bluuebunny/crossref_metadata_2025_split huggingface dataset:
Report 4: A Comparison of Some Instrumentation Methods for Hydrodynamic Bearings
Authors: Ettles C. M. M. 
Published: June 2010

The type of data required to check the operation of hydrodynamic bearings is discussed together with some of the more common instrumentation methods. Attention is drawn to the following methods of film thickness measurement: measurement of the operation of whole bearing parts; the capacitance and inductance methods, their characteristics, advantages and disadvantages; optical methods. The measurement of local film pressure is discussed as also is individual pressure tapping, the installation of thermocouples, and the requirements for zero conduction error. The advantages of mounting instrumentation in the moving surface are given together with some design points for this type of dynamic transducer.
Report 8: Determination of Coefficients of Friction during Compressive Deformation
Authors: Male A. T. 
Published: June 2010

A technique is described for determining coefficients of friction in a simple forging operation involving the deformation of a flat ring-shaped specimen between flat dies. This technique involves only the measurement of the change in shape of the ring upon compression and does not require a knowledge of the mechanical properties of the metal under the conditions of testing. It is therefore applicable over a wide range of testing conditions with respect to temperature, amount and rate of deformation, lubrication, etc. This technique has been used to study the limiting conditions of several lubricants for hot and cold working. The possible application of frictional data obtained by this technique to mechanical working operations is discussed.
Report 16: Photoelastic Analysis of Journal Bearings: Preliminary Investigations
Authors: Preater R. W. T. 
Published: June 2010

Determination of the stress distributions associated with composite shell bearings under static and dynamic loading conditions is discussed briefly. Experimental work recently started at The City University, using the three-dimensional ‘frozen stress’ photoelastic technique, is described. Preliminary static loading tests have been carried out over a range of low temperatures, prior to stress freezing, on a simple bearing and shaft assembly made in Araldite. One successful stress freezing cycle has been completed and the pressure distribution at the point of stress freezing is shown compared with low temperature distributions for a constant duty parameter. It is anticipated that, at the time of presentation of this report, the stress distribution at the lubrication surface, as determined by analysis, may be shown compared with the recorded pressure distribution.
Report 17: Design of a Test Rig to Assess the Effect of Three Loading Parameters on Rolling-Bearing Performance
Authors: Jones D. B. , Yardley E. D. 
Published: June 2010

In order to obtain information on the performance of certain types of 70 mm bore roller bearing for use in motors of advanced construction, a test rig which will reproduce the load and speed parameters expected to be encountered in service has been designed. The rig can apply steady axial and radial loads and an axial impact to give service conditions considerably more arduous than those which would be recommended by the bearing manufacturers. The programme of work is especially concerned with the effect of various axial impact loads on the performance of roller bearings which are already subjected to steady axial and radial loads. This report covers in detail the design of the test rig and outlines the range of test conditions available, and the types of bearing that can be tested.
Report 20: Developments in the Measurement of Oil-Film Thickness in Dynamically Loaded Bearings
Authors: Butcher A. E. 
Published: June 2010

This report describes the development of a capacitive system for the measurement of oil-film thickness in big-end and centre main bearings of a 600 h.p., 600 rev/min, diesel engine. The object of this work was to compare the theoretical prediction of bearing behaviour with the practical case. Engineering aspects of these measurements are given in the 1967 Institution of Mechanical Engineers Review Paper on dynamically loaded bearings. Reasons for the development of this system are given, along with a description of measurement techniques, including transmission of signals from the moving big-end to the measuring instruments. Data recording, analysis, and presentation of results are also described. One of the most significant features of this work was the manner in which the bearing distorted during an engine cycle. This has shown the need for further experimental measurements, which in turn have made it necessary for further development or partial automation of the measuring system.
Paper 3: Transient Heat Flow Investigations Using an on-Line Computer
Authors: Smyth R. 
Published: June 2010

This paper describes some experiences using an on-line computer for transient heat flow investigations. It has been possible to link the experimental equipment to the core of a small high-speed digital computer by way of a multiplexer arrangement which enabled the output of several sensors attached to the experimental equipment to be monitored, sampled, and stored in the computer core at an exceptionally fast rate. It has been shown that, provided access can be had to such a computer installation, it is possible to accurately investigate the output of thermocouples which have a time constant of less than 0·25 μs. The sampling rate ensures that frequency components above 10 kc/s in the transient heat flow phenomena can be accounted for. The use of on-line data sampling, described in this paper, ensures that the laborious and time-consuming task of retrieving data from, say, film records or ultra-violet records, can be rejected as well as the effort of transferring such data to a medium suitable for input to a high-speed digital data-processing computer with the possibility of accompanying errors involved owing to manual handling of the data. The use of multi-channel inputs to the control computer set-up ensures that a maximum of 64 signals can be accommodated simultaneously (although only five are described), and with the sample rates resulting from the use of the on-line equipment, it provides a means of monitoring phenomena such as shock propagations, flame propagations, etc., which might otherwise have been impossible within the accuracy range desirable. A full description is given of the requirements of the auxiliary equipment necessary for the investigation of transient heat flow using the control computer.
Paper 7: The Measurement of Skin Friction in Pressure Gradients Using a Static Hole Pair
Authors: Duffy J. , Norbury J. F. 
Published: June 2010

