bluuebunny/crossref_metadata_2025 huggingface dataset:
Paper 12: Gas Turbine Fuel and Control Systems
Authors: Warne E. H.
Published: June 2010

Following a preliminary introduction on the necessity for fuel and control systems, it is proposed to deal in some detail with the requirements of modern gas turbine engines from the point of view of both pumping of fuel and the control. In general the paper deals with aircraft type systems.

Over the last 20 years specifications have been increasing in size and the need for the additional requirements will be discussed in relation to the various types of engines. Considerations of control for two- and three-shaft engines for both civil (subsonic and supersonic) and military use are covered, as also are the somewhat different requirements for helicopters. In addition to main engine control, the effects of reheat, supersonic nozzles and variable engine geometry will be discussed. Reference is also made to the increasing severity of environment on high speed aircraft. Following this, the problems of pumping are considered and a review of the types of pumps available is made comparing their relative advantages and disadvantages in relation to the application, and indicating the general trends in this field.

On control systems the types of control available will be discussed including hydromechanical, electric and fluidic, and the basis on which the optimum choice can be made for any particular engine will be dealt with. The requirements for control, both for steady running and limiting will be explained, and once again a typical example of a control system is briefly described.
Paper 13: Recent Developments in the Control of Industrial Gas Turbines
Authors: McArthur M. J. , Charles P. W.
Published: June 2010

This paper describes the control systems required for the application of gas turbines to fully automatic generating stations, and mechanical drives such as natural gas compressor stations.

Gas turbine power plant has definite advantages in that for the power output it lends itself to relatively simple fully automatic operation of the overall plant and rapid starting and loading. The relatively low capital cost and size have resulted in widespread applications of this type of plant.

The large gas turbine plant can be divided into two main categories:

(1) Aero powered gas turbines. (2) Pure industrial gas turbines.

The role of the control system is not only to adapt the gas turbine to the particular application but to ensure the safety and protection of the plant at all times.

The control functions include:

Those necessary for the particular application, e.g. power turbine speed control.

Those necessary for the protection and correct operation of the gas turbine system, e.g. balance of multiple gas generators discharging into power turbine.

The peripheral systems, e.g. automatic sequence systems for starting.

This paper is based on the author's recent experience in this field.
Paper 14: The Advancement of Controls with Modern Gas Turbines
Authors: Abraham G. A.
Published: June 2010

One of the claims attributed to gas turbines by their pioneers was their simplicity of design. Although this claim can still be applied to some engines, others with variable intake geometry, bleed valves, movable guide vanes, multi-staged turbines and recuperators have stretched the definition of simplicity.

The control of these engines to satisfy the varying demands has also become complex and aggravated by the mixing of control media.

The paper discusses advancements in control technology and how these advancements can affect both the design and application of gas turbines.
Paper 16: Case for the Single-Shaft Vehicular Gas Turbine Engine
Authors: McLean A. F.
Published: June 2010

This paper reviews gas turbine cycles most favoured for vehicular use. It suggests the single-shaft turbine engine as a possible contender for a lower cost approach, where fuel economy requirements are not met by complexity of cycle but by operation at higher turbine inlet temperatures. The question, ‘Where does the engine end and the transmission begin?’ is discussed, and an example of an infinitely variable transmission is explored as a means for overcoming the performance deficiencies of the single-shaft machine. The paper examines the advantages and disadvantages of this type of turbine engine with respect to acceleration and torque characteristics, fuel consumption, engine braking, initial cost, and design for simplicity and high temperature.
The Load-Carrying Properties of Metal Dialkyl Dithiophosphates: The Effect of Chemical Structure
Authors: Allum K. G. , Forbes E. S.
Published: June 2010

The extreme pressure (e.p.) and mixed lubrication or antiwear (a.w.) properties of a range of metal dialkyl dithiophosphates have been examined using the four ball machine. The results show that the nature of the metal atom is a major factor in determining these properties, and that the factors governing e.p. and a.w. activities are different. Thus the order of decreasing e.p. activity is Bi(III) > Ag(I), Pb(II) > Sb(III), Sn(II) ≥ Cd(II), Fe(III), Ni(II) > Zn(II), whilst the order of decreasing a.w. activity is Cd(II), Zn(II), Ni(II) ≥ Fe(III) > Ag(I) > Pb(II) > Sb(III), Sn(II) > Bi(III) for a series of 4-methylpentyl-2 and n-hexyl salts. The nature of the alkyl group has a lesser effect on either e.p. or a.w. properties. Possible explanations for these results are presented.
The Hydrodynamic Lubrication of Piston Rings
Authors: Lloyd T.
Published: June 2010

Although the piston ring is a critical component in a reciprocating engine and although its successful functioning depends upon adequate lubrication, very little work has been done on the analysis of piston ring operation as a phenomenon of hydrodynamic lubrication. This paper outlines briefly the theoretical and experimental work that has been done, and produces a new analysis particularly suited to solution by computer.

