bluuebunny/crossref_metadata_2025 huggingface dataset:
Paper 32: Lubrication and Wear Problems in the Textile Industry
Authors: Catling H. , Pratt G. C. , Wilson W. H.
Published: June 2010

Each stage of production in the textile industry presents its own bearing and friction problems. In addition there is contamination by oil or grease from bearings and gears of the fibres, yarn, or fabric being processed. Dust and fly penetrating every part of a machine clogs gears and bearings and makes effective lubrication very difficult. Sealed rolling contact bearings, self-lubricating plastics or porous metal, and unlubricated bearings based on plastics have found acceptance because of their ability to run cleanly without attention for long periods, but solutions to bearing problems must be cheap as well as effective because a single machine may have thousands of bearings.

Difficult bearing conditions which have been resolved after much research and development work are found in the high-speed spinning spindle rotating unbalanced at 12 000 rev/min or more, and the ring and traveller where steel runs on steel at high pressure and velocity.

Existing conventional textile processes have reached such a level of development that further major advances are likely to require completely new techniques but there is still much that engineers can do to increase the reliability, efficiency and smooth operation of conventional machines which will remain in the majority for many years to come. Lubrication plays a vital part in achieving optimum performance.
Paper 34: Lubrication in a Marine Environment
Authors: King H. F. , Glassman N.
Published: June 2010

The lubrication of machinery in a marine environment is not without challenges for researchers, designers and operators. These challenges stem in navy ships from the presence of salt water and salt-bearing air in contact with machinery already designed to the outside limits of high output and light weight. Thus, to users of machinery in a marine environment, the mastery over sea water is directly related to machinery reliability, maintainability and capability. For a machinery user such as a navy there are some additional lubrication problems caused by the need to conserve space in machinery design and the need to proceed quietly.

This paper will be concerned with five machinery lubrication problems arising from the marine environment. They may be considered typical of and peculiar to that environment. They are timely because their solutions must be shared in by those in research and design as well as by the machinery operators.

The cases are as follows:

(a) The protection of vapour spaces in operating turbines by volatile rust-inhibiting chemicals in the lubricating oil. (b) The operation of petroleum oil hydraulic systems in the presence of sea-water intrusion. (c) The selection of lubricating greases for quiet ball bearings. (d) The development of a lubricant for a ‘marinized’ aviation gas turbine. (e) The lubrication of diesel engines of such weight-to-output ratio as to be competitive with steam and gas turbine propulsion.

Each case will be presented by reviewing the background of the problems, the approaches considered in their solutions, the status of the solutions and expected future developments.
Paper 19: Lubricants for Fluid Film and Hertzian Contact Conditions
Authors: Fowle T. I.
Published: June 2010

Petroleum oils. Their nature, types, and method of refining are briefly introduced and followed by a discussion of their properties, constitution, and the important effects of their aromatic and of their non-hydrocarbon constituents. The effects of oil oxidation, including effects on bearing metals, and thermal decomposition are referred to and a number of the more important oil additives are described. An indication of useful oil life in relation to temperature and other conditions is given, and the importance of performance testing under rimulated service conditions is described.

Water-containing lubricants. Water-in-oil, oil-in-water, and water–glycol solutions are described, together with their special properties such as fire-resistance. Their performances as lubricants, including effect on fatigue pitting, are briefly discussed.

Synthetic oils. Dibasic acid esters, neopentyl esters, triaryl phosphate esters, chlorinated diphenyls, fluorocarbons, polyglycols, silicones, and polyphenyl ethers are described in terms of structure and physical properties. Their stability to oxidation, thermal degradation, and hydrolysis are discussed as are their effects on materials of construction, their load-carrying capacity under various conditions, and toxicity.
An Introduction to the Concepts Involved in Vehicle Testing
Authors: Macmillan R. H.
Published: June 2010

Research covers a spectrum from pure research, through applied research and development, to market research. The most appropriate places for each kind to be pursued are discussed, together with the types of staff, instrumentation and facilities for testing that are essential to all research work. The three main areas of industrial research and testing are applied research, development testing and production testing; the particular requirements of each are considered.

