bluuebunny/crossref_metadata_2025 huggingface dataset:
Third Paper: Intake Noise from Axial Flow Turbochargers and Compressors
Authors: Sharland I. J.
Published: October 2007

One of the factors that has to be considered when planning the installation of a turbocharger or gas turbine is the amount of noise that is likely to be radiated from the intake. Frequently such plant employs axial flow compressors, either single-or multi-stage. The object of this paper is to describe how noise is generated in that type of compressor.
Measures to Counter Fatigue Failure in Railway Axles
Authors: Maxwell W. W. , Dudley B. R. , Cleary A. B. , Richards J. , Shaw J.
Published: October 2007

This paper reviews the experience in London Transport of fatigue cracking in railway axles, and presents the results of laboratory fatigue tests on full-scale axle specimens under simulated rotating bending. The investigation was undertaken with the aim of entirely eliminating fatigue cracking and fretting under the press fits of wheel-axle sets. Whilst cold rolling of wheel seats, which is standard L.T. practice, strongly inhibits the propagation of such fatigue cracks, it does not prevent their initiation. The introduction of a stress-relieving groove, such that the edge of the press fit overhangs the groove, leads to a marked reduction in fretting and increase in life of test specimens, and the results of a limited service test suggest that the presence of such a groove reduces the stresses under the wheel hubs to a level at which cracking is eliminated. Since the presence of a press fit near to a groove increases the stress level at the root of the groove it is desirable to cold-roll the grooves, and a suitable rolling technique employing three rollers of slightly different profile radii has been developed.
Fire-Resistant Fluids for General Hydraulic and Steam Turbine Systems
Authors: Wilson A. C. M.
Published: October 2007

Major items of C.E.G.B. power plant are now being designed to operate at high steam temperatures and hydraulic pressures. In consequence, the risk of fires due to leaking petroleum lubricants is increasing. Suitable fire-resistant (f.r.) fluids are therefore desirable. Some of these have, however, given rise to difficulties in service due to changes in their physical and chemical properties.

The physical properties of non-aqueous synthetic f.r. fluids (i.e. phosphate esters and chlorinated diphenyls) have been surveyed, and their chemical stability and anti-corrosion properties determined.

Whilst the physical properties of the phosphate esters are better than those of the chlorinated diphenyls the chemical stability and corrosion properties are much worse.
First Paper: Extrusion of Aluminium and Copper
Authors: Austin E. R. , Davies R. , Bakhtar F.
Published: October 2007

This paper describes the results of cold backward extrusion tests on aluminium and copper specimens, using test rigs in which impact velocities up to 300 ft/s could be obtained. The maximum energy available was 10 000 ft lbf, but for the work described here, 6000 ft lbf were adequate for the extrusion of billets of 1-in diameter, 1.5-in long. Comparison was made with extrusion at very low speed, and the effect of impact velocity on extrusion pressure and mean work of deformation assessed.

For aluminium, reductions of area of between 44 and 86 per cent were examined. Surprisingly little variation in deformation energy over the speed range was noted, but the optimum impact speed appeared to be in the region of 50-80 ft/s.

In the case of copper, where impact speeds up to 240 ft/s were investigated, the optimum impact velocity was about 60 ft/s.

A limited series of tests in combined forward and backward extrusion was also carried out in both materials. It was found that both reduction in area and impact velocity had a marked effect on the relative proportions of metal extruded in the two directions.

Mention is also made of metallurgical examination into the effect of high-speed working on the properties of extruded metals.
Calculation of Flow through Cascades of Blades Having Relative Motion and the Generation of Alternating Pressures and Forces Due to Interaction Effects
Authors: Parker R.
Published: October 2007

A method is given for calculating the incompressible flow of a perfect fluid through multiple cascades of blades with one or more cascades moving relative to the frame of reference. Finite differences are used and the stream function evaluated by relaxation. From this velocities and pressures are calculated throughout the field for a sequence of relative blade positions allowing the spatial and time variations to be obtained.

The method is applied to an i.g.v.-rotor combination with three values of axial spacing. The results show that the mechanism of blade row interaction is that the i.g.v. prevents accelerations of the fluid in the direction normal to the i.g.v. camber line which would occur if the i.g.v. were not present.

