bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow Pattern in Diesel Nozzle Spray Holes
Authors: Bergwerk W. 
Published: October 2007

The paper presents a study of the flow in spray holes of 0.2 to 2.5 mm diameter and shows how the changes in cavitation pattern affect the appearance of the jet. The influence of the cavitation number, Reynolds number, the upstream edge sharpness, and the length/diameter ratio is investigated. A cavity first formed near the upstream corner, but soon caused the jet to leave the wall altogether so that only the upstream corner had any effect on the flow. Under noncavitating conditions the emerging jet had a ruffled appearance, but under conditions when the jet had left the wall, it emerged smooth and glass-like. The glass-like stage could only be obtained with very accurately made spray holes, and any disturbance upstream, such as occurs in actual Diesel nozzles, caused the jet to appear ruffled at all times. The discharge coefficient was found to vary with Reynolds number and cavitation number and a contour map covering Reynolds number of 1000 to 20 000 and cavitation number of 0·2 to 100 is presented.
Optimum Design of Thin Circular Plates on an Elastic Foundation
Authors: Galletly G. D. 
Published: October 2007

An analysis is given of a thin, constant-thickness, circular plate subjected to uniform lateral pressure. The plate is assumed to rest on an elastic foundation and to be elastically restrained at the edges against rotation and vertical deflection. The equations for the magnitude and location of the maximum stress in the plate were programmed for an electronic computer and curves obtained for both these quantities for various values of two dimensionless parameters. These curves are presented in the paper and it is shown how the optimum design of a constant-thickness circular plate can be quickly effected with their aid. One interesting result of the analysis is that it is possible to design plates in which the maximum stress is between 25 and 50 per cent smaller than that in similar plates with simply supported ends. This possibility does not appear to have been appreciated before and its utilization has obvious economic advantages. Another result of interest is that the value of the dimensionless elastic rotational restraint parameter giving minimum thickness is almost a constant for most cases occurring in practice. A brief discussion is also included of the application of the curves obtained for homogeneous plates to the design of perforated tube-plates.
Free-Convection Heat Transfer in the Inclined Open Thermosyphon
Authors: Martin B. W. 
Published: October 2007

This paper describes a fundamental experimental investigation of heat transfer by free convection in a static heated tube, sealed at its lower end, and arranged so that the inclination of the tube to the vertical can be varied. Heated fluid adjacent to the tube wall forms an annulus which is discharged from the open end into a suitably cooled large reservoir, while a central core of cool fluid is continuously drawn into the tube by way of replacement. The case of the vertical tube under both laminar and turbulent flow conditions has been previously studied (Martin (1)†) and the present work continues the investigation of the system. Inclination of the tube sets up a secondary acceleration normal to its principal axis. The pressure gradients which are thereby induced should assist the circulation of fluid from the cold to the hot stream, thus reducing the thickness of the annulus and increasing the area of the core. The increased effectiveness of the system might then be expected to improve the heat-transfer rate. This is found to be true in laminar flow (of the boundary layer type) except for small tilting angles. The weak secondary pressure gradients which then occur are believed to be responsible for mingling of the fluid particles on the common boundary, and this reduces the heat transfer. The same general trends are apparent even when there is some degree of turbulence in the system. The stable turbulent regime is not of the boundary-layer type, because of the tendency for the cool entering fluid also to become turbulent, but what is called fully mixed flow, where the two turbulent streams mix. This causes reduced circulation and heat transfer. Under these conditions sufficient tilting of the tube eventually brings about the elimination of the mixing effect and a more efficient transfer of fluid particles between the two streams. The greatly increased heat transfer appears to be consistent with a stable turbulent boundarylayer flow regime, which, if attained, would improve the effectiveness of the open thermosyphon as a cooling device for both nuclear reactors and gas-turbine rotor blades.
The Influence of Elastic Deformation upon the Motion of a Ball Rolling between Two Surfaces
Authors: Johnson K. L. 
Published: October 2007

When a ball rolls between two surfaces, in general, a tangential contact force and a relative angular velocity of spin are present at each point of contact. Both these actions give rise to tangential frictional tractions transmitted across the contact surface which are shown to result in a velocity of creep of the ball in a direction perpendicular to the nominal rolling path. The magnitude of the creep velocity depends critically upon the magnitudes of the tangential force and the velocity of spin. If these actions are small there is negligible slip between the contacting surfaces and the creep motion is predominantly a function of the elastic properties of the materials. At larger spin velocities slip extends over a greater proportion of the contact area and the creep is influenced by the frictional properties of the surfaces. Creep measurements have been made over a wide range of conditions of rolling. The results are reduced to non-dimensional form, in terms of two parameters expressing the effect of tangential forces and spin respectively. The resistance to rolling has been measured and is shown to control the axis about which the ball rolls. The detailed mechanism of the rolling process is discussed.
Application of Pneumatic Equipment to the Centralized Control of Compressors
Authors: Martin E. N. , Wilkinson T. W. 
Published: October 2007

