bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the Optimum Level of a Steam Power Station Turbine House from Hydraulic and Constructional Considerations
Authors:   Hydraulic Plant and Machinery Group, Dartnell L. M. 
Published: October 2007

The time taken to construct large-capacity thermal power stations is becoming increasingly important and demands close attention. During the constructional period large capital sums are invested without return and as the demand for electricity is ever increasing early availability of generating plant is of consequence. Subject always to satisfactory load-bearing conditions the level of a coastal or esturine power station turbine house is hydraulically related to sea level. An investigation has been made into the economical depth of excavation for the turbine house as plant erection cannot commence until basic building work is complete. The investigation shows that the optimum level of a turbine house is amenable to calculation and two methods of establishing the level are described. The first method involves equating the financial value of lost generation to the savings in civil engineering consequent upon reduced excavation. The second method balances generation lost at low water with increased generation at high water. The results demonstrate that acceptance of periodic small reductions in electrical generation reduce excavation depth, construction time, capital cost or operating cost. The study involves variation in sea level with moon phase, cooling-water pump flow, hydraulic gradients, condenser vacuum and turbine power. Extension in coverage of the conclusions permits power station design engineers to select an optimum turbine house level, subject to consideration of relevant civil engineering factors, in the early design stages.
Disposal of Flue Dust from a Large Generating Station
Authors:   Steam Plant Group, Nicholson G. , White E. G. 
Published: October 2007

The paper presents an example of the practical application of the principles of controlled long distance pumping of a mixture of flue dust and water, at comparatively high concentration and low velocity, based on recent research into the hydraulic transportation of solid materials. Precise hydraulic theory is not discussed as this has been dealt with in detail elsewhere. General details of the main features of the generating station, its location, the reasons for choosing hydraulic transportation, and the arrangements for ultimate storage of the flue dust are described. Brief details are given of design parameters, plant arrangement, test results, running costs and operating experience.
Mechanical Aids to Permanent Way Engineering
Authors:   Railway Engineering Group, Conran D. A. S. 
Published: October 2007

The paper describes equipment which is used to assist in the maintenance of the permanent way and deals particularly with changing methods and the effects of new designs of track components. Powered plant is employed on all sections of this work on British Railways. In depots and for day-to-day maintenance on the line small machines such as rail saws, nut runners, mechanical hoes, hedge trimmers and welding machines are used. The cleaning of ballast is done by special machines and pockets of deep clay are removed by excavators. Track is renewed in pre-assembled lengths by purpose-designed track-laying machines, and rails are welded into continuous lengths. The ballast is consolidated and levelled by powered tampers with levelling equipment and track-recording trolleys are used to pin-point any unevenness which would prevent smooth running. The limitations imposed on plant design are stressed, since equipment must be within the loading gauge—an onerous condition in Britain—and must cause as little interruption as possible to traffic. Consequently plant must travel rapidly and be quickly set up and disengaged. Plant must have a high speed of operation, and also be extremely reliable.
Comparative Experiments on Surge Tank Performance
Authors:   Hydraulic Plant and Machinery Group, Pearsall I. S. 
Published: October 2007

The dual function of a surge tank is to reduce water-hammer waves in power station piping systems and to act as a rate-of-flow equalizer, from which immediate water or storage requirements following turbine load changes can be met. Design requirements are based on predictions of surging in the tank. Experimental performance figures from model and full-scale tanks are compared with various theoretical methods. Experimental investigations include comparison between the simple, widened, conical, throttled, differential and twin-type tanks, showing their uses and respective advantages. The effects of modifications of design are also examined. Finally, experimental results are presented which show the variation of water-hammer pressures with the different types of tank and system arrangement.
An Experimental Impact-Extrusion Machine Driven by a Linear Induction Motor
Authors: Johnson W. , Laithwaite E. R. , Slater R. A. C. 
Published: October 2007

The linear induction motor as a planar development of the conventional rotary machine is described and the fundamental differences between it and the conventional machine are discussed. The effects of the discontinuities which occur in the linear machine, either in the stator as ‘short-stator’ effects or in the ‘translator’ as ‘short-translator’ effects, are discussed. The secondary member of the linear machine is referred to as a ‘translator’ in order to distinguish it from the rotor of the conventional rotary counterpart. The exploitation of the double-sided stator system is also briefly discussed. A linear induction motor has been constructed as an accelerator specifically for axi-symmetric impact extrusion. Some elements of design employed in the construction, together with a description of the model impact-extrusion machine, are given. The linear induction motor consists of a twin arrangement of double-sided stator systems, side by side, and in the same plane. The kinetic energy possessed by a mass accelerated in guides between the two stator systems is used for impact extrusion and the mass is propelled by the force exerted on a single-plate ‘dual translator’. The linear induction motor functions as a ‘short-translator’ machine. Experimental results presented show the nature of the accelerated motion of the mass, the force-slip characteristic, and how the overall energy efficiency of the linear induction motor is related to the root mean square phase voltage. Impact forward extrusions were performed for which \ in and 1 in diameter billets of pure lead and 1/2 in diameter billets of tellurium lead and super-pure aluminium were used. Some evidence is presented to show the limitations of impact extrusion.
High-Rate Forming: First Paper: Experiments on Clamped Circular Blanks Subject to an Underwater Explosive Charge
Authors: Johnson W. , Sowerby R. 
Published: October 2007

