bluuebunny/crossref_metadata_2025 huggingface dataset:
An Experimental Investigation of Forced Convection to Supercritical Pressure Water in Heated Small Bore Tubes
Authors: Harrison G. S. , Watson A.
Published: October 2007

SYNOPSIS The paper describes the results of experiments on forced convection heat transfer to water at 245 bar flowing through small-bore tubes heated at approximately uniform flux. Basic similarity criteria for forced convection to variable property fluids are established and experimentally demonstrated. An estimate of the demarcation between forced and mixed convection is arrived at by observing departures from similarity, and comparing the results with those of previous workers. Finally, some unusual time dependent wall temperature distributions are presented which suggest that axial conduction in the test section wall may be particularly important in highly variable property situations.
Development of Velocity and Temperature of the Flow behind a Moving Shock Wave in a duct
Authors: Deckker B. E. L. , Weekes M. E.
Published: October 2007

SYNOPSIS Development of the velocity and temperature of the flow behind a shock wave propagating in atmospheric air in a smooth rectangular duct has been followed by hot wire anemometry. Averaged data were analyzed iteratively to yield the velocity and temperature at several points. Property distributions close to the wave front are non-uniform. Far from the front, the steady velocity profile is approximately the same as for flow in a rectangular duct. The temperature profile develops in a similar manner to the velocity but it is difficult to define the boundary layer edge because the temperature decreases with time.
A Mechanical Torque Converter, and Its Use as an Automobile Transmission
Authors: Williams Frederic , Tipping D.
Published: October 2007

SYNOPSIS A torque converter is described in which the prime mover is directly coupled to a pulsator unit which produces an alternating torque. Sprag-type clutches are used to rectify this torque and to transmit it to the converter output shaft.

A developed version of this basic design for use as an automobile automatic transmission is described and theoretical and experimental performance curves are given which show that an automobile drive is possible which approaches a manual transmission for fuel consumption and performance.
The Mechanics of Flash in Drop Forging-Temperature and Speed Effects
Authors: Dean T. A.
Published: October 2007

SYNOPSIS Forging tests have been made using axisymmetric cavity dies with various flash geometries.

For a particular flash geometry greater ‘rise’ was obtained with thinner flash. Also greater rise was obtained on a hammer than on a press, the load requirements being greater on the higher speed machine. Modes of metal flow were similar at all preheat temperatures. Theoretical treatment of the later stages of die filling, considering metal flow to be significant only in the region of the flash land, is able to describe the main features of the experimental results.
Investigation into Some Aspects of the Computation of Diesel Engine Combustion
Authors: Williams T. J. , Whitehouse N. D.
Published: October 2007

SYNOPSIS The effect upon computational cost and accuracy of various assumptions in diesel combustion models was investigated by comparing the performance of a range of models and by comparing the results of computation with experimental results.
Treatment of Separated Flow in Cascades by a Source Distribution
Authors: Railly J. W.
Published: October 2007

Provided that separation on the blades of a cascade takes place aft of the leading edge, the hypothesis that suction side velocity outside of an enlarged boundary layer remains constant is used as the starting point in a potential flow solution assuming that blades and enlarged bounary layers are thin compared with chord. Representing thickness, boundary layers and wake by a source distribution, an integral equation for the latter is deduced and numerical solutions are found for a nearly two-dimensional rotating radial impeller for various diffusion ratios on the suction side of the blades.

The method is valid, incompressible flow for any blade-to-blade surface that is a surface of revolution and in the presence of stream sheet thickness variation.

The theory is compared with experiments conducted on a radial impeller and good agreement with velocity distribution and impeller tip pressure rise is shown. Predictions of blade work may be obtained using a shape factor found from the experiment but loss coefficient predictions are too low. The conclusion is drawn that a three-dimensional influence is involved in the displacement growth on the impeller blades.
The Simulation of Air Fuel Mixing in High Swirl Open Chamber Diesel Engines
Authors: Morris C. J. , Dent J. C.
Published: October 2007

SYNOPSIS The air fuel mixing process in the high swirl open chamber diesel engine is simulated by a steady state gas jet injected into a steady air swirl flow. The results from the simulation show good agreement with engine studies using high speed photography.

