bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of Centrifugal Spray Nozzles for Outputs Up to 1,800 Gallons Per Hour
Authors: Doble S. M. 
Published: October 2007

Work previously carried out on spray nozzle design† provided data from which spray nozzles of defined characteristics could be constructed having an output range of from 4 to 200 gal. per hour. This proved inadequate for several plant installations, so work has now been completed extending the range up to 1,800 gal. per hour with spray cone angles up to 150 deg. Section I deals with the design of the nozzle and the calibration results at various working pressures; section II gives the methods used for determining the volume distribution in the spray cone, the spray cone angle and the particle size distribution with some typical results; and in section III, nomograms relating the critical dimensions of the spray nozzle with output, pressure, and spray cone angle are given, with details of the use of these nomograms. As a result of the previous work and this present work, it is possible to give the exact dimensions necessary for a nozzle to deliver any quantity of water from 4 to 1,800 gal. per hour in the pressure range of 20 to 100 lb. per sq. in. Further, by the correct selection of the number, shape, and size of the channels in the distributing washers and the exit orifice diameter, a spray cone angle of any value up to 150 deg. can be obtained.
Journal Bearing Lubrication and Design
Authors: Thomson A. S. T. 
Published: October 2007

The paper summarizes the results of an experimental investigation on the effects of variation in bearing width and radial clearance on the operating conditions of centrally loaded clearance journal bearings, the bearing arc being kept constant at 120 deg. The investigation, which was carried out prior to 1940, is complementary to an earlier paper by the author in which the effects of variations in bearing width and arc of embrace were investigated. The experimental results are compared with theoretical values modified by the relevant leakage coefficients. The measure of agreement obtained indicates that theoretical values so modified may be used with confidence in design. A short series of experiments is described; in these, high-point contact at starting and stopping is eliminated by supplying oil to a groove in the loaded side of the bearing at a pressure sufficiently great to overcome the applied load. The effect of a groove on the loaded side of the brass under various conditions of lubrication is investigated.
Modern Cutting Tools and Machine Tool Design
Authors: Eatough C. 
Published: October 2007

The object of tool research is to reduce the cost of production. The paper describes how the cost of production is determined to a great extent by the rate of feed; and high cutting speeds have been developed in order to give high rates of feed. The changes in machine design which have been brought about by the introduction of carbide tools are discussed, and also the limitations of the tools are mentioned. One of the limitations is the necessity for cutting at high speeds, and this has brought to light many machine design problems in view of the necessity of providing not only for high speeds but for wide speed ranges, as carbide tools cannot be used at present for low-speed tools such as threading dies. Tool life is largely determined by cratering and the rate of crater growth is dealt with at varying speeds and feeds. Reasons are given for the effectiveness of the grooved type of turning tool which encourages the formation of corkscrew type chips.
Researches into the Deformation of Metals by Cold Rolling
Authors: Ford Hugh 
Published: October 2007

A large number of experiments have been carried out on an experimental cold rolling mill installed at Sheffield University by the Steel Industry, and this paper summarizes the results obtained. The experimental technique is described, and details are given of the mechanical tests made on the strip materials used. In connexion with various theories of rolling, the yield stress characteristic of the strip is required. Two methods of determining the yield stress—one depending on a tensile test, the other on a compression test—are put forward. The principal theories of rolling are examined in relation to the experimental results. Using the theory of Orowan as criterion, it is found that the theories of von-Karman and Ekelund yield satisfactory accuracy for practical calculation of the roll force over the normal range of cold rolling conditions. These theories do not allow the torque to be directly calculated, but it is shown that the “lever arm” method can be modified to allow for roll flattening, and can then be used, in combination with the simple methods for roll force, to determine the torque. It was considered that a method of calculation was required, simpler than Orowan's exact method, yet applicable when rolling with strip tension. A new theory was evolved which fulfils these requirements, and is examined in relation to the experimental results. The method allows of further simplification, so that calculation is reduced to a minimum, most of the information being obtained from graphs, with very little loss of accuracy. It is shown that there is an approximate relationship between the roll force and the corresponding energy of deformation. This relationship is used in the “energy method” for rapid calculation of rolling schedules.
The Part-Load Performance of Various Gas-Turbine Engine Schemes
Authors: Mallinson D. H. , Lewis W. G. E. 
Published: October 2007