The resultant pressure differences across the i.g.v. are the primary source of alternating forces and provide sources of discrete frequency noise at typical blade row axial spacings. The present investigation is confined to the near field and estimation of noise radiation is beyond its scope; however, if the analysis is used to design blades producing the minimum fluctuating pressures, relatively low noise radiation should result.
The Effect of Flatness of Joint Faces upon the Static Stiffness of Machine Tool Joints
Authors: Thornley R. H. , Connolly R. , Koenigsberger F.
Published: October 2007

This paper looks into the types of flatness errors produced in typical machining operations. The effect of these flatness errors on the pressure/deflection curves of the surfaces is reported. An empirical relation, based on the experimental results, between surface deflection and mean interface pressure is suggested. The effect of bonding joints is shown to eliminate plastic deformation of the surfaces and produces a joint having linear characteristics.
Research on Solid Lubricants for Use within Gas-Cooled Power Reactors
Authors: Parry A. A. , Mitchell L. A.
Published: October 2007

The gas-cooled power reactors operated by the C.E.G.B. are refuelled on-load. Thus there are a number of devices which operate in the coolant, and solid lubricants offer an attractive solution to the lubrication problems encountered. These problems are discussed, and the characteristics of suitable lubricants are elucidated. The main requirement is that of long lifetime at constant (but not necessarily extremely low) friction.

Present solutions to some of the problems are described, and their limitations are pointed out. A brief review of some possible solid lubricants is given, with an indication of the temperature ranges within which they are usable.

Results of friction and endurance tests on sprayed films of unbonded molybdenum disulphide, tungsten disulphide and graphite are presented for tests at 200 and 400°C. At 400°C tungsten disulphide was the most promising lubricant, whereas molybdenum disulphide was best at 200°C. In general, lifetimes of sprayed films showed a wide scatter.

Preliminary experiments on some hot-pressed composite materials containing a metallic (nickel) matrix and a lubricant powder (tungsten diselenide or calcium fluoride) are described. None of the formulations tested was fully satisfactory at 100°C or 400°C when both wear rate and friction were considered. However, all proved superior to plain nickel when rubbed against stainless steel.

The important factors in the method of application of solid lubricants are not understood. It is clear that much more basic research is needed, and the directions this might take are discussed.
The Rational Treatment of Temperature and Temperature Scales
Authors: Haywood R. W.
Published: October 2007

The terminology of that branch of science concerned with temperature has always been in a most unsatisfactory state. Concepts which are essentially different in kind, such as those of thermodynamic temperature and scales of temperature, are still universally described in identical terms, and completely different quantities continue to share the same symbol. This unscientific state of affairs should not be allowed to persist. The rational treatment of the subject set out in this paper endeavours to remove these existing confusions and ambiguities.
Second Paper: Hydraulic Lock with Single-Land Pistons
Authors: Dransfield P.
Published: October 2007

Experiments are described in which the break-out force associated with hydraulic lock on single-land pistons is measured. The test pistons used were of 0.5-in diameter × 1 in long, with diametral clearances in their bores in the range 2-20 × 10-4 in. The pistons were subjected to axial pressure drops in the range 0-5000 lbf/in2. The finish of the pistons and bores was closely controlled as regards surface finish, roundness and parallelism. It was found in all cases that a relatively small inherent lateral force acted on the pistons. The lateral force-pressure profile was found to increase linearly with clearance. Beyond a particular pressure for each clearance used, the lateral force necessary to generate hydraulic lock disappeared.

Leakage flow rates were measured and used to help assess the attitude of a test piston in its bore.

An hypothesis is given which explains the presence of hydraulic lock with single-land piston configurations. The hypothesis relates the hydraulic couple due to small residual tilts of pistons in their bores, and the mechanical friction in the reaction bearing required to support the piston against axial pressure forces. Experiments designed to test the hypothesis give positive support to it.
An Experimental Study of Some of the Factors Affecting the Contact Conditions and the Slip between a Rolling Ball and Its Track
Authors: Hailing J. , Al-Qishtaini M. A.
Published: October 2007

The problem of a rolling ball subjected to combined normal load and tangential tractions has been studied for a variety of operating conditions. It is shown that for dry steady state loading the resultant slip may be explained in terms of a microslip theory based on the differential elastic straining of the ball and the track. Such results necessitate a careful experimental technique in which the surfaces must be free from contamination and loose wear debris. It is also shown that the preceding arguments are not significantly affected by dynamically varying loads or by speed variations in the range 0-150 in/min.

The slip behaviour is found to be markedly affected by the presence of a lubricant. The behaviour with load and speed now indicates a definite hydrodynamic effect, although the theoretical film thickness is considerably less than the surface roughness. These results agree well with the results of other investigations for similar conditions. Using these experimental results and theoretical considerations a tentative power law formulation for the slip under such conditions is proposed.
Chatter When Machining Aluminium Alloy: An Investigation Using a Structural Model
Authors: Johnson B. M. , Andrew C.
Published: October 2007

This paper describes an experimental investigation of machine tool chatter, in which the machine tool structure was replaced by a model, two-degrees-of-freedom structure with adjustable and consistent vibration characteristics. Primarily non-regenerative chatter, and secondarily regenerative chatter, were investigated for orthogonal cutting of an aluminium alloy with both conventional and restricted-contact cutting tools. The results are presented in the form of stability charts; these show the limiting widths of cut which can be machined without chatter, for given sets of machining and structural conditions.