The analysis assumes:

that the shape of the piston ring face is parabolic, but not necessarily symmetrical; that the lubricant viscosity is constant under the ring, but may vary in any fashion over the piston stroke; that oil film disruption may be represented by calculating oil pressure assuming no disruption and then discarding negative pressures; that the pressure upstream and downstream of the ring and the load on the ring may vary cyclically over the stroke; that there is circumferential symmetry; and that the motion of the ring parallel to the cylinder face is that of the piston, while the motion perpendicular to the cylinder face satisfies the force balance.

Using the simple example of the symmetrical ring face, isoviscous lubricant, constant load, zero upstream and downstream pressures, and sinusoidal piston motion, it is shown that there exists a parabolic shape which maximizes the minimum oil film thickness. Comprehensive results are presented for this case. The use of the more general analysis is illustrated for a diesel engine design for which the ring face shape has been measured.
Paper 3: Reliability Prediction
Authors: Green A. E.
Published: June 2010

Reliability has been described as a parameter of design. Where there is a large amount of capital at stake, or a risk to human life, the characteristic of reliability becomes very important. The designer may base his estimates of reliability on: (1) field experience; (2) sample testing; (3) prediction. In high risk situations it is suggested that prediction techniques play an essential part in early design.

The need is stressed for the quantification of reliability; this will tend to remove the subjectiveness and thereby help communication. The methods of prediction are considered, based on a suitable reliability definition. These methods range from obtaining a consensus of opinion from a body of people to the mathematical modelling techniques employed by individual designers and assessors.

The reliability data available on component parts are surveyed and used as the basis for describing current techniques for predicting the reliability of equipments and systems. In particular, the techniques for the safety analysis of various modes of failure are considered.

The correlation between predicted and practical results is described for some applications.

Conclusions are drawn on the general applicability of the prediction methods and the requirements for an organized reliability data bank.
Paper 6: The Philosophy of Failure in Engineering Systems
Authors: Marsh W.
Published: June 2010

The possibility of failure and the consequences of failure are present in the mind of the engineer. The designer counteracts both to the best of his ability, taking into account the processes involved, material behaviour, cost, and delivery schedules. The technique of including an intentional weak link to minimize the consequences of failure is well known. Similarly, by using a number of machines instead of one, failure will cause reduced performance rather than complete loss. The use of stand-by machines and redundancy have thus become established engineering methods. The advent of nuclear power has led to the development of safety systems in which total failure cannot be tolerated. Similar duties in which failures must not occur exist in aircraft control systems. These duties have led to the development of precise methods of analysing safety. The success of the analyses depends upon the accurate reporting and cataloguing of product failures. This emphasizes the increasing importance of the service department function. Significant increases in product reliability have been obtained by providing the designer with development testing results, service department experience, and a theoretical analysis of failure probabilities.
Paper 8: Design Problems in Relation to the Safety and Reliability Requirements of Steel Boilers and Pressure Vessels
Authors: Carmichael R.
Published: June 2010

The boiler and pressure vessel industry had its beginning in satisfying the power needs of industrial emergence. Its earliest products, which were built by ‘eye’ and ‘rule-of-thumb’ methods, gave rise to frequent explosions with disastrous results. Out of this, with the cry for safety, came the slow transformation of a manufacturing art into an engineering science, with highly beneficial effects. This was largely achieved by the gradual introduction of construction codes based on technical knowledge and experience. Technological advance, however, outstrips codes; but codes must not be allowed to inhibit creative thought and development. Herein lies a potential source of accident; therefore no new design should be translated into effect without full technical appraisal and practical test. Examples taken from experience indicate the manner of meeting the demand for new criteria and the challenge of new design, while preserving the principles of safety and reliability.
Paper 11: The Control of Quality in Power Plant: (A Large User's Campaign against Manufacturing Defects)
Authors: Burgess N. T. , Levene L. H.
Published: June 2010

As an extensive user and purchaser of engineering products, the C.E.G.B. has a national responsibility for ensuring a continuous improvement in the quality and reliability of power plant. There has always been close collaboration between the C.E.G.B. and its suppliers in research and design; this collaboration has become closer in recent years as technology has rapidly advanced in the power station field. To permit timely and trouble-free commissioning of large boiler/turbo-generator units with satisfactory reliability in service, the C.E.G.B. and its suppliers are now appreciating the need for an equally close relationship throughout the manufacturing and erection stages. To assist in this, a Quality Control Unit was set up at C.E.G.B. Headquarters to encourage plant suppliers to accept the principles of quality control, and so bring about improvements in their organization and product.