Centralized control of a compression plant, in which the speeds of a number of large compressors are remotely controlled by pneumatic means, has been in full operation since 1955. In this paper are discussed the principal design features leading to the choice of pneumatic equipment, the application of which is illustrated by detailed descriptions of typical machine installations. Descriptions of the control-room layout and the means adopted for ensuring reliability of the compressed air supply are also included.
Present-Day Feed-Water Treatment for High-Pressure Boilers
Authors: Hamer P. 
Published: October 2007

The paper is concerned with industrial boiler plant generating steam for power and process at pressures of 1000–2000 lb/in2 and having a high make-up of treated feed water. The capital and running costs of the water treatment plant and process are therefore much more important than in power station boilers where make-up is small. A few figures are given to illustrate this point and a plea is made that water treatment should be studied carefully at an early stage in any project for new boilers. The quality of feed and boiler waters now in use, or recommended, is shown in two tables and it is clear that above about 1500 lb/in2 the trend is toward ‘pure’ feed water, though this may not be essential. The next section discusses the control of steam purity to prevent corrosion and deposits, by elimination of carbon dioxide and oxygen, addition of volatile amines, control of the concentration of salts and silica in the boiler water, and the possibility of steam washing. A short description is given of the circumstances which, it is believed, have caused numerous cases of corrosion in high-pressure boilers, and countermeasures are suggested. These comprise strict deaeration of the feed water, addition of alkalis to the boiler feed water, to prevent corrosion in the pre-boiler equipment and in the boiler, and the avoidance of hot spots or sluggish flow by boiler design and operation. The paper concludes with a reference to the prevention of corrosion in boilers which are standing during erection or normal operation, and to acid cleaning.
Design and Construction of Power Station Feed Heaters
Authors: Bigg J. V. 
Published: October 2007

The paper presents a survey of a number of aspects of the design and construction of feed heaters for present-day steam-turbine cycles. Many papers have been published in recent years which cover a variety of the detail factors which can enter into the design of a feed heater (for example, the design of tube plates). No attempt has been made to add to such information. The aim of the paper is to present the overall picture and to confine detail description to those items where existing literature is scanty or where the author feels that information of interest can be presented. Firstly, a methed is discussed whereby the optimum economic size of the individual feed heater can be investigated. This is followed by consideration of the thermal design of the heater nest, and of the pattern of temperature difference introduced by the advent of heaters containing desuperheating and drain-cooling sections. Several methods are shown by which such sections may be arranged in a feed-heater nest. The remainder of the paper deals with particular aspects of detail construction. The choice of tube materials and their safe working stresses is discussed. The problem of the production of a satisfactory roller expanded tube to tube-plate joint is examined in some detail, together with methods for the consistent production of this joint. An account is given of development work on means for evaluating the soundness of expanded joints by both non-destructive methods and by tube pull-out tests. A description is given of the investigational work which has taken place and has led to the introduction of welded tube to tube-plate joints with both ferrous and non-ferrous tubes. Information is presented regarding the amount of torque necessary to achieve desired loadings in heavy bolted constructions and the problem of achieving uniform bolt loading is discussed. A method of investigation is described which enables the resilience of compressed asbestos jointing to be examined when subjected to a cycle of loading, including heating which simulates working conditions as closely as possible. The main problems occurring in the design of tube plates and heater headers are examined in a brief discussion.
The Strength of Rails with Particular Reference to Rail Joints
Authors: Wise S. , Lindsay D. , Duncan I. G. T. 
Published: October 2007