For non-regenerative chatter, it was found that the limiting width of cut: increases with a decrease in the structure's cross-receptance between the directions normal and tangential to the cut surface; increases with a decrease in cutting speed, but in a manner depending on the structural characteristics; is substantially independent of the mean undeformed chip thickness; increases by at least 25 per cent if contact is restricted to a length approximately equal to the undeformed chip thickness.

For regenerative chatter it was found that the limiting width of cut: was approximately one half of the limiting width for non-regenerative chatter, for the otherwise similar machining and structural conditions investigated; increases with a decrease in cutting speed; increases by at least 25 per cent if contact is restricted to a length approximately equal to the undeformed chip thickness.

Theoretical predictions of non-regenerative chatter with a conventional tool, based on independent measurements of machining force oscillations during tool vibration, agree well with experimental results.

For regenerative chatter with a conventional tool, the theory was based on the superposition of machining force oscillations arising from tool vibration and from removing a wavy surface. The predictions were in error at low cutting speeds, indicating that the force oscillations are not superposable at this condition.
Rolling Contact Fatigue Crack Initiation in a 0.3 per cent Carbon Steel
Authors: Dawson P. H.
Published: October 2007

The results of a number of pitting experiments carried out over some years on a particular combination of steels led the author to the conclusion that the pre-pitting crack was initiated by asperity interactions. The results of the detailed examination of the specimens from a number of tests are presented. They provide quantitative evidence in support of the hypothesis which was first published by S. Way in 1937. It is shown that the hypothesis is compatible with various recently published research work on pitting in through hardened and soft steels of the type used in gearing.
An Experimental and Analytical Investigation of the Gas Exchange Process in a Multi-Cylinder Pressure-Charged Two-Stroke Engine
Authors: Benson R. S. , Galloway K.
Published: October 2007

The results are given of a comprehensive investigation of the pressure and temperature diagrams in a multi-cylinder two-stroke engine during the gas-exchange process. A six-cylinder turbocharged two-stroke diesel engine was fully instrumented to record transient pressures in three cylinders, in the scavenge belt, and in a number of positions in a specially designed exhaust pipe. Transient-temperature records were taken in the exhaust pipe. Steady-flow tests were carried out on the inlet ports, the exhaust valves, and the exhaust pipe. The steady-flow data were then used in a computer programme (see references (9) (12)‡) to predict the pressure in the cylinder and the pressures and temperatures in the exhaust pipe.

Discounting some measured cylinder-pressure records, which were suspect, the investigation showed good agreement between the predicted and measured pressures in the cylinders and exhaust pipe. The analysis of the temperature records showed there was evidence of mixing and longitudinal heat transfer in the exhaust pipe; however, the mean computed temperature in the exhaust pipe at the nozzle end agreed with the measured temperature. Comparison of the measured and computed mass flows at the nozzle end of the pipe using the theoretical diagrams gave good agreement. It was concluded that the computer programme was a satisfactory method for calculating the pressures in the cylinder and exhaust pipe during the gas-exchange process.
Designing without Models
Authors: Rodenacker Wolf G.
Published: October 2007

Designing can be understood as an artistic or as a scientific activity. From the scientific point of view design can be considered as data processing. The working steps, which have to be carried out in designing, can be deduced from the physical experiment. These working steps are the choice of the function or the purpose of a machine, the choice of the physical process and the choice of the design features to enforce this physical process. For every step the possibilities of realization are explained. The method will be applied to the design of a wire-drawing machine. To begin with the black box is drawn to describe the change of the properties of the wire inside the machine. Then the steps of realization of the contents of the black box will be shown from the functional structure of the machine to the drawings for the manufacturing process. Important factors are included, such as the suppression of the disturbances of the physical process, the interaction of man and machine, and the criteria for the selection of the optimal solution. In this way one is able to do design work without having models.
Design of Centrifugal Pumps with Computer Aid
Authors: Peck J. F.
Published: October 2007

The design of centrifugal pumps involves a large number of interdependent variables, so that there are several possible alternative designs for the same duty. One of the most difficult design problems is to predict the impeller ‘head slip’, i.e. the difference between the theoretical head for an infinite number of impeller vanes H th ∞ as derived by Euler, and the theoretical head deduced from the net horsepower given to the fluid passing through the impeller after deducting external losses H thn.

In a previous experimental paper (1)† the author showed that the head slip was related to the mean blade loading and this has been applied in the present paper. He also suggested that the mean blade loading was an important factor in cavitation problems, having an advantage over the Thoma cavitation constant, as it allows for variations in the number of impeller vanes.