An account is given of the work of the C.E.G.B., which collaborates with contractors on quality assurance matters and certain manufacturing problems at works and on sites. There is also co-operation on specifications, standards of acceptance and non-destructive testing, and the assessment of sub-contractors. In addition, the Quality Control Unit acts on feedback data from the field, and details are given of some recent operational failures resulting from manufacturing defects, and their cost to the Board.
Paper 13: Creep Deformation and Fatigue Failure of Structural Materials
Authors: Darlaston B. J. L.
Published: June 2010

In support of the vast amount of stress analysis work on components, considerable effort is required to provide suitable materials behaviour models. Simple laboratory tests on uniaxially loaded specimens under constant temperature condition provide the bulk of data, but methods are required to translate these data to multiaxial conditions with non-uniform cyclic loading and cyclic temperature.

The material behaviour laws, therefore, are aimed at meeting two requirements: first, to predict the deformamation response in terms of the imposed loading conditions and the previous history of the material; and second, to analyse the stress or strain cycles to predict failure. This paper reviews the steps being taken at Berkeley Nuclear Laboratories, C.E.G.B., and elsewhere to achieve these two objectives.
Paper 16: The Management of Maintenance and its Impact on Safety and Failure of Components
Authors: Fair D. R. R. , Maxwell E. W.
Published: June 2010

The various influences exerted by management at different levels of an organization to secure reliable and continuing operation of electricity generating plant are dealt with.

Consideration is given to the requirement at the top executive level for the strategic planning and scheduling of plant outages for maintenance and overhaul, to ensure the minimum cost of production from an integrated supply system consistent with obtaining long-term reliable operation of individual plants. Also considered is the requirement for various management levels at those plants to provide detailed planning of work content, resources, and logistics associated with maintenance of individual plant items.

The collection and analysis of plant performance data, to determine correct work content and frequency of routine maintenance to provide an economic balance between outages due to maintenance and outages due to failure, are studied together with the constraints imposed by statutory inspections.

Diagnostic testing of electrical and mechanical plant to help reduce plant outage time, and the influence of non-destructive testing techniques on reducing expensive cascading failures, are examined. The influence of correct utilization of tools, maintenance equipment, and methods of working on minimizing plant down time and the use of special equipment to facilitate inspection of inaccessible plant in both the conventional and nuclear fields are also considered.
Paper 21: Planning for Failures
Authors: Brook R. H. W.
Published: June 2010

When a serious failure situation has developed, an expensive crash programme is usually required. If in-service data are analysed as a routine, then impending trouble may be foreseen and management decisions made to minimize the cost. A reliability analysis can help to establish a failure pattern compatible with intuitive engineering assessment so that, from a realistic prediction, alternative courses of action can be considered.

A recent gas-turbine engine problem which has caused six component failures is analysed, and alternative replacement strategies are considered. It is suggested that to adopt the intuitive compromise strategy could be the most expensive in this case.
Paper 23: Component Defects: An Airline's Experience
Authors: Redgate C. B.
Published: June 2010

The impact of component reliability on a major airline is discussed and the more frequent modes of failure of the various types of component are examined in detail. Accurate trouble-shooting of component defects is an increasing problem with the trend to greater system complexity and higher aircraft utilization, resulting in a high proportion of removals for unconfirmed faults. The methods of improving this situation are reviewed. It is concluded that in many areas insufficient effort is made to apply in-service experience to the design of new components.
Paper 24: Economics of Failure: Management Influence
Authors: Bowling A. G. , Marks P. A.
Published: June 2010

Top management must treat a failure as seriously as if it were a lost sale. A good original design incorporating the lessons of the past, by including the good features and excluding the bad, is the best way of avoiding expensive secondary damage. Effective determination of priorities requires a full understanding of the technical and economic aspects of the failure, and both manufacturer and customer must reach a rapid and economic solution to what is their joint problem. Effective communication, direct involvement, and clear presentation of the facts at all levels, in both customer's and manufacturer's organizations, are vital.
Paper 27: Supplier/Customer Relationship
Authors: Shaw J. F. St G.
Published: June 2010

The need for definition of the rights and duties of each party to a contract is discussed. The development of standard conditions of contract is traced. The risks undertaken by both parties are considered in relationship to the type of contract agreed upon and the guarantees which may be expected both on technical performance and completion.

The types of organization provided by both customer and supplier to carry out their relative responsibilities are reviewed in relation to the efficient and timely completion of the works and to the avoidance or settlement of disputes. The status of the ‘engineer’ is defined, and his function in securing proper observance by both parties of their responsibilities is enlarged upon.
Paper 29: Systematic Design Review and Fault Analysis
Authors: Green J.
Published: June 2010

Comprehensive failure analysis methods are currently available to electronic designers, extending to the use of computers to estimate the probability of failures.

The mechanical designer has few such tools at his disposal. The paper presents two practical methods of reviewing a mechanical design to improve its reliability. The first is a potential fault analysis, which considers each component and its relation to the function of the whole. The use of this analysis as a project control method is also shown. The second method is a systematic design review method, which aims to consider every aspect and function of a design and its components, to ensure that no factor has been overlooked. The application of these methods is discussed.
Paper 30: Cause and Effect of Failure—an Insurer's View
Authors: Brown J. C.
Published: June 2010

Engineering insurance has its origins in a nineteenth-century co-operative for the inspection of boilers, and plant inspection remains a large part of the business. The companies concerned together employ about 2250 surveyors throughout the country.

