bluuebunny/crossref_metadata_2025_split huggingface dataset:
Present Tendencies in Water Turbine Machinery
Authors: Fulton A. A. 
Published: October 2007

As the high specific-speed water turbine has been fully described elsewhere, the paper concentrates on the present state of knowledge and details of design of the remaining types of water turbines, namely, Francis turbines and Pelton water wheels. In the absence of any spectacular developments in performance, efficiency, or speed regulation during the last twenty years, notable progress has been made in several other directions, such as the increased size of units, the more advanced state of knowledge regarding the incidence and avoidance of cavitation, and the use of special materials and devices to combat particular problems. On the subject of cavitation, the paper stresses the importance of the influence which the discharge velocity from the runner has on the allowable static suction head, and so directly on the occurrence of cavitation. The author goes on to describe how the effects of localized cavitation can be eliminated both in Francis and Pelton turbines, and thereafter reviews the settings and arrangements of Francis and Pelton turbines which are mostly favoured to-day, including brief references to arrangements of special interest. The latter part of the paper discusses the new ideas which are being tried out in the design and manufacture of the various portions of the two types of turbines dealt with in the paper. Among such features are included the use of welding in the repair of runners and in the manufacture of casings, and other portions of water turbines; the use of rubber in runner clearances and water-lubricated bearings; the researches carried out to determine the best form and shape of suction tubes for double-runner turbines; the difficulties encountered in the cracking and fixing of Pelton buckets; and finally, a review of the several types of main inlet valves at the disposal of the turbine designer.
The Conversion of the Stanton 3-Inch High-Speed Wind Tunnel to the Open Jet Type
Authors: Bailey A. , Wood S. A. 
Published: October 2007

The 3-inch high-speed wind tunnel developed by Stanton has been converted in the Engineering Department of the National Physical Laboratory to the open jet principle, the working jet now being contained in a square glass-sided chamber. The pressure in the observation chamber can be controlled within certain limits by altering the axial length of the gap between the inlet and outlet, and the presence of standing waves in the jet can be largely eliminated by bringing the chamber pressure to a value equal to that in the jet at the chamber inlet. In place of the divergent jet used by Stanton, an approximately parallel working jet has been obtained in the modified tunnel by using inlet nozzles with profiles determined by a graphical construction based on the “characteristic curve” method given by Busemann. An optical system has also been fitted enabling Schlieren photographs of the flow pattern to be obtained. Measurements of the wave systems set up round model cones indicate agreement with the theory established by Taylor and Maccoll which they found to accord with the results of larger-scale firing trials on conical-headed shell, thus providing evidence of the close similarity between conditions in the tunnel and on the full scale.
Water Hammer in Pipes, Including Those Supplied by Centrifugal Pumps: Graphical Treatment
Authors: Angus Robert W. 
Published: October 2007

The damage done to pipes as a result of water hammer is so serious that no engineer can afford to neglect it in the design of long pipes, particularly those under low heads. Unfortunately the problem has appeared to many to be very intricate, and indeed the mathematical treatment is so involved and so lengthy that few practising engineers would attempt to solve water-hammer problems mathematically. In many cases a purely arbitrary rule has been employed in finding the pressure rise, with little knowledge on the part of the engineer as to whether the formula fits his case or not, and thus much money may be wasted on too heavy a line, or, on the other hand, it may be so light as to be dangerous. In the following treatment of the subject, the rigid theory has first been explained and some problems have been solved, but most of the paper deals with the elastic (and correct) theory. A problem is first worked out by the arithmetical integration method in order to establish ideas and to make the subsequent argument clear. The fundamental equations giving rise to Allievi's equations must be clearly understood for a grasp of the true relationships that exist, and these have been treated in some detail, but it is safe to say that if the argument has been followed up to the end of the general equations, no difficulty will be experienced with the graphical treatment. In explaining the diagrams, very simple cases are first dealt with and the elegance of the method will make an appeal at once. The water-hammer pressure can be found for any simple pipe, and at any point on the pipe, and for any chosen gate movement, and results can be obtained with accuracy in less than thirty minutes in simple cases. For compound pipes, the solution is nearly as rapid. The pressures arising in the discharge lines from pumps have been fully discussed in the case of pumps with small inertia, and also in cases in which the inertia is large enough for consideration, when an existing pump has been employed to supply the data used. The accuracy of the method is beyond question; where intersections are at small angles the exact points are hard to determine, but this trouble may easily be avoided by changing the scales. If a slide rule is used in solving the problem mathematically the corresponding case will be encountered.
The Application of the Locomotive to Traffic Working
Authors: Fairless Thompson 
Published: October 2007