An attempt to quantify fuel dispersion has been made through the introduction of a mixing parameter, which allows for combustion system geometry in addition to fuel jet and air swirl momenta.
The Relevance of the Institution of Mechanical Engineers
Authors: Mcewen Ewen
Published: October 2007

This year's Presidential Address departs from the autobiographical approach commonly adopted because I wish to express my views on the important issues which confront the Institution, the profession and the individual mechanical engineer in our 130th year. It is a personal testament and will be regarded as wise, opinionated or outrageous, depending on the degree of accord felt by the reader.
Experimental Observations on the Thermal Performance of a Rotating Coolant Circuit with Reference to the Design of Electrical Machine Rotors
Authors: Morris W. D. , Dias F. M.
Published: October 2007

SYNOPSIS This paper presents the results of an investigation into the influence of rotation on the thermal and hydrodynamic characteristics of a rotating coolant circuit which has relevance to the design of cooled rotors for electrical machines. Tests conducted with a fixed pressure drop across the entire rotor circuit demonstrate that increases in rotational speed can produce consequential increases in the temperature of the simulated winding. This is true for the case where the energy dissipation is constant.
Energy Recovery by the Incineration of Solid Waste Development, Present Status, and Experiences in Germany
Authors: Thömen K. H.
Published: October 2007

Starting with a review of the development of incinerator plants from simple destruction units to installations for heat recovery, the author surveys different aspects of a complex theme.

Using the concept of ‘heat production’, the composition of the refuse and the operating conditions which are important in the planning and construction of an incinerator are considered.

The paper then discusses the choice of furnace equipment and the conditions to be imposed on it, using as an example the ‘Düsseldorf roller grate system’. The configuration of the furnaces is also dealt with in the light of experience in the construction of the boilers.

Finally, under the heading ‘Operating Experiences’, facts are given about the reliability of incinerators, with special emphasis upon the problem of corrosion of the boiler-tubes.
The Influence of Oil Lubricated Journal Bearings on the Dynamics of Rotating Systems
Authors: McCallion H. , Wales D. R.
Published: October 2007

SYNOPSIS A computer program representing a shaft and rotor whirling in bearings which allows for realistic oil film boundary conditions and non-circular bearing profiles has been developed. It gave good agreement with experimental results published by Brown and France.

With the aim of increasing understanding of the influence of bearing profile on system instability, the program calculates the timewise variation of the energy in translational motion supplied to the rotor by oil film forces. One case is illustrated.
Transfer Function Reduction
Authors: Whalley R.
Published: October 2007

SYNOPSIS A method of generating reduced order models from the Laurent series expansion of a transfer function is examined by means of the Hankel Matrix and its correspondence to the field of rational functions. The approach enables particularly simple results to be derived regarding the composition of the reduced form and the avoidance of non minimum phase characteristics therein.
The Advanced Passenger Train
Authors: Boocock D. , Newman M.
Published: October 2007

Synopsis The history and development of British Railways' Advanced Passenger Train (APT) are discussed. The technical objectives are considered in the context of their value to commercial and operating performance. Among the technical aspects discussed are dynamics of guidance and suspension, aerodynamics, power and transmission, braking, and lightweight body structures. Highlights of the research and development programme are described, with reference to laboratory and track testing of the experimental train (APT-E) and associated experimental vehicles. The paper concludes with a description of the design of the prototype electric train (APT-P), of which three are currently being constructed for operation on the London/Glasgow route.
Experimental and Theoretical Identification of Air Ingestion Regimes in Pump Sumps
Authors: Swainston M. J. C.
Published: October 2007

SYNOPSIS

Results are presented of experimental observations made during investigation of the basic causes of vortex formation which show that air ingestion and vortex formation phenomena can be divided into three regimes corresponding to three ranges of submergence.

Simple theoretical modelling of the flow in which the suction pipe is replaced by a point sink, shows that the occurrence of vortex formation is associated with the behaviour of the surface stagnation point.

The theoretical results are compared with the extensive experimental data of Denny (4).
Seat Belts-Some Aspects of Compulsory Wearing in New South Wales, Australia
Authors: Vaughan R. G.
Published: October 2007

The effects of compulsory seat belt wearing have been evaluated for the most populous Australian State — New South Wales. Wearing rates are now very high and although surveys have shown increasing acceptance of the safety value of belts, a sizable minority of motorists apparently only wear their belts because of the law. Compulsory belt wearing appears to have saved a substantial number of vehicle occupant lives, with the main saving being among young adults. Urban deaths appear to have been affected more than rural deaths. There is tentative evidence of reductions in serious injuries among occupants. A side effect of the law has been increased usage of restraining systems for young children.
West Coast Main Line Operational Performance following Electrification from Weaver Junction to Glasgow
Authors: Ribbons R. T.
Published: October 2007

Some of the problems experienced since the electrification of the line from Weaver Junction to Glasgow are described and the solutions adopted explained. These include the failure of the overhead line at neutral sections, rail damage caused by high axle loads, tyre damage due to braking problems, loss of adhesion on gradients and improvements to the sanding gear. The paper concludes with a section on the problems of the thyristor locomotive.
A Plasto-Hydrodynamic Analysis of the Lubrication and Coating of Wire Using a Polymer Melt during Drawing
Authors: Thompson P.J. , Symmons G.R.
Published: October 2007