The paper describes some of the more common types of plant failure met by the insurance companies and discusses their causes and remedies. Failures may cause damage not only to the item concerned but to surrounding plant and property and may affect the ability of an undertaking to remain in profitable business. The availability of insurance cover for most engineering risks is explained.
Isokinetic Sampling in a Dense Gas-Solids Stream
Authors: van Breugel J. W. , Stein J. J. M. , de Vries R. J.
Published: June 2010

A short description of the isokinetic sampling technique is given. The technique, which in itself is not new, is here applied to a dense solids-gas mixture. An analysis is presented of the factors in (1) the measuring procedure, and (2) the geometry of the probe, that influence the accuracy with which gas and solids flux profiles can be measured. Finally, a few random examples are given of profiles as measured in our 0·3-m diameter riser.
Prediction of Pressure Gradients in Pipeline Systems during Two-Phase Flow
Authors: Chisholm D. , Sutherland L. A.
Published: June 2010

Simple procedures using charts for predicting friction/pressure gradients during turbulent-turbulent flow in pipes and the pressure changes over bends, changes of section, and valves are presented. For friction/pressure gradients comparison is made with the procedures of Baroczy, Lockhart and Martinelli, Martinelli and Nelson, Collier, Becker et al., and Thom.
A Theory for the High-Speed Flow of Gas-Solids Mixtures under Conditions of Equilibrium and Constant Fractional Lag
Authors: Cole B. N. , Bowers H. M. , Mobbs F. R.
Published: June 2010

A theory is presented for the high-speed, one-dimensional flow of a gas-solids mixture, assuming constant fractional lags of temperature and velocity between the solid particles and the gas. A mixture speed of sound is is derived and used as the basis of a mixture Mach number. Expressions are deduced which are parallel to many well-known relationships in orthodox one-dimensional gas dynamics. The investigation covers frictionless flow in a variable area duct and flow with friction in a constant area duct. The effect of solids volume is also taken into account.
Influence of Particle Size Distribution on the High-Speed Flow of Gas-Solid Suspensions in a Pipe
Authors: Mobbs F. R. , Bowers H. M. , Riches D. M. , Cole B. N.
Published: June 2010

Experiments on the flow of air-solids mixtures through long straight lengths of brass and nylon pipe, under choking conditions, are described. The powders conveyed are polystyrene, silica, and steel shot. Experimentally determined pressure distribution curves are used to compute the variation of gas and solids, velocities, and temperatures along the pipes, taking into account the size distribution of each powder. The predicted values of gas and solids velocities are compared with experimental values obtained by pitot tube traversing, and a highspeed photographic technique, respectively.
Phase Distributions in Flow of an Air-Water Mixture round Bends and past Obstructions at the Wall of a 76-mm Bore Tube
Authors: Gardner G. C. , Neller P. H.
Published: June 2010

Flow in upflow bends and past obstructions was examined both visually and with a traversing probe, which measured the local time average air concentration. Various features of the flow are described, and principal among these concern the competition between centrifugal and gravitational forces for bends and the factors affecting a separated region downstream of an obstruction.
Two-Phase Vertical Flow Maps
Authors: Golan L. P. , Stenning A. H.
Published: June 2010

In this paper a vertical downward flow map and a vertical upward flow map are presented. A comparison of the two flow maps shows that significant differences exist between the two directions of flow. The experimental work was performed with an air-water flow in a 11/2-in inside diameter transparent tube.
Hydrodynamic Instability in a Full-Scale Simulated Reactor Channel
Authors: Collins D. B. , Gacesa M.
Published: June 2010

An experimental programme has been carried out to investigate parallel-channel instability in a full-scale simulated nuclear reactor channel operating in vertical high-pressure boiling-water upflow. Experimental data have been obtained using a vertically mounted test section containing two 19-rod electrically heated bundles with a total heated length of 195 in. The test section was operated in parallel with an unheated by-pass between common inlet and outlet headers. The characteristics of the observed test-section and by-pass flow oscillations are described in detail. Data are presented showing the effect upon test section flow stability of bundle electrical power, inlet subcooling, operating pressure, feeder pressure loss coefficients and the ratio of by-pass flow-rate to test-section flow-rate.
Two-Phase Critical Flow under Diabatic Conditions
Authors: Bergles A. E. , Kelly J. T.
Published: June 2010

This paper summarizes an experimental investigation of steam-water critical flow in heated tubes. A wide range of data was taken for water at pressures below 100 lbf/in2 (abs.) in tubes of small diameter. It is demonstrated that critical flow conditions can occur in subcooled boiling at low exit subcoolings. At equilibrium qualities below about 0·04, the data differ significantly from adiabatic data for a similar exit geometry. The deviations can be explained in terms of the additional non-equilibrium effects present in heated flows. For higher qualities, the diabatic data are in good agreement with adiabatic data, and can be approximately predicted by a slip equilibrium model.
Performance Analysis of an Air-Lift Energized Propulsion Duct
Authors: Moore W. N. C.
Published: June 2010

