bluuebunny/crossref_metadata_2025 huggingface dataset:
Knock in Dual-Fuel Engines
Authors: Karim G. A. , Klat S. R. , Moore N. P. W.
Published: October 2007

The paper describes some aspects of the findings of an investigation which was initiated mainly to obtain a better understanding of the phenomenon of knock under dual-fuel operation and to determine the effect of various operating parameters on the knock-free performance limits and the nature of these limits. Some common gaseous fuels such as methane, propane, ethylene, acetylene, hydrogen and some of their mixtures were used as the main fuels. A method is suggested to relate changes in the knock-limited power output of a dual-fuel engine with the intake temperature of the charge and the nature of the main fuel used.
Self-Ignition of Propane-Air Mixtures in a Supercharged, Motored Reciprocating Engine
Authors: Annand W. J. D. , Abayazid O. M.
Published: October 2007

An experimental investigation has been made of the relation to operating conditions of the self-ignition behaviour of propane-air mixtures, in a motored reciprocating engine of 4.8 in bore, at 15.75:1 compression ratio. At each of two speeds, intake pressure was varied up to 22 lbf/in2 abs, and the effect of variation of intake temperature and mixture strength upon self-ignition was observed. The results are presented in terms of measured intake conditions and of computed compression-end conditions, and are compared with those of Moore and Roy. It is shown that a single-step Arrhenius reaction is not an adequate model for correlation of the observations.
Third Paper: Causes of Movement in Reinforced Concrete Turbo-Blocks and Developments in Turbo-Block Design and Construction
Authors: Fitzherbert W. A. , Barnett J. H.
Published: October 2007

The C.E.G.B. are installing single shaft turbo-generators of 500 and 660 MW with solid coupled shafts. It is important to assess the extent to which the operation of these large machines might be affected by changes in alignment resulting from differential movements in the turbo-generator blocks. The paper sets out the development of turbo-blocks against the evolution of turbo-generators and associated plant; and discusses the problems which have emerged as a result. The authors investigated 12 existing reinforced concrete turbo-blocks in the 120-200 MW range to establish the extent and cause of differential movements in the concrete and their resulting effects on the machine. Level measurements were taken over a period of about three years on the machine floors and basements of these blocks. These readings were correlated with changes in concrete temperature, moisture content and variations in ambient conditions. Conclusions are drawn from the investigation which can affect the design and construction of concrete turbo-blocks and particularly certain procedures for machine alignment. The continued investigation on the 500/660 MW blocks now under construction is described, as well as methods adopted for the better distribution of heat in the turbo-blocks. Current procedures for design and construction of turbo-blocks are reviewed, relative merits of concrete and steel blocks compared, and the changing roles of plant manufacturer, civil engineer and block contractor/manufacturer considered. The tentative views formed by the authors from this study, from continental sources and from their discussions with power station superintendents and staff are submitted for discussion.
Hydrodynamic Factors Affecting the Design of Valve Plates and Thrust Bearings
Authors: McKeown J. , Milner D. A. , Shute N. A. , Turnbull D. E.
Published: October 2007

The limitations of analyses of the characteristics of viscous flow systems based on the assumption of constant fluid viscosity have been recognized for a considerable period of time and attempts to overcome them have previously been made by suggesting the use of a ‘mean effective’ value of viscosity. It has become increasingly obvious, however, that the large changes which often occur in the value of the viscosity of most hydraulic fluids suitable for use in fluid power and lubricating systems can no longer be disregarded and a more exact study of the results of the effects produced by variations of both pressure and temperature on the viscosity of such fluids is desirable.

The present work contains such an analysis, and consideration is given to a system wherein combined Couette and Poiseuille flows occur. Predictions are made of the effects produced under certain operating conditions by the variation of the viscosity of the fluid with both the instantaneous values of the fluid pressure and the fluid temperature. Methods of applying these results to studies of the operation of valve plates for axial piston pumps and motors, radial face or mechanical seals and hydrostatic thrust bearing design are indicated.

Approximate methods of allowing for the effects of heat losses by conduction through the rigid boundaries of the film are suggested and some results of a computer study of these conditions are described.
Effect of Dropwise Condensation on the Thermal Efficiency of a Triple Effect Water Distillation Plant
Authors: Poll A. , Potter C. J. , Powell A. W.
Published: October 2007

The dropwise condensation promotion of a power station triple effect evaporator fed with softened water resulted in a significant improvement in the apparent heat transfer coefficients across the effects, and a resultant improvement in the net output of 10-15 per cent. This improvement was limited by the thermo-compressor capacity and an improvement to 35 per cent has been calculated if this restriction were removed. Slight condensate contamination by stearic acid occurred, but the quality generally remained acceptable for steam generating plant make-up.
Bearings for the Rotors of a 500-Megajoule Storage Generator
Authors: Inali E. K.
Published: October 2007

This paper describes the bearings of a homopolar generator which has been built to store 560 × 106 J and capable of discharge at currents up to 1.6 × 106 A. The contra-rotating steel rotors are in a magnetic field which produces a tilting torque of 3 × 109 lb in/rad of tilt, and they must run in either direction at any speed up to 900 rev/min. Conventional bearings and bearing clearances could not be used to restrain the tilt, so annular thrust bearings 92 in in diameter were designed to run on the flat faces of the 139-in diameter rotor discs. Each bearing is supplied with 1500 ft3/min of air at 96 lb/in2. The rotors are centred by hydrostatic bearings lubricated with oil.
Iatromathematics to Biomechanics
Authors: Kenedi R. M.
Published: October 2007

‘They're infiltrating every sphere

Except perhaps theology,

And now we find the engineer

Researching in biology.