Two wall static holes of different sizes will give different readings of static pressure and the observed pressure difference is a function of the local skin friction. The static hole pair has, therefore, been proposed as a skin friction measurement device. This paper describes experiments which have been carried out to assess the accuracy of the static hole pair for the measurement of skin friction in favourable pressure gradients. The holes were formed in the wall of a pipe so that the device could easily be calibrated, and the favourable pressure gradient was then generated by inserting a central fairing. The skin friction values obtained from the device were compared with those measured by a Preston tube. Results showed that the static hole pair is capable of measuring skin friction within about 2 per cent, but a number of practical difficulties are involved, including the necessity to measure very small pressure differences. Brief consideration is given to the use of the static hole pair in adverse pressure gradients.
Paper 8: Measurement of Pulsating Air Flow by Means of a Bi-Directional Orifice Meter
Authors: Waters T. F. , Imrie B. W. , Cole B. N. 
Published: June 2010

This paper discusses experiments carried out to investigate the errors involved when applying the steady flow methods of air measurement to air flows which are pulsating at frequencies between 30 and 130 cycles per second (Hz). The mass flow measurements for steady and pulsating flow conditions are obtained by using four different sizes of bi-directional square-edged orifice plates with D and D/2 pressure tappings and a comparison of discharge coefficients for the subsonic flow of air in a 1-in diameter pipe, and the measurements cover a range of mass flows up to 0·03 lb/s. Attempts are made to determine suitable correction factors and thus establish a commercially satisfactory means of air flow measurement from the delivery side of a two-lobed, Roots-type positive displacement blower. The following effects are discussed: (1) the significance of the non-dimensional parameters involved, and (2) the effect of pulse shape.
Paper 9: The Removal of Water from Low-Pressure Steam Turbine Blades by Trailing-Edge Suction Slots
Authors: Ryley D. J. , Parker G. J. 
Published: June 2010

This paper reports an experimental research undertaken to explore the performance of a suction slot located in the trailing edge of a representative low-pressure steam turbine fixed blade. Tests have been made on a 1-in wide section of a full-size hollow blade mounted in a single-blade test section. Typical turbine pressures were reproduced down to 3 inHg (abs.), and blade exit Mach numbers varied in the range 0·57–1·10. With round entry lips, the slot operated satisfactorily in any blade orientation, as it completely removed quantities of water that were in excess of the amount expected under operating conditions. Square entry lips gave somewhat poorer performance.
Paper 14: Discharge from a Cylinder through a Poppet Valve to an Exhaust Pipe
Authors: Woods W. A. , Khan S. R. 
Published: June 2010

This paper is concerned with the gas exchange processes which occur in an engine. Previous work has been concerned with unsteady flow within the exhaust pipework; the present investigation provides a link between the cylinder and the pipe. The modifications to the pulse generator machine which was used to simulate an engine are described, and an account is given of the tests carried out with the machine. The previous steady flow tests are briefly summarized and the unsteady flow tests which were carried out are summarized with the aid of a table. The paper also presents a discussion of the test results and of calculations carried out to compare with the experiments. The main conclusion from the results is that a very satisfactory method has been devised for calculating the gas exchange processes occurring in an engine model. The main detailed conclusions are: (1) The dependence upon pressure ratio of the effective area of a poppet valve need not be taken into account for the analysis of unsteady flow tests. (2) Calculations on unsteady flow and gas exchange should be made on a theoretical model which has an exhaust pipe equal in length to the actual external exhaust pipe plus the length of the ‘exhaust bend’. (3) The method of calculation using the cylinder boundary conditions is an improvement on the previous type of calculations, which used a ‘pressure input’ as a boundary condition. Finally, the present work on a pulse generator with fixed piston using cold air, has provided a means of calculating the gas exchange processes from a knowledge of the release and supercharge pressures and the engine geometry. It has, therefore, provided an important link between the engine cylinder and the exhaust pipe system.
Paper 19: Slow Transient Compressible Flow through Orifices
Authors: Deckker B. E. L. , Chang Y. F. 
Published: June 2010