For preliminary design of the main dimensions the author has plotted a number of dimensionless parameters to a base of specific speed and derived mathematical equations for them which can be fed into a computer for rapid solution. The suggested computer programmes are in Fortran IV language and in four sections:

(1) Internal hydraulic losses, related to Reynolds number and relative roughness of the flow passages, external losses, efficiencies, and horsepower. (2) Impeller outlet dimensions, with allowance for head slip based on the mean blade loading. (3) Impeller inlet, eye diameter, inlet angles, etc. (4) Estimation of the direction and magnitude of the absolute velocity leaving the impeller, and determination of the throat areas of volute casing or diffuser vanes. Also estimation of required net positive suction head (n.p.s.h.), again based on the mean blade loading.

These programmes have been check tested on the International Computers and Tabulators (I.C.T.) 1905 computer at Loughborough University of Technology and give results which agree with the test results within 1 or 2 per cent over a wide range, except for very small pumps. To illustrate the method worked examples of impeller and diffuser are given in the Appendices, and corresponding results of a number of other alternative designs for the same duty are shown in a table.

The main advantage of the computer aid is that it permits a wide range of design constants to be investigated in a very short time, so that the optimum design can be selected more readily. Consequently the skill and experience of the designer are still required, as the optimum design is a compromise between high efficiency with low running power costs, and low production costs to secure an order against severe international competition.
Approximate Determination of Basic Data for Twin-Hoist Motor A.C. Electric Overhead Travelling Grabbing Cranes
Authors: Morgan B. V.
Published: October 2007

In system design of a bulk materials handling plant it is essential, in the early stages, to be able to quickly assess the effects of various layouts and designs. A plant using a twin-hoist motor a.c. electric overhead travelling (e.o.t.) grabbing crane would require the study of various plant layouts. For any particular layout under investigation the total cost will be a combination of crane costs, civil and structural costs and power supply costs which are all interrelated. Use of the graphs and empirical equations contained in this paper will enable the appropriate crane data to be approximately determined such as crane cost, wheel loads and power consumption. The establishment of these facts will enable the plant layout engineer to determine the cost of the civil, structural and electrical sectors and hence the overall costs.
Analysis of Wear in a Spherical Joint
Authors: McLeish R. D. , Skorecki J.
Published: October 2007

Certain hip prostheses are essentially ball and socket joints with the materials of such characteristics that most of the wear must occur in the socket. For the most common movement, walking, the applied force and the axis of rotation are substantially constant in direction. It is shown that the direction in which wear takes place in the socket is not necessarily the direction of the applied force and the relationship between the two directions is investigated theoretically. The results should be applicable to any ball and socket joint where both the force and the axis of rotation are constant in direction.
Mechanics of Orthogonal Machining: Allowing for the Effects of Strain Rate and Temperature on Tool-Chip Friction
Authors: Fenton R. G. , Oxley P. L. B.
Published: October 2007

An analysis of orthogonal machining is given in which the mean angle of friction usually used to describe the frictional condition at the tool-chip interface is replaced by the average shear stress along this interface. If this shear stress is expressed as a function of strain rate and temperature, using a velocity-modified temperature, there is good agreement between theory and experiment.
Refuse as a Fuel: First Paper: Municipal Refuse as a Fuel
Authors: Watson R. H. , Burnett J. M.
Published: October 2007

Quantitative and qualitative information on domestic refuse as a fuel is given; attention is drawn to its heterogeneous nature and variability in properties both short term and long term. Modern equipment for incineration is referred to and particular reference is made to the associated aspects of flue gas attemperation and chimney emissions.

Potential usage of the heat produced by incineration in boiler or other heat exchanging plant is discussed in terms of functional considerations and economics; in Appendix 1 a more detailed study of the economics of generation of electricity is made. It is concluded that there is no prima facie case for heat recuperation of all incinerators and in the present circumstances each case must be examined on its merits.
The Fatigue Strength of Large Single-Pinned and Double-Pinned Connections Made from Alloy Steel FV520B
Authors: White D. J.
Published: October 2007

Fatigue tests have been conducted on single-pinned and double-pinned lugs made from alloy steel FV520B and loaded by means of 2 in diameter pins. The effects of pin fit for both clearance and interference and of various treatments were investigated. The treatments included side relieving the lug hole, bushing the bore, applying the Sulfinuz process to the lug or overstraining the lug bore. Two conditions of mean stress were investigated, namely, pulsating or repeated tension and 15 tons/in2 mean tension.

Basing comparison on the fatigue strength at 30 × 106 cycles, the untreated lugs with close fit pins showed the lowest strength of all. Both clearance and interference fits were beneficial and by appropriate choice, the fatigue strength could be at least doubled and in some cases trebled. Lugs which had side relief, had been bushed, Sulfinuz treated or which had overstrained bores also gave worthwhile increases in fatigue strength and the strength ratios were generally in excess of 2.

An increase in mean stress significantly reduced fatigue strength for all lugs tested, except for those with close fit or clearance fit pins.