There on the operation floor

If you should stop and peer

With surgeons ankle-deep in gore

You'll see—an engineer.’

T. Gibson ( Uncollected Verses, 1964)
Composite Self-Lubricating Bearing Materials
Authors: Lancaster J. K.
Published: October 2007

A survey is given of progress in the development of self-lubricating materials for load-carrying components (bearings and gears) or for transfer lubrication (rolling element bearing retainers). Various methods for producing composites of inorganic solid lubricants, metals, polymers, carbons and ceramics are briefly described, and some suggestions for further work are included.
First Paper: Human Response to Intense Low-Frequency Noise and Vibration
Authors: Guignard J. C.
Published: October 2007

The frequency-dependent effects of mechanical vibration on human comfort and working efficiency are now clearly recognized, as are the effects of airborne noise on hearing. But vibration and intense noise at very low frequencies can also provoke disturbing non-auditory symptoms which are as yet ill understood.

Moreover, the establishment of frequency-and time-dependence of these effects calls for further research.

The author reviews current problems in this field and mentions the work of the International Organization for Standardization aimed at defining limits of acceptable human exposure to vibration and intense noise.
Vibratory Feeding
Authors: Redford A. H. , Boothroyd G.
Published: October 2007

A brief review of previous work on the mechanics of vibratory conveying is presented followed by a new theoretical analysis of vibratory feeding on a track which vibrates with simple harmonic motion and where a phase difference may exist between the parallel and normal components of the track motion.

For a wide range of practical conditions, the theoretical predictions are found to agree closely with the results of experimental tests. These show that certain fundamental limitations exist in the performance of conventional feeder drives where the two components of track motion are in-phase.

From further theoretical and experimental work, it is shown that under conditions where the appropriate phase difference exists between the two components of track motion, many practical advantages over conventional vibratory feeding are obtained. With a new design of vibratory bowl feeder drive based on the results of the work, significantly higher conveying velocities may be obtained under stable feeding conditions and, further, these high conveying velocities are virtually independent of the coefficient of friction between the component and the track.

The results of the present work apply equally to the design of spiral elevators and in-line vibratory feeders.
Some Cavitation Effects in Spool Valve Orifices
Authors: McCloy D. , Beck A.
Published: October 2007

The existence of cavitation in hydraulic equipment leads to inefficient operation, mechanical damage, and vibration. The performance of valves in fluid power control systems is affected by cavitation. The spool valve finds numerous applications in this field and it is essential that these effects be thoroughly understood. In this paper a study is made of the occurrence of cavitation and its effect on the discharge characteristics of spool valves.

It is shown that over a range of flow conditions cavitation has a profound effect on the flow coefficient.
Second Paper: Extrusion of Steel and Titanium
Authors: Austin E. R. , Davies R. , Bakhtar F.
Published: October 2007

This paper describes the results of forward and backward extrusion tests on steel and titanium specimens at very high impact speeds, using reductions in area of 44 to 86 per cent. The specimens were in all cases of 1-in diameter, 1.5 in long. For the cold forward extrusion of steel, impact speeds over the range 68-310 ft/s were used. Comparison of mean extrusion and work of deformation at these high speeds was made with the values arising at very low speed. Extrusion pressures were minimal in the impact velocity range 40-80 ft/s.

Tests using steel billets preheated to temperatures between 300 and 600°C showed no great advantage in preheating above 400°C. This degree of preheating showed considerable advantages over the cold process, in that extrusion pressures were much reduced, product quality was improved, and higher extrusion ratios could be obtained. Limited backward extrusion tests at 66 ft/s proved the feasibility of the process.

Gold forward extrusion of titanium at 65 and 167 ft/s was successful only at the relatively low reductions in area of 44 and 61 per cent. At higher degrees of deformation, the extruded product broke into small pieces.
Influence of Coupled Asymmetric Bearings on the Motion of a Massive Flexible Rotor
Authors: Morton P. G.
Published: October 2007

The rotors of a majority of rotating machines are supported upon bearings whose flexibility has a significant effect on the dynamics of the system. Supports incorporating hydrodynamically maintained oil films in particular, in addition to possessing different stiffness and damping in mutually perpendicular planes, exhibit non-reciprocal coupling between motions in these planes. The author develops the equations of motion for a rotor-bearing system of this type, and describes how both the response to an out-of-balance forcing and the unstable behaviour of such a system may be predicted by evaluating separately the dynamical characteristics of the rotor and the bearings. The method is applicable to systems in which the rotor is axisymmetric and has an arbitrary mass and stiffness distribution symmetrically disposed about its centre of span. Some new aspects of the resonant and unstable behaviour of rotating shafts are brought out due to the nature of the method of solution.