This three-part paper describes recent work on rails carried out by the Research Department of British Railways. Part I details the rail sections considered, theoretical considerations of longitudinal bending strength and an analysis of failures in service. Part II describes a site investigation which was made into the dynamic stresses experienced by rail joints under traffic. Stresses in both flat bottom (F.B.) and bull head (B.H.) rail joints have been measured with both normal and abnormal conditions of sleeper packing. Electrical resistance strain gauges were used at the calculated positions of maximum stress in each fishbolt hole, and at other positions in the joint. The work initially covered the effects of steam locomotives and steam hauled stock, but was later extended to a second site so that electric locomotives and multiple unit electric stock could be similarly covered. The investigation brought out the marked influence of speed, wheel diameter and axle load on the magnitude of the stresses induced; and in view of the prospective increase in speeds, and the employment of diesel electric and electric locomotives with heavy axle loads on smaller wheels than as is usual currently, importance attaches to these results and their implications on the life expectancy of rail steel under fatigue loading. Part III describes fatigue tests which have been made on B.H. and F.B. rails, both plain and when drilled with fishbolt holes. The susceptibility to cracks starting at bolt holes, due to shear stresses in the web, is compared for the two rail sections, and some consideration is given to various methods of increasing the resistance to cracking of this type. It is shown that ordinary atmospheric corrosion greatly reduces the fatigue strength of rails, and any proposed method of reducing bolt hole failures must therefore take this into account.
An Approximate Analysis Giving Design Data for Corrugated Pipes
Authors: Palmer P. J. 
Published: October 2007

This paper gives an approximate method of analysis for corrugated pipes and ducts, of the type in which the corrugations have a constant radius of curvature. The method is applicable to corrugations of any included angle, provided that the radius of curvature of the corrugation is small compared with the radius of the pipe. The analysis is carried out using the principle of minimum strain energy, in which the smallest possible number of terms are employed. The advantage of the method is that results giving extension, bending stress and circumferential stress can be evaluated for corrugations with different included angles, and simply presented in graphical form. These results are then readily available for design considerations covering corrugated pipes with internal pressure, axial load, and bending moment. The approximate results are compared, where possible, with some results from more precise methods of analysis, and also with some experimental results, and the comparison shows the present method to be sufficiently accurate for design considerations.
Leak Tests on Calder-Type Reactors
Authors: Smith J. K. , Cheetham J. 
Published: October 2007

The operation of the first reactors at Calder Hall revealed a significant leakage of carbon dioxide coolant. Tests have been carried out on subsequent reactors to establish the leakage rate and to trace and minimize this loss of coolant gas. This paper deals with the tests carried out on Calder reactors 3 and 4 and Chapelcross reactors 1 and 2. The authors outline the various methods used to determine the rate and to locate the origin of gas leaks. A number of conclusions have been reached on design aspects and several suggestions are made for improving gas tightness of future plants of a similar construction.
Plane Strain Theories of Drawing
Authors: Green A. P. 
Published: October 2007

A review is given of existing theories of drawing under conditions of plane strain†, and these theories are extended in certain respects. Comparison between accurate and approximate theories in which work hardening is neglected, shows that one of the approximate theories is reasonably accurate in predicting the distribution of pressure on the die, and the effect of friction on the drawing load. A new approximate method is proposed to allow simultaneously for work hardening, friction, and redundant work, in calculating die pressures and drawing loads. Redundant work is allowed for by suitably modifying the stress-strain curve of the metal. Formulae are derived for drawing through a wedge-shape die, using analytical approximations for the stress-strain curve. Similar formulae have not yet been found for dies with a cylindrical profile. The possible errors involved in calculating a mean coefficient of friction from the measurement of forces acting on each half of a wedge-shape die are analysed.
Design of Modern Boiler Feed Pumps
Authors:   Hydraulic Plant and Machinery Group, Anderson H. H. 
Published: October 2007

Feed pumps for large steam power stations must accept severe thermal shocks in order to protect the boiler from such shocks, since boiler failure would be catastrophic. The treatment of feed water to give minimum corrosion of the boiler may result in a liquid which is quite erosive at the flow speeds associated with a high-pressure pump. In this paper the research into transient thermal phenomena is described, and it is shown how modern feed pumps for steam power units up to the largest powers visualized are designed to give symmetry of construction, of flow and of stresses in order to withstand rapid temperature changes without distortion of alignment. Modern steam and gas turbines similarly aim at symmetry about the shaft axis. Illustrations are given of how erosion is avoided and performance improved by mathematical control of the acceleration within the pump and by the use of superior materials.
Performance of Some Plain Bearing Materials under Boundary Conditions at Low Temperatures
Authors:   Lubrication and Wear Group, Hargreaves R. , Tantam D. H. 
Published: October 2007