Applied research must be relevant to vehicle functioning, and projects may arise from new scientific discoveries, from novel ideas originating within a research organization, or from an urgent industrial need. In each case test techniques must be developed to obtain the data given in each category.

Development testing requires the design and construction of laboratory rigs and proving facilities to obtain data in the most economical way. Production testing is directed mainly to the control of product quality and demands techniques and facilities which can be operated continuously and on a large scale. The types of facility needed for each of these applications are considered, with a view to giving an overall view of the matters discussed in detail in the papers of this Symposium.
Paper 5: Some Aspects of Tyre and Vehicle Vibration Testing
Authors: Barson C. W. , James D. H. , Morcombe A. W.
Published: June 2010

Instrumentation techniques are discussed. Particular emphasis is given to those techniques which have been developed to give immediately interpretable results from complex vibration data.

The relative merits of various test methods for the evaluation of tyre vibration performance are indicated. Of particular importance in this respect is the difference between rolling and non-rolling testing. This is illustrated during discussion of cross-ply/radial-ply comparisons using various test methods, and also comparisons between radial tyres of slightly different construction.

A necessary vibration property of a tyre is its ability to absorb single obstacles such as ‘cat's eyes' or road joints. Attempts have been made to simulate such objects on a drum, and various methods of analysing the resulting impulse to the axle are compared. As yet no generally acceptable method of analysis has been found.

The majority of vehicle testing is done using vibrator excitation, as this tends to minimize tyre differences. However, problems involving low frequency excitation due to once per wheel revolution inputs are usually investigated on both drums and vibrators. This type of problem often arises when longitudinal compliance has been introduced in the suspension. Typical curves from suspensions of this type are shown.

An example showing one of the principal modes of oscillation of a tyre is given.
Paper 13: Liquid Metal Flow in a Complex System of Passages
Authors: Greene D. A.
Published: June 2010

To achieve the necessary flow conditions in a particular liquid metal heat transfer experiment it has been necessary to design a rather complex pipework system. An analysis of the system has been made, and flow predictions in various parts of the system as functions of valve operation are given. Comparison is made with the experimental results obtained on the rig.

The effect of various parameters such as thermal density changes and cavitating flow, caused by large temperature changes and driving pressure heads, is briefly discussed.
Paper 10: Pressure Losses in the Inlet and Outlet Casings of Axial Flow Turbines for Turbo-Chargers
Authors: Simpson C. W. , Scarlett D. E. Y.
Published: June 2010

During initial design studies for a new range of turbo-chargers it was apparent that a considerable gain of efficiency could be achieved by a reduction of turbine casing losses. In this paper the theoretical and experimental pressure losses obtained from rig tests on the inlet and outlet casings for old and new designs will be presented. The inlet casing tests were completed on an axial entry casing with transition from circular to semi-annular section. The effect of this transition piece on gas incidences is also shown for the semi-annular nozzle entry.

Studies on the outlet casing as a transition from annular through radial to axial flow have been completed and will be presented as a pressure loss coefficient for various designs. The tests have been undertaken with both convex and flat plate radial diffusers, with or without swirl. Different outlet ducts were used to determine the effects on pressure losses in the casings, and the results are discussed.

Finally, the gains in overall turbine efficiency obtained by adopting the beneficial results from these tests are considered.
Paper 1: The Design and Development of an Inlet Volute for an Experimental Air Turbine
Authors: Ryan P. G.
Published: June 2010

One of the problems which arose during the design of an experimental air turbine was the design of a suitable inlet volute. It was considered that to obtain reliable flow measurements within the turbine without laboriously traversing around the complete turbine annulus, a smooth, evenly distributed flow at inlet was imperative.

An analytical approach was considered in the first instance, but the problem appeared so complex that it was decided to perform a purely experimental investigation.

This paper outlines the reasons for selecting a particular type of volute for the purpose, and describes the initial design, aerodynamic tests on a quarter-scale model, and the subsequent modifications which led to a final design of volute.
Paper 12: Fluid Flow Losses in A.C. Generator Stator Ventilating Ducts
Authors: Carew N. J. , Freeston D. H.
Published: June 2010

This paper reports an experimental investigation into the ventilation characteristics of the air gap/radial duct combination in electrical machines. The problem is basically of the manifold type in which the machine air gap is compared to the supply duct and the radial ventilating ducts represent the branches.

