bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study of Water Flow in Full-Size Test Rig for Water-Cooled Turbo-Generator Rotor
Authors: Csillag I. K. 
Published: October 2007

The demand for electric power has doubled in the last decade. The most economical way to meet this demand is by building large-output generating units. The study of the major factors which determine the output of such generators shows that the only effective way to increase the output is by improving the cooling of their windings. For that reason design has progressed from air-cooling to indirect hydrogen-cooling, then to direct hydrogen-cooling. Now the trend is towards direct water-cooling where the water is in direct contact with the copper windings. The introduction of water into the stator winding was established in 1956 (1)† and was in fact directly responsible for the present increase in unit rating. The introduction of water to a rotating winding presents difficult problems in both design and manufacture. The test rig dealt with in this paper was built to study some of these problems and to carry out experimental investigations on a full size model of the special hydraulic features for a water-cooled turbo-generator rotor. The investigations were concentrated around the following five different problems which are dealt with in detail: (1) increase in pressure drop due to rotation; (2) free-rotating seal (inlet seal) (2); (3) vacuum-breaking device (water outlet) (3); (4) loss-distribution in the rotor; (5) measurement of the rotor vibrations in various operating conditions.
Second Paper: Cooling Equipment for Internal Combustion Engines
Authors: Montgomerie G. A. , Forbes M. K. 
Published: October 2007

The several positions in engine fluid systems in which cooling equipment is commonly used are examined and the fluid pressures and temperatures to which the heat exchangers are subjected outlined. General considerations affecting the designs from the points of view of performance (heat transfer and power loss) and environment (chemical and mechanical) are examined and amongst other points it is shown that the best ratio of cooling surfaces in a secondary surface heat exchanger is If ρ = 1 this reduces to r = √ R which is very different from the usual recommendation that r and R should be equal. The second part of the paper is descriptive, and deals with the mechanical design of heat exchangers used for cooling engines in various applications: marine engines; stationary engines; locomotive and railcar engines; agricultural machinery; road vehicles; and aircraft.
Investigation of the Discharge-Voltage Method of Measuring the Thickness of Oil Films Formed in a Disc Machine under Conditions of Elastohydrodynamic Lubrication
Authors: Dyson A. 
Published: October 2007

It is reported in the literature that the ‘discharge-voltage’ method offers a simple means of measuring the thickness of oil films between moving metal surfaces. To confirm this report it is necessary to compare discharge-voltage measurements with film thickness measured by an alternative method. So far as the author is aware no such comparison of measured film thicknesses in elastohydrodynamic lubrication conditions has been published. Under these conditions, a suitable alternative way of estimating the thicknesses of oil films between moving metal surfaces is to measure the electrical capacity between them. This method has been applied to a disc machine and a short programme of work undertaken to compare film thickness estimated in this way with the results of discharge-voltage determinations. It was found that there was some relation between discharge voltage and film thickness but that, in general, this relation was non-linear and depended on the slide/roll ratio and on the temperature. It is therefore concluded that the discharge voltage does not measure the thickness of oil films in the simple way suggested; there were some indications that it may be possible to use it to measure relatively thick films, of the order of 40 μin (1 μm) or thicker, at high slide/roll ratios.
Influence of Rotor Metal on Bearing Failures Generally Classified as the Machining Type
Authors: Karpe S. A. 
Published: October 2007

An unusual and often severe type of journal and thrust bearing failure has been encountered in both marine and land-based turbine installations. These failures have occurred with steel rotors running against high-tin babbitt metal. From the outward appearance of damage, these failures have been called ‘machining’ or ‘wire-wool’ failures. The potential magnitude and known consequences of this type of failure on large machinery units has led to the undertaking of an extensive research programme. The objective of the programme is to determine the causes, mechanisms, and means of eliminating or reducing the risk of such failures. This paper discusses the results obtained from a bench-scale apparatus, run under defined conditions, in which service-type failures can be reproduced. Main emphasis in this paper is on the influence of steel rotor metals on failure susceptibility. Also treated is the influence on failure susceptibility of chlorine-containing, load-carrying additives in the oil environment. The failure mechanism strongly implies that rotor steels can be developed which are less susceptible to this type of failure.
Investigation of Diesel Engine and Turbocharger Interaction
Authors: Kellett E. , Betteridge J. F. , Mistovski M. 
Published: October 2007

