bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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.
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.
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.
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.
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.
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.
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.
Low-Cycle Fatigue Behaviour of Gas Turbine Alloys
Authors: Evans W. J. , Tilly G. P. 
Published: October 2007

The low-cycle fatigue characteristics of an 11 per cent chromium steel, two nickel alloys and two titanium alloys have been studied in the range 20° to 500°C. For repeated-tension stress tests on all the materials, there was a sharp break in the stress-endurance curve between 103 and 104 cycles. The high stress failures were attributed to cyclic creep contributing to the development of internal cavities. At lower stresses, failures occurred through the growth of fatigue cracks initiated at the material surface. The whole fatigue curve could be represented by an expression developed from linear damage assumptions. Data for different temperatures and types of stress concentration were correlated by expressing stress as a fraction of the static strength. Repeated-tensile strain cycling data were represented on a stress-endurance diagram and it was shown that they correlated with push-pull stress cycles at high stresses and repeated-tension at low stresses. In general, the compressive phase tended to accentuate cyclic creep so that ductile failures occurred at proportionally lower stresses. Changes in frequency from 1 to 100 cycle/min were shown to have no significant effect on low-cycle fatigue behaviour.
Investigation of Bearing Misalignment Problems in a 500 Mw Turbo-Generator Set
Authors: Ettles C. , Wells D. E. , Stokes M. , Matthew J. C. 
Published: October 2007

An elasticity analysis to calculate the distribution of all bearing loads in a turbo-generator set is presented from first principles. It is shown that the movement of bearing pedestals caused by the thermal distortion of the foundation can cause considerable changes of load distribution between bearings with consequent problems of oil film instability and shaft whip. Acute misalignment encountered in practice can cause some bearings to take a negative load. The development of a computer programme is described, which can be used to investigate a range of possible cold re-alignments. A separate analysis of the particular type of bearings used shows that the load capacity is completely adequate in the downwards direction, but greatly reduced in the upwards direction. Upwards loads of static or dynamic origin should be avoided with the type of journal bearing design considered here.
Surface Roughness of Graphite and Its Effect on Friction Factor
Authors: Warburton C. 
Published: October 2007

Experimental results are presented for friction factor and surface finish measurements on eight graphite tubes machined to give a range of surface finishes from smooth up to the maximum roughness likely to occur in a reactor. Correlations are given which allow estimation of friction factor from graphite surface finish measurements. The results are compared with those obtained by Nikuradse in his sand-grain roughness tests. Except at low values of es+, agreement is good, enabling the heat transfer similarity law of Dipprey and Sabersky to be used to predict any increases in Stanton number due to surface roughness.
Four-Cylinder, Four-Cycle Engine with Two Reciprocating Components
Authors: Baker A. J. S. , Cross M. E. 
Published: October 2007

Without introducing novel technology, the advantages of the Cross cool-combustion chamber have been combined in a compact engine form. This has enabled a practical engine to be developed in a comparably smaller envelope than would be possible with a conventional arrangement. An eccentric crank mechanism is used, which eliminates swinging connecting rods and thus generates simple harmonic motion at the pistons. The Cross rotary valve enables the bore-stroke ratio to be reduced significantly without combustion penalty and a bore-stroke ratio of 1:7 has been chosen for a prototype. The practical development of this engine is described, together with the rationale of its conception. In the present climate of fuel shortage, it is anticipated that low fuel consumption and octane requirement, which have been well demonstrated for the Cross combustion chamber, will be of considerable importance, while the compactness of the complete engine should offer significant installational advantages.
The Vane Bearing—A Self-Pressurizing Journal Bearing
Authors: Ettles C. 
Published: October 2007

If the shaft of a journal bearing could be made to have a number of pressure sources which travel with the shaft, the load capacity of the oil film could be greatly enhanced. This paper describes the development of a concept in which the pressure sources arise from a positive displacement effect due to the eccentricity of the shaft within the bearing. The configuration has similarities to the rotor of a vane pump in which the entry port is open and the exit port closed. The bearing could be described as a hybrid hydrodynamic-hydrostatic bearing where the hydrostatic supply is self-contained and self-generated. A number of methods of causing this self-pressurization are discussed. A theoretical analysis shows that load (or Sommerfeld) number improvement factors in the range 3–10 are quite feasible at the expense of an increased flow and power requirement.
The Application of Double Conical Journal Bearings in High Speed Centrifugal Pumps — Parts 1 and 2
Authors: Ettles C. , Svoboda O. 
Published: October 2007

Conical bearings can in principle support a combination of radial and axial load. Their application to centrifugal pumps is considered, which allows the thrust bearing of the conventional arrangement to be dispensed with. It is shown that with low pressure oil lubrication, the axial load of this type of bearing is limited to the ratio (axial load/radial load)=Tan A, where A is the half angle of the cone. Methods of avoiding this limitation are considered. The feasibility of water lubricated inclined journal bearings for centrifugal pumps is analysed. A ‘Vee’ configuration double conical journal bearing is considered with a central high pressure feed from the pump outlet. Although the enhancement of viscosity due to turbulence is not as great as anticipated, the bearing is shown to have an adequate axial and radial load capacity. It is shown that flow compensation or restriction to each side of the bearing is necessary to maintain the escaped flow at an acceptable level. The limits of bearing operation are set by acceptable film thickness rather than excessive temperature rise. For this reason, the correct choice of bearing materials to run under thin film or no film conditions in the presence of dirt is probably more important than correct hydrodynamic design.
A Theoretical Investigation of the Effect of Initial Velocity and Temperature Lag on the Flow of a Gas-Solid Suspension through a Convergent-Divergent Nozzle
Authors: Mobbs F. R. , Baum M. R. , Cole B. N. 
Published: October 2007