Theoretical predictions are compared and agree very well with the results of tests on a 1380 lb model rotor supported on two 4 in diameter cylindrical journal bearings.
Third Paper: Traction in Elastohydrodynamic Contacts
Authors: Plint M. A.
Published: October 2007

Measurements of frictional traction in a circular elastohydrodynamic contact have been made over a comprehensive range of conditions. The results suggest the existence of a limiting shear strength in the fluid film and this is shown to be a function of temperature and contact size. Existing theories of fluid behaviour under extreme conditions of stress are considered and some modifications are suggested.

The contribution of asperity contact to surface traction is examined.
Fourth Paper: Shear Behaviour of Elastohydrodynamic Oil Films at High Rolling Contact Pressures
Authors: Johnson K. L. , Cameron R.
Published: October 2007

The variation with sliding speed of the traction transmitted by E.H.L. oil films has been measured in a rolling contact disc machine, at contact pressures up to 260,000 lbf/in2 and at various rolling speeds and disc temperatures. From the traction measurements at very low sliding speeds, under isothermal conditions, the variation in apparent viscosity of the oil with pressure and temperature has been found. The variation with temperature at high pressure was exponential with an index similar to that at low pressure. The variation with pressure showed a striking reduction in the rate of increase with pressure in the high pressure region (> 105 lbf/in2).

At high sliding speeds the traction coefficient was found to approach a common ‘ceiling’, which was largely independent of contact pressure, rolling speed and disc temperature. The ceiling appears to be a function of sliding speed only; it falls from 0.07 at 5 in/s to 0.04 at 60 in/s.

Using the measurements of apparent viscosity obtained at low rolling speed, it has been shown conclusively that the limitation (or ceiling) in traction at intermediate sliding speeds cannot be explained by Crook's theory of a reduction in Newtonian viscosity by frictional heating. Alternative explanations based upon plastic shear of the lubricant when a critical shear stress is reached are much more consistent with the observations. But further work is necessary to elucidate fully the behaviour of E.H.L. films in sliding.
Bulge Formation in Strip Drawing with Light Reductions in Area
Authors: Johnson R. W. , Rowe G. W.
Published: October 2007

This paper presents some theoretical and experimental studies of the phenomenon known as bulge formation, during drawing with light reductions under conditions of plane strain. Experimental observations of the initiation of bulging agree approximately with values predicted by earlier theories. The development of the bulge as drawing proceeds has not hitherto been studied. A simple analysis is presented which predicts the growth and equilibrium height of the bulge and the influence of friction. This is substantiated by measurements with cold-worked aluminium.
An Analysis of the Geometry of Gear Hobbing
Authors: Hannam R. G. , Andrew C.
Published: October 2007

This paper describes an analytical examination of chip formation in the hobbing of spur gears. The process is analysed by considering relative rather than absolute motion, and is reduced to a two-dimensional problem. The mathematics were carried out on a digital computer.

The analysis shows the number of hob teeth engaged in forming a gear tooth space, the shapes of the chips and the volume of metal removed. The analysis is applied to a given hob and gear and the results indicate that: the flanks of the hob teeth remove a greater volume of metal than the tips, but the tips accomplish their metal removal in fewer cuts and are therefore loaded more severely; the volumes of metal removed by, and hence the wear on, the two flanks of a hob tooth are unequal; the machining forces exert a fluctuating and reversing torque on the worktable.
Some Recent Research in Turbo-Machinery
Authors: Horlock J. H.
Published: October 2007

Research on turbo-machinery carried out at Liverpool University in the period 1958-66 is reviewed. The work described includes:

(1) The accurate determination of two-dimensional incompressible flow in cascades; and an assessment of the effects of contraction of the mainstream. (2) A study of the nature of the flow on the end walls of compressor cascades, including the prediction of the laminar and turbulent boundary layer development on these walls. The interaction of these boundary layers with flows due to tip clearance is discussed. The effect of separation of the flow from the end walls upon the contraction of mainstream and the stalling performance of the blading is important and is strongly dependent on the aspect ratio of the cascades. (3) A series of experiments on rotating machines. The performance of compressor blading in stationary cascades and in the blade rows of an axial compressor is compared and the effect of aspect ratio on compressor stage performance is determined. A number of observations are made on the stalling of compressor stages and calculations of the three-dimensional flow in turbo-machines are reported.
Stimulating Technological Innovation in Industry: The Role of the Ministry of Technology
Authors: Maddock I.
Published: October 2007

The methods used by the Ministry of Technology to stimulate technological innovation in industry are described, primarily concerning the activities of the Engineering Group of the Ministry. The phases of surveying the scene, the diagnostic steps and the actions that are taken to bring about improvements are followed through. The paper presents a picture of the powers, objectives and machinery of the Ministry of Technology and examples are given of the measures that are used, their application to specific industries, and the attention given to creating an advancing technological base.
Boundary Layer Effects in the Turbulent Spiral Vortex Flow of a Compressible Fluid
Authors: Scott B. F.
Published: October 2007

Because of the characteristically narrow impeller tip width in a proposed supersonic centrifugal compressor design, boundary layer effects in the vortex chamber are likely to be significant.