Comparing the present results with those obtained on lugs one-quarter the size, a considerable size effect is evident for some conditions, large lugs being weaker than small lugs.
An Investigation into Flange Forces in Winch Drums
Authors: Bellamy N. W. , Phillips B. D. A.
Published: October 2007

This paper describes a series of experimental tests which were carried out to investigate the forces acting on a winch drum during multi-layer rope winding. Consideration is given mainly to flange forces which are one of the prime causes of winch drum failure. A new method of measuring flange forces is demonstrated and comparisons are made of test results for different rope constructions, rope tensions and spooling. To aid winch designers and operators, flange design curves are suggested which may be used to predict the failure limits of winch drums.
An Investigation of Steady and Unsteady Flow through a Napier Turboblower Turbine under Conditions of Full and Partial Admission
Authors: Craig H. R. M. , Edwards K. J. , Horlock J. H. , Janota M. , Shaw R. , Woods W. A.
Published: October 2007

The paper presents the results of tests on an axial-flow turbine and describes how they are obtained, in steady and unsteady flow. An analysis of turbine-test results obtained under the unsteady operating conditions is then given. It is shown that over a limited range of cyclic operation the mass flow and power output may be predicted by assuming that the turbine operates instantaneously as it would under steady-flow conditions (at the same expansion ratio and the same non-dimensional rotational speed) and integrating over the engine cycle. At high pressure ratios, pulse frequencies and rotational speeds, this ‘quasi-steady’ analysis gives a slight overestimate of mass flow and power output but the error in turbine efficiency is very small.
Thermal Effects in Slider Bearings
Authors: Hahn E. J. , Kettleborough C. F.
Published: October 2007

The authors have shown previously by solving numerically the relevant mathematical equations describing lubricant flow, heat transfer and thermal distortion of bearing components in a slider bearing of infinite width, that, for the particular operating and boundary conditions assumed, thermal distortion rather than variation of the lubricant properties is the cause of hydrodynamic lubrication of initially parallel, radially grooved, thrust bearings. In this paper, numerical solutions are presented to show the effect of relaxing these conditions. The beneficial effect of thermal distortion is proved to hold generally and the importance of proper mixing of the lubricant at the inlet is illustrated. Comparison of numerical solutions with existing experimental observations shows only a qualitative agreement. A realistic three-dimensional mathematical model of a slider bearing of finite width is derived from basic equations, and the solution of the resulting equation, allowing for variable lubricant properties and thermal distortion of the bearing components, is developed and discussed.
A Theoretical and Experimental Study of a Liquid-Lubricated Hydrostatic Journal Bearing
Authors: Betts C. , Roberts W. H.
Published: October 2007

The use of mechanical pumps for circulating high-temperature liquid-sodium coolant in nuclear-powered fast reactors emphasizes the problem of designing suitable bearings. This paper presents a semi-empirical theory which describes the (static) performance of a hydrostatic jet journal bearing for such applications where the flow through the bearing is predominantly turbulent. The theory covers both viscous and turbulent regimes of flow. In the presentation non-dimensional groups are plotted to facilitate direct application of the theory to specific design problems.

Experiments using paraffin and water as the working fluid are described; Reynolds numbers of approximately 1700 and 7000 respectively were achieved—compared with Re in excess of 20 000 likely to be encountered in practice.

The design and performance of an 8 in diameter bearing for a 6000 gal/min mechanical sodium pump prototype are briefly described.
Dynamic Characteristics of an Oil Hydraulic Constant Speed Drive
Authors: Healey A. J. , Stringer J. D.
Published: October 2007

Experimental and analytical studies are made of an oil hydraulic system which uses a pressure compensated flow control valve for speed regulation. The study concerns dynamic response with special reference to the effects on the system of the sudden application of a retarding force to the mass it is moving.

Equations of a typical ‘meter-out’ type of system are first developed and solved. The consequent predictions are then compared with experimental results from an apparatus which simulated a machine tool application. The advantages of incorporating a restrictor in the inlet (supply) line are then examined both experimentally and analytically using an analogue computer.

The results show that the mathematical models give satisfactory predictions of the maximum changes of velocity and pressure occurring during the transients. The restrictor reduced the magnitudes of these transient changes and also eliminated ‘stick-slip’ oscillations at low speed.

It is concluded that the methods of analysis outlined in this paper could be used to advantage in the design of practical systems.
Design Methods for Model-Reference Adaptive Systems
Authors: Phillipson P. H.
Published: October 2007

The ‘M.I.T. rule’ and two Lyapunov synthesis methods of design are critically reviewed. The latter are the input modification scheme of Grayson and Parks' method for the determination of parameter-adjusting feedback loops. For large inputs such methods are unsatisfactory: this is demonstrated by root locus plots for the step response of a second-order system with adaptive gain.