The results of experiments on the dynamic free stretch forming of peripherally clamped circular blanks of brass and mild steel subject to an underwater explosive charge are given for use in connection with studies on explosive metal forming. The results are presented in six parts. part 1: Some results for the effect of hydrostatic head above the charge on the polar deflection suffered by a blank are given and it is shown that for some otherwise fixed sets of parameters, at a depth of about 18 in below the free water surface the polar deflection is greatest. Illustrations of how strain distribution and the plastic work done on a blank vary with hydrostatic head are also given. In particular it is shown that the energy received from an explosive charge by a blank may greatly exceed the fraction expected by reference to the solid angle subtended by the blank at the point charge. With the aid of some blank speed measurements an attempt is made to relate the kinetic energy acquired by the blank to the plastic work done on them. part 2: The measured maximum speed of deformation over the central portion of blanks is shown to be less than 300 ft/sec (rupture excluded). For some circumstances that two phases of motion exist is incontrovertible, and the mechanism responsible for these, we believe, is as follows. In the first phase the speed is dependent upon stand-off distance and is a consequence of the primary shock wave and subsequent cavitation and diffraction effects that occur as a result of the shock wave impinging on the blank. The second phase (arising only with the larger stand-off distances) occurs some time later and may be accompanied by a greater deformation velocity; it is thought to be due to a water hammer or similar effect. part 3: An attempt is made to present generalized results for the maximum polar deflection incurred as a function of both charge weight and hydrostatic head. part 4: This shows how the density of a curtain of air-bubbles, measured by aerator pressure, inserted at the walls of the confining tank reduces the polar deflection or damage a blank may sustain. part 5: A short empty cardboard cylinder (sealed at each end with a layer of polythene) inserted between the blank and charge leads to increased polar deflection, other things remaining the same. part 6: Deals with gas-bubble pulsation and generally confirms the Willis formula, namely, that for charges not too near a free water surface or an underwater blank, the period of oscillation is proportional to (charge weight)1/3 and (the ambient pressure at the charge)−5/6.
Sixth Paper: Explosive Welding and Cladding: An Introductory Survey and Preliminary Results
Authors: Bahrain A. S. , Grassland B. 
Published: October 2007

This paper reviews the published literature on the explosive welding of metals and the related subject of pressure welding. The mechanism of explosive welding is closely associated with that of shaped charges with metal linings, so a brief résumé of the theory of such charges is given. It is also noted that fluid waves are sometimes generated at the weld interface in explosively welded joints, and the mechanism of their generation is discussed. Experiments are reported on the explosive cladding of mild steel with stainless steel, 70/30 brass, and high-conductivity copper. These have been aimed at establishing the effect of impact angle, weight of charge, and the thickness of the flyer plate on the form of the weld achieved. The mechanical strength of the welded joints has been investigated by shear, tension, and bend tests, and the variation of hardness across the weld interface has also been examined. Results of these various tests are presented and discussed. It is concluded that explosively cladded material has some advantages over conventionally pressure cladded material. In particular it is probable that the strength of the welded interface is much stronger. With large charges and small angles of impact it is possible for the parent plate to suffer from shock damage which can be clearly seen under a microscope, but it is not known if this is harmful to the mechanical properties. Hardness is increased each side of the interface but a reduced value is measured close to the interface.
A Generalized Analysis of Regenerative Feedheating Trains
Authors: Weir C. D. 
Published: October 2007

The basic feature of the paper is the development of the exact characteristic equation for a feedheating train composed of a number of cascaded heater groups in which each heater is taken to be of a rather general type. With the aid of this equation a systematic computational procedure may be devised which permits the variation of the train performance resulting from changes in the heater characteristics to be exactly and easily determined. A differential method, suitable for most practical analyses, and based on a series expansion of the characteristic equation, is also presented in some detail. The relation of the content of the paper to the ultimate objective of estimating variations in cycle heat rate resulting from changes in feedheating train performance is discussed in Appendix III. Appendix II contains an example of a complete feedheating calculation and compares the results of exact analyses of variations with those obtained by the differential method.
Transmission of Power by Sinusoidal Wave Motion through Hydraulic Oil in a Uniform Pipe
Authors: Foster K. , Parker G. A. 
Published: October 2007