The authors are concerned with the proper provisioning of turbochargers and fuel-injection equipment for diesel engines, particularly in the automotive class. Medium-speed engines are run at high mean effective pressures and there is a tendency towards similar outputs in automotive engines. Because of transmission demands these outputs will be required over a wide speed range and the relation of engine air and fuel requirements is examined. The simple turbocharger is not ideally suited to wide range matching and the extent of the compromise inherent in fixed geometry compressors and turbines is discussed. In order to survey engine, turbocharger, and fuel-system interactions tests are reported where turbocharger limitations are avoided by the use of two units in series. Engine operating limits were selected on the basis of safe engine factors and the output assessed with respect to the principal variables of turbocharger pressure ratio and engine compression ratio. The resulting compromise between high cylinder pressures and smoke control tended towards a traction-type torque curve with a higher-than-conventional fall-off in torque with speed. A suggestion was verified that smoke occurred at higher air/fuel ratios as the charge density increased. Nevertheless accepted methods of heat-release prediction from rate of injection characteristics were not affected by variation in charge density.
Ejector Compression of Natural Gas for Small Turbines
Authors: Walker G. 
Published: October 2007

Natural-gas-fuelled total-energy systems for supplying the utility demands of residential and commercial buildings typically require 500 s.h.p. for the machinery drives. Although gas turbines are competitive prime movers in this size range, difficulties arise from the need to compress the natural gas fuel to the pressure of the turbine combustion chamber. In this study the use of non-condensing single-and two-stage steam-jet ejectors was analysed for gas compression to a pressure of 150 lb/in2. Steam-supply conditions from 5000 to 1000 lb/in2 and 800 to 1200°F were considered; methane was supplied at 15 lb/in2 and 60°F. The specific steam consumption (lb steam per lb gas) of a two-stage ejector was found to be much better than that of a single-stage ejector. The minimum specific steam consumption (6 lb steam per lb gas) occurred at the extreme steam conditions considered in the study. The steam-methane mixture this produced was not flammable when mixed in any proportion with air. Of several methods considered to reduce the steam content of the mixture delivered by the ejector, only one, post-ejector cooling and condensate removal, was suitable for analysis. Cooling-water flow rates in excess of 14 lb water per lb gas were necessary to produce potentially flammable mixtures. Estimates were made of the major effects on turbine engine performance arising from the use of a steam ejector for gas compression. A comparison was drawn for two idealized cycles and for two others in which realistic values of component efficiencies were included. In each series the gas was compressed by conventional means in one cycle and by means of a steam-jet ejector in the other. The steam injected with the methane in the turbine combustion chamber caused an appreciable decrease in the cycle temperatures and significant improvement in both the turbine output and thermal efficiency. When the additional heat input necessary to generate the steam for the ejector was included, the overall thermal efficiency of the steam-ejector cycle was less than that of the conventional cycle.
First Paper: A General Approach to Hydraulic Lock
Authors: Dransfield P. , Bruce D. M. , Wadsworth M. 
Published: October 2007

The present state of knowledge on the hydraulic lock phenomena of oil hydraulic control system components is reviewed briefly. A general one-dimensional solution of the Reynolds equation which governs hydraulic lock is presented. The solution embraces the particular solutions of past workers, and allows ready solution for piston-cylinder configurations for which a one-dimensional solution is adequate. A general method for making full solutions of the Reynolds equation is presented, requiring the use of a digital computer for particular solutions. Pressure distribution, the lateral force on the piston which produces hydraulic lock, and the location of the lateral force can be obtained. The commonly occurring case of a single-land piston lying tilted in its bore is examined in detail. The limit of accuracy of a one-dimensional solution is clearly shown by illustrating the discrepancies between the one-dimensional and two-dimensional solutions for several configurations.
The Pattern of Batch Manufacture and Its Influence on Machine Tool Design
Authors: Williamson D. T. N. 
Published: October 2007

The majority of today's machine tools were developed in the first half of the 19th century. They have been improved; but not radically altered. For 150 years batch manufacture of engineering components has been carried out in factories using these machine tools as originally intended. Big factories have had more machine tools and more people but always the same basic organization, or lack of it. Because the organization has not changed, increased size has destroyed communication, and is destroying skill. A different type of organization could use the same men and equipment with great benefits if it were oriented towards the current problems. Numerical control is capable of revolutionizing batch manufacture but it has not done so, because these new machine tools have been incorporated into the old organizational structure. By lifting numerical control out of its present context and designing round it a completely new organization, order-of-magnitude improvements are possible. The first attempt to do this, and its performance, are described, together with a glimpse into the future showing the even greater improvements which will be possible when manufacture is integrated with design.
The Engineer in Society
Authors: Vickers Antony 
Published: October 2007

The paper is in three parts. The first concerns the social and economic implications of technological progress with particular reference to electric power generation, the iron and steel industry and transportation. The second part relates to the fundamental principles of money as a means of payment and a measure of value; also explains the controlling factors which regulate the purchasing power of money. In the third part the author suggests what might be achieved if, by more modern economic policies, redundant resources were to be transformed into national assets and increased gross national product.
Medium Speed Diesel Engine Noise
Authors: Bertodo R. , Worsfold J. H. 
Published: October 2007

