-Y.
Published: February 2007

A curved elastic sheet is flattened on a rigid flat plate by vertical end forces. The problem is governed by a non-dimensional parameter, B, which signifies the relative importance of flexural rigidity to the applied force and the natural radius. The elastica equations are solved by elliptic functions, perturbation for small B, and numerical integration. Force-displacement characteristics and sheet configurations are found. The results may be applied to sandwiched leaf springs.
The Behaviour of Circular Tubes with Large Openings Subjected to Axial Compression
Authors: Montague P. , Horne M. R.
Published: February 2007

Circular, thin-walled, steel tubes, with elongated, non-axisymmetric openings subjected to compressive, longitudinal load are examined. Thirteen laboratory tests are described in which careful measurements were made of displacements and strains. The tested specimens were in two geometrically dissimilar groups and their modes of failure were found to be different; in one group the free edges of the openings buckled before failure of the tube and in the other group large displacements at the free edges coincided with the reducing axial stiffness of the tubes.

Two theories are proposed to explain these different kinds of behaviour and their predictions compared with the experimental results.
Balancing of Flexible Rotors during Operation
Authors: Van de Vegte J.
Published: February 2007

Previous theoretical and experimental work on balancing rotating systems without interrupting operation is extended to multi-disc flexible shaft systems with two balancing planes.
Mass Velocities under Choked Flow Conditions in Two-Phase Flashing Pipe Flow
Authors: Chisholm D.
Published: February 2007

Equations are developed for predicting the mass velocity under choked flow conditions in two-phase pipe flow. Predictions are compared with experiment and the most widely used alternative prediction procedures.
An Experimental and Theoretical study of Lubricant flow rate in Static, Grooved, Rectangular Thrust Bearings
Authors: Hargreaves D. J. , Taylor C. M.
Published: February 2007

The work to be described here was undertaken in the preliminary stages of a research programme designed to study the true extent of lubricant films in non-stationary, grooved, rectangular thrust bearings. In such externally pressurized bearings an air-lubricant interface may be formed. The study of this interface was seen as a useful step in a consideration of film formation and flow rate prediction in liquid film journal bearings.
On the Time-Dependent Spin Creep of a Railway Wheel
Authors: Newland D. E.
Published: February 2007

This paper describes two theoretical calculations of the fluctuating spin creep of a railway wheel rolling on straight track. The first calculation is of the transient spin moment which occurs when a constant spin creep angular velocity is applied suddenly to a rolling wheel. This may occur, for example, when a wheel passes over a discontinuity in the rail and rolling contact is resumed suddenly. The second calculation is of the fluctuating spin creep moment which occurs when a coned railway wheel rolls along a slightly corrugated rail.

The analysis is highly idealized, using the approximations of the simplified theory of Kalker and assuming that the area of slip is limited to a negligible proportion of the area of contact. In the first calculation, the area of contact is assumed to be circular; in the second calculation, it is assumed to be rectangular.

Subject to these far-reaching assumptions, the results of the calculations suggest that oscillatory fluctuations in spin creep may be initiated by rail discontinuities and irregularities. Such oscillatory fluctuations in conditions at the contact patch may have a role in the development of rail corrugations.
The Dynamic Response of Railway Track to High Frequency Lateral Excitation
Authors: Grassie S. L. , Gregory R. W. , Johnson K. L.
Published: February 2007

The dynamic response of railway track to lateral forces is investigated. Experimental data in the frequency range 50–1500 Hz suggest that track laid on wooden sleepers is adequately represented as a beam (the rail) on a damped elastic support (the ballast). For concrete-sleepered track the railhead appears to move significantly on the lateral flexibility of the web, and a simple continuous model is developed from which its lateral dynamic response may be found.
The Measurement of Dynamic Cutting Force Data and its Application to the Prediction of Chatter
Authors: Burdekin M. , Kilic S. E.
Published: February 2007

A method and the related equipment to obtain dynamic cutting force coefficients under simulated regenerative chatter conditions are described. The coefficients in both thrust (normal to the cut surface) and the main cutting (tangential) directions for orthogonal cutting are presented for various cutting conditions.