The paper describes methods by which the analysis of steam locomotive power can be most advantageously applied to traffic working in the case of railways not having special testing facilities, such as dynamometer cars. The first section describes the method used for the determination of cylinder and boiler output, the treatment of locomotive and train resistances, and the application of these factors to train loading, speed, and running time. The calculation of fuel and water consumptions on a horse-power-hour basis is given, also the method of application to train working. The second section describes the procedure for the practical application of locomotive power to traffic working, and the measurement of train capacity in terms of ton-kilometres per train hour.
Overhead Electric Travelling Cranes
Authors: Ellis John H. 
Published: October 2007

The installation of an overhead electric crane is often left in the hands of specialist manufacturers. Plant engineers, however, need to ascertain service and performance requirements when considering an installation, and they often rebuild or modify existing cranes in order to reduce production and maintenance costs by improving the reliability of the crane service. The paper considers some of the factors affecting the installation of suitable cranes for particular duties, and deals briefly with some of the important features of design. A few service troubles are dealt with and some instances are quoted from the experience of a steelworks maintenance department with reference to the subject of improvements and maintenance costs.
The Distortion of Metals by Cold Working
Authors: Wainwright H. A. 
Published: October 2007

The paper deals with current conceptions of cold working and its varied effects on the metal undergoing deformation. The mechanism and behaviour of single metal crystals and polycrystalline aggregates, whilst undergoing cold working deformation, are outlined. Two aspects are treated, namely, block slip and “twinning”. The X-ray examination of a polycrystalline metal under deforming stresses is mentioned, together with the formation of flow lines, better known as Lüder's lines. The effect of cold work on the mechanical, physical, electrical, and chemical properties of materials is then considered in some detail, together with the practical aspects of the changes wrought. The paper concludes with a brief summary of the subject, and the more important theories are reviewed in order to see how far they explain all the phenomena observed.
The Pressure Distribution in a Convergent-Divergent Steam Nozzle
Authors: Binnie A. M. , Woods M.W. 
Published: October 2007

The paper describes experiments performed to determine the pressure distribution in a convergent-divergent steam nozzle of rectangular cross-section. By means of pressure tappings drilled along the axis, it was found that, in the course of its passage through the nozzle, initially superheated steam expanded continuously until condensation commenced, when a sharp rise of pressure (of the order of 1 lb. per sq. in.) occurred. Up to this point the observations were consistent with the predictions of Callendar's equation for the isentropic expansion of superheated and supersaturated steam: the friction loss was small as far as the throat of the nozzle, but in the divergent portion it was of appreciable magnitude. The Wilson line was determined after allowances for the effects of friction had been made. The pressure rise was also investigated in detail and was found to be accompanied by a decrease of velocity and an increase of total heat. At the peak of the rise, where continuous expansion recommenced, the steam was probably not in thermal equilibrium. Additional tappings were placed across the throat, where the pressure observations were in close agreement with the values demanded by Taylor's theory. This theory, which does not assume uniformity of conditions over cross-sections of the nozzle, is more accurate in the neighbourhood of the throat than the classical theory of Reynolds.
The Effect of Circumferential Pitch of Steam Turbine Blades on Torque as Compared with “Biplane Effect” on the “Lift” of Aerofoils
Authors: Dowson Robert 
Published: October 2007

It is known that the “lift” of biplanes and triplanes per unit of wing surface is inferior to that of a monoplane, and that the degree of departure depends upon the gap-chord ratio. Published data indicate that the lift increases with increasing gap, apparently towards some limiting value. Regarding steam turbine wheels as rings of multiplanes, it may be asked, Is there any direct evidence that the torque on each blade is influenced by the presence of the other blades?. Many experiments have been made to determine the optimum circumferential pitch for a given blade shape, but most of these have aimed simply at arriving empirically at the best efficiency, without inquiry into the factors involved. The experiments described in the paper were carried out with low-velocity reaction blading, and were aimed at eliminating as many factors as possible, so as to make a clear issue of the effect of spacing the runner blades closer or wider apart. These experiments indicated that the effect of circumferential spacing on maximum torque was fairly critical, and that from the optimum point the torque declined less rapidly with increasing spacing than with decreasing spacing. The decline in torque with increasing spacing is due probably to lack of proper guidance of the steam, only a portion of which gives up energy to the runner blades, the remainder doing little useful work. On the other hand, the curve of force per blade is found to be increasing with increased circumferential pitch, towards some optimum value (beyond the range of the experiments). This curve resembles closely that published for the increased “lift” on a biplane as the planes are spaced farther and farther apart. The experiments are of interest on account of the above analysis and comparison, but no definite conclusion is possible without further investigation.
The Transmission of Superheated Steam over Long Distances
Authors: Genève L. F. C. A. 
Published: October 2007