The factors affecting the pressure drop and flow distribution arising from the change in air direction from circumferential in the air gap to radial in the ventilating ducts are examined. First, the influence of slot wedge and duct spacer position, relative to the air gap, was observed in a qualitative manner using a water table model; the resulting flow patterns are illustrated. Second, the same duct configurations were tested in a model of a stator segment using air as the working fluid. The results of pressure drop and mass flow distribution are presented for variations in gap static and dynamic pressures together with curves showing the distribution of pressure losses along the ducts. Finally comparisons are made between model and full-scale measurements with a brief assessment of instrument problems.
Paper 7: Fluid Flow Losses Associated with the Cooling of Electrical Machines
Authors: Bennett R. B. , Poole R. M.
Published: June 2010

One of the limitations in the design of electrical machines is that of the temperature rise of the machine components. The most effective method of limiting the temperature rise is to duct the cooling medium to the source of loss, without unduly inhibiting the electrical design. This often results in complicated fluid flow paths, which cannot be designed exclusively from the point of view of maintaining ideal flow conditions, in both stationary and rotating members.

As the fluid flow conditions, generally, are not ideal, the only effective method of determining the loss factors is by practical means. To establish the duct losses and flow distribution under simulated conditions, full-size and scale models of components of electrical machines (e.g. direct hydrogen-cooled turbine generators, a.c. machines, and d.c. machines) have been made and tested. The loss factors which have been obtained are compound factors for a particular geometry and result from the effects of entry and exit conditions, changes of section and, where applicable, the effects of rotation. No attempt to separate the losses has been made, except where well-documented losses, such as friction, are involved.

This paper illustrates the types of fluid flow paths encountered in electrical machines and presents the loss factors, obtained from tests, for some of these arrangements.
Paper 8: Pressure Losses and Erosion in Condenser Tube Inlets
Authors: Tucker A. C. N.
Published: June 2010

From water model studies of two types of power station condenser, it has been deduced that the erosion of condenser tube inlets is due to a non-uniform inlet water-box flow distribution which results in damaging impingement flows in tube entries.

The impingement flow can be reduced either by fitting bell-mouths to the tubes, or by deflection of the cooling water flow at the condenser inlet to prevent it crossing the faces of tubes.

Some assessment has been made of the pressure losses in tube inlets, and these losses have been translated into drops in operational efficiency.
Paper 11: Diffuser Performance with Distorted Inflow
Authors: Tyler R. A. , Williamson R. G.
Published: June 2010

A series of conical and annular diffuser geometries was tested in the National Research Council's 10 ft ×20 ft propulsion tunnel, under conditions of non-uniform inlet velocity distribution, generated by the operation of a short entry pipe in cross flow.

The results suggest a wide applicability of the simple distortion factor, defined by the ratio of maximum to mean velocity in the inlet cross-section, to the prediction of pressure recovery in diffusers and diffuser exit settling pipes.

A marked effect of inflow distortion on optimum diffuser geometry was indicated. The correlation of Sovran and Klomp was corroborated for the range of inlet distortion factor pertaining to the original data.
Paper 3: Steady Flow Tests on Twin Poppet Valves
Authors: Woods W. A.
Published: June 2010

This paper presents the results of an experimental investigation of steady flow through a pair of exhaust poppet valves.

An account is given of the gas exchange process on engines which use poppet valves and the reason why pressure losses should be kept to a minimum is explained. Tests carried out on the cylinder head of a uniflow two-stroke cycle engine are described following a brief description of the apparatus used.

The results of a simple analysis of incompressible flow are also given. It is shown that the two previous models of flow through a valve, namely the sudden enlargement and constant static pressure, both give unrealistic pressure losses for large area ratios, i.e. at high valve lifts. A new model is introduced which leads to realistic pressure losses at small and large area ratios, i.e. at low and high valve lifts.

Effective areas for the present tests are calculated on the basis of the constant pressure model, and details of calculation of pressure losses are outlined.