An algorithm which is developed to predict chatter instability by combining the receptance of a machine tool with the dynamic cutting data is also presented. Comparison of experimentally-determined stability charts of a centre lathe with the predicted ones is made to evaluate the reliability of the method.
The Transfer Matrix Method for the Vibration of Compressed Helical Springs
Authors: Pearson D.
Published: February 2007

The partial differential equations of motion are obtained for a helical spring subject to a static axial force, the typical element of the spring having six degrees of freedom. The wire cross-section can be any doubly symmetrical shape. The overall transfer matrix is calculated and its application is discussed for obtaining the response to forced sinusoidal vibration. Natural frequencies are found from the transfer matrix by iteration. Comparisons are made with published experiments on the natural frequencies of helical springs, made from round wire, with and without a static axial force. Comparison is also made with published theory for the static buckling of helical springs. Information is given on the effect on the natural frequencies of the static axial force, helix angle, number of active turns, ratio of helix to wire diameter, Poisson's ratio, shear coefficient, and the end conditions. The calculation of the normal modes is discussed.
Oil Film Thickness and Pressure Distribution in Elastohydrodynamic Point Contacts
Authors: Mostofi A. , Gohar R.
Published: February 2007

In this paper, a general numerical solution to the elastohydrodynamic point contact problem is presented for moderate loads and material parameters. Isobars, contours and regression formulae describe how pressure and oil film thickness vary with geometry, material properties, load, and squeeze velocity, when the rolling velocity vector is at various angles to the static contact ellipse long axis. In addition, the EHL behaviour under spin is examined. The theoretical predictions of film thickness compare favourably with other numerical solutions to the point contact problem, as well as with experimental results which use the optical interferometry method to find film thickness and
Cavitation in Vortex Diodes and Its Significance in Diode Pumps
Authors: Priestman G. H. , Tippetts J. R.
Published: February 2007

Vortex diodes handling liquids are subject to the effects both of cavitation and Reynolds number. The apparent complexity of their characteristics makes design and simulation difficult. To some extent, however, this complexity is artificial and can be reduced.

The effect of cavitation is most severe in the forward state. The usual characterization in terms of Thoma's cavitation number (based on pressure drop and downstream pressure) obscures a much simpler relationship using the upstream pressure explicitly. This yields simple equations which cover the cavitating regime. The non-cavitating characteristics are shown to be well predicted by established data on the operation of diffusers. Experimental data vindicating this is taken from Zobel, Syred et al, and our own experiments.

Cavitation in the reverse state is not simplified but it is much less important for the diodes quoted. The practical implications of these results in diode pump applications are examined and quantified.
Construction of Power Stations Designed and Built as Single Units
Authors: Masding H
Published: February 2007

This paper sets out an assessment of the value and practicality of the construction of fossil fired generating plant designed and built as single units and includes a proposal for the design and layout of a single unit designed to maximize the benefits derived from this concept.

The conclusion is that an acceptable design of power plant, based on the construction of single 600 MW units, can be developed for the UK system which could prove to be advantageous in construction time, in capital cost and in running cost. The layout applies equally effectively to large ‘green field’ sites or for replanting existing stations; in addition, the plant can be replicated in detail and thereby reduce design and engineering costs. Finally the layout can also be applied in principle to smaller units for overseas utilities as required by their system developments.
Future Coal-Burning Stirling Engines
Authors: Walker G , Fauvel R , Srinivasan S , Gustafson R , van Benthem J
Published: February 2007

The high price and limited availability of oil fuel forces a return to coal as the primary fuel. This provides unprecedented opportunities for applications of Stirling engines to stationary power and automotive application over a broad spectrum. For heavy automotive application in railway locomotives and the larger off-highway mining and earth moving vehicles, it appears possible for Stirling engines of corresponding power and efficiency to replace diesels in the same installation envelope. Proposals are presented for the conversion of diesel engines to Ringbom—Stirling engines using air as the working fluid, water as the lubricant and with high pressure steam injection for power boost at peak load conditions. An experimental proof-of-principle Ringbom-Stirling diesel conversion presently under development at the University of Calgary is briefly described.
Heat Transformers: Present State of a New Technology
Authors: Rojey A , Cohen G , Cariou J P
Published: February 2007

The problem of making use of low-level calories is a general one, in the light of the amount of thermal waste in numerous sectors. It is important both in the utilization of new energy sources available in thermal form and in the industrial field. In these cases, the low-level heat recovered can be utilized by means of systems operating on trithermal absorption cycles without compression and expansion devices. Recent progress in this field suggests that the extensive development of such techniques is likely. The performance attained with a new heat transformer developed by the Institut Français du Petrole is described. Various examples of industrial applications are presented and the economics are discussed.
Microcomputer Control of Hydro Turbines
Authors: Marshall A G , Winning D J , Davie H , Grant N F
Published: February 2007

A description of the application of microcomputers to the governing of hydro turbines for electricity generation on the UK public electricity supply system is presented. Experience has been gained using experimental equipment fitted to operational generating plant and a dramatic improvement in response to system frequency disturbances has been demonstrated.
The Engineering of the National Transmission System of the British Gas Corporation
Authors: McHugh J
Published: February 2007

Outlines the development of the national gas transmission system over the past fifteen years. Describes the design, construction and operation of terminals, compressor stations, storage facilities and the central control system.
The Performance Potential of Limited Cooled Diesel Engines
Authors: Watson N , Kyrtatos N P , Holmes K
Published: February 2007

A mathematical model is used to predict the performance of a turbocharged diesel engine with a partially insulated combustion chamber. The model is briefly described, with emphasis on heat transfer aspects and prediction of combustion chamber surface temperatures.