A study is undertaken of the lubrication of steel wire drawing using a Christopherson tube and a polymer melt as a lubricant. Primary objectives of the study are to determine the criteria under which a thin, well adhered coat of the polymer is deposited on the wire after drawing. An analysis determines these criteria and enables the polymer coat thickness to be obtained for given operating conditions. Several flow defects are observed and discussed.
The Solution of a Vibration Problem on a Turbine-Compressor Set Mounted on a Steel Foundation
Authors: Ramsden J.N. , Stoker J.R.
Published: October 2007

The paper describes a vibration investigation undertaken as part of the commissioning of a 12 M.V. steam-turbine driven blower. The set which was mounted on a flexible steel foundation. suffered severe vibration of the exhaust-end pedestal of the turbine. Early attempts to cure the vibration had failed. To avoid further delays it was decided to make a theoretical model of the machine and its foundation and to develop this until it agreed with measurements taken at site. Having proved the theoretical model it was then to be used to try out suggested modifications to the foundation to see if a solution could be found. The first stage of the work was to make site measurements of the machine's vibration pattern over the speed range of the machine. Recordings were made and analysed of the motion of various points on the shaft, bearing housings, casings and supporting structure in sufficient detail to demonstrate the validity of the theoretical model's predictions. The theoretical model used finite element techniques to model the shaft and the foundation structure. The shaft, mounted via hydrodynamically-lubricated bearings in the structure, was spun over the speed range of the machine and the response to unbalance of the shaft and structure computed. It was found that considerable detail was required in the idealisation before the predictions finally agreed with the site test results. When this agreement was obtained a modification involving a central column under the centre bearing pedestal was put into the theoretical model. It was predicted that this modification would reduce the peak vibration by 78 percent. When the real column was fitted to the foundation the vibration level was found to have been reduced by 75 percent.
Elastohydrodynamic Lubrication in Human Joints
Authors: Higginson G. R.
Published: October 2007

Recent developments in the analysis of elastohydrodynamic lubrication (EHL) of solids covered by soft layers, are applied to the big load-bearing human joints. It is concluded that the chances of generating a full film by conventional rolling/sliding EHL are small; but for loads of short duration the squeeze film mechanism looks very promising.
Piston Ring Scuffing during Running-in—the Influence of Lubricants and Materials
Authors: Willn J. E. , Brett P. S.
Published: October 2007

A mechanical test rig and a single-cylinder test engine have teen used to study the influence of lubricants, materials, and surface finish, in relation to scuffing failure of piston rings and cylinder bores. Good correlation between the mechanical rig and the engine was demonstrated when scuffing performance in the two devices was rated in terms of a factor involving contact pressure and sliding velocity. With the many features investigated, a wide range of results was obtained, and the work has thereby brought attention to various modifications which can be made in order to alleviate problems of scuffing which can occur particularly during engine “break-in”.
Influence of Droplets on the Properties of Liquid Fuel Jets
Authors: Pirouz-Panah V. , Williams T.J.
Published: October 2007

The influence of droplet motion on the properties of a fuel jet was investigated. Droplet histories, evaporation rates and induced gas motion were computed and the fuel jet properties compared with that of a steady-state jet. It is concluded that droplet size has an important effect upon penetration and that the model should be extended to take account of a range of droplet sizes and simplified by neglecting transient effects.
A Jaguar in Military Camouflage
Authors: Brewer J.H.
Published: October 2007

The well established Jaguar 4.2 litre engine was selected as the most suitable power unit for the tracked and wheeled versions of the Combat Vehicle Reconnaissance. This paper gives the background leading up to this choice and the modifications and development required for both the engine and ancillaries to enable the engine to operate successfully in a military environment.
Reduction of Critical Axial Thermal Stresses in Turbine Rotors
Authors: Gregory J. F. , Fleming A. S. , Horvay G.
Published: October 2007

Analysis shows that advantage may be taken of the thermal stress end conditions in cylindrical configurations to reduce axial thermal stress in turbine rotors.
The Investigation of Derailments
Authors: Duncan I. G. T. , McCann J. B. C. , Brown A.
Published: October 2007

The concept, history, and operation of the Derailment Investigation Service maintained by the Research and Development Division of the British Railways Board is discussed, together with the nature and sources of the body of technical and numerical data which has been established. The mechanisms and causes of derailment are also described and the relevance of vehicle condition, track geometry, operating circumstances, and vehicle dynamics discussed.
Performance and Emission Predictions for a Multi-Cylinder Spark Ignition Engine
Authors: Benson R. S. , Baruah P. C.
Published: October 2007

A comparison is made of experimental results and predictions of performance and emissions from a multi-cylinder spark ignition engine over a range of air-fuel ratios and two throttle settings. The results showed that a simplified two zone combustion model, a seven reaction scheme for nitric oxide formation, a partial freezing model for carbon monoxide and the inclusion of chemical reactions and variable specific heat along the pathlines in the wave equations gave good agreement with the measurements at the common pipe junction and exhaust outlet, but due to cyclic dispersion and maldistribution of fuel between cylinders the predictions of the emissions in the exhaust manifold adjacent to the cylinder were not so good.