The blockage effect caused by placing the exhaust valves near the cylinder wall is given in the discussion of the test results. This is zero for 0 < l/d < 0·08, but reaches a maximum blockage of 10 per cent at l/d = 0·28. With unrestricted twin valves the effective area is about twice that of a single valve up to l/d = 0·18 with a progressively larger effective area at lifts up to 13 per cent higher at l/d = 0·4. A comparison is also made with other data readily available.

The pressure losses determined from the tests were analysed using a parameter derived in the simple theory.

The parameter used is found to be almost independent of pressure ratio and the results are presented by means of this pressure loss parameter as a function of valve lift. The representation provides a quantitative method of comparing the performance of a given configuration of valve and port. On this basis the twin poppet valves are shown to give a slightly higher pressure loss than a single valve.
Paper 4: High-Output Medium-Speed Diesel Engine Air and Exhaust System Flow Losses
Authors: Wallace W. B.
Published: June 2010

This paper gives the results of air-flow tests through two-stroke cycle and four-stroke cycle diesel engine cylinder heads and ports on steady-flow low-pressure air flow rigs.

An analysis is made of the pressure drop through a diesel engine cylinder head inlet port system which shows the effect of the various parts of the system on flow loss. This also includes the effects of valve lift, valve seat angle, and valve shape on isentropic area.

A comparison is made between tandem and Siamese porting on a four-stroke cycle engine cylinder head. The results of tests on uniflow scavenged two-stroke cycle inlet ports and exhaust valves are also included.
Paper 8: Thermal Comfort
Authors: Chrenko F. A.
Published: June 2010

The subjects of heating and ventilating are very wide and their practical applications necessitate much detailed technical information. This is given very satisfactorily in the usual textbooks written for engineers. However, such books are apt to deal somewhat hastily with the theories upon which good practice should always be based. This applies especially to the subject of thermal comfort.

It is evident that large diversities of opinion are apparent when people are questioned concerning their feelings of warmth over quite a wide range of temperature. This has led some to state that it is better not to rely upon personal feelings of comfort in environmental investigations. The following brief introduction to thermal comfort endeavours to show not only that this is a mistaken notion but that the subjective factors of thermal comfort have been successfully assessed and correlated with the physical factors of the environment.
Paper 2: Heating and Ventilating Aesthetic Theory
Authors: Rathbone R. A.
Published: June 2010

This paper attempts to show the relationship between physiological responses to an environment and aesthetic pleasure. It does so by tracing the transference of primal pleasure-pain reactions to analogous perception and thence through pattern perception to the function of contrast as a fundamental aspect of aesthetics. It elaborates these ideas as they affect heating and ventilation and suggests lines of thought which might prove fruitful in the relevant field of environmental design.
Paper 3: Application of Factory-Made Air-Conditioning Units
Authors: Taylor F. M. H.
Published: June 2010

The paper states why air conditioning is necessary particularly in office blocks in cities, where noise, dust and heat from office machinery together with solar heat gain through large glass areas are experienced. The relatively small addition to building costs in incorporating air conditioning is shown.

The distinction between air handling, ventilation and air conditioning is defined and the constituent parts of a complete air-conditioning unit are enumerated.

The requirements in terms of fresh air needs, temperature and relative humidity for the normal applications of air-conditioning units are tabulated.

A comparison of the main categories of air-conditioning equipment is made, dealing with high and low velocity as well as special laboratory type units. A typical performance specification is also given together with data sheets for collecting the necessary design data and cost comparisons.

The paper concludes with a discussion on system design incorporating factory-made equipment and literature references.
Review Paper 4: Basic Principles of Bearing Testing-Machine Design
Authors: Neal P. B.
Published: June 2010

The basic requirements in the design of bearing testing-machines are examined and the advantages and disadvantages of different general arrangements discussed. Particular attention is given to the subject of friction measurement in bearings. Additional factors arising in the design of a machine for dynamically loaded bearings are considered.
Report 5: An Optical Method of Measuring Film Thickness
Authors: Higginson G. R. , Reed S.
Published: June 2010

This report describes a method which is being developed specifically to measure the film thickness in a journal bearing carrying a steady load. In such a bearing the lubricant film is essentially parallel and its area very large. The requirement therefore is for a method which will measure a local value of the distance between two curved but parallel surfaces about 10 μ apart.