The discharge of compressed air from a cylinder has been studied experimentally. The effect of initial pressure and of orifice geometry on the expansion in the cylinder and on the transient flow through the orifice has been examined in detail. During expansion, radial and axial temperature gradients are established which result in departures from isentropic behaviour. The state can be reproduced analytically only by using a variable polytropic index whose values are dependent on the history of the expansion. From dimensional considerations the effects of fluid dynamical variables and of heat transfer on the transient flow have been isolated.
Paper 25: Unsteady Compressible Flow in a Pipe with a Non-Return Disc Valve
Authors: Kaddah K. S. M. I. , Woollatt D. 
Published: June 2010

A simple non-return disc valve was tested in a pipe in which an unsteady flow was produced. The valve was tested with its disc fixed in position and was also tested with the disc controlled by a spring. Records were taken of the unsteady pressure diagrams at various points in the pipe and the disc displacement diagram. To obtain the boundary conditions required for the unsteady flow calculation, it was first necessary to examine the flow in the valve under steady flow condition. The results of this investigation are briefly described. It was found that the disc displacement diagram in unsteady flow can be calculated with reasonable accuracy from the pressure drop across the valve by integrating the equation of motion of the disc numerically. The equation of motion contains terms for the inertia of the disc, the spring force, and the gas force. Viscous friction damping forces were negligible for this valve. Once the disc displacement is known, the pressure diagram can be calculated using the steady flow values for the pressure loss across the valve and the normal methods for one-dimensional unsteady flow calculations.
Paper 38: Water Drainage from a Cascade of Hollow Slotted Low-Pressure Turbine Blades
Authors: McAllister D. H. , Moore C. T. 
Published: June 2010

To prevent or minimize the erosion of the last row rotor blades in large high-speed steam turbines it has been proposed to remove the film of water on the surfaces of the last row stator blades before it reaches the trailing edges and is swept off by the steam drag into the path of the rotor blades. The paper describes experiments with a cascade of hollow stator blades with various dispositions of slots providing communication from the blade surfaces to the hollow cavity. The same cascade was used in turn with three different wet air tunnels, the experiments thus covering a wide range of Mach number and Reynolds number. With suitably disposed slots, and bleeding a very small proportion of the working fluid, about 90 per cent of the deleterious water can be removed, thus preventing it from striking the moving blades.
Paper 39: The Flow of Wet Steam in a Turbine
Authors: Kirillov I. I. , Yablonik R. M. 
Published: June 2010

This article considers methods of calculating condensation processes in wet steam turbines. Equations are given for determining the rate of nucleation, the growth of droplets, and the wet steam parameters. The condensation processes within the blade ring of a steam turbine are used by way of example. It is made clear that the condensation process is continuous at large enthalpy gradients. Under these conditions the theory of discontinuous condensation will not represent the actual process. Calculations based on the kinetic theory of phase change agree well with experimental findings. The constructional features of the blading which operates within the Wilson zone can have a considerable effect on the extent of the undercooling and on the size of the droplets. The trajectories of the droplets in the space between blade rings can be determined using standard approximate equations. The Coriolis force has a considerable influence on the motion of the entrained liquid within the moving blades. Under the influence of this force the liquid may move either with the flow or against it.
Paper 8: Corrosion Problems in Motor Vehicles
Authors: Enrico F. , Ferraro I. , Marciante A. , Natale T. 
Published: June 2010

Purely chemical or electrochemical corrosion is covered by this survey, which does not deal with damage due to combined effects of wear and chemical agents. Two main classes of corrosion—‘internal’ and ‘external’—may be considered. In the section headed ‘Internal corrosion’, the following topics will be discussed: exhaust valves corroded by combustion gases; silencers subject to corrosion due to the acid condensates collecting in the colder regions; cooling systems subject to corrosion due to chlorinated water and unsuitable additives; and cylinder liners corroded even when inoperative. In the section headed ‘External corrosion’, in view of the environmental conditions to which a vehicle is exposed in service—meteorological agents, contaminated atmospheres, abrasion and dents caused by sand and gravel, chemical action of the salts used for ice removal from roads—protective treatments have been classified as follows: ( a) electrochemical; ( b) by paints. In class ( a), after discussing the typical case of damage to fuel tanks, the various galvanic treatments recommended for carbon and stainless steel, brass, and alloys of aluminium, zinc, and magnesium have been described. In class (b), where protection by paints is dealt with, problems related to car bodies have been particularly emphasized.
Paper 4: Surface Integrity—A New Requirement for Surfaces Generated by Material-Removal Methods
Authors: Kahles J. F. , Field M. 
Published: June 2010