Marine propulsion systems that use pressurized air for the direct energization of a propellant water stream offer a mechanical simplicity that could be countered by an inadequate efficiency for the energy transfer process. At commercial vessel speeds a sufficient pressure at the air injection section necessitates injection at depth, energy transfer occurring while the two-phase flow is rising and accelerating prior to discharge at the water line. The presumption of a simple stratified flow model for the analysis of the rig test results leads to a semi-empirical performance prediction procedure that facilitates evaluation and optimization of full-scale design proposals.
Calibration of a Small Venturimeter for Wet Steam at Low Reynolds Number
Authors: Bennett M. D. , Martin K.
Published: June 2010

A device was required to measure the flow rate of steam through a small thrust bearing over the range 0–1·5 kg/h at pressures varying from 4·5 to 10 bar abs. and for steam quality varying from 0·75 dry to 100°C superheat. The ranges appeared to be outside those of existing instruments and not covered by existing design data for differential pressure devices; nor could the authors find any published work on the metering of wet steam at these low flow rates. Accordingly a 12·7-mm diameter venturimeter having an area ratio of 0·25 was made from stainless steel and has been calibrated for wet steam using a compounded differential U-tube manometer. The manometer and associated equipment is extremely simple and cheap to construct, and consists entirely of easily machined parts and standard pipe fittings. The results indicate that the discharge coefficient is very low and approximately a linear function of Reynolds number over the range tested.
Hydrodynamic Studies of Two-Phase Upflow in Vertical Pipelines
Authors: Jepsen J. C. , Ralph J. L.
Published: June 2010

The object of this study was to obtain data on the radial variation of gas- and liquid-phase mass flux profiles in two-phase upflow in vertical pipelines. Experimental data were obtained on the radial gas-liquid flux, impact pressure, and linear liquid-phase velocity profiles for superficial gas- and liquid-phase velocities ranging from 20 to 125 ft/s and from 5 to 15 ft/s, respectively. Studies were made on 1-in, 4-in, and 8·4-in vertical pipelines and in a 1-in i.d. by 8·4-in o.d. vertical annular flow pipeline. Gas-liquid systems studied were air-water, air-aqueous glycerol, and air-tetrabromoethane.

In Part 2 time-averaged radial liquid hold-up and linear-phase velocities were estimated from radial mass flux and impact pressure data. Estimates were also made on the magnitude, frequency, and velocity of the flow disturbances. Empirical correlations for mean liquid hold-up and pressure drop were developed from experimental data.
A Study of the Performance of Inertia Air Filters
Authors: Gee D. E. , Cole B. N.
Published: June 2010

This paper presents an experimental and theoretical study of the design and performance of inertia air filters, with particular reference to rail traction duty. Using a specially constructed test rig, performance testing of commercially available filters was carried out over a wide range of operating conditions. Subsequently, a more fundamental study of some design variables was carried out in a small-scale test rig. The testing was supported by a theoretical approach using a digital computer model of the inertia filtration process. The results of the work indicate that the inertia filter is suited to high-volume, low pressure drop applications. However, operational difficulties, owing to dust build-up occurring within the filter and variations of bleed ratio, may be encountered.

The theoretical model was shown to reproduce all the major operating characteristics of the filters measured in the test programme, and to respond to design changes in a similar way to that indicated by earlier published work. A hypothesis of the mechanism of separation is proposed, and it is suggested that the performance of new filter layouts can be examined at the design stage. Supporting work describes the selection, measurement, and production of a suitable range of polydisperse solids for the test programme.
Two-Phase Air-Water Flow in a Slot-Type Distributor
Authors: Madden J. M. , St. Pierre C. C.
Published: June 2010

Experimental data have been obtained for two-phase air-water flow through a slot-type distributor. Air and water flow rates through the slot were measured as the pressure drop across the slot was varied for fixed values of the main stream quality, the total mass flux, the slot length, and the slot width. Five different slots were cut in the side of a vertical 1-in internal diameter plexiglass tube and a controlled pressure drop across the slot was used to remove a portion of the main stream. Three slot lengths were used: 1·66 in, 4 in, and 6 in. The mass flux was varied from 200 000 to 500 000 lb/h ft2 and the air quality ranged from 0·2 to 0·7 at a system pressure of 50 lb/in2 (abs.).