The optical method described below can be used either in transmission with two transparent bodies or in reflection with one transparent and one opaque. In the intended applications the reflection technique will be used, with a semi-reflecting layer on the surface of the transparent body.
Report 13: Pressure Developed in the Lubricant Film between Two Contacting Surfaces in Relative Motion
Authors: Fergusson B. , Ross D. , Ismail M. A. , Gohar R.
Published: June 2010

An apparatus has been developed for the measurement of the pressure distribution in the lubricant between a roller and a flat plate in relative motion.

A hole of diameter 0002 in is drilled in a flat plate which is mounted on a co-ordinate table. A traverse of the pressure zone in two directions is effected by moving the co-ordinate table in discrete steps, so that the lubricant pressure at each location is transmitted through the small hole. Connecting to the small hole is a pressure transducer which feeds a signal, proportional to the pressure, to an ultra-violet recorder. Conversion of the recorder print-out to pressure is accomplished by calibration of the transducer and the recorder against known pressures
Report 19: Testing of Bearing Materials and Lubricants under Cavitation Conditions
Authors: Rachman D.
Published: June 2010

A novel adaptation of magnetostriction oscillator technique to lubricant and bearing material testing is described. This consists of vibrating the end of a transducer at right angles to a stationary specimen surface, causing formation and collapse of cavitation bubbles in the separating fluid film, In order to control the temperature and properties of the separating film, a flow is introduced through a central hole in the stationary specimen. This limits the temperature rise, ensures the removal of the debris and supplies continuously fresh working fluid. A steady state condition with regard to loss of material can be reached within about an hour with a white metal specimen in a lubricating oil. It has been found that the temperature at the specimen face is not critically affected by changes in the rate of flow over a range from 10 cm3/s to 20 cm3/s. The actual temperature rise is quite moderate, being of the order of 2°C for water and 15°C for Shell Vitrea 33 oil operating at 26°C inlet temperature. With the oil flow interrupted, the temperature rises by about 50°C in 2 minutes with a tendency of the rise to continue. It is suggested that the method offers a unique opportunity for controlling the cavitation environment of bearing materials and lubricants.
Report 22: Experimental Techniques for the Assessment of Temperatures Attained by Sliding Surfaces
Authors: Powell D. G. , Earles S. W. E.
Published: June 2010

Research has indicated that surface temperature is of prime importance in determining the behaviour of materials suitable for use in sliding bearings. Consequently, some assessment of the surface temperature developed is desirable in many investigations of the tribological properties of a combination of materials and environment.

This report outlines the experimental techniques available for measuring surface temperature, several of which, though developed basically as research tools, are suitable for routine testing. The capabilities and limitations of each method are discussed and, in deciding the most convenient method to use, in practice must be jointly considered with the type of temperature variation which is to be expected.
Paper 4: Terminal Laminar Convection in a Uniformly Heated Rectangular Duct
Authors: Morris W. D.
Published: June 2010

For the laminar flow of a fluid with constant properties in a uniformly heated rectangular duct with no viscous dissipation and internal heat release, an exact solution for the fluid temperature field is presented in the form of rapidly convergent infinite series. Expressions are subsequently derived for the variation of limiting Nusselt number, based on unweighted and weighted mean temperature differences, with duct aspect ratio.

It is shown that previously published approximate solutions for the weighted Nusselt number—determined using numerical techniques—are in agreement with the more versatile exact solution to better than 1 per cent.
Paper 5: Research at C.E.R.L. on Turbine Blade Erosion
Authors: Moore M. J. , Langford R. W. , Tipping J. C.
Published: June 2010

Water drops shedding from a cascade of turbine fixed blades have been observed under simulated operating conditions in the C.E.R.L. steam tunnel. The sizes and velocities of the water drops are correlated with conditions downstream in the wake of the blades. The results are shown to be in good agreement with observations made in turbines, and are used to predict the extent and pattern of erosion on a following moving blade row. Upon comparison of the predicted pattern with the actual damage to a moving blade it is found that the impacting drops create pits in the metal surface which are smaller in diameter than the water drops. The physical process occurring when a drop impacts on a surface containing a small pit is illustrated by simple laboratory tests. The impact pressure generated in the water drop causes the front face of the drop to accelerate and strike the base of the pit at up to three times the impact velocity of the drop. This fundamental process accounts for the characteristic pitting of eroded surfaces, and also for the changes in erosion rate observed during continuous water drop bombardment of specimens in material test rigs.
Paper 6: A Rotating Pressure Transmission System for Turbo-Machinery Experiments
Authors: Hodskinson M. G.
Published: June 2010