The predicted air flow and indicated power agreed well with experiment.
Prevention of Steam Turbine Blade Erosion Using Stator Blade Heating
Authors: Akhtar M.S. , Black J. , Swainston M.J.C.
Published: October 2007

Previous work on the phenomenon of the erosion of the moving blades in steam turbines is reviewed, which has shown that this is due to the accumulation of coarse water on the stationary blades.

The basic physics of the accumulation is considered and the conclusion is drawn that this is due to condensation. This can occur even on adiabatic blading, but is expected to be particularly prevalent on blades whose interior is at a reduced pressure (and hence temperature) for suction purposes. Tests are reported on the heating of a single blade mounted in a steam tunnel downstream of a small steam turbine. The turbine exhaust could be arranged to be either wet or superheated. These tests showed that condensation on the blade could be prevented using only small amounts of heating. Methods of applying this system to full size turbines are considered and preliminary economic effects estimated, with encouraging results.
Reduction of Noise and Vibration in Roller Chain Drives
Authors: Nicol S. W. , Fawcett J. N.
Published: October 2007

Particularly at the higher sprocket speeds, one of the main sources of noise and high-frequency vibration in a roller chain drive is the impact which occurs each time the driving sprocket collects a roller from the chain span. A method of guiding the chain so as to virtually eliminate these impacts is described. Details are given of experimental tests in which a simply-constructed guide device greatly reduced the amplitude of the high-frequency vibration of a drive, and produced a very significant lowering of the noise level.
The Leyland Titan
Authors: Bretherton K. , Heath B. K. , Platt E.
Published: October 2007

This paper describes the objectives, design and development of the Leyland Titan integral high bridge double deck bus.
The Combustion of Coal in Fluidised Beds
Authors: Thurlow G. G.
Published: October 2007

The development of fluidised combustion of coal from small-scale laboratory experiments in the early 1960's to the present day, when the first commercial applications are being designed and constructed, is described, concentrating on the contributions made by the National Coal Board and others in the United Kingdom. It is shown that significant efforts are being made to exploit this technology both in the UK and overseas. The potential advantages of fluidised combustion which justify these efforts are described, and examples are given to illustrate the engineering features of boiler plant fired by the fluidised combustion system, and some of the design problems the designer needs to overcome.
Tribology in Manufacturing Engineering
Authors: Halling J.
Published: October 2007

The paper covers work done at Salford University and identifies those aspects of tribology which are important to both the design of metal working machines and to the tool/workpiece interaction. After identifying the important tribological problem areas some examples of possible methods of solution are indicated using the work at Salford University for typical examples. Inevitably the paper identifies many questions to which there are currently very limited answers and thereby indicates the areas for further research. It should however be stressed that the author does not claim to have produced a comprehensive review on tribology in manufacturing engineering. Rather the style of the paper is to question the way forward and in some cases even to propose answers.
Compressible Flow through Square Edge Rectangular Orifices
Authors: Deckker B. E. L.
Published: October 2007

The results of a systematic experimental investigation of compressible flows through rectangular orifices, in particular the effects of the variables transverse length/height, a/b, and axial length/equivalent diameter, l/de, are presented and discussed. Non-monotonic changes in the mass flow rates due to changes in these variables are revealed by normalization using circular orifice data allowing the experimental results to be interpolated over a continuum of each of variables, namely, 1≤a/b≤300 and 03≤ l/de<<3.0. A universal prediction for circular orifices is also given.
Comparison of Stochastic Identification Techniques for Dynamic Modelling of Plastics Extrusion Processes
Authors: Kochhar A. K. , Parnaby J.
Published: October 2007

The important plastics extrusion process is briefly described and the difficulties of modelling the process from physical considerations are outlined. A number of stochastic process identification techniques, i.e. correlation, spectral analysis, generalized least squares, instrumental variable, correlation matching, maximum likelihood and Box-Jenkins algorithms are briefly reviewed.

The results of experimental work carried out on a laboratory plastics extruder, using random perturbations in screw speed, are presented. From a comparison of the results of different identification methods, it is suggested that although correlation and spectral analysis techniques can help in improving the understanding of the process mechanisms, the type of models best suited for high level feed-forward computer control are of the Box-Jenkins and maximum likelihood structural forms.
Modelling the Dynamics of Coal and Mineral Cutting
Authors: Edwards J. B.
Published: October 2007

A dynamic model is developed for coal and mineral cutting machines which exhibits all their important behavioural characteristics. In particular, the model produces the characteristic hopping motion observed in practice to take place at frequencies closely related to the speed of rotation of the cutting head. The low-frequency instability of simple, integral load-control systems is also verified by simulation.