A Lyapunov synthesis procedure is proposed which is a composite solution. The feedback loops of Parks are employed but an input modification signal is superimposed. This can be conveniently chosen from existing signals to add a fourth order negative definite term to V, thus promoting a greater degree of stability for large inputs. Results from an analogue computer study are included. The method is general in application.
Geometry and Leakage Aspects of Involute Rotors for the Roots Blower
Authors: Ritchie J. B. , Patterson J.
Published: October 2007

For maximum operating efficiency of Roots type blowers, the leakage of compressed air through clearance must be reduced to a minimum. At the same time it is desirable to keep the design as compact as possible. The following analysis endeavours to show, for involute rotors, the effect of the geometrical design variables, pressure angle, rotor tip radius, and base circle radius, on leakage and compactness.

Firstly limits of permissible values of the geometrical design variables, to allow correct mating between rotors, are established. Within these limits, relative blower compactness and carry-over of compressed air back to the inlet tract is obtained for the ideal blower with no clearance between relative rotating parts. The analysis and results are expressed in dimensionless form independent of blower size, and results are compared with cycloid rotors.

Leakage through blower clearances, in terms of the geometrical design variables, is then determined for a range of pressure ratios, and the dependence on blower size is examined.

It is concluded that optimum design values cannot be obtained. A compromise solution between minimum total leakage and maximum compactness is necessary, depending on the operating requirements for a particular Roots blower.
Management and the Engineer
Authors: Earle A. F.
Published: October 2007

Engineers were the first managers. Their pre-eminence has been overtaken by accountants and men of broader training, and acceleration of business studies will increase this displacement. Mention is made of the advantages and special problems of engineers in business studies. The graduate engineer has many opportunities but the situation is less satisfactory for non-graduates. The desirability of finding solutions is stressed, particularly because of the central importance of engineering industries in Britain.
Ocean Engineering
Authors: Bishop R. E. D.
Published: October 2007

Only the sea can meet a greatly increased demand for protein, for minerals, for fresh water or for power generation. Any of these requirements alone would ensure that man's interest in the oceans must quicken. In fact we have all of these needs and more besides, so that the case for closer study of the sea is overwhelming.

This lecture is in two parts. The first points out the need for teaching and research in ocean engineering and describes briefly a scheme that has been set up in an attempt to meet a part of the country's needs. The second examines some of the wider problems of British industrial involvement in marine technology. The obstacles to progress are substantial and some suggestions are offered on how they might be overcome.
The Performance of Steelworks Equipment in Service
Authors: Lake R. A.
Published: October 2007

The processes of an integrated steelworks are coking, sintering, smelting, refining and re-heating for rolling. Most of the machinery is conventional or specialized mechanical handling equipment and rolling is a special form of such mechanical handling. Such equipment is an assembly of basic mechanisms such as shafts, bearings, couplings, gears, brakes and hydraulic actuators.

The paper gives experiences in service of these mechanisms and deals more generally with the E.O.T. cranes which play a large part in the handling of steel from one process to the next. These experiences are drawn from the Spencer Steelworks which went into production in 1962.
The Measurement of Gas Temperature Using the Gas Jet Generator
Authors: Barnes J. H.
Published: October 2007

Work done so far indicates the feasibility of using a gas jet generator as a temperature-frequency converter for the measurement of air or gas temperature up to 2000°R. In its optimum configuration for stability and level of output, the gas jet generator is not quite of constant wavelength characteristic. This does not matter, provided that any particular configuration is calibrated by using an airstream of known stagnation temperature and these results are used to predict the performance with other specified gases or gas mixtures. In comparison with thermocouple instruments such as the sonic suction pyrometer the gas jet generator is superior from the transient response and mechanical strength aspects, but inferior for steady state measurements, particularly at the higher temperatures. This is because its sensitivity decreases with increase in temperature owing to the square root relationship between the velocity of sound and absolute temperature.
The Supersonic Aerothermopressor
Authors: Smith I. K.
Published: October 2007

This paper describes the results of an experimental investigation carried out on a small-scale aerothermopressor both in subsonic and supersonic flow. These are compared with numerical solutions of the equations originally derived by Shapiro. In subsonic flow the agreement between theory and experiment closely follows that of previous investigators but in supersonic flow there is a considerable difference between the estimated and measured static pressure distribution along the duct. Photographic studies of the initial break-up of the water spray in supersonic flow show that the spray does not distribute itself uniformly across the duct as in subsonic flow. A variety of techniques of water injection designed to overcome this shortcoming are described and some improvement is possible. However, this discrepancy between theory and experiment is still so great that it appears that the supersonic aerothermopressor must be inferior to its subsonic counterpart.
Performance of Inward Radial Flow Turbines under Non-Steady Flow Conditions
Authors: Wallace F. J. , Adgey J. M. , Blair G. P.
Published: October 2007

The paper describes theoretical and experimental work on pulse operation of inward radial flow turbines, together with certain essential steady flow data. Power measurement was by means of a specially developed high speed dynamometer, capable of speeds up to 10 000 rev/min, which is described in some detail.