The literature on the gas turbine already contains much information concerning the performance of the “constant-pressure” cycle both in its simple form and in its more complicated forms involving intercooled compression, reheated expansion, and heat exchange. Such information enables the design performance of a particular engine to be estimated, but there appears to be very little published work to help the designer to foretell what changes in performance are to be expected when particular engines operate at non-design conditions. What work there is seems to have been restricted to very simple engines, and is often further limited by the assumption of unalterable component performance characteristics. In this lecture we attempt to include in a general comparison of part-load performance characteristics not only the simpler designs but also some of the more complex turbine engines which will be needed for land and marine applications. At the same time, by considering, in appropriate cases, the influence of changes in the assumed component performance features on the part-load operation of an engine, a broadening of the basis of comparison is made possible. As a result of the work we shall describe we feel that, although as yet so little of the possible field of investigation has been surveyed, it is nevertheless possible to indicate the main guiding principles by which the comparative part-load performance of different gas turbine schemes may be assessed.
The Development of Variable Specific Heat Charts and Graphs, and their Application to Internal Combustion Motor Problems
Authors: Walker W. J. , Rogers C. 
Published: October 2007

The paper describes the development of a method of investigation, both analytical and graphical, into problems relating to internal combustion motor design and performance. The authors have provided a chart, together with auxiliary graphs, by means of which theoretical indicator diagrams may be constructed for any internal combustion engine cycle under conditions of variable specific heat. It may also be used for studying any indicator diagram obtained under test conditions. The main feature of the chart is the provision of means to enable it to be used for any hypothetical or initial conditions encountered in practice. It has been so generalized as to enable it to be used, not only for the examination and construction of indicator diagrams involving expansion down to atmospheric pressure or to the initial compression volume, but to any degree. The auxiliary graphs provide a means whereby the thermal efficiency, mean effective pressure, and other essential quantities may more easily and readily be calculated than has previously been possible. To illustrate the method of using the charts and graphs, examples have been worked out for the dual combustion cycle, the Diesel cycle and the constant volume cycle.
The Design and Operation of the Parsons Experimental Gas Turbine
Authors: Bowden A. T. , Jefferson J. L. 
Published: October 2007

The paper describes the principal design features of the Parsons 500 h.p. experimental industrial gas turbine, and records the operating results obtained in running the plant since December 1945. A section is devoted to some of the preliminary investigations on the compressor, combustion, and heat exchanger components, undertaken prior to the building of the unit. Some of the early work on the axial-flow compressor is, it is considered, of particular interest. One of the most important questions remaining to be answered in gas-turbine operation, is the quality of the oil fuel which can be regularly and reliably burned. Details are included in the paper of operating results using a residual oil fuel. Considerable trouble was experienced as a result of the building up of deposits in the turbine blading; these deposits are analysed and compared with the parent oil-fuel analysis, and photographs of spindle and cylinder blading show the nature of the build-up.
Further Researches in Fluid Flow through Beds of Granular Material
Authors: Rose H. E. , Rizk A. M. A. 
Published: October 2007

In this paper the results of previous researches are extended and equations developed by means of which the resistance to fluid flow offered by a bed of spherical or non-spherical material may be computed with reasonable accuracy. The equations cover a range of porosity of the bed from 30 per cent to 90 per cent and practically the whole of the technically important range of Reynolds number, while particle shapes ranging from spheres to hollow cylinders, shell insulators and wire nails are covered. A new curve for wall-effect, depending upon Reynolds number, is also included. It is believed that the present work is of more general application than any which has previously been suggested.
The Dynamic Principles of Machine Foundations and Ground
Authors: Crockett J. H. A. , Hammond R. E. R. 
Published: October 2007

Recent research on soil dynamics and machine foundations has revealed that there are correct design principles for vibrating foundations which can be used without dependence on empirical methods. The most important discovery has been that any ground can oscillate at its own particular natural frequency, and machines and ground quite often vibrate in resonance. Stress waves, some with similar properties to light and sound waves, are of considerable and often of paramount importance, for their interaction can lead to structural failure. The authors have considered only steadily running machines and have merely indicated the mathematics, the designer being advised to consult the proper engineering text-books for a fuller account. They hope that the problem has not been over-simplified and that their conclusions may form a sound basis for future design practice.
Preliminary Report of Developments in Interrupted Surface Finishes
Authors: Martz L. S. 
Published: October 2007