The effects of initial velocity and temperature lags between the solid particles and the gas in the high speed flow of a gas-solid mixture through a convergent-divergent nozzle are investigated. The results are interpreted physically in terms of the relative importance of heat, momentum, and kinetic energy transfer between the solid particles and the gas, and nozzle area variation. The influences of solids loading, solids specific heat, solids density and particle diameter on the flow process are also examined.
The Rotary Fuel-Injection Pump as a Source of Cyclic Variation in Diesel Engines, and its Effect on Nitric Oxide Emissions
Authors: Wing R. D. 
Published: October 2007

Cyclic combustion variations have been demonstrated to exist in a direct injection Diesel engine to a surprisingly large extent. With the aid of an on-line computer engine-test facility statistical and correlation analyses were carried out to verify a strong relationship between the cyclic combustion variations and variations in the timing of fuel injection. The importance of these cyclic variations in the reduction of nitric oxide emissions from the engine is shown by experimental results and computer combustion model predictions. The overall effect on nitric oxide emissions is, however, small over most of the operating range of the engine.
The Unit Strength Concept in the Interpretation of Beam Test Results for Brittle Materials
Authors: Stanley P. , Fessler H. , Sivill A. D. 
Published: October 2007

SYNOPSIS Brittle materials are usually characterised in terms of the “modulus of rupture” obtained from the results of fracture tests on beam specimens. This is not a fundamental quantity. Alternative quantities (the mean strength of unit volume and of unit area) are introduced which are independent of the size of the specimen and the form of test, which allow the correlation of results from different tests, and which may be validly used in design calculations. After an outline of the necessary theory, the derivation of the two “unit strengths” and their use in correlating test results are illustrated using fracture data from a series of reaction-bonded silicon nitride beams. Minimum values obtained are:- mean uniaxial fracture stress of unit volume, 140 N/mm2 per cm3; mean uniaxial fracture stress of unit surface area, 180 N/mm2 per cm2. A means of allowing for the effects of contact friction in the analysis of beam fracture test data is presented. The ignoring of these effects may result in a significant over-estimate of strength. The measured coefficient of friction decreased with increased load intensity.
Translational Energy Exchanged between an Oil Film and a Cyclically Loaded Journal — A Theoretical Study
Authors: Mccallion H. , Wales D. R. 
Published: October 2007

SYNOPSIS Predicting the stability of rotating systems at intermediate and large whirl amplitudes is costly. This paper suggests a cheaper' approximate method based upon an overall energy balance. By representing the force exerted on the bearings as combinations of constant forces and cyclically varying forces, the influence of bearing geometry, and other factors on the magnitude and direction of the energy flow between oil film and rotor for a complete cycle was investigated and found significant. It is suggested that designers should check stability of intermediate or large amplitude whirls by an overall energy balance.
Methods for Determination of Composition and Thermodynamic Properties of Combustion Products for Internal Combustion Engine Calculations
Authors: Way R. J. B. 
Published: October 2007

SYNOPSIS Two alternative methods are described for the calculation of gas composition. These are:- 1. Complete chemical equilibrium; 2. A combination of chemical rate equations for some slower reactions with partial equilibrium for faster reactions. Some calculated results are given in the form of comparisons between the two methods, showing the changes in gas composition caused by a temperature rise and fall with a constant rate of change of temperature. Equations are also given for the thermodynamic properties of individual species which may be used together with the appropriate gas composition to obtain properties of the gas mixture.
The Failure of Elastohydrodynamic Lubrication of Circumferentially Ground Discs
Authors: Dyson A. 
Published: October 2007

SYNOPSIS A new theory is developed in an attempt to explain the scuffing failure of circumferentially ground discs. The characteristics of the surfaces of a particular pair of such discs just before scuffing took place have been analysed in detail. The roughness of the surfaces has been taken into account in the treatment both of the hydrodynamics and of the contact mechanics of the system. The disc bulk temperature at which high hydrodynamic pressures just fail to be generated shows a reasonable agreement with the temperature observed just before scuffing. The implications for the mechanism of scuffing are discussed.
A Comparison of Methods for Measuring the Frequency Response of Mechanical Structures with Particular Reference to Machine Tools
Authors: Taylor H.R. 
Published: October 2007

The measurement of the frequency responses of machine tool structures is necessary because of the association between frequency response and chatter with consequent limitation of productivity. Various alternative techniques have been suggested. The paper describes comparative measurements of the frequency response of two systems using several techniques. The techniques examined were (1) Sinuoidal excitation with digital analysis, frequency incremented manually. (2) Slowly swept sinusoidal excitation with analogue analysis. (Traditional method). (3) Fast swept sinusoidal excitation with digital analysis. (4) Impulse excitation with digital analysis. (5) Band-limited random excitation with digital analysis. The results show the fast swept sinusoidal and impulse methods to be the most satisfactory.