Steady flow tests confirmed the expected trends of mass flow and torque as functions of turbine speed and overall pressure ratio, and in addition proved the reliability, consistency and accuracy of the dynamometer. The unsteady flow analysis of Appendix 1 which is unique in incorporating a very full description of rotor geometry as well as of the complex nozzle-rotor interspace conditions, was applied to two particular experimental cases and gives good agreement with respect to pressure variation in the pipe system, turbine volute and at nozzle exit, but rather less satisfactory agreement with respect to power.

Further theoretical work is summarized at the end of the paper.
Fatigue Tests on a Diesel Engine Crankshaft
Authors: Barton J. W. , Cox H. L.
Published: October 2007

The paper describes fatigue rigs developed at the Admiralty Engineering Laboratory, West Drayton, to test single-throw crank test pieces cut from multi-throw diesel engine crankshafts under bending and under torsion. Both rigs operated at resonance with slipping clutch excitation. The pieces tested under torsion indicated a fatigue limit for failure at the oil hole under a stress range equal to the tensile strength of the material; the effects of imperfect finish to the oil hole surface and of non-metallic inclusions in the material were also shown. The fatigue limit under bending corresponded to a stress range in the fillet somewhat less than the tensile strength; possible reasons for this are suggested.
Availability of Power Stations and Their Equipment
Authors: Shannon W. B. , Campbell W. W. , Carstairs R. , Dollin F. , Frankel A. , Hirst A. W. C. , Sherry A.
Published: October 2007

Comprehensive and self-consistent data relating to plant availability and outage rates are essential for the assessment of plant performance, thereby enabling standby requirements to be estimated, plant extensions planned and the performance of different types of plant compared. The present paper deals with the essential requirements that must be met to ensure the comparability and adequacy of the statistical data.

Five main points are emphasized in the paper:

the assessment of plant performance is best given by outage rates, stated in terms of time; three classes of outage are described; namely forced, deferable and planned. Shortfall is considered separately; since the practical consequences of the three kinds of outage will in general be very different, and since one may affect another the record must always include the three outage rates shown as separate items; to permit the assessment and comparison of statistics from different sources the record should also include an output factor—(total output of item during period/rated capacity x total hours in period), a service factor—(total hours of item in service during period/total hours in period) and the number of starts during the period under review; statistics from plants of very dissimilar properties and design and with widely different operating regimes should be compared cautiously.
Angular Contact Ball Bearings: Track Position at High Speeds
Authors: Falcon K. C. , Andrew C.
Published: October 2007

The track position of the balls on the outer race of an angular contact bearing of the series and size used on the main shaft of aero gas turbine engines was measured in a test rig. The test rig was capable of simulating the operating conditions of the bearing with respect to axial load, inner race speed and high lubricant flow rates. The contact angle, defined by the track position, was deduced from the measurement of sub-surface displacements in the race using a number of small transducers embedded therein. The resulting contact angles were compared with values predicted from a number of unconfirmed theories in current use. At conditions of high speed and low load the correlation is poor; an over-estimation of the cage speed, arising from the false assumption that gross ball slip does not occur, gives rise to an over-estimation of the changes of contact angles from their nominal values.
Procedure for Obtaining the Performance of a Kaplan Turbine from a Detailed Model Test Result
Authors: Salami L. A.
Published: October 2007

In this paper a study is made of existing literature on scale formulae since 1955 and a general formula which embraces most of these formulae is derived. A separate scale formula is evolved for volumetric efficiency. After demonstrating how the new procedure for scale effect on hydraulic efficiency could be applied a discussion on the limitations of some very recent scale formulae is given. Finally, the influence of various turbine parameters on scale effect is illustrated.
Survey of Twisted Blading Development in Steam Turbines
Authors: Smith A.
Published: October 2007

The development of steam turbine blading with high tip to hub diameter ratios over the last 50 years has been traced with particular emphasis on the reasons for adopting twisted blading in low pressure turbines. The aerodynamic concepts of the more generally accepted design bases for twisted blading are discussed and comparisons made between the efficiencies of selected twisted designs and straight blading. Current methods in the development of transonic low pressure blading for large 3000 rev/min central power station units are also described and the paper concludes by comparing the theoretical and measured steam angles across the last stage of a one-third scale model of a 136-in tip diameter low pressure turbine.
Optical Elastohydrodynamics
Authors: Foord C. A. , Wedeven L. D. , Westlake F. J. , Cameron A.
Published: October 2007

In Part 1 an extended series of pictures are given showing the shape of a point elastohydrodynamic contact. Extremely good fringe visibility is obtained by taking account of the reflectivity of the semi-reflecting chromium layer on the glass plate and the reflectivity of the steel balls. The shape of the contact is quite different from the Hertzian shape frequently assumed. Figures are given for pure rolling, pure sliding and skewed contact giving a slide/roll ratio of 016. Careful collimation permits the 30th fringe order to be observed.