Expanding interest and investigation in the development of interrupted surface finishes indicates the current trend renascent as the result of experience during the 1939–45 war with various types of mechanical equipment. It is here attempted only to highlight the results of service use and laboratory tests in three generic types: mechanically, chemically, and electrolytically generated surface finishes and their combinations. Because of the innumerable variables involved by the wide range of functional use, only the most general conclusions are drawn to prompt further study and investigation of this promising development, and to emphasize the desirability of avoiding controversial interpretations and attempted correlations until more data are available.
The Ideal Performance of Petrol Engines
Authors: Leah A. S. 
Published: October 2007

A method of calculating the ideal thermal efficiencies of petrol engines is described which may be of value when thermodynamic charts for the particular fuels and mixture strengths under consideration are not available. Results of such calculations are given for engines running on octane, benzene, and ethyl-alcohol at compression ratios between 4/1 and 9/1 and at various mixture strengths. From the relationships between thermal efficiency, specific fuel consumption, volumetric efficiency, mixture strength, and indicated mean effective pressure, new charts based upon the familiar “consumption loop” diagram are developed. These charts yield information not generally obtained from the consumption loop diagrams, and the volumetric efficiency of the engine may be determined. The ideal consumption loops based upon a standard volumetric efficiency are included on the charts, and these values are readily corrected to the actual engine conditions by a simple construction. This enables a direct comparison between actual and ideal engine performance to be made, from which the relative merits of engines running under widely diverse conditions can be determined.
A Generalized Analysis of the Regenerative Steam Cycle for a Finite Number of Heaters
Authors: Haywood R. W. 
Published: October 2007

The paper establishes a theoretical basis for approximate relationships which have been found to apply to feed heating calculations for a wide range of operating conditions. The designer, looking for short-cut methods in the calculation of multistage feed heating problems, will not find sufficient accuracy in the approximations to satisfy his more precise requirements. Other papers† have already catered for such requirements, but it is hoped that the present paper will give the designer and student a more complete understanding of the problem. The determination of the optimum range of feed heating, and the improvement in heat consumption due to feed heating at the optimum condition, for a system employing n feed water heaters is investigated in the paper. A simple approximate relation is derived for these two quantities by expressing them non-dimensionally in terms of the respective quantities for a system employing an infinite number of heaters. The optimum distribution of heating amongst the heaters in the system is also determined analytically.
Application of the Method of Characteristics to the Transient Flow of Gases
Authors: Kestin J. , Glass J. S. 
Published: October 2007

Although problems relating to non-uniform flow of a compressible fluid have been tackled by a number of workers, investigations have generally been limited to the study of one-dimensional non-viscous adiabatic flow. This type of flow, however, is associated with so many problems encountered by mechanical engineers that an easy and reliable method of solution is extremely important. The method of characteristics described in this paper provides a comparatively simple method of solving such problems by a graphical process. It consists essentially in the simultaneous construction of two corresponding diagrams:— (a) The state diagram showing the changes in the state of the fluid produced by spreading disturbances. (b) The position diagram depicting the spreading of the disturbances. The graphical construction of these diagrams is based upon certain special mathematical properties of the equations which describe the motion and enable boundary conditions corresponding to any particular problem to be readily taken into account. Applications include the phenomena occurring in internal combustion engine exhaust and intake pipes, in particular, those relating to the Kadenacy system of scavenging. It is also applicable to the type of flow encountered during the emptying of cylinders, in pulsating ram jet engines and, in general, in any engine making use of the intermittent flow of gases. The phenomena occurring in long indicator passages during tests on high-speed engines also come within its scope.
Gas Cooling and Humidification: Design of Packed Towers from Small-Scale Tests
Authors: Carey W. F. , Williamson G. J. 
Published: October 2007

On plants in which gases are processed, the gases are often brought into direct contact with water—usually in packed towers. The purpose may be to cool a hot gas, to increase the humidity of a gas, or, in the well-known special case of water-cooling towers, to cool water by contact with atmospheric air. These processes involve simultaneous transfers of sensible heat and water vapour, and existing methods of analysis are complex and laborious, except for the cooling of water, for which Merkel's total-heat method has long been available. Merkel's approximate solution offers the engineer a simple method of working out, for any operating conditions, the amount of heat transferred and the “driving force” available for transferring it. The present paper generalizes the total-heat method and, with a permissible sacrifice in accuracy, preserves the essential simplicity of the water-cooling treatment for gas-cooling and humidification processes. To complete the design of a packed tower, a knowledge is required of the characteristics of the packing. Information obtained in small towers is given for a number of packings, and a worked example shows how to apply the method of treatment, and the packing data presented, to the design of a large plant tower.
The Effect of Macro-Roughness on the Performance of Parallel Thrust Bearings
Authors: Salama M. E. 
Published: October 2007