Experimental investigation of air flow in rotating blade rows is widely regarded as desirable, but is rendered difficult in practice because of high rotational speeds and the large number of pressure tappings required. The design and operation of a system using the Scanivalve and able to transmit pressures from a rotor running at 8000 rev/min is described in this paper. Some experience in the use of the system with blade surface measurements on a small (8-in diameter) centrifugal impeller is discussed. Attention is paid to sources of error in pressure readings, including the rotating head correction to convert the transmitted pressure reading into actual pressure at the point of measurement.

Theoretical relative velocities in the impeller have also been obtained with Algol computer programmes for isentropic flow in the axi-symmetric and blade-to-blade directions. A comparison is made between experimental and theoretical relative velocities in the impeller in which the flow is essentially incompressible at the test speed. It is concluded that flow separation occurs early in this particular impeller channel. On the evidence of the results obtained so far, some further uses and developments of the pressure transmission system are discussed.
Paper 10: Unsteady Flow in a Branched Duct
Authors: Deckker B. E. L. , Male D. H.
Published: June 2010

The results of an investigation into the behaviour of a finite amplitude pressure wave at the junction formed by the intersection of two ducts of equal cross-sectional area are presented. Using a shock tube to produce waves with amplitudes varying from 1 to 37 lb/in2 (g), pressure measurements were made in three junctions in which the side branch formed an angle of 45, 90, and 135° with the main branch. The results are compared with a theoretical analysis which is based on the assumption of one-dimensional, quasi-steady, adiabatic flow. Differences in the theoretical and experimental values have been found at the junction entrance when the velocity at the entrance is subsonic and in the side branch when the velocity at the entrance is sonic. These differences are explained in terms of the wave action known to occur within the junction.
Paper 11: A Potential Flow Model for a Closed Separation Region
Authors: Duggins R. K.
Published: June 2010

A potential flow model is proposed for the simulation of a closed separation region where a flow reattaches to the wall from which it has previously separated. The model is intended for large Reynolds numbers, for which condition the vorticity in the fluid is assumed to be concentrated along the initial part of the dividing streamline and at the centre of the circulatory flow in the separation region. Using empirical data for the location of the reattachment point, the proposed model is applied to the problem of flow separation at the inner corner of an unequal elbow, and a comparison is made between the calculated and the experimentally observed flow patterns.
Paper 16: The Equilibrium of a Bubble Nucleus at a Solid Surface
Authors: Gaddis E. S. , Hall W. B.
Published: June 2010

Existing models for the equilibrium of a bubble at a heated surface are discussed; an alternative model is presented, based on conduction as the dominant mechanism in the liquid and on vapour transfer within the bubble. No artificial restrictions are made at the boundaries and the only condition to be fulfilled by the mathematical solution is continuity of temperature and heat flux at the liquid-vapour, liquid-solid, and vapour-solid interfaces. The characteristic distance in the undisturbed liquid, at which the liquid and the vapour temperatures are identical, is determined as a function of dimensionless parameters which contain the physical properties of fluid and wall material in addition to nucleation cavity size.
Paper 17: Inception of Nucleate Boiling of Water at Pressures above Atmospheric: Characteristics of a Horizontal Surface Bearing a Normal Distribution of Cavities
Authors: Grant I. D. R. , Patten T. D. , Carrie G. M. H.
Published: June 2010

It is known that the onset of nucleate boiling at a solid surface is related to the dimensions of cavities on the surface. In this paper it is proposed that a commercial surface be characterized by a normal distribution of cavity sizes, and on this basis a theory is developed for the prediction of heat transfer characteristics in the weak nucleate boiling regime. The theory is developed simultaneously with the presentation of the results of experiments carried out on pool boiling of water from a heating surface bearing cavities of equivalent radii from 50 to 550 μin. Discrepancies between experiment and theory are discussed.