The paper briefly reviews past work on diesel engine noise with particular reference to medium speed engines. A survey carried out on a large number of British and European turbocharged and water-cooled dieseis having bores in the range 2 3/4 in to 33 in (∼ 70 mm to 840 mm) clearly indicated at least two main sources. A qualitative analysis of the problem suggested these to be due to combustion and piston transverse motion in the liner clearance space. None of the engines examined had an International Standards Organization rating lower than Noise Rating 85. A comparison of theoretical trends with those obtained from the survey proved encouraging and application of the analytical findings to five specific engines having bores of 5 in, 8 in, 10 1/4 in, 12 1/2 in and 14 1/4 in (∼ 127 mm, 200 mm, 260 mm, 320 mm and 360 mm) yielded reasonable estimates of the overall noise, but poor approximations to the relevant frequency spectra. Much more work on the effects of crankcase attenuation would appear in order. It is concluded that the wider acceptance of medium speed dieseis will not lead to increased noise problems provided appropriate action is taken at the design stage. Broad design recommendations are presented and the causes of variations of noise with time and of engine to engine scatter discussed. The marked improvements obtained on a 14 1/4 in (∼ 360 mm) bore engine are shown.
Pressure Fluctuations Due to Interaction between Blade Rows in Axial Flow Compressors
Authors: Parker R. 
Published: October 2007

The paper presents the results of a theoretical and experimental investigation into the potential flow interaction effects between blade rows in an axial flow compressor stage. The investigation is concentrated on the inlet guide vane/rotor interaction and shows that the passing of the rotor blades behind the guide vanes produces large pressure fluctuations on the surfaces of the guide vanes. The available method of computation is not yet adequate for prediction of absolute values of pressure amplitude but does provide a sound basis for comparison between alternative designs.
Development of Spanwise Velocity Profiles through Cascades and Axial-Flow Turbomachines
Authors: Swainston M. J. C. 
Published: October 2007

The development of the spanwise velocity profile in the incompressible viscous flow through cascades is approached from a new point of view. This approach shows the way in which the cascade loading, the secondary losses, and the inlet-flow conditions interact to produce the downstream profile. The analysis leads to the establishment of a family relationship for experimentally occurring profiles. An empirical velocity-profile shape is determined which has the same properties as the experimental family, and this is used to demonstrate the way in which the mean secondary losses are distributed over the blade height. The profile development is studied in multi-stage machinery, and the formation of an equilibrium state after some few stages is shown. Work-done and blockage factors are computed for 50 per cent reaction compressor stages.
Experimental and Analytical Studies of the Compression Ignition of Fuel-Oxidant Mixtures
Authors: Karim G. A. , Watson H. C. 
Published: October 2007

The paper describes an approach for predicting the time variation of the state of a non-adiabatic reacting charge undergoing a change in density, such as that in a motored autoigniting engine or the ‘end gas’ of a spark ignition engine. To describe accurately the rates of chemical reactions involved and to account for the production of intermediate combustion products and their survival, detailed chemical kinetics involving chain reactions are employed. To test the approach developed, hydrogen gas is employed as a fuel in the closely controlled environment of a specially developed compression apparatus which is closely akin to that of the piston engine, yet more amenable to control and analysis. Subject to the availability of reliable detailed kinetic data for the reactions involved very good agreement between theory and experiment can be achieved. The future implications and utilization of such an approach is discussed.
An Analysis of Impeller and Volute Losses in Centrifugal Fans
Authors: Myles D. J. 
Published: October 2007

The measured losses from tests on five centrifugal fan impellers of different blade angle, running at constant speed in a given volute, are analysed. Impeller and volute losses, expressed as a fraction of the dynamic exit pressure relative to impeller and volute respectively, are correlated with a diffusion factor over a wide volume flow range. The results are applied to other impellers and volutes. The low volume flow range of operation is also considered.
Isotopes in Radiotherapy: Medical and Engineering Considerations
Authors: Shapiro J. S. , O'Connor A. D. 
Published: October 2007

In Part 1 by Mr J. Shapiro, the merits of the chosen combined shielding design are explained. The geometry of the radiation head is given including the source movement mechanism. The problem, basic principle and engineering embodiment of the radiation beam definition and control mechanism are discussed. The fundamental approach and engineering solutions of the radiation head alignment system are described. The remote control of the unit and the treatment sequence are briefly reviewed. In Part 2 by Dr A. D. O'Connor, the radioactive isotopes suitable for use in large treatment units in radiotherapy are reviewed with special reference to cobalt 60. In comparison with X-ray generators of such quality, such units are more reliable. The features of design of a unit desirable for isotope teletherapy are set out. The methods of treatment planning and execution are described and the advantages obtained from the Servotec Canterbury unit enumerated.
Identification of Mechanical Sources of Noise in a Diesel Engine: Sound Originating from Piston Slap
Authors: Fielding B. J. , Skorecki J. 
Published: October 2007