In Part 2 detailed design considerations needed to give sharp single and multiple beam interference pictures are studied. Subjects considered are the qualities of the rolling pair, the degree of collimation and the design of collimators. The choice of reflecting layer and light sources is discussed. Methods of estimating phase change on reflection are described. A technique making possible film thicknesses down to 100 Å (0.4 μin) is given.
Problems Arising from the Water Cooling of Engine Components
Authors: French C. C. J.
Published: October 2007

The local heat flows through the walls of components which form the boundary of the combustion chamber of internal combustion engines operating at high engine ratings exceed those found in most engineering equipment. Despite this the coolant-side face is normally in the ‘as cast’ condition, sometimes with core sand adhering to or embedded in the surface and a rust film, which is almost always present in the case of ferrous components. It is also common for additives such as glycol, soluble oils and/or corrosion inhibitors to be added to the coolant.

This paper describes the techniques employed in, and gives the results of, an extensive series of tests into the effect of such surfaces and additives on heat transfer and then goes on to describe the use of the resulting data to predict the operating temperatures of diesel engine components in service.

The paper also describes the design techniques that have been evolved to permit satisfactory engine operation under highly rated conditions.
A Study of the Stick-Slip Motion of Machine Tool Feed Drives
Authors: Bell R. , Burdekin M.
Published: October 2007

The phenomenon of ‘stick-slip’ oscillations of the feed drives of machine tools is an important problem in the design of certain types of machine tools. The factors contributing to this particular type of instability are studied both experimentally and analytically with the aid of a simple model based on dynamic measurements. The experimental work is restricted to a scraped cast iron-cup ground cast iron slideway interface. The principal experimental variables are lubricant viscosity and the natural frequency of the drive. The dynamic observations provide evidence and data that enable the use of a simple model rather than the more usual application of an involved analysis. The consideration of analytical and experimental results allows further understanding of the mechanism of feed drive instability to be developed.
The Rotary Forging Concept and Initial Work with an Experimental Machine
Authors: Slater R. A. C. , Barooah N. K. , Appleton E. , Johnson W.
Published: October 2007

The rotary forging process is based on a recognition of the fact that the axial force required to effect a desired deformation during, for example, an upsetting operation may be reduced if the plastically deforming zone is confined throughout to a small region beneath the upper platen. The top portion of the workpiece is then rotated through this plastic zone thus resulting in a progressive deformation.

An experimental rotary forging machine has been designed and constructed which incorporates a lower platen capable of axial movement only, whilst the upper conical platen is capable of rotation about the central axis of the machine and also about its own inclined axis.

The principal design features of the experimental machine are described and the results of some preliminary experiments using the machine are presented. Operation of the experimental machine has demonstrated the feasibility of the process.

The effect of the axial force on the rotary forging of cylindrical specimens having a height/diameter ( H/D) ratio of unity and for a fractional reduction of 0.5 is discussed. Pure lead at ambient temperature was used, as a model material, to simulate the rotary forging of steels in the approximate temperature range of 700-1400°C. A comparison is made between the axial force required to rotary forge and conventionally upset identical pure lead cylinders. It is shown that the optimum axial force required for slow rotary forging is a small fraction of that required for the conventional slow upsetting of circular cylinders having H/D ratios of less than unity.
Reduction of Noise at the Design Stage: A Case Study of a Lightly Loaded Assembly
Authors: Satter M. A. , Downs B. , Wray G. R.
Published: October 2007

An experimental and analytical study is made of the noise emission from the drawroll assembly of a textile draw-twisting machine. As an alternative to resorting to acoustic absorption techniques or the use of expensive high damping materials, investigations are made into the basic method of noise generation in the assembly. This leads to the incorporation of small design changes and the significantly lower noise emission thereby achieved is compared with the original emission. Aimed at the machine designer, the presentation is made in a straightforward, non-mathematical fashion.
Fuel Drop Vaporization under Pressure on a Hot Surface
Authors: Temple-Pediani R. W.
Published: October 2007

The evaporation lifetime of liquid fuel drops in contact with a hot surface is investigated at pressures of up to 69 atm. Modes of evaporation and drop behaviour at subcriticai and supercritical conditions of temperature and pressure are described. It is shown that at any subcriticai pressure the lifetime is a minimum at a surface temperature just above the saturation temperature; the lifetime at all supercritical pressures is a constant minimum when the surface temperature is 60 degC or more than the critical temperature of the liquid. The heat flux to a drop in the contact modes of evaporation has a maximum value comparable to the peak heat flux obtained in boiling heat transfer work. Subsidiary tests at atmospheric pressure investigate the influence of surface material, surface finish, and initial drop temperature upon the lifetime; the transient surface interface temperature during evaporation is also investigated. The application of the data to deposited fuel in engines is discussed.