The radial pressure gradient in the chambers sweeps retarded fluid towards the centre of curvature of the streamlines, thereby creating a ‘cross-flow’ in the boundary layer which is three-dimensional. Although the flow geometry has axial symmetry, the cross-flow is not independent of the streamwise flow. The momentum—integral method is adopted, together with assumptions concerning the velocity profiles; the energy equation is solved with the assumption of an adiabatic wall.

Simultaneous solution of the free stream and boundary layer equations yields results emphasizing the critical dependence of the transverse deflection and growth of the boundary layer on the whirl component of the velocity. Separation cannot be predicted, but effects in the free stream can be estimated when the perturbations are small.

Although the results are related to compressor performance, the method is generally applicable in situations where the idealizing assumption of spiral vortex flow is acceptable.
Commissioning of Medium-Scale Chemical Process Plant
Authors: Kingsley R. J. , Kneale M. , Schwartz E.
Published: October 2007

The commissioning procedures and philosophies applicable to a medium-scale company are outlined.

Project information is channelled through research and pilot-plant reports, design circulars, and relevant committees. Lists of commissioning preparations are given, including inspection, testing, process simulation, manuals and operating documents, training of staff, control procedures, safety, and maintenance preparations.

The philosophy of the commissioning organization is indicated, emphasizing the position of the Chief Technologist. Many common start-up difficulties are described, with particular reference to personnel and human problems. A favourable commercial climate is very important: company and commissioning policies must be integrated.

Criteria are given for terminating the commissioning effort and the setting up of the subsequent Plant Development Committee.

The paper concludes with commissioning experiences abroad.
Use of ‘Free’ Scavenge Air in the Development of Two-Stroke Loop-Scavenged Engines for Turbocharging
Authors: Wood J. H.
Published: October 2007

A brief historical description of the special characteristics of Crossley two-stroke c.i. engines is employed to justify the use of an independently driven and controlled source of compressed scavenge air in an extensive series of engine tests, from the analysis of which novel techniques were evolved for assessing: (1) scavenge air pressure drop and flow, using static engine flow tests; (2) i.h.p. from brake test results; (3) b.h.p. using a special turbocharger performance factor chart. These techniques may well be of use on other types of engine.
Basic Factors in the Design of Hydraulic Circuits
Authors: Kibble J. D.
Published: October 2007

This paper is concerned with the design of hydraulic systems of the type containing one or more rams or rotary motors driven by a pump having a relief valve or other means of controlling the flow so as to limit the pressure. The choice of working pressure is discussed and it is concluded that there is no inherent advantage in the use of high pressures analogous with that of high voltages for electrical power transmission.

The other factor investigated is the selection of pipe and valve sizes. The customary use of a standard flow velocity as a guide for this purpose can give very unsatisfactory results. As a better basis, an estimate of the allowable pressure loss is recommended, this being obtained from considerations of efficiency or from a novel parameter, ‘hydraulic regulation’. The latter is the ratio of the pressure loss at full working speed to the maximum pressure, and is a measure of the extent to which a system slows down under heavy loads.
Stresses in Oil Lubricated Bearings
Authors: Ibrahim S. M. , Mccallion H.
Published: October 2007

Stresses in a bimetal strip of white metal bonded to steel, to simulate a journal bearing shell or a thrust bearing ring, have been calculated for various loading conditions. The stresses arose from: fluid pressure loading on the bearing surface whilst the back was supported on a complete rigid surface; locating and holding forces, e.g. compression due to nipping-up the bearing; elastic deformation of the bearing housing; differential thermal expansion and temperature gradients, and incomplete support of the bearing shell when subjected to fluid pressure on its bearing surface. Points at which fatigue damage is likely to originate are apparent.

The stresses were calculated numerically from displacements which were found, by an iterative method, to satisfy a finite difference analogue of the governing differential equations.
Rugeley Dry Cooling Tower System
Authors: Christopher P. J. , Forster V. T.
Published: October 2007

Steam power stations are one of the biggest users of water and the increasingly heavy demand for water, for all purposes, throughout the world has caused serious studies to be made of methods of providing a cooling facility for steam turbines independent of a water supply.

The studies revealed that a system devised by Professor Heller provided the most economic and practical solution for large steam turbines. It uses the atmosphere as a heat sink for the turbine exhaust heat by a combination of jet condenser, closed water circuit, heat exchangers cooled by air and a cooling tower. Although there is a water circuit to be filled initially, no further water is required.