The orifice equation employing discharge coefficients was successful for calculating cross-flow rates. Two-phase flow discharge coefficients are correlated as a function of the ratio of slot velocity to mainstream velocity. At low cross-flow velocities or large mainstream velocities the hydraulic resistance to cross-flow increased by as much as an order of magnitude. The axial pressure rise across the slot was also measured for both single-phase air and two-phase air-water flows. Values of the momentum correction factor, which accounts for the diverging stream not leaving at right angles to the main flow channel, were determined.
Some Experiments on Sonic Velocity in Two-Phase One-Component Mixtures and Some Thoughts on the Nature of Two-Phase Critical Flow
Authors: Barclay F. J. , Ledwidge T. J. , Cornfield G. C.
Published: June 2010

The pressure drop characteristics and flow rates encountered in measurements of flashing water flow in parallel-sided pipes cannot be simply related to the thermodynamic equilibrium theory of the velocity of sound in homogeneous two-phase one-component mixtures. It is shown in the paper that the velocity of propagation through such a mixture is different in magnitude, both to the thermodynamic equilibrium theory and to the theory postulating no phase change. Measurements of the velocity of propagation of compression and rarefaction waves in atmospheric pressure stagnant boiling water are described and interpreted. Some aspects of bubble motion in a pressure gradient are discussed. Measurements in stagnant water are not precisely relevant to the case of flowing liquid in which the vapour component is slipping positively with respect to the liquid. The effect of slip is discussed.

It seems to the authors that some relationship between the sonic velocity obtained from their tests and the critical velocity correctly defined in terms of local pressure slip and void fraction should exist. The data which should be extracted from a critical flow experiment are suggested.
Removal of Entrained Liquid Droplets by Wire-Mesh Demisters
Authors: Bradie J. K. , Dickson A. N.
Published: June 2010

This paper is concerned with the factors governing the performance of wire-mesh demisters, and in particular with their application to entrainment removal in pool boiling systems. The efficiency of a demister pad is derived from the collection efficiency of a single wire, and from this a minimum vapour velocity for efficient droplet removal is determined as a function of droplet size. Correlations for both single-phase and two-phase pressure drop through the demister are given together with a correlation between vapour and liquid velocities when flooding of the demister occurs. These correlations are discussed in relation to experimental results on demisters obtained in the present programme together with published data for packed beds. The effect of the height of the demister above the interface in pool boiling systems is discussed, including the allowable velocities in the vapour space and through the demister.
Structure of Turbulence Close to the Interface in the Liquid Phase of a Co-Current Stratified Two-Phase Flow
Authors: Jeffries R. B. , Scott D. S. , Rhodes E.
Published: June 2010

Turbulence data are presented which were measured by hot-film anemometry in the liquid phase of a two-phase co-current stratified flow of air and water in a rectangular channel. Mean velocity profiles, u', v', and u' v' intensity distributions were measured across the liquid phase, with special attention being given to the vicinity of the interface. Distributions of total shear stress, eddy viscosity and turbulent energy have been calculated.
Effect of Rapid Steam Off-Take on Natural Circulation in Boilers
Authors: Simpson H. C. , Rooney D. H. , Callander T. M. S.
Published: June 2010

This paper describes investigations into the effect of a sudden change in system pressure, caused by rapid steam off-take, on a natural circulation loop. The work was carried out on a two-tube experimental boiler with a water drum connecting the bottom of the riser and downcomer tubes, which were respectively 2 in o.d. x 9 s.w.g. and 11/4 in o.d. x 6 s.w.g., giving a riser to downcomer flow area ratio of 3·9.

The experimental range covered starting pressures of 1000, 800, 650, and 500 lbf/in2 (gauge), with pressure drops of 100 lbf/in2 at rates ranging from 1 to 34·5 lbf/in2 s. Heat fluxes to the riser tube ranged from 21 000 to 136 000 Btu/h ft2 and initial mass velocities from 0·70 to 1·11 million lb/h ft2 in the downcomer tube. During the transients, continuous recordings were taken of system pressure, circulation, pressure difference, and fluid density at a point in both the riser and the downcomer tube, using the gamma-ray attenuation method.

The system behaviour was analysed theoretically by setting up the appropriate two-phase conservation equations and solving them using (1) a finite difference method, (2) a stepwise solution on the basis of quasi-steady flow. The first method was eventually discarded in favour of the second. The theoretical flow models considered in the analysis include a vapour core annular type flow in the riser, and a homogeneous type flow in the downcomer, during the transient. The theoretical results are compared with the experimental data.
Wagons and the Private Owner
Authors: Farquharson F. K.
Published: June 2010

This paper relates the experience of a large private owner during a programme of fleet modernization over the last five years. The benefits obtained, together with the technical and other difficulties encountered, are described. The obstacles that history always provides to innovations are discussed and solutions are outlined. Operating experience with 45- and 100-ton cars is related, and progress in block train operation is reported. From the private owners' viewpoint some astringent observations are made upon the attitude of British Rail, but suggestions are made which would largely remedy the situation. Design features and characteristics of cars are given and experiments with individual features are discussed.
Wagon Running Gear
Authors: Koffman J. L.
Published: June 2010