An analysis is made of the viscous power losses in a liquid-filled pipe under oscillatory compressible flow conditions, particular attention being paid to Shell Tellus 27 oil in a 7/8 in diameter pipe, 80 ft long. Using an effective friction coefficient to take into account oscillating flow, the efficiency and the power-carrying capacity of the pipe are calculated for four discrete values of resistive output load. It is shown that if the load is not equal to the characteristic impedance of the pipe, then the efficiency is reduced and the power capacity depends upon the frequency of operation of the pipeline. A mismatched load should be resistive with the pipe preferably tuned to the quarter wavelength frequency supplied from a constant pressure generator. Relative power output increases under these conditions are achieved at the expense of efficiency and increased pipe pressure. Agreement between theory and experiment for the load conditions considered is good.
Further Experiments with Forged Nozzles in Pressure Vessels
Authors: Kitching R. , Olsen B. E. 
Published: October 2007

The investigation was a continuation of previous work involving the measurement of strains in the vicinity of forged rings of the type used to connect cylindrical ducts to large spherical shells. On two such rings of different shape strains were measured for the following loading conditions: internal hydraulic pressure in the vessel; axial loads applied to the nozzles; bending moments applied to the nozzles. Results for these two designs of ring, and two designs previously reported, have been compared. An approximate method of assessing elastic stresses (in such rings) due to the effect of axial loads and bending moments has been found reasonably reliable as a design method. A method previously found to give reliable predictions for the effect of internal pressure gave, for the two specimens considered here, lower estimates of maximum stress than the experimental maxima.
Low-Endurance Fatigue Strength of Thick-Walled Cylinders: Development of a Testing Machine and Preliminary Results
Authors: Austin B. A. , Crossland B. 
Published: October 2007

Owing to the nature of the stress system in a thick-walled cylinder it is possible to produce fatigue failures in such components after a relatively few repetitions of internal pressure, while still maintaining dimensional stability. This is particularly true for cylinders in which stress raisers are present, a situation of considerable practical importance. The present paper covers in some detail the design and development of apparatus capable of repeatedly applying to cylinders internal pressures of up to 40 tonf/in2. Results are presented for such tests on plain bored cylinders of two diameter ratios, 1.4 and 1.8, and on cylinders in which radial holes have been drilled, the latter having a diameter ratio of 2.25. The investigation has been confined to a 2 1/2 per cent nickel-chromium-molybdenum steel, with an ultimate tensile strength in the region of 58 tonf/in2; the results are intended to supplement the long life data obtained for this material by other investigators.
Characteristics of a Two-Stroke Opposed-Piston Compression-Ignition Engine Operating at High Boost
Authors: Wallace F. J. , Wright E. J. 
Published: October 2007

The paper describes an experimental investigation arising out of theoretical work by one of the authors (1)†, of the thermodynamic performance of a production opposed-piston compression-ignition engine under conditions of very high boost. By operating the engine with substantial internal cooling in the form of excess scavenge air, b.m.e.p.'s of the order of 230 lbf/in2-at a boost pressure ratio of 3/1 were achieved without imposing excessive thermal or mechanical loading on the engine, and at very high brake thermal efficiencies, exceeding 40 per cent in several instances. The primary independent operating variables were: boost pressure ratio, trapped air/fuel ratio, scavenge ratio, engine speed and simulated compressor efficiency. Very satisfactory agreement with predicted performance figures was obtained and, in addition, a promising correlation of aggregate heat transfer from the engine cylinders with the above operating variables has been devised. The investigation is to be regarded as preliminary to a differential compound engine project, based on theoretical performance predictions by one of the authors (2), in which the engine is merely part of a power unit comprising, in addition, compressors, turbines and differential gearing.
A Reassessment of Metering Orifices for Low Reynolds Numbers
Authors: Kastner L. J. , McVeigh J. C. 
Published: October 2007