The first application of the system—the dry cooling tower system—to a large turbine was designed and built by the English Electric Company Ltd for the C.E.G.B. at their Rugeley Power Station and this paper describes the project and its behaviour in service.
Job Shop Scheduling with Regular Batch Arrivals
Authors: Eilon S. , Pace A. J.
Published: October 2007

This paper describes a simulation exercise of a hypothetical machine shop consisting of five non-identical machines. Jobs arrive in batches, each job having its own routing and operation time specifications, the average times being normally distributed. Nine alternative loading rules are investigated and the SI rule (the selection of the job with the shortest imminent operation) is found to be the most effective in reducing the mean job throughput time and delay factor, when the batch size is comparatively small. For large batches, however, the results suggest that the SI rule is not the most effective. Ways to reduce the variance of job waiting times are also investigated.
Tapered Spool Controller for Pressurized Oil Film Bearings
Authors: Morsi S. A.
Published: October 2007

The first part of this paper is concerned with the description of the different methods commonly used in compensating pressurized oil film bearings. The load-oil film thickness relationship for different methods of compensation and the power dissipated in bearings are given for the sake of comparison.

The second part of this paper is designed to suggest another method of compensation, the theoretical analysis, the design equations of which have been presented.
Computer-Based Management Information in a Small Company
Authors: Goulder B. , Moss A. , Shaw R.
Published: October 2007

The use of computers in the management of medium and large engineering factories is well established. This paper is concerned with the development of a system of management control in a small engineering company using a desk-sized computer on site and a medium-power computer at the local College of Technology. The system, though simple and relatively cheap, provides for production control by means of machine loading charts and exception reports of jobs overdue, cost control, quality control, production statistics and bonus computation. Systems flow charts and examples of output are included. Emphasis is placed on the human aspects of implementing the system, and the immediate effects of the system on the management of the company are discussed.
Void Fractions in Two-Phase Flow: A Correlation Based upon an Equal Velocity Head Model
Authors: Smith S. L.
Published: October 2007

An expression is obtained for void fraction in two-phase flow based upon a simple physical model. The model assumes an annular flow regime with a liquid phase and a homogeneous mixture phase flowing with equal dynamic head.

Excellent correlation is obtained with a wide range of experimental data, indicating a significant improvement over current methods.
Alternative Fluids for Power Generation
Authors: Wood B.
Published: October 2007

In the search for an alternative fluid to water for large power plant, examination of basic properties discloses no other single fluid which advantageously covers the entire range of temperature from 1050° to 80°F, offers so high a heat drop per pound, or so low a boiler feed debit. Most alternative fluids have a lower sonic velocity. Discussion is therefore confined to three cases of substitution:

(a) In a binary superposition cycle above steam. (b) In a binary subposition cycle below steam. (c) In low temperature recuperation applied to process heat or gas turbine exhaust heat.
A General Analysis of Multi-Recess Hydrostatic Journal Bearings
Authors: Davies P. B.
Published: October 2007

A number of assumptions enable the effects of both pressure and velocity induced flow between adjacent recesses to be included in an analysis of multi-recess hydrostatic journal bearings. Consideration of the rate of energy dissipation within a bearing enables an optimum speed variable to be defined which relates the speed of shaft rotation to the other describing parameters involved. The behaviour of a particular orifice compensated bearing of high aspect ratio was investigated at large values of eccentricity ratio and it was revealed that considerable interaction occurred between the recesses. The performance of the bearing was found to be determined jointly by its pressure ratio, speed variable and, significantly, the direction of loading. Considerable variations inload capacity occurred with changes in these parameters and it is shown that the range of operation of multi-recess bearings may be limited as some recess pressures may drop to the ambient pressure. The application of these results to practical designs is suggested.
Theory of Hydrodynamic Lubrication for a Spinning Sphere
Authors: Snidle R. W. , Archard J. F.
Published: October 2007

In this paper the authors present a classical type of solution to the problem of a sphere spinning on a curved surface in the presence of a lubricant. The necessary conditions for hydrodynamic lubrication are shown to exist in this situation which is a simulation of one element of the kinematic conditions which occur in angular contact bearings. The theory assumes that the lubricant is 1soviscous and that the surfaces are rigid; the pressure distribution has been deduced for these assumptions which correspond to the conditions under light loads. The complications which occur under heavier loads are discussed.
Further Study of a Low-Pressure on-off Pneumatic Servomechanism
Authors: Burrows C. R. , Webb C. R.
Published: October 2007

This paper compares experimental and theoretical transient and frequency response results for a low-pressure on-off pneumatic servomechanism comprising a polarized relay with dead zone and hysteresis operating a four-way flapper-nozzle valve via a torque-motor. The valve operates a linear pneumatic motor which drives a load in the presence of Coulomb friction and stiction. Position, velocity, and quasi-transient pressure feedback are provided. The effect of dynamic conditions on the valve characteristics is discussed.
Mechanics of Orthogonal Machining: Predicting Chip Geometry and Cutting Forces from Work-Material Properties and Cutting Conditions
Authors: Fenton R. G. , Oxley P. L. B.
Published: October 2007