This paper describes results of wear tests made on journal bearings for use at liquid oxygen and liquid nitrogen temperatures, i.e. at −183°C and −196°C, also the design of large bearings in use at these temperatures. The problem of operating plain bearings at low temperatures, particularly in immersed conditions in liquid oxygen or liquid nitrogen, is one of using materials with suitable mechanical properties at these temperatures together with chemical and physical requirements associated with successful dry-bearing combinations in these two conditions of differing reactivity. It is desirable for apparatus to be interchangeably used for handling liquid oxygen and liquid nitrogen and bearing combinations which can be used for this are described.
Performance of Grain Augers
Authors: Roberts A. W. , Willis A. H. 
Published: October 2007

With the growing increase in the bulk handling of grain, the grain-auger type elevator is now being widely used. While some theoretical analyses of the grain auger have been made and performance data for particular size augers have been obtained, little information is available for general design purposes. This work, which is based on an experimental approach, is aimed at producing such information. The investigation has been carried out using a small scale model auger which allowed a comprehensive range of tests to be conducted on a more manageable basis In the first part of the investigation, a study is made of the auger performance characteristics with the aim of determining the conditions for most efficient operation. An examination is made of output and volumetric efficiency in relation to speed, angle of elevation and choke length (the length of exposed screw projecting from the lower end of the casing). The effect of casing clearance on auger output is also partially examined. In addition, the variation of auger horsepower and overall efficiency with speed and angle of elevation is observed In the second part of the investigation, equations are developed and design charts given which enable the performance of augers to be predicted. The equations and charts are based on the application of dimensional analysis and dynamic similarity and apply to augers of the same geometrical proportions as those of the model. The data apply mainly to granular materials of similar shape and properties to wheat. A comparison is made between the predicted performance with the actual performance of a 6-in. auger, good agreement being obtained The investigation shows that many combinations of auger size, speed and angle of elevation may be adopted for a particular conveying application and general recommendations are given regarding the choice of these variables for efficient operation
Method of Predicting Some Aspects of Performance of a Diesel Engine Using a Digital Computer
Authors:   Internal Combustion Engines Group, Whitehouse N. D. , Stotter A. , Goudie G. O. , Prentice B. W. 
Published: October 2007

While the design of diesel engines is necessarily based upon some estimate of the pressure and temperature conditions expected in the cylinder and in the air and exhaust manifolds, such estimates have usually been very approximate. The suitability of the design has to be proved, or improved, during a considerable programme of rigorous development As engines become more highly rated the value of more accurate early estimates of engine performance, as a guide to the designer, becomes more obvious. The paper describes a method of calculating this information by digital computer based on a fundamental approach to the processes involved. It is demonstrated that the cylinder pressures and temperatures, exhaust gas temperatures, fuel consumption, air flow, heat losses, piston and wall temperatures and engine output so calculated, correlate very well with experimental results Using this technique, different combinations of engine variables can be ‘tested’ by computation to reduce the range of engine tests necessary to develop the optimum design, and allow the designer and the development engineer to concentrate their practical experience and technical ‘know-how’ on the formidable problems of mechanical development and combustion improvement
A Standard Contaminant for Oil Filter Testing
Authors:   Lubrication and Wear Group, Weare A. T. 
Published: October 2007

The paper describes the work carried out in the preparation of a ‘natural’ contaminant of a definite and reproducible composition for use in tests on oil filters. The arbitrary limits set in the specification of the contaminant are based on various factors from data on used oil filters and previous knowledge gained in the examination of used engine oils The preparation of the contaminant from the raw material is described in detail, and reference is made to a method of testing filters which is used to make sure that the standard contaminant affects a filter in a consistent manner. Detailed methods of chemical analysis for inorganic constituents and particle size measurement are given in the appendixes to the paper
Laboratory Assessment of Diesel Fuel Filters
Authors:   Lubrication and Wear Group, Onion G. , Rothwell A. J. 
Published: October 2007

The choking of fuel filters in most services is caused by soft organic trace constituents of the fuel, and is independent of the extraneous contaminants over the range of concentrations normally encountered in service It is possible for a filter which is reasonably efficient initially to deteriorate in service to such an extent that most of the damaging contaminants applied pass through the filter. Such a filter, when tested with hard particles only, can show a continuously improving efficiency due to the filtering action of the bed of retained particles. The choking life, as determined by the quantity of hard particles it retains before reaching a chosen limiting resistance, is a measure of the effective filtering area and the volume available for retained contaminants rather than of the life which would actually be experienced in service. It is therefore important in testing fuel filters that the service choking process should be reproduced A combined choking and particle transmission test is described which gives information on the service life to be expected and on the particle transmission of the filter at any stage during that life. The methods of preparation and specification of the powders and choking medium used in this test are also described