In view of the importance of accurate measurement of flow rate at low Reynolds numbers, there have been numerous attempts to develop metering devices having constant discharge coefficients in the range of pipe Reynolds numbers between about 3000 and 200 and even below this latter value, and some of these attempts have achieved a reasonable degrees of success. Nevertheless, some confusion exists regarding the dimensions and range of utility of certain designs which have been recommended and further information is necessary in order that the situation may be clarified. The aims of the present investigation, which is believed to be wider in scope than any published in this field in recent years, were to review and correlate existing knowledge and to make an experimental study of the properties of various types of orifice in the low range of Reynolds numbers. Arising from this it was hoped that a design might be evolved which not only had a satisfactorily constant discharge coefficient throughout the range but was also simple to manufacture and reproduce, even for small orifice diameters of the order of 0.5 in or less, and it is believed that some success in attaining this aim was achieved. The first section of the paper contains a review of previous investigations classified into three main groups. In the second part of the paper, experiments with various types of orifice plate are described and it is shown that a properly proportioned single-bevelled orifice has as good a performance in the low Reynolds number range as that of any of the more complicated shapes.
Dynamics Analysis of a Nuclear Boiler
Authors: M'Pherson P. K. , Collins G. B. , Guppy C. B. , Sumner A. 
Published: October 2007

A dynamics analysis of a nuclear boiler based on a steam-generating, pressure-tube, heavy-water-moderated design is presented. In effect the plant is very similar to a La Mont recirculating cycle. A detailed mathematical model to represent plant dynamics (linearized, full power) is discussed with special reference to the boiling channel, steam drum, and recirculating loop. A simplified model is derived for analogue computer studies. Dynamic performance is discussed in terms of: (1) boiler only (no reactivity feedbacks): influence of pressure feedbacks, steam drum design, subcooling, recirculating delay; (2) complete plant (including reactor): as above but including influence of void coefficient. The two most important results are: (1) the strong dependence of plant behaviour/stability on the degrees of float allowed to pressure; (2) the possibility of designing an inherently stable and self-regulating plant with a small positive void coefficient. Finally, conclusions are drawn on the complete dynamic analysis under the heads: (1) optimal plant design; (2) control system design; (3) development of analytical/computing methods; (4) research into two-phase physics.
Flow Theory and Performance of Tangential Fans
Authors: Ilberg H. , Sadeh W. Z. 
Published: October 2007

The investigation reported here deals with the conditions of flow through a tangential fan. In order to gain a better understanding of the flow an experimental apparatus for testing the fan was designed. Detailed measurements of velocity and pressure through the impeller interior were carried out. The results indicate that a combined vortex is the main component of the flow, namely, a forced vortex, surrounded by a potential vortex (free vortex). The centre of the combined vortex lies inside the impeller and its location does not change with impeller speed. A suitable theoretical model of the flow was developed and acceptable correlation was found between it and the measured flow field. It was found that the flow regime through the impeller interior could be controlled and that the location of the combined vortex centre and its strength would be regulated by the shape and location of a diffuser baffle. A secondary flow perpendicular to the main flow, hitherto not mentioned, was found and an explanation of this phenomenon is offered. Test results show that the fan efficiency increases with increasing impeller speed in the test range. Previous available works on the subject are reviewed.
Metering of Steam-Water Two-Phase Flow by Sharp-Edged Orifices
Authors: James Russell 
Published: October 2007

This paper describes work conducted on the passage of steam-water mixtures through standard sharp-edged orifices for the prediction of flow conditions. When the stagnation enthalpy or alternatively the dryness fraction at the orifice is known, it is shown that the mass flow rate can be approximately determined. For the case where a steam-water mixture passes through a pipeline to the atmosphere or to a low-pressure receiver so that critical flow occurs at the outlet, both the mass flow rate and the stagnation enthalpy may be approximately evaluated using an orifice meter in series with a pressure tapping located at the point of critical flow. In this case, a trial-and-error method is necessary. The experimental results were within a range of dryness fractions from 1 per cent to 56 per cent, orifice pressures from 75 to 275 lb/in2 abs., differentials from 15 to 780 mmHg under water and flow rates from 54 700 to 508 000 lb/h. Orifices of 5.591 and 6.615 in diameter were installed in 7.9-in diameter pipes which were equipped with radius ( D and D/2) taps. The method employs a correlation between the homogeneous dryness fraction x, and a corrected dryness fraction x m necessary for evaluating the two-phase density used in the conventional single-phase meter equation.
Experience with Value Analysis as a Working Tool
Authors: Davies H. 
Published: October 2007

Value analysis programmes in connection with the large scale production of two packaged liquid rocket engines are described. At the time of writing, costs in the order of $6.73 million had been removed from the total contract price of $70 million. The fundamentals of the technique, organizational and motivational approaches and working examples are analysed and the implications reviewed. Value analysis is seen to exhibit no undesirable effects on fringe areas such as quality and reliability. It is concluded that a well structured value analysis programme is a most desirable management tool in carrying out the discipline of cost reduction.