Frequency-response analysis is shown to predict the practically observed and simulated system behaviour. the analysis necessitating a describing-function approach to the modelling of stick/slip effects in the machine haulage system, which are shown to exercise an important control on the limit-cycling of the regenerative cutting dynamics. The analysis is shown to be applicable to systems using both conventional haulage (feed) systems of low stiffness, and also to stiff transmission systems.
Spectral Factorization of the Transfer Matrix
Authors: Whalley R.
Published: October 2007

The structural decomposition of linear multi-variable systems which can be represented by a transfer matrix is investigated. A factorization procedure is proposed and the necessary mathematical techniques to achieve this form are outlined. The result obtained is applied to the synthesis of the Wiener-Hopf optimum filter and a pre-compensator design procedure that leads to non-interaction in multi-variable systems is proposed. Relaxation of the decoupling compensator by taking approximations of the transfer functions contained therein gives rise to a condition of diagonal dominance rather than non-interaction in the combined system which enables simpler feedback strategies to be realized. The applicability of the factorization procedure to problems in circuit analysis and aerodynamics is commented upon and the suitability of the method to automatic computation is emphasized.
Leadership by Engineers
Authors: Garnett John
Published: October 2007

To survive, society depends, amongst other things, on the successful implementation of the ideas of engineers. To implement his design or conceptual thought, the engineer relies increasingly on the co-operation of large numbers of people: other engineers, draughtsmen, fitters, supervisors and men and women in design, construction, production and maintenance.

This lecture suggests that the benefits of engineering will come to our society only if engineers give more attention to achieving the commitment of the gifts of other people in making things happen. An outline is given of some common sense leadership actions which engineers must take during the last twenty years of the twentieth century if our society is to advance.
Orifice Restrictor Losses in Journal Bearings
Authors: Pink E. G. , Stout K. J.
Published: October 2007

Details of a study concerning orifice restrictor losses in externally pressurized gas lubricated journal bearings are given. The type of compensation considered is the pocketed orifice design.

The analysis presented includes the effects of pressure recovery in the pocket and entrance loss effects at inlet to the bearing film. Also, by treating the flow in the bearing film local to the pocket as radial flow, the effect of dispersion is accounted for.

It is shown that good agreement exists between computed and experimental results in pressure profiles and also for load capacity up to touch-down conditions.

From the analysis, the effect of the inherent compensation factor, number of orifices and pocket diameter on load capacity is discussed.
A New Technique for Estimating System Uncertainty in Design
Authors: Blockley D. I. , Ellison E. G.
Published: October 2007

Components operating in modern power plant, such as nuclear reactors, gas and steam turbines are subject to complex loading cycles at elevated temperatures so that combined creep/fatigue damage often occurs. Estimates of the life of these components are difficult because of the indefinite nature of the assumed constitutive model and also of the relevant material properties. In an attempt to handle this problem, a new predictive technique is presented which is based on the concept of ‘fuzzy sets’ (1). The basic ideas behind fuzzy sets are simply explained and then applied to test results previously obtained (2) on a 1 Cr Mo V steel. A simple linear cumulative damage rule is used for illustration.

Using the method, estimates of system uncertainty can be made which can then be combined with random uncertainty of the parameters to obtain a probability measure of the number of loading cycles to failure of a component. Cumulative distribution functions for the system uncertainty in the test results are produced and their usefulness to the designer discussed.
A Pillar Dynamometer to Measure the Forces on Discs Cutting through Rock
Authors: Drew S. D. , Hignett H. J. , Johnson P. E. , Crabb G. I.
Published: October 2007

This paper describes the design, development and application of pillar dynamometers to measure the forces on discs cutting through rock both in field trials using full-face tunnelling machines and in laboratory experiments.
Engine Design Experiences and Development of Critical Components
Authors: Robinson J. E.
Published: October 2007

The paper provides a review of a number of engines for which the author had some personal design and/or development involvement and responsibility. Details are given of methods of construction and technical performance which illustrate progress in engine design over the last forty years, and the contribution made in development by engine component specialists.

Predictive techniques and uses of specialized rig tests used in piston assembly development are described, which reduce development costs and time, and improve engine reliability. Quality control techniques are briefly compared and the need is shown for a greater degree of ‘in-process’ control, to be developed in the next decade, to obtain improved quality levels with no concurrent cost increase.

It is suggested that the main prime movers in use during the first two decades of the next century will still be recognizable as reciprocating engines, but that efficiencies will be improved by reduced friction and by a more efficient response to engine load demand.

It is believed that in the search to conserve the world's fuel resources, and in the increasing demand for improvements in the ecology and consumer protection, there will be an increasing demand—and recognition—for the dedicated engineer.
Development Work on Steam Vent Pipe Silencing
Authors: Clayton J. K. , Cramer S. H.
Published: October 2007

The paper describes the practical steps taken in the development of a light-weight steam discharge silencer, mounted at the outlet of the vent pipe.