This work was initiated to investigate the effect of surface macro-roughness on the performance of the parallel-faces thrust bearing and, at the same time, to find a rational explanation of its behaviour. The problem is treated both theoretically and experimentally and the main result arrived at indicates that macro-roughness is a prime factor in the behaviour of the bearing, as it provides passages which both feed the surfaces with the lubricant and allow the formation of hydrodynamic films so that the performance corresponds closer to that for film lubrication. Further work on micro-roughness is proceeding.
The Gas Turbine in Perspective
Authors: Constant Hayne 
Published: October 2007

A survey is made of the progress that has been achieved in Britain over the last decade in improving the performance of gas-turbine components. The effect of these improvements on the performance of jet-propulsion engines is then shown. An attempt is also made to foresee the probable future trend of progress and to assess the nature of the important problems which have still to be overcome before the gas turbine can be more generally applied.
Some Fluid Dynamic Research Techniques
Authors: Carter A. D. S. , Andrews S. J. , Shaw H. 
Published: October 2007

One of the main features characterizing gas-turbine technology has been the aerodynamic approach adopted towards such items as the axial compressor and turbine, the ducting components, and so forth. This has necessitated a lot of research into many basic fluid dynamic problems which had hitherto received little or no attention. Equipment has had to be constructed and special techniques developed or adapted to meet the new requirements. This lecture gives an account of such work, with particular reference to the methods adopted at the National Gas Turbine Establishment (N.G.T.E.). In the first part of the lecture the simple cascade tunnel has been described. Its design involves many features encountered in work of this nature, and touches on many basic principles. Following this, some special forms of cascade tunnel are described. For example, heat-transfer tunnels, an icing tunnel, and annular tunnels are considered as departures from the conventional. Following a few notes on ducting research, the final section deals with general instrumentation techniques. The measurement of air pressures and direction is considered, together with the measurement of gas and wall or blade-surface temperatures. Some mention is made of boundary layer investigation and high-speed flow visualization. An apparatus for determining the potential flow past blades is also described. All these have been selected as examples representing techniques which have contributed in some way to our knowledge, and hence to the development of the gas turbine.
Analytical Investigation of Certain Types of Machine Frames Cut from Steel Plate, and Experimental Verification of Some of the Results by Photo-elasticity
Authors: Sag N. 
Published: October 2007

Closed machine frames consisting of constant-section uprights and variable-section top and bottom bridges, as illustrated in Fig. 24 and loaded as indicated., are often fabricated from steel plate. They are used in the construction of punch and press frames and are subjected to dynamic loading. The design of such frames involves the solution of a statically indeterminate problem. The expression for the indeterminate moment involves the numerical solution by tables† of improper integrals such as The object of this paper is to find dimensionless solutions of such frames and investigate the influence of the x = hmax/ h0 ratio on the static and energy load capacity of these frames. Some results of the theoretical investigations are verified by photo-elastic analysis.
Naval Gearing—War Experience and Present Development
Authors: Joughin J. H. 
Published: October 2007

While the reduction gearing fitted in turbine-driven naval ships generally gave reliable service in the 1939–45 war, there were some costly exceptions. Turbine blade failures resulting from vibration, “scuffing” on trials (fortunately cured by hand dressing), and breaking of teeth at the roots, causing extensive damage requiring replacement of the gear-set, were experienced. Examination of these failures revealed shortcomings in manufacture and design, which have now been largely remedied, and it has been possible to establish standards of manufacture necessary to ensure reliability, and to make economic use of available techniques and materials. The use of harder steels hobbed and shaved in a heat-treated condition, or steels, case-hardened and then ground, or, in the very large sizes, air-hardened and ground, now presents no technical obstacle. Gears of alternative designs—hobbed and shaved, or case-hardened and ground—are being made for service at sea. They will be subjected to the same load conditions. Other gears of identical design will be subjected to “back-to-back” tests on shore to investigate their further possibilities. The modifications to pinion helices to compensate for deflexion under load and to safeguard against misalignment, the methods by which they are being applied to these test gears, and the opportunity they provide for making effective use of the full length of pinions, are all examined.