A recently developed theory of orthogonal machining is used to calculate chip geometry (including tool-chip contact length) and cutting forces for SAE 1112 steel over a wide range of cutting conditions. A comparison with experimental results shows excellent agreement for most of the cutting conditions considered.
Second Paper: Some Basic Considerations in the Design of Petro-Forge High Energy-Rate Forming Machines
Authors: Chan L. T. , Bakhtar F.
Published: October 2007

This paper describes a method for the design and evaluation of the performance characteristics of combustion driven high energy-rate forming machines which have since been given the name Petro-Forge. The treatment is based on the use of a number of simplifying parameters derived from results on an earlier model. The first part of the working stroke, involving the opening of the seal, has been treated numerically and used as a basis for a simple expression giving approximately the same result. Hence, the variations of the energy output with the individual design parameters have been examined. The application of the expression to the design and performance characteristics of a Mk II machine are finally discussed in comparison with the observed results.
Integrated Iron and Steel Works as Users, Producers and Converters of Energy
Authors: Clay Henry
Published: October 2007

Historically the making of iron and steel in any quantity was confined to places where fuel—originally wood carbon, but since the dawn of the Industrial Revolution, coal—was cheap and local ore available, but even so the industry is such a large user of fuel that the need to conserve it has meant that the total energy concept has been understood in the integrated iron and steel works for at least 50 years. However, it was not until roughly 15 years ago that big improvements in ironmaking and major changes in steelmaking completely altered the fuel and energy balance of a modern works.

These changes have been fostered by a rise in the price of coal compared with other fuels and compared with costs generally; also by the development of ‘tonnage’ oxygen plants and by the availability of bulk carriers for oil and ore. The effects on the fuel and energy balances are considered.

Although in such a heavily capitalized industry widespread adoption of new processes is inevitably slow, still further changes can be foreseen and some of these may greatly affect the energy requirements of the steel works of the future. Natural gas may compete, not only with oil as a fuel, but also with coke as a reducing agent in making iron. Ore already reduced to iron may be shipped to the United Kingdom at a price that will make the integrated iron and steel works a thing of the past.
Servo-Valve Controlled Isolation Systems
Authors: Soliman J. I. , Tajer-Ardabili D.
Published: October 2007

Active isolation systems using nozzle-flapper valves and pneumatic springs are capable of much improved isolation characteristics when compared with conventional isolation systems, but they suffer from the fact that large quiescent leakage flows are required for satisfactory dynamic performance of the isolation system (1)‡. This quiescent power loss due to quiescent leakage flow is a very serious problem, because high pressure air is consumed when no useful work is done. In this paper it is shown how quiescent leakage flow is eliminated by replacing the nozzle-flapper valve with a critically centred servo-valve. The damping produced by the quiescent leakage flow in a nozzle-flapper controlled isolation system is produced by ‘transient pressure feedback’ obtained by connecting the pneumatic spring to a surge tank through capillary resistances, in a servo-valve controlled isolation system.
The 2-Stage Rotary Engine—A New Concept in Diesel Power
Authors: Feller F.
Published: October 2007

The report covers a period of six years of research leading to the design and manufacture of a compression ignition rotary engine of 350 hp for use in military vehicles. The work carried out to obtain good combustion and effective gas sealing is described in some detail. Outline drawings and data of the new engine are given and size comparisons are made with present-day engines.
First Paper: Imperfections in Vacuum Remelted Precision Steel Balls Which Affect Ball Race Performance
Authors: Haines D. J.
Published: October 2007

In a study of ball motion in an angular contact ball race the author found that precision steel balls having their centre of mass displaced from the true geometric centre of the ball show tendencies to run in a ‘heavy end outwards’ condition resulting in preferential wear of parts of the ball surface.

Three techniques are described which permit the sorting of balls and the elimination of those which limit race life due to errors in ball sphericity and errors in centre of mass position.
Condensation Phenomena in High Speed Flow of Steam
Authors: Campbell B. A. , Bakhtar F.
Published: October 2007

This paper, starting from the nucleation theory, treats numerically the condensing flow of steam in a nozzle and compares the results with existing experimental observations. It is shown that the location of the condensation shock in the theoretical solutions is sensitive to the values adopted for the friction factor, condensation coefficient and variations in surface tension at small droplet sizes. By using friction factors reported in the literature, good agreement between theoretical and experimental results is obtained when the condensation coefficient is taken as 0036 and the surface tension is taken to vary in accordance with Benson and Shuttleworth's model.
Overhaul Policies for Mechanical Equipment
Authors: Hastings N. A. J. , Thomas D. W.
Published: October 2007

Repair costs for mechanical equipment tend to increase with age. A mathematical expression relating mean repair cost to age is developed and is shown to be valid in practical cases. The expression is used as a basis for determining the economic life of equipment for the situation where a number of overhauls may occur before replacement. It is shown how the optimal number of overhauls can be determined as a function of the cost and effectiveness of overhaul.
Some Design and Development Considerations for An Industrial Classification System
Authors: Middle G. H. , Connolly R. , Thornley R. H.
Published: October 2007

The factors which influence the design of a classification system are considered by reviewing the coding languages available and comparing them with the ideal characteristics of a classification system. The structure of classification codes is also discussed.