With various degrees of valve throttling of superheater start-up valves as well as safety valves, the sound pressure level (SPL) effects at the vent pipe outlet were analysed before and after silencing.

Various configurations of the silencer were tested on steam discharge, some resulted in increased attenuation. Throughout the development programme, steam flow rates were measured along with SPL.
Improvement in the Torque Characteristic of a Two-Stroke Opposed Piston Diesel Engine
Authors: Blencoe W. R. , Few P. C. , Picken D. J.
Published: October 2007

This paper gives details of an investigation into the improvement of the torque characteristics of a turbocharged Commer TS3 two-stroke diesel engine.

At low engine speeds when there is a need for a rising torque characteristic the desirability of using a combustion chamber before the turbine is investigated:

(a) theoretically using a computer matching program, and, (b) experimentally by removal of the scavenge blower and incorporating a combustion chamber in the exhaust ducting.

Theoretical and experimental work is reported in this paper.
Skin Friction Sensor and Its Applications on the Surface of a Circular Cylinder
Authors: Aly S. , Cunningham J.
Published: October 2007

This paper describes the development of a sensor for the direct measurement of shear stress on the surface of a cylinder in cross-flow. The development, operation and performance of the device are explained. Some of the applications of the device to the measurement of skin friction under various now conditions are given. In addition, the use of the device in the measurement of the Strouhal Number is shown.
Water Hammer Phenomena in Thermal Power Station Feed Water Systems
Authors: Wilkinson D. H. , Dartnell L. M.
Published: October 2007

The phenomenon of water hammer in stagnant hot fluid systems has been manifested by the fracture of a number of cast iron valves and other components in power station low pressure feed water systems and other similar systems.

A comprehensive investigation proved necessary into all aspects of this phenomenon. The investigation involved a survey of water hammer events, experimental work, data acquisition, pressure testing, calculation of forces and the determination of the strength of individual components.

From this work has sprung a clear understanding of the sequence of events occurring when pressure is reduced on hot feed water and flash steam is produced which subsequently escapes or condenses and fluid columns recombine at speed and produce pressure pulses.

Experimental and theoretical work has revealed the magnitude of such pressure pulses and also revealed that steel pressure parts will not fail when subjected to the forces arising from thermodynamically induced water hammer, because steel pipes limit transient hydraulic pressures by dilating and steel valves are sufficiently strong.

The dynamic response of complex pipework system to stimulation by water hammer events requires further investigation, but practical experience indicates that failure of steel system components is unlikely from dynamic movements, although damage may be suffered by pipe hangers, seismic restraints etc.
Tunnel Cleaning Machines
Authors: Ridge N. , Faulkner F. J. S.
Published: October 2007

The paper considers the problems presented by dirt and metallic dust in underground railway tunnels. The paper deals with the origins of the problem and its nature and present methods of clearing the dust. From this point the paper covers the development of the tunnel cleaning train currently being commissioned for London Transport and its equipment for the collection and disposal of the dust, the operation of the train and the special traction and other equipment.
The Non-Steady Flow of Gases and Vapours from Pressure Vessels
Authors: Sallet D. W. , Palmer M. E.
Published: October 2007

The flow of gases and vapours from pressure vessels to the atmosphere is investigated. Two major points are addressed, first, the non-steady mass flow rates and the non-steady pressure and temperature variations, due to the finite size of the pressure vessel, and second the effect on the blow-down process if the vapour is not assumed to be a perfect gas, as is suggested in current pressure vessel safety codes, but if a more realistic equation of state is selected to describe the thermodynamic behaviour of the vapour. For the non-steady outflow of perfect gases analytically derived correction functions are given with which the complete blow-down phenomena can be calculated from the well known steady flow equations. For the non-steady outflow of real gases and vapours a calculation method is described and the computer algorithm is given. Both calculation methods are discussed and compared in examples using propane vapour as the flowing medium and the dimensions of a rail tank car for the pressure vessel.
A Design Criterion for Maintaining Contact at Plain Bearings
Authors: Earles S. W. E. , Kilicay O.
Published: October 2007

Clearances at connections of mechanical systems may allow contact to be momentarily lost between the interconnected elements resulting in impact loading, the generation of noise and deterioration of the bearing surfaces. Determining, from a zero-clearance analysis of the mechanism, the reactive force R at a bearing and its rate of change of direction, the criterion is proposed that provided (/ R)/(rad s-1/N) > 1 then contact will be maintained at the bearing. The criterion is shown to apply to a four-bar and a five-bar mechanism having two clearance bearings and subjected to rotary and oscillatory inputs.
Repowering of Slough Estates for Optimum Energy Conversion
Authors: Clifford D. , Coates R. , Park A.
Published: October 2007