The paper deals with certain fundamental aspects of wagon design and performance. Torsional rigidity of four-wheel and bogie wagons, forces imposed by the track on the running gear, and the stresses imposed by the vehicles on the track are considered, with particular reference to the establishment of an economically justifiable common goal based on all-round optimum performance. Bogie rotational resistance, lozenging forces, friction, and hydraulic damper performance requirements are briefly dealt with before particulars of the performance of modern four-wheel and bogie wagons are provided. The paper concludes with a brief reference to future trends regarding wagon design.
Heat Transfer Rig for Hydrogen-Cooled Generator Field Windings
Authors: Davidson D. F.
Published: June 2010

The maximum output from large turbine generators is limited mainly by the temperature rise of the rotating field winding. Hydrogen at a pressure of several atmospheres is normally used to cool this winding by direct contact with the copper. Accurate knowledge of surface heat transfer coefficients is essential to ensure that the average winding temperature rise does not exceed the specified value.

A heat transfer rig was built to test full-size rotor coils in hydrogen and to compare actual with predicted copper temperatures. The construction of the rig is described, together with details of its operation and the various problems which had to be overcome. Tests were carried out on two designs of rotor coil. In one case the flow is laminar, and in the other it is turbulent. The test results are compared and the various heat transfer coefficients evaluated.
Problems of Flow and Heating in Turbo-Generators with Water-Cooled Rotor Winding
Authors: Lambrecht D.
Published: June 2010

Water cooling of a stator winding has already been proved to be reliable, and water cooling of a rotor winding has now been developed to such an extent that it can be used for turbo-generators with large unit ratings. After a short description of the construction of the prototype, the paper discusses the design problems encountered and presents the results of measurements and practical experiences obtained during operational testing. The paper finally presents an explanation of the performance characteristics of a water-cooled rotor.
Some Designs for Mountings Incorporating Two Rolling Bearings and a Grease Relief System
Authors: Mullett G. W.
Published: June 2010

The designs for grease relief systems of the valve type for a mounting containing a single bearing are already well known. In some machinery, however, the bearing requirements cannot be satisfactorily met by a single bearing. In these cases a pair of bearings in the one mounting is needed. The design of the mounting is further complicated if, in addition to pairing the bearings, a grease relief system is also required.

The paper gives eight outline sketches covering various designs of two-bearing grease valve mountings. All have been rig tested and the efficiency of each design categorized. For the experimental work 3-in (76·2-mm) bore medium series ball and roller bearings were used. These were grouped into six pairs. Each pair was tested, either paired in contact or axially spaced apart. Shaft speeds ranged from 1070 to 3600 rev/min, DN = 82 000 to 275 000. In the relief systems, either one or two valve discs were variously positioned above, below, and between the bearings. The paper should be of value to design engineers.
IP Dynamic Anti-Rust Test, Lubricating Greases
Authors: Spicer F. E. H.
Published: June 2010

The Institute of Petroleum has recently published a test method (IP 220/67) for assessing the rust-prevention characteristics of greases. Specially selected and preserved double-row, self-aligning ball bearings are used as test specimens.

The test, which lasts for 164 1/2 h, is dynamic, the grease film being produced and part of the test being performed with the bearings rotating partially submerged in distilled water. The performance of the grease is assessed by estimating the area of rust on the outer races of the test bearings.

The precision of the test method was established by an extensive international correlation programme involving 30 laboratories from five European countries. This showed a precision which varied according to the performance level of the test greases. The results of tests with greases affording very good protection and with greases affording very poor protection against rusting gave better precision than results from greases with intermediate performance levels.
Apparent (Dynamic) Viscosity and Yield Strength of Greases after Prolonged Shearing at High Shear Rates
Authors: Scholten G. J.
Published: June 2010

Where sealed, grease-lubricated sleeve and ball-bearings are used with once-only lubrication for life, the rheological properties of the grease as a function of the service life are important in connection with the load-carrying capacity and the sealing capacity. To calculate the bearing capacity of a journal or spiral-groove bearing it is important to know the relation between the rate of shear and the shear stress in the lubricating film, i.e. the apparent viscosity, as a function of time. For sealing of the bearing the value of the yield strength of the grease, after shearing, is also important as a function of time. To measure these two magnitudes, a rotating-cylinder type of viscometer and a cylinder type of yield strength meter have been constructed. The viscometer permits the determination of viscosity up to shear rates of about 5 × 105 s-1, while the yield strength meter can ascertain the ultimate strength, after stressing, with shear rates of up to 105 s-1—both being determined within the temperature range 25–125°C. A number of commercially available greases have been tested.
Paper 2: Behaviour of Rarefaction Waves at the Junction of a Branched Duct
Authors: Male D. H. , Chelsom R. A. , Deckker B. E. L.
Published: June 2010

The results of an investigation into the behaviour of rarefaction waves at a junction formed by the intersection of two ducts are presented. Pressure measurements have been made in junctions in which the side branch forms an angle of 45°, 90°, and 135° with the main branch. In the 90° junction the effect of the area of the side branch to that of the main branch is examined; the values of the ratios being 1·0, 0·5, and 0·25. The amplitude of the incident rarefaction waves varies from 3 to 20 inHg.