The design of structures for modern industry has created stringent service, reliability, and safety requirements. Present manufacturing specifications for surfaces are concerned primarily with geometry, which includes surface roughness and accuracy. The need is growing to consider not only surface geometry per se, but also the nature of alterations in the surface layer. Typical surface layer modifications, as a result of temperature, stress, and environment during material removal, include phase transformations, plastic deformation and fracture, and chemical changes. These various changes in the surface layer become increasingly significant with the more extensive application of materials such as high-temperature alloys, high-strength steels (including the maraging steels), refractory alloys, titanium, and beryllium. Some of the non-conventional machining methods, such as electrical discharge machining and grinding, electrochemical machining and grinding, and laser beam machining, can generate surface layer characteristics quite different from those produced by conventional methods. Surface alterations may also affect the residual stress, and with it the accuracy of thin section hardware, as well as decrease some of the significant mechanical and physical properties, such as fatigue strength, stress corrosion resistance, and fracture propagation rate. Control of surface layer characteristics, consistent with design requirements, develops ‘surface integrity’ which, in turn, leads to reliable service performance. A general review of previous work on the subject of surface integrity is presented. Typical microstructural surface alterations are illustrated, and the residual stress induced in the surface and its correlation with dimensional accuracy is demonstrated. A survey is presented relating machining methods to fatigue strength and stress corrosion characteristics. Finally, some guidelines are suggested for the practical implementation of surface integrity by means of processing specifications. Some consideration is given to the cost of implementing surface integrity requirements and their effect on production rates, including precautions concerning needless over-emphasis for certain manufacturing requirements. The data presented in this paper manifest that the metrologist's technical jurisdiction should be extended in depth from the Ångström range to the millimetre subsurface level.
Paper 5: Preparation and Properties of Molecularly Flat Surfaces
Authors: Winterton R. H. S. 
Published: June 2010

Very smooth surfaces may be prepared by cleaving suitable crystals of mica and other lamellar solids. Large areas of these surfaces are free from steps, even 1 molecule high, as may be shown by multiple beam interference techniques. In this paper the nature of contact between mica surfaces has been investigated and strong adhesion has been found. The application of tangential loads to cause sliding results in severe surface damage—Amonton's law is not obeyed. If a monolayer of calcium stearate is spread on the surfaces, damage is eliminated and the shear strength of the interface falls to one-fortieth of its previous value. Surface energies of mica, and mica coated with monolayers, have been measured and, in addition, these very well-defined surfaces are suitable for measuring the range of action of surface forces.
Paper 6: Assessment of Face Seal Performance Based on the Parameters of a Statistical Representation of Surface Roughness
Authors: Mitchell L. A. , Rowe M. D. 
Published: June 2010

Most methods commonly used to describe real surface roughness do not provide adequate information to enable predictions to be made of fluid leakage between two surfaces. To carry out such an analysis it is essential to know the depths of the remaining valleys at all stages of compression. It is shown that, when the distributions of peak and valley levels are defined, load-compression and load-leakage relationships can be derived if wedge-shaped asperities of constant apex semi-angle are assumed. The results suggest that a convenient quantity for specifying the form of a surface profile is the ratio of the distance between the mean peak and mean valley levels to the standard deviation of the distributions ( d/σ). For the best sealing performance d/σ should be as large as possible, whilst the centre-line average (c.l.a.), which provides a measure of the scale of the roughness, should be as small as possible.
Paper 24: New Developments in Surface Characterization and Measurements by Means of Random Process Analysis
Authors: Peklenik J. 
Published: June 2010

New developments in engineering and science in systems involving surfaces (friction, wear, contact deformation, reflection, electrical conductivity and resistance, heat transfer, tolerances and fits, etc.) require more comprehensive characterization of their micro- and macro-geometrical texture. Previous experience exhibits the fact that a statistical description of a surface by means of the first and second moment of the ordinate probability density distribution such as c.l.a. or r.m.s. and other parameters is not adequate. This paper discusses the more recent developments of surface characterization, considering a two- and/or three-dimensional random process by means' of the auto- and cross-correlation functions, power spectra, and the slope probability distribution parameters. A representative number of surfaces manufactured by a variety of metal-removal processes have been investigated in order to achieve, first, the differentiation of the surfaces with the same c.l.a. and r.m.s. values, and second, the separation of the periodic and random components in the surfaces. It is shown that the new techniques may disclose the differences in the internal structure of the surfaces. The elementary correlation functions, which may describe analytically the types of real surface profiles, are employed for the design of the surface topography system based on the correlation lengths and correlation wavelengths. On a number of practical examples there is shown the applicability of the proposed surface classification which is independent of the surface generation process. The theoretical approach and the experimental confirmation of the conclusions represent basically a new tool for comprehensive surface characterization. However, it should be considered that such a description requires a data requisition and processing by means of digital or special statistical computers. This circumstance does not affect the basic research work, but it is impractical for workshop application. Therefore new parameters and measuring methods have been developed to make the use of more comprehensive surface characterization methods possible in practice.