Because the local industrial considerations may affect the ideal designs, an indication of the organizational problems of implementing a classification scheme are mentioned.

A classification scheme developed to assist in the implementation of a group technology (G.T.) manufacturing system is described. The description includes the general form of the scheme, the classification codes developed and examples of how the scheme is used. Design considerations for the implementation of the G.T. system affect the choice of the code definitions. These considerations for the particular scheme are, therefore, discussed. The method of bringing together components to form various technological groups of parts necessary for the G.T. concept is also discussed.
An Experimental Investigation of the Influence of Strain-Rate and Temperature on the Flow Stress Properties of a Low Carbon Steel Using a Machining Test
Authors: Stevenson M. G. , Oxley P. L. B.
Published: October 2007

Results obtained from machining and conventional slow-speed compression tests are used to calculate the constants σ1 and n in the empirical stress/strain equation σ = σ1***enover a range of strain-rates (10-3to 2·8 times 104/s) and temperatures (room temperature to 200°C) for a low carbon, free machining steel. The results are consistent with those obtained for a similar material using high-speed tension tests. Some results showing the influence of higher temperatures (up to 800°C) on the flow stress are also obtained from the machining tests by considering the flow along the tool-chip interface. These results show a dynamic strain-ageing effect similar to that found in high-speed tension and compression tests on similar materials.
Chatter in Gear Hobbing
Authors: Hannam R. G. , Andrew C.
Published: October 2007

This paper describes an investigation into the characteristics of chatter in gear hobbing. The likelihood of chatter occurring was shown to increase with feed-rate, depth of cut and gear diameter; it was also shown to be critically dependent on the material being cut.

Chatter was found to be of the regenerative type, occurring in bands of speed in a manner similar to its occurrence in milling operations. On a given machine and for a given gear material, the factor deciding whether chatter would arise was shown to be the magnitude of the mean total chip-width being cut by the flanks of the hob teeth. This magnitude was computed for various machining conditions from a knowledge of the hob and gear geometries, the feed-rate and the depth of cut.

The machine's design was considered in terms of the vibration characteristics at the hob-blank interface; the dynamic stiffness of relative motion tangential to the gear blank was shown to be critical. Special techniques were used to derive the associated torsional characteristics of the work-table system experimentally.
Elastic-Plastic Computations as a Basis for Design Charts for Torispherical Pressure Vessel Ends
Authors: Townley C. H. A. , Findlay G. E. , Goodman A. M. , Stanley P.
Published: October 2007

A series of elastic-plastic calculations has been carried out on torispherical drumheads subject to internal pressure. From the results of this analysis, master curves have been prepared which are independent of factors such as the ratio of design stress to yield stress and the ratio of design pressure to test pressure. These curves provide a rational starting point, from which Code Drafting Committees can derive, in simplified form where necessary, design factors to meet the requirements of specific Codes of Practice. An example of this use of the master curves is included.

Correlation between the theoretical analysis and the available experimental data on torispherical drumheads is shown to be good. Conversely, the experimental results show that drumheads designed using factors derived from the master curves will perform satisfactorily in service.

The principles illustrated in this paper can be applied to many other types of component commonly used in the pressure vessel industry. In this way, it is possible to provide a series of master curves which would form a rational basis, common to all codes, for the preparation of detailed design rules.
Combustion Problems in the Petro-Forge
Authors: Al'Omar A. F. , Bakhtar F.
Published: October 2007

The paper describes an experimental investigation into the combustion of suspensions of liquid fuels in cold compressed air. The data presented include measurements of air swirl in the chamber as well as the characteristics of a fully developed spray. The combustion experiments are aimed at determining the influence of spray size and penetration on the process.
Some Early Experiences of Mechanical Vibration in Marine Engine Systems
Authors: Wilson W. Ker
Published: October 2007