Plant currently under construction for repowering Slough Estates is described. This will not only provide the basis for replacement of ageing plant, but will enable the existing steam turbines to work as part of a high efficiency cycle. The principles relating to the combined generation of steam and electrical energy are reviewed for existing and possible plant configurations, with a view to optimizing the energy conversion. The choice of a gas turbine and fully fired heat recovery boiler to provide extra power plus steam for existing purposes is shown to be justified by the savings in fuel and other operating costs over a typical year's operation. The new plant will burn gas, residual oil or distillate oil, and fuel treatment plant is an essential part of the equipment. The energy savings indicated using technology already available in Britain point the way to future developments.
The Flow Characteristics of a Piston-Cylinder Assembly with an Off-Centre, Open Port
Authors: Morse A. P. , Whitelaw J. H. , Yianneskis M.
Published: October 2007

Laser-Doppler anemometry has been used to measure the mean and r.m.s. values of the velocity components of the flow in a reciprocating assembly containing an off-centre, open port in the cylinder head and a flat piston. The port was inclined at an angle of 60° to the head and gave rise to a three-dimensional flow with no significant compression. The rotational speed was 200 rev/min, ensuring fully turbulent flow.

The measurements were restricted to the axial and circumferential velocity components and were made on three radial planes in order to describe the flow in sufficient detail. The results are presented in the form of radial profiles and vector diagrams in both the axial and cross-stream planes. The main flow pattern on the intake stroke is of the same general shape as that previously obtained with a symmetric port, a large vortex occupying the space bounded by the indrawn jet with a much smaller vortex in the corner between the cylinder head and wall. These vortices are however no longer symmetrical about the cylinder axis, but vary in both size and intensity with circumferential position. In the cross-stream plane, the primary vortex is characterized by the presence of a stress-induced swirling motion on either side of the plane of symmetry with velocities significantly greater than the circumferential velocity of the jet. At mid-stroke, these vortices rotate counter to the jet, but at 144° ATDC, the direction of rotation reverses over part of the length of the vortex and is in the same sense as the jet motion. On the exhaust stroke, the flow patterns are relatively simple with quasi-parallel axial flow and little swirl until the port is approached, when the outgoing jet accelerates and begins to rotate in a direction opposite to its motion on the intake stroke.
The Piston Ring at Top Dead Centre
Authors: Moore S. L. , Hamilton G. M.
Published: October 2007

Using capacitance transducers the oil film thickness between the compression ring and the cylinder liner of a diesel engine has been investigated in the region of top dead centre. Results are presented from two engines, one supercharged and the other normally aspirated. Calculations of the film thickness have been carried out and these are compared with the measured results.
Analysis of a Double Crank Mechanism Applied to a Yarn Guide Traverse
Authors: Wright I C
Published: October 2007

A theoretical study is made of the suitability of a double crank mechanism to impart motion to the yarn guide of a spinning machine. The theoretical predictions are compared with the structure of packages wound on a test rig incorporating a double crank mechanism. Errors in the theoretical predictions are found to be acceptably small. Finally, the double crank package is compared from the standpoint of density distribution with a package produced on a standard production machine. The results of this comparison indicate that the double crank drive may be a suitable alternative to the usual cam-driven traverse rod.
Practical Aspects of Fracture Mechanics in Engineering Design
Authors: Burdekin F M
Published: October 2007

Fracture mechanics has been applied to great effect in some high technology industries but to a much lesser extent in general engineering. This is in part due to the continual stream of complex research papers which concentrate on extending frontiers of knowledge, and do not give a perspective view of the potential applications of the subject to design. The general principles of fracture mechanics can be applied to the prevention of failure in a wide range of engineering situations, however, without a detailed knowledge of the mathematical background.
Backing a Winner—The Engineer's Contribution to UK Agriculture
Authors: Bell R L
Published: October 2007

After briefly outlining the nature and importance of agriculture in the UK, attention is focused on the part played during the post-war revival by the agricultural engineer. Looking to the future the main body of the paper illustrates, via examples involving different engineering disciplines, how the research and development engineer is using analytical and experimental techniques to facilitate the design and development of improved machinery and systems. Modern measurement and control techniques offer new opportunities both to the researcher and, via the agricultural engineer, to the farmer. Although the early dramatic phases of mechanization are over, it is shown that agricultural engineering continues to offer exciting challenges to young engineers to contribute to a vital industry.
Power Transmission and Control in Shearers
Authors: Knight G C
Published: October 2007

This paper discusses the special problems of power transmission and control in shearers for longwall mining, and reviews the ways in which changes to improve the machine's mining capabilities have made targets for reliability more complex to achieve*.
Analysis of Power Plant Deaerator Storage Tank Instabilities
Authors: Cranfield R R , Wilkinson D H
Published: October 2007