The development of the quasi-steady flow pattern has been obtained by Schlieren photography. This information, together with the pressure measurements, has been used to develop a quasi-steady, one-dimensional, semi-empirical analysis of the flow. The results of this analysis are in good agreement with the pressure measurements and can be used as boundary conditions for the examination of pipe networks by the method of characteristics.
Paper 3: Non-Steady Flow in Internal Combustion Engine Inlet and Exhaust Systems
Authors: Benson R. S. , Foxcroft J. S.
Published: June 2010

Previous work on non-steady flow in exhaust systems has shown that the method of characteristics can be used to predict the flow conditions to a high degree of accuracy. In these calculations the pressure at the inlet port or valve was considered to be constant. Recent work on the effect of pulsating flow on centrifugal compressors has shown the importance of considering non-steady flows in the inlet systems of supercharged engines.

Predictions of the non-steady flow in inlet systems, usually based on acoustic theory, have only been accurate in particular cases. In this paper the method of characteristics has been applied to the study of non-steady flows both in the inlet and exhaust systems of internal combustion engines. Comparisons are made between the calculated and experimental results obtained on a multi-cylinder pulse generator. Tests on both single- and two-cylinder units were carried out and measurements of the inlet pipe pressure, exhaust pipe pressure, cylinder pressures and temperatures, and inlet and exhaust mass flows were made. Comparisons between the theoretical predictions and the test results were extremely good; in all the cases the pressures were in close agreement. The inlet predicted mass flows were all within +9 and −4 per cent of the measured flows, the standard deviation being 3·1 per cent. The exhaust mass flows were all within +8 and −12 per cent of the measured mass flows, the standard deviation being 4·3 per cent. It was considered that the method gives reliable predictions of the flow processes in internal combustion engines.
Paper 24: A Study of Column Separation following Valve Closure in a Pipeline Carrying Aviation Kerosine
Authors: Swaffield J. A.
Published: June 2010

The occurrence of column separation on the upstream side of a valve following valve closure has been the subject of a series of experiments on a test rig utilizing Concorde L56 alloy fuel piping and Esso Aviation Kerosine Specification 2494.

A Fortran IV computer program based on the method of characteristics has been employed to solve the quasi-linear hyperbolic partial differential equations governing the propagation of transient pressures and to predict the duration of vapour cavities formed either at the valve or at any point in the pipeline. Comparison of computer and observed results indicates an accuracy within 3 per cent for the first peak following valve closure and for the duration of the vapour cavities, and within 10 per cent for the later pressure peaks following vapour cavity collapse.
Paper 26: A Solution to Lagrange's Ballistic Problem with Gas on Each Side of the Projectile
Authors: Woods W. A.
Published: June 2010

This paper presents a brief review of the ballistic motion of pistons, and includes a survey of rapid expansion machines used for the study of thermodynamic properties of gases. The datum solution is given to the problem of the piston being propelled by a perfect gas expanding isentropically through a simple wave. The problem concerning the motion of a piston in a tube with gas on each side of the piston is discussed and the solution is presented. It is shown that this problem can be discussed in terms of four dimensionless parameters, and the results of calculations are presented graphically in terms of the parameters developed.
Paper 31: Capsule-Pipeline Flow—A Theoretical Study
Authors: Garg V. K. , Round G. F.
Published: June 2010

Theoretical predictions of the behaviour of various parameters governing the free flow of a single, very long, denser-than-liquid carrier, cylindrical capsule in a horizontal pipeline are reported in this paper. The study was carried out for average flow velocities of approximately 1–10 ft/s in pipes of diameters 4, 6, 12, and 24 in with diameter ratios varying from 0·9 to 0·99. While two liquid carriers—water and an oil ( μ = 10 cP and sp. gr. = 0·85)—were used, the eccentricity of the capsule-pipe system was fixed at 0·999. The theoretical solution was found to be in good agreement with the experimental results.
Paper 34: Effects of Variable Specific Heats and Gas Composition on Unsteady Flow Calculations
Authors: Benson R. S. , Wild A. , Woollatt D.
Published: June 2010

A numerical method has been developed for the solution of one-dimensional non-steady flow problems including the effects of friction, gradual area change, heat transfer between the gas and the pipe wall, longitudinal variations, and discontinuities in gas composition and entropy. The fluid considered obeys the perfect gas equation of state, but the specific heats may vary with temperature. The method is not intended for use when shocks are present, but will give an approximate solution if shocks occur.

The accuracy of the new method has been checked against existing methods for more simple cases, and although the new method has been found to be slightly superior it is more complicated, much slower, and the boundary conditions are more difficult to develop. For this reason, it is suggested that the new method be used to check on the adequacy of the existing simpler methods for each new application. The methods have been compared for the case of a typical diesel engine exhaust system and it has been found that the earlier methods are adequate for all practical purposes.