Everything which is struck rings; everything has a particular ring.—Pythagoras of Samos (582-507 B.C.) The lecture is divided into the following sections. Introduction. Early days. Camshaft drives. Camshaft drive at free end and after end of crankshaft; later developments. Mass balancing of internal-combusion engines. Single-piston assemblies; unbalanced centrifugal and inertia forces. Mass balancing opposed-piston engines. Ship vibration; scavenge-crank balance weights; scavenge-pump reciprocating parts; crankshaft-coupling-bolt failures; change of firing order; results and conclusions from vibration tests. Differential-stroke (mass-balanced) opposed-piston engines; first fully balanced opposed-piston engines; lever-driven scavenge pumps. Transverse (rolling) vibration of engine frame. Experimental determination of the natural frequency of transverse (rolling) vibration of opposed-piston engines; transverse vibration of engine frame in twin-screw ships and its control. Torsional vibration. Investigation of side-connecting-rod failures; investigation of torsional vibration; retiming the crankshaft system; general; marine steam reciprocating engine. Devices for controlling torsional vibration. Tuned and damped vibration absorbers; dynamic vibration absorbers in opposed-piston-engine propulsion systems; Bibby peripheral grid springs; vibration absorbers at free ends of crankshafts; experimental absorber with peripheral helical springs; Doxford-Bibby absorber. Later history. Large six-cylinder opposed-piston engines; alternative viscous-friction dampers; modified vibration absorber; stiffer crankshafts; P-type engines; J-type engines.
The Conflict between Traction and Stability in Passenger Cars
Authors: Grylls S. H.
Published: October 2007

The understeer of front-engined rear-wheel driven cars diminishes with speed. The paper deals with reasons for this phenomenon, the usual palliatives for which reduce available traction.
Studies of the Deposition of Sub-Micron Particles on Turbine Blades
Authors: Parker G. J. , Lee P.
Published: October 2007

The paper describes the continuation of work to evaluate the magnitude of diffusional deposition of small particles on turbine blades. Apparatus and techniques similar to those described in an earlier paper have been employed. Modifications were necessary to overcome the problem of electrostatic charging of the deposition surface affecting the deposition results. Test results for the distribution of deposited particles around the blade have been obtained for three mass median diameters of 0·13, 0·19 and 0·24 μm and the influence of the level of turbulence at inlet to the cascade assessed. A theoretical treatment is derived which satisfactorily predicts the experimental results for the case of low inlet turbulence level.

The paper also gives details of the technique, using electron microscopy, of obtaining size distribution data for the minute particles.
The Influence of Fretting and Geometric Stress Concentrations on the Fatigue Strength of Clamped Joints
Authors: Wright G. P. , O'Connor J. J.
Published: October 2007

Fretting damage and geometric stress concentrations are known to affect the fatigue strength of clamped joints. The relative magnitudes of these effects were examined in a series of experiments whose results are interpreted in the light of theoretical stress analysis. When full allowance is made for geometric stress concentrations, it is found that fretting can reduce the fatigue strength of B.S. L65 by a factor of about 3. A mechanism is proposed to explain this phenomenon.
Elastohydrodynamic Lubrication of a Line Contact
Authors: Wymer D. G. , Cameron A.
Published: October 2007

In Part 1, optical interferometry is used to study an elastohydrodynamically lubricated line contact between a taper roller and a glass plate under pure rolling conditions. The results give detailed information on film profiles and show the effects of end blending, lubricant starvation, deep scratches and static oil entrapments. In Part 2, oil film thicknesses in an elastohydrodynamic line contact are measured using optical interferometry and compared with theory. Two empirical formulae are derived for film thickness in the central region and at the exit constriction. In addition to the optical measurements, electrical measurements (resistance and capacitance) are made simultaneously, enabling a direct comparison to be made.
Predicting a Material's Machining Characteristics Using Flow Stress Properties Obtained from High-Speed Compression Tests
Authors: Hastings W. F. , Oxley P. L. B. , Stevenson M. G.
Published: October 2007

A theory is given for calculating chip geometry, cutting forces, etc., from fundamental work material properties and cutting conditions. The flow stress properties of the work material (0·16 per cent carbon steel) used in the analysis are taken from high-speed compression test results. The theory predicts the main trends observed in machining experiments and a limited comparison with experimental results shows good quantitative agreement. A possible explanation for the occurrence of a built-up edge, involving the dynamic strain ageing (blue-brittleness) of the chip along the tool-chip interface, is considered and found to be consistent with the results.
Second Paper: Recent Studies on Rotary-Engine Lubrication
Authors: Breau J. Y. , Miller B. J. , Möller P. , Rogers T. W.
Published: October 2007

Rotary-engine lubrication studies have been conducted on four engines covering the two types of rotary engine now in production. Metallic or carbon-metallic apex seals were used.

Results presented have been obtained with 13 different oil formulations, including passenger-car-engine oils corresponding to API SC, SD or SE categories, automatic-transmission fluids of the Dexron II type, and oils for two-stroke engines. Seven different test procedures have been used in these investigations, employing either engine bench test stands or vehicles on chassis dynamometers.

Satisfactory rotary-engine performance has been obtained with oils containing from 0 to 1·2 per cent by weight of sulphated ash. The ability of the base stock to provide good film thickness has also been found of benefit in reducing rotary-engine wear. Passenger-car-engine oils can be excellent rotary-engine lubricants and those oils corresponding to the latest API SE classification exhibit better performance than previous API SC or SD oils. Automatic-transmission fluids have also given promising results.