First the trade-off between performance improvement (efficiency) degree of insulation, combustion chamber surface temperature and exhaust gas energy is examined. It is shown that the high surface temperatures in the cylinder, due to insulation, cause volumetric efficiency to fall. However, this reduction is offset by increased boost pressure from the turbocharger due to greater exhaust gas energy. The contribution to overall reduction in heat loss from cylinder head, piston and liner and their effect on engine efficiency are presented and discussed.

Various turbo-compound systems are examined and it is shown that most systems become unmatched when working over the wide speed and load range necessary for vehicle application, unless a variable geometry turbine or a variable ratio gearbox (this maintains compound power at part load) are used. Furthermore, substantial overall performance benefits can only be obtained with very efficient turbomachinery.

Rankine bottoming cycles are more effective than fixed geometry turbo-compounding at low load, but their normal efficiency is limited by high condenser temperature, and they would be difficult to install in a compact European truck.

It is concluded that the ultimate improvement in engine specific fuel consumption of an adiabatic turbo-compound engine is 20 per cent (excluding the savings from fan and water pump). However, drastically new design concepts are necessary, if engines are to be built that approach this degree of insulation. Meanwhile redesigned conventional engine types will offer substantial reduction in cooling system requirements with more modest thermal efficiency benefits.
Two-Shift Operation of 500 MW Boiler/Turbine Generating Units
Authors: Beatt R J I , Birch W L , Hinton S E , Kelly M , Pully M J , Wright G R L , Wright W
Published: February 2007

The paper describes the preparation for, and current practice of, daily intermittent, or ‘two-shift’, operation of large modern oil-fired 500 MW generating units by the South Western Region of the Central Electricity Generating Board at Fawley and Pembroke 2000 MW power stations.
Design and Performance of Silicon Carbide Product Lubricated Bearings
Authors: Kamelmacher E
Published: February 2007

Operational experience of using radial and thrust bearings with both stationary and rotating surfaces made of solid tubes of reaction bonded silicon carbide are discussed. Particular attention is given to the bearing behaviour at high fluid pressure which prevents cavitational fluid film rupture. Several cases of bearing instability at such conditions are described, and comparison with the theoretical stability criteria derived from the short bearing fluid film equations with inertia effects at the laminar flow is made. Segmented bearings suitable for application in a cavitation free environment are described.
The Efficient Use of Energy in Packaged Air Compressor Sets
Authors: Laing P D
Published: February 2007

Some 10 per cent of all electrical power used in industry is employed compressing air. The great majority of this compressed air is today produced by packaged oil injected screw compressor sets. This paper analyses where the energy or power goes and how best to make use of it. Subjects covered include the efficiency of the compressor itself the different types of part load control and the use of waste heat.
Automated Storage and Handling of Cores and Moulds in a Foundry
Authors: Lee R W
Published: February 2007

A recently installed automated materials handling system in a UK foundry is used as a vehicle to describe an engineering answer to an inventory management problem. The automated activity is between the production of cores and moulds from a sand/epoxy raw material and issuing them to the next stage of production—casting. Initial fragility of the product called for controlled physical movement and a limited useful product age required a close control over stocks and issues. Conveyors, storage and retrieval machines and other elements of the installation are described in terms of how they carry out functions of movement. Computers, programmable logic controllers and hard wired logic are described in hierarchical and functional terms.
An Integrated Computer Aided Engineering System for Prototypes and Tooling of Automotive Parts
Authors: Humphreys H R O
Published: February 2007

Increasing emphasis is now being placed on the benefits of an integrated system with the basic information generated at the draughting stage being held on the computer and manipulated to produce cost estimates, drawings, production control information, machine control and certification of quality. The integration of these functions, together with the integration of component production, prototype manufacture and toolmaking, can result in reduction of both lead times and cost of production. The application of CAD/CAM within Delta is of general interest because Delta's companies (average size 300–400 employees) are in many ways typical of mechanical engineering companies and the specification of the computer aided design and manufacturing system which Delta has introduced, would be applicable to many small to medium sized engineering companies.
High Speed Trains Throughout the World
Authors: Bouley J
Published: February 2007

This paper reviews the development of high speeds throughout the world, with details of the records attained and commercial speeds worked in four countries where the 125 mile/h threshold has been reached or even exceeded. Achievements on conventional track in Great Britain, France and Federal Germany are outlined and the two examples of new purpose-built lines specializing in high speed passenger traffic in Japan and France are described in detail.
Available and Projected Trends in Urban Rail Vehicles
Authors: Howard D F
Published: February 2007