Experimental data on the influence of pressure (range, atmospheric to 750 lb/in2 (abs.)) and subcooling (range 0–12 degF) on the overall heat transfer rates are also presented.
Paper 18: Fluid Dynamic Aspects of Unsteady Flow in Branched Ducts
Authors: Deckker B. E. L. , Male D. H.
Published: June 2010

Unsteady flow through three-branched pipe configurations has been investigated with the object of finding boundary conditions suitable for use in the analysis of high-amplitude waves using the method of characteristics. The schlieren method and the hydraulic analogy were used to obtain qualitative information about the quasi-steady flow patterns. Quantitative information concerning these patterns was obtained by the measurement of stagnation pressure losses and of the static pressure distribution. Several methods of deriving boundary conditions have been reviewed, and it is considered that those obtained directly by experiment are the most convenient to use.
Paper 20: Application of Non-Steady Flow in a Rotating Duct to Pulsating Flow in a Centrifugal Compressor
Authors: Benson R. S. , Whitfield A.
Published: June 2010

This paper deals with a theoretical approach to study the non-steady flow and wave action in a centrifugal impeller and vaneless diffuser, and also to predict the non-steady flow performance of a centrifugal compressor. This was carried out by replacing the compressor unit by a model which consisted of a simplified rotating duct, a vaneless diffuser, and a cone-shaped pipe which replaced the scroll.

A theoretical technique using the method of characteristics and the development of the non-steady flow equations to a rotating duct and radial diffuser is given. The development of the theory and the difficulties encountered are described. In particular, the techniques developed for starting a computer calculation are described.

In order to maintain homentropic flow in the impeller and diffuser all losses were assumed to occur at the impeller inlet. A pressure loss boundary condition was developed to enable the steady pressure ratio-mass flow characteristics to be computed. When these values agreed with the experimentally determined characteristics, the boundary condition at the rotor inlet was such that the pressure loss terms allowed for the impeller and diffuser losses.

The theoretical results obtained are compared with corresponding experimental results, and the possibility of using this theoretical technique as a design tool is discussed.
Paper 24: Heat Transfer in Rotor Cooling Ducts
Authors: Le Feuvre R. F.
Published: June 2010

This paper is concerned with heat transfer to air passing through the axial cooling ducts of rotors. The measurements have yielded data for a range of axial to rotational velocities and of duct spacing, pitch-circle diameter, and length-to-diameter ratio.

The results, in terms of the ratio of rotating to stationary heat transfer coefficients, show the important parameters which govern the increase in heat transfer due to rotation. Under certain conditions, an increase in heat transfer of 100 per cent is achieved.
Paper 27: Heat Transfer to Steam-Water Mixtures Flowing in Uniformly Heated Tubes in which the Critical Heat Flux has been Exceeded
Authors: Bennett A. W. , Hewitt G. F. , Kearsey H. A. , Keeys R. K. F.
Published: June 2010

Experiments are described on evaporative heat transfer to boiling water in upflow in a vertical electrically heated 0·497-in inside diameter tube at 1000 lbf/in2 (abs.). The main objects were to measure the surface temperature profiles in the region beyond the dry-out point in the channel where liquid ceased to flow on the channel wall, and to investigate the behaviour of the dry-out ‘interface’ between the ‘wetted wall’ and the ‘dry wall’ regions. The test section was made from ‘Nimonic’ as this can withstand the highest temperatures in the ‘dry wall’ region and also has a low temperature coefficient of electrical resistivity, thus allowing a uniform heat flux to be maintained with wide axial temperature variation. The temperature in the ‘dry wall’ region first increased rapidly with distance from the dry-out point, after which it either increased at a slower rate or, at high mass velocities, even decreased. The dry-out ‘interface’ moved reversibly down and up the channel as the heat flux was increased and decreased. Local surface temperatures showed no hysteresis with cycling of heat flux, in contrast with the pool boiling situation.