The aim of the paper is to obtain as accurate a solution as possible to problems arising in the transmission of superheated steam over long distances for ( a) industrial heating and ( b) power generation. After a general survey, with a description of two typical installations, the problem is discussed under headings ( a) and ( b), and the usual practice in fixing steam velocities is given. The present state of knowledge of radiation losses is reviewed; first, the standard English practice of using a coefficient based on the pipe surface and varying with the thickness of the insulating material; and second, the method, used mainly in America, which involves conductivity coefficients. The effect of air currents on heat loss is investigated and a new equation is deduced for the equivalent velocity past the pipe, due to natural convection. Standard formulæ for the coefficient of friction and the viscosity of steam are discussed; for the former a new formula of the rectangular hyperbola type is derived from Carnegie's results and corrected for roughness. Steam viscosity is considered in the light of Speyerer's and Sigwart's investigations; curves of Sigwart's results are plotted on a convenient base of logarithms of pressures. Conditions during flow in a horizontal straight pipe with perfect insulation are considered and new equations, simplifying the problem, are derived from the fundamental equations. The author treats from a new viewpoint the problem of power transmission by steam over long distances, based on the loss of available Rankine heat drop. Numerical examples are worked out, as also is the effect of air currents on the coefficient of heat loss. Finally the limiting factors, including the effect of radiation losses, in the long-distance transmission of steam are analysed and their practical importance is discussed.
Practical Problems in Spring Design
Authors: Berry W. R. 
Published: October 2007

The author draws attention to the difficulties facing the engineer to whom spring design is merely incidental. These difficulties are mainly due to the complicated formulæ concerned, to lack of information regarding the materials, and to incorrect appreciation of the real functions of the spring. Standard formulæ require corrections for the effect of curvature; without these adjustments very dangerous results can be obtained. Corrections due to Wahl and Woods are incorporated in the formulæ, and finally two nomograms, for stress and deflexion calculations respectively, are produced to enable these involved formulæ to be handled easily and rapidly. Consideration is given to physical properties, and it is pointed out that except for special conditions of service, the torsional elastic limit of the material is the most important physical property of the material in most helical tension and compression springs. Data are given for this property for patented carbon spring steel and for chromium-vanadium spring steel. Tolerances and limiting conditions are considered, and an arbitrary figure of 70 per cent of the torsional elastic limit is adopted as the maximum safe stress. Curves of load-carrying capacity are given for all standard gauges from 0·020 to 0·50 inch diameter-Special service conditions are finally considered, and suggestions made for dealing with them. In an Appendix are given various examples illustrating the use of the curves and nomograms, and the derivation of some special formulæ.
Deformation and Fracture of Mild Steel Under Cyclic Stresses in Relation to Crystalline Structure
Authors: Gough H. J. , Wood W. A. 
Published: October 2007

The paper describes an extension of a recent research into the characteristics of the deformation and fracture of metals under static and fatigue stressing as revealed by precise methods of X-ray diffraction. The four series of fatigue tests were designed specially to take into consideration the cases where the upper stress of the cycle is in the immediate neighbourhood, first, of the ultimate tensile strength, and second, of the static yield point of the material. Accurate records have been made throughout of the changes in shape of the specimen. The structure has been examined by the X-ray method at the end of the test in every case, and also, in certain cases, at various interrupted stages. The results have shown that, in general, the observed changes in structure, even under the most critical conditions of stress, are similar in nature to those found in the previous work. It has also been established that, under a safe range of stress, the damage to the structure is equivalent to that caused by a single sustained application of a static stress equal in amount to that of the maximum stress of the cycle. Further, the additional and progressive damage caused by cycles of an unsafe range of stress leads to a complete fragmentation of the whole or part of the specimen. Finally, the results of the complete series of alternating and pulsating direct stresses have been reviewed in relation to the deformation in the specimen; the conclusion is reached that, though complicating factors are present, the average stress of the cycle appears to have only a small effect on the fatigue resistance of the material.
The Problem of Economic Foundry Production
Authors: Ronceray Eugène 
Published: October 2007