In some power plant deaerators storage tank steam is caused to flow over the surface of the water on its way to the condensing head. This steam flow, which may become very large under transient load operation, low pressure feed heater bypassing or isolation, may create water waves, a hydraulic gradient and possibly spray which carries over into the deaerator head via the steam transfer pipe to result in high differential pressure. This may lead to head flooding, surging discharge, tray stack damage, and also give rise to problems with associated components; for example vent condenser flooding. Steam transfer pipes may constitute a forcing system resulting in tank contents sloshing and severe vibration. These events in turn may precipitate an instability (the Kelvin-Helmholtz instability) whereby waves may grow to bridge the gap between water surface and tank crown to form a water-piston. A piston so formed is rapidly propelled along the tank to impact with a hammer-like blow causing serious internal and external damage and jeopardizing safety. The sequence of events finally precipitating the onset of the water piston is complex and renders an analytical approach which might establish design criteria difficult, for this reason simple modelling is suggested. This paper describes such studies using one-twelfth scale models of late generation 500-660 MW units, from which the parameters governing instability are evaluated.
Effects of Flow and Geometry Boundary Conditions on Fluid Motion in a Motored IC Model Engine
Authors: Arcoumanis C , Bicen A F , Vlachos N S , Whitelaw J H
Published: October 2007

Measurements of ensemble-averaged axial velocities and the r.m.s. of the corresponding fluctuations, obtained by laser-Doppler anemometry, are reported for axisymmetric flow in a non-compressing piston-cylinder assembly motored at 200 rev/min simulating an IC engine. The inlet geometry comprised an open valve, located centrally and flush with the cylinder head, with seat angles of 30° and 60° and incorporating 30° swirl vanes. Results are presented for bore-to-stroke ratios of 0.83 and 1.25 and swept-to-clearance volume ratios of 2,3 and 9. The results indicate strong similarities between the flow structures for different stroke and clearance; a system of vortices is formed with a large vortex occupying most of the flow space and with smaller vortices in the corners between the wall, piston and cylinder head. The influence of valve seat angle is more pronounced and results, for the 30° angle, in adherence of the incoming jet to the cylinder head with increase of the overall turbulence levels and creation of stronger and longer living vortices.

Previous results obtained in related compressing and non-compressing flow configurations are reviewed and, together with the present results, enable the influence of a wide range of possible geometric and flow boundary conditions to be quantified.
Performance and Design of Plug-Type Check Valves
Authors: Kubie J
Published: October 2007

Plug check valves are frequently used in high pressure systems where parallel pump operations are envisaged, in order to prevent flow recirculation through the out-of-service pump. Serious operational problems are sometimes encountered with these valves during pump changeovers. Full equations of the dynamic behaviour of the plug check valves are derived and results are obtained for their performance in a typical power plant system. Criteria for the design of the plug check valves are also developed.
Submarine Propulsion in the Royal Navy
Authors: Horlick Ted
Published: October 2007

The paper outlines the history of submarine propulsion from the early days, through the hydrogen peroxide plants on Explorer and Excalibur to the setting up of the nuclear submarine programme. The building of the submarine prototype at Dounreay, the purchase of the Dreadnought plant from the US and the design and construction of the Valiant class submarines formed the base for developments in the 1960s leading to the highly successful Resolution and Swiftsure class submarines. Lessons learned from the design, building and operation of nuclear submarine propulsion plants are discussed and the future requirements for unproved operational characteristics and for higher nuclear safety standards are examined against the constraints of keeping unit costs under control. The success of the nuclear submarine programme is shown by the position today where the Royal Navy has sixteen nuclear submarines in service, a new submarine class under construction and work on the next generation of nuclear propulsion plants well advanced.
Powder Compaction: Fundamentals and Recent Developments
Authors: Fischmeister Hellmut F
Published: October 2007

The lecture reviews processes and mechanisms of powder compaction in dies, by cold or hot isostatic pressing, and by various other methods. The review will also include the hot and cold forging of powder preforms. Key problems of the main processes will be discussed, such as mass flow in the powder bed during compaction, which is required to achieve homogeneous density distribution in a part, or the role of powder lubrication.

Applications of powder compaction are described using examples from such areas as the manufacture of sintered machine parts, high-strength automotive parts made by powder forging, the fabrication of mill shapes from powder (e.g., high speed steel or stainless steel tubing), and the production of aircraft engine parts by hot isostatic pressing.
Engineering for Humanity
Authors: Thring M W
Published: October 2007

When one looks at the twenty-first century it is clear that the extrapolation of high technology must lead to disaster. The factors are arms escalation, increase of the gap between rich and poor countries, growth of deserts, exhaustion of easily won raw materials, especially hydrocarbons, the cumulative effects of pollution, and increasing unemployment. Necessary steps towards a stable world are for the rich countries to accept a considerable reduction in their use of resources, to provide everyone with an interesting and well paid job and to shift a steadily increasing fraction of their engineering R & D resources from weaponry to co-operative production of equipment for the poor countries.