A method of predicting the wall temperature profile in the ‘dry wall’ region has been developed. In this method, the heat-transfer process is considered as being in two steps: wall to superheated steam continuum, and steam continuum to water droplets. The first step was calculated from standard single-phase steam heat-transfer correlations, and the second step was calculated on the basis of simultaneous heat transfer to, and steam diffusion from, the droplets. It was important to take account of the slip between the droplets and the steam. Satisfactory agreement was obtained between measured and predicted wall temperature profiles.
Paper 28: Turbulent Heat Transfer to Air in the Vicinity of the Entry of an Internally Heated Annulus
Authors: Roberts A. , Barrow H.
Published: June 2010

A new theoretical analysis has been made of turbulent heat transfer in the region of simultaneously developing hydrodynamic and thermal boundary layers in annular flow.

A boundary layer-potential stream model has been used to describe the flow, heat transfer being predicted through the use of a modified Reynolds analogy. Skin friction data for the inner heated wall have been obtained from correlations pertaining to boundary layers on immersed bodies.

Experiments have been made with air in the entry region of internally heated annuli with radius ratios 2·1 and 4·0. Satisfactory agreement between theory and experiment has been achieved.
Paper 29: Heat Transfer during Two-Component Mist Flow across a Heated Cylinder
Authors: Finlay I. C. , McMillan T.
Published: June 2010

The results of a study of heat transfer and hydrodynamic phenomena during flow of an air-water mist across a heated, horizontal cylinder are reported.

Local and average heat-transfer coefficients have been obtained, under conditions of constant heat flux, on the outer surface of a 19-mm outside diameter cylinder. Air flow rates corresponding to approach velocities of 20–75 m/s have been explored with mixture qualities in the range 0–9 per cent by weight of liquid phase.

Heat-transfer coefficients were found to be strongly dependent on mixture quality, and increases in the average value of the surface heat-transfer coefficient of twenty times the corresponding dry gas values were recorded with mixture qualities approaching 9 per cent by weight of liquid.

Under all conditions explored, a liquid layer was observed to form over the front half of the tube, between forward stagnation and separation. An intense bouncing or splashing action of droplets impinging on this layer was observed and measured.

Average values of surface heat-transfer coefficient were found to be correlated in terms of the quality and Reynolds number of the mixture and of Nusselt numbers based on average and stagnation point heat-transfer coefficients.
Paper 33: Hydrodynamics of Surface Films: Modelling Laws for Two-Phase Flows Containing Dilute Surfactant
Authors: Kenning D. B. R.
Published: June 2010

The presence of surface-active material may modify appreciably the flow patterns in two-phase flows. A frequently employed model for the surface adsorption process is used to derive similarity conditions for such flows. The limitations of this model are discussed in relation to the formation of surface films on open channel flow of water containing dilute surfactant.
Paper 35: The Influence of Mass Velocity on Friction Pressure Gradients during Steam-Water Flow
Authors: Chisholm D.
Published: June 2010

From analysis of data for the flow of steam-water mixtures in tubes at pressures between 3 MN/m2 [435 lb/in2 (abs.)] and 17·5 MN/m2 [2540 lb/in2 (abs.)] equations for friction pressure gradient are developed. These equations allow for the influence of the ‘mass velocity effect’, not previously allowed for in accepted correlations. The equations are in a form making them applicable at the critical point, and are compared with the data of Miropolskii, Isbin, and Berkowitz for steam-water flow.
Paper 40: Superimposed Laminar Forced and Free Convection between Vertical Parallel Plates when One Plate is Uniformly Heated and the Other is Thermally Insulated
Authors: Rao T. L. S. , Morris W. D.
Published: June 2010

Laminar flow between two vertical parallel plates, with one of the plates uniformly heated and the other thermally insulated, has been studied theoretically for the case where gravitational buoyancy modifies an otherwise forced convection regime. Velocity and temperature fields for two conditions of flow—heated upward flow and cooled upward flow—have been derived. From these results heat transfer and pressure drop data have been calculated and similar tendencies to those which occur in uniformly heated vertical pipe flow were found.
Paper 9: The Measurement of Turbulent Velocity Fluctuations and Turbulent Temperature Fluctuations in the Supercritical Region by a Hot Wire Anemometer and a ‘Cold’ Wire Resistance Thermometer
Authors: Bourke P. J. , Pulling D. J. , Gill L. E. , Denton W. H.
Published: June