The paper examines the rapid growth in urban railway development throughout the world and notes that the systems involved almost exclusively rely on electric traction. The basic characteristics of various types of urban railway and their operation are explained and a comparison is drawn between selected vehicles on overseas systems. The UK scene is then examined together with the salient features of British vehicles used on urban railway systems. Conclusions are drawn as to the requirements of a future urban railway vehicle.
The Design, Development and Manufacture of a New and Unique Tennis Racket
Authors: Haines R C , Curtis M E , Mullaney F M , Ramsden G
Published: February 2007

This paper describes how a revolutionary new process was devised for producing top quality tennis rackets from carbon fibre reinforced thermoplastic by a specially developed injection moulding process. The product and process were evolved following an initial study by a multi-discipline team in January 1978 which led to a fully engineered manufacturing process starting production in November 1980.

The new racket undercuts the price of competitors' carbon fibre composite rackets in a market sector of growing importance, and the ‘added value’ of the product is significantly higher than that for conventional wooden rackets currently manufactured by the Company. When other comparisons are made with wooden racket manufacture, the new product and process show advantages in nearly every aspect of production efficiency.

The new racket and process which are protected by three patents, won a Design Council Award in 1981 and was the winner of the Willis Faber Manufacturing Effectiveness Award organized by the Institution of Mechanical Engineers in May 1982.
Computer Aided Engineering: Its Effectiveness in Avionics
Authors: Gooch I D , Miller C T , Morgan D R , Wallace T A H
Published: February 2007

The paper describes computer aided design and manufacture and its effectiveness for the production of avionic components. A recent development is the generation of machining parameters from the input of the geometry of the component. The advantage of group technology machining cells are discussed together with the use of computerized inspection and computerized production control. The effect of the complete integration of design and manufacture with a high investment in computer aids is illustrated by three case studies.
Wealth Generation—Our Essential Task
Authors: Small B W
Published: February 2007

Wealth generation is the responsibility of those who design and make our engineered products. Others can do nothing more than create a sympathetic environment. Improving our manufacturing effectiveness, in its broadest business sense, is essential and an absolutely practical proposition. If most of our engineering businesses and factories were as good as our best our share of world trade would quickly improve.

Five actions are suggested as the ingredients of a revival programme. We need to: (i) accept that too many of our factories are obsolete; many of them, if designed anew for today's purpose, would not remotely resemble existing operations; (ii) stop being tolerant of the 15–30 per cent excess cost in our products; (iii) become more commercially aggressive in applying new technology such as CAD/CAM and FMS; (iv) substantially improve our national skills and capacity to plan and implement more competitive operations; (v) encourage every engineering business unit, that does not have at least one major radical improvement programme under way, to start one now.

While most revival programmes will require investment, the imperative ingredient is people, especially the creative engineer. Wealth generation is our essential task.
Advances in the Manufacture of Aerospace Fasteners
Authors: Howard R A , Skinner L E
Published: February 2007

T. J. Brooks Limited achieved a 42 per cent increase in output in 1981 through the introduction of unique manufacturing processes, developed in-house, to become the European leader in aerospace fastener technology. Creation of the right industrial climate where change is accepted enabled this increase to he achieved with no overall increase in labour.
Design for Manufacture Using a CAD/CAM System—A Methodology for Turned Parts
Authors: Plummer J C S , Hannam R G
Published: February 2007

This paper describes a design methodology which has been developed to ensure that turned parts are designed for manufacture. The methodology has been incorporated in a software package which is used interactively on a CAD/CAM system. The methodology ensures that the choices offered to a designer during the design stage are such that turned parts can be produced to company standards using the manufacturing facilities available. The software package automatically selects the necessary raw material, the appropriate tool assemblies, and the necessary machine tools required to manufacture each component as its design process is carried out.
Mount Newman—a Keystone Development
Authors: MacGregor I K
Published: February 2007

Describes the discovery of the Mount Newman iron ore deposit in Western Australia, development of the mine, construction of port facilities, rail link and town in the 1960s and present day operations.
Development and Application of Continuous Dress Creep Feed Grinding
Authors: Parrott E
Published: February 2007

In 1979 Bristol University concluded some work, on behalf of Rolls-Royce, on continuous dress creep feed grinding. This work had only been applied to flat faces at that point. In November 1979 it was decided to embark on a production implementation plan based on profile work and involving development work in line with production implementation.

This paper describes the theory of continuous dress creep feed grinding, explores the development work required and the implementation procedure and experience gained in the production of turbine blades in Product Centre 02 at Rolls-Royce, Derby.