The sound produced by the piston slap of a diesel engine is investigated by standard methods of sound and vibration analysis augmented by correlation of incidence of individual transient components. This latter technique makes use of information obtained from the tuned outputs of the noise signal, focusing attention on the incidence of single-frequency transients. The contribution of piston slap to the overall noise emitted by an engine is studied analytically by examining equations for the transverse motion of the piston and experimentally by varying engine parameters such as piston-cylinder clearance, gudgeon-pin offset, and piston lubrication. By considering the various distinct characteristics, an insight is gained into the mechanism of noise generation and radiation.
Determination of the Dynamic Characteristics of Machine Tool Structures
Authors: Chowdhury I. , Sadek M. M. , Tobias S. A. 
Published: October 2007

The ‘operative harmonic response locus’ of a machine tool structure, which is required for the prediction of machining stability, must be determined by vibration tests carried out under conditions which simulate closely those arising during cutting. This requires that such tests be performed while the tool or the workpiece spindle is rotating, the vibrations being excited by a small harmonic force superimposed on a large constant pre-load. It is not possible to satisfy these conditions with vibrators working on electro-dynamic or electro-hydraulic principles and so an electro-magnetic vibrator was designed and developed to meet the above requirements (2). This excitor can be used with all types of machine tools, but in the present investigation its application is restricted to lathe and horizontal milling machines. The effects of the rotational speed of the lathe spindle and milling machine spindle, of the exciting force amplitude and of the pre-load magnitude and direction on the response data, are investigated. It is found that the lathe structure behaves in a linear fashion whereas the behaviour of the milling machine is non-linear.
Hydraulic Lock Forces on Tapered Pistons
Authors: Hessey M. F. , Martin B. P. , Brighton D. K. 
Published: October 2007

When a piston subject to an axial pressure drop has to be moved periodically along a bore sticking often occurs owing to hydraulic locking between the piston and the bore. The locking is caused by the hydrostatic pressures acting along the annulus between the two surfaces. The hydraulic instability may be reduced by using a piston tapered to give a converging film shape in the direction of flow, and this paper considers a large number of tapered configurations. The hydraulic pressures are calculated by a solution of Reynolds' two-dimensional equation using a digital computer, and the resultant force and its line of action are obtained. From these results empirical equations for the locking force and its line of action are derived which are valid for a wide range of conditions. The values predicted by the equations agree well with experimental and theoretical results given in the literature.
A Comparison of the Performance of Three Model Axial Flow Turbines Tested under Both Steady and Pulse Flow Conditions
Authors: Daneshyar H. , Edwards K. J. , Horlock J. H. , Janota M. S. , Pearson R. D. , Shaw R. 
Published: October 2007

Three turbines, covering a range of reaction of +20 per cent to − 10 per cent at their blade roots, have been tested under both steady and ‘pulse flow’ conditions in order to assess their degree of suitability for turbo-charger application. The results have been analysed in a way which enables efficiencies to be plotted against a mean non-dimensional blade speed irrespective of the level of pulsation. This method of presentation enables the results to be used directly for design purposes and in matching calculations. Thus the efficiency penalty due to pulse flow, the effect of pulse flow on the choice of turbine size, and the preferred degree of reaction under pulse flow may be assessed. For the present tests the range of variation in gas speed under pulsing conditions is thought to compare in severity with that produced when a single turbocharger is connected to three cylinders of a large two-stroke marine engine. For this case the design having the highest degree of reaction is shown to give an efficiency four percentage points higher than either of the other designs. It also has a clear advantage under steady flow. The intermediate design, having zero root reaction, corresponds to the type of turbine conventionally used in turbo-chargers and is shown to be the one most sensitive to losses in efficiency resulting from pulsation. It appears therefore that substantial improvements could be made in turbines for future turbocharger designs by increasing the reaction. Further testing of these turbines under modified pulse conditions, with significant windage period, is advocated. The advantage of the high reaction design must be demonstrated for such conditions before a change of design reaction could be regarded as fully justifiable.
The Development of Inventions
Authors: Coombs T. A. 
Published: October 2007

The lecture describes some of the problems of putting inventions into practical use, drawing largely on the author's experience in the National Research Development Corporation. The functions of NRDC in exploiting inventions and in supporting their development are described. Various sources of inventions—private individuals, public research, and industrial companies—are discussed with particular considerations which arise in each case. Methods of assessing research and development projects are described and the importance to be attached to the technical, management, and selling aspects is examined. The lecture is illustrated by some of the unexpected incidents which can occur. Although the author is unable to make startling confidential revelations he takes examples from successful and unsuccessful NRDC projects. He attempts to draw some conclusions which may be of general interest to those associated with the many interesting aspects of innovation.