The paper describes methods of obtaining the greatest efficiency in the foundry by the simplest possible means, a principle of the first importance. The author has had forty years' experience of foundry practice, during which he has often changed his opinion on particular points, as requirements have grown, and as the means of realizing them have developed. Economy in transport in the foundry depends on sound organization of methods. The preparation and stocking of sand are of no less importance. Continuous discharge from the sand mill is advocated, and the various means of transporting and handling the sand are described, and the suitability or otherwise of different types of apparatus discussed. Mould conveyers and the positions of the moulding machines relative to them are also considered. The conclusion is drawn that with care the simplest plants can be profitably mechanized.
Pressure Calculations for Oil Engine Fuel-Injection Systems
Authors: Giffen E. , Rowe A. W. 
Published: October 2007

The paper gives details of a method of calculation for use in determining the pressure variations in the normal fuel-injection system. This method, besides dealing with the transmission of pressure impulses from one end of the pipe to the other, includes those modifying conditions present in an actual system, namely the capacity effects at the pump and at the nozzle, the action of the pump delivery valve, and the varying conditions in the spring-loaded injection valve. The results of a calculation on a typical injection system have been incorporated in the paper. A diagram of nozzle pressure, obtained experimentally from the same system, is also included for comparison with the results of the calculation. This experimental diagram agrees so well with the calculated results that the treatment described may be regarded as giving a very close approximation to the actual conditions in the injection system.
Mechanical Engineering Problems in Marine Transport
Authors: Freeman Sterry B. 
Published: October 2007

This, and the following papers by Mr. Stanier, Mr. Ottaway, and Mr. Gouge, were to have been read at the Joint Meeting of the Institution with the American Society of Mechanical Engineers in New York, which was cancelled owing to the outbreak of war. The problems of mechanical engineering in marine transport are concerned with the steam engine and, in recent years only, with the oil engine. The problems vary from one type of service to another and the relative merits and cost of the various types of machinery available are compared. It is necessary for the engineer to satisfy the requirements of the shipowners and the surveyors in the most economic manner. The drawbacks and advantages of the two fuels, oil and coal, are contrasted and their effects assessed. The problems concerned with turbines, boilers, and oil engines are summarized. Electric transmission of power and mechanical gearing are reviewed, and the paper concludes by considering large handling plant and stating the position of the mechanical engineer with respect to problems of marine transport.
The Circulation of Water and Steam in Water-Tube Boilers, and the Rational Simplification of Boiler Design
Authors: Lewis W. Yorath , Robertson Struan A. 
Published: October 2007

The authors stress the need for a sound theory of circulation in water-tube boilers, to enable weight and space to be saved and efficiency and reliability to be increased. They establish, as a standard of excellence with which other boilers may be compared, a simple boiler consisting of a single drum and a single U-tube. The paper consists of three parts. Part I describes the nature of the change from water to steam; in part II the flow in the simple U-tube boiler is calculated; and in part III the features of various departures from the standard U-tube, met with in practice, are discussed. An improved type of tube, approaching very nearly to the standard U-tube, is evolved, allowing much simplification of boiler design, with the advantages of excellent circulation, high gas speeds, and higher heat transmission rates. Other rational simplifications and improvements are also rendered possible, which enable substantial reductions to be made in the cost of manufacturing, installing, and maintaining boilers of any pressure and capacity, for any service, ashore or afloat. The MS. of this paper was received at the Institution on 10th November 1938. The paper was presented for discussion at an Extra General Meeting of the Institution on 1st March 1940.
Some Problems Connected with Steam Turbine Governing
Authors: Higgs-Walker G. W. 
Published: October 2007

The recent growth in the size of steam turbines has made desirable the use of governing systems using two or more relays working in series to operate the governor valves. The rise in initial steam pressures and the increase in the number of turbine cylinders which has accompanied this growth has increased the relative energy of the steam entrained in the steam chests, cylinders, and interconnecting piping so that this entrained steam has become a most important factor in problems concerned with the stability of governing and with the maximum temporary speed rise when load is suddenly removed. The present investigation has been made to determine the effect of the number of relays and of the entrained steam energy on governing stability and on temporary speed rise. The problems have had, to some extent, to be treated separately as the inclusion of governor inertia, multiple relays, and entrained steam lead to stability criteria of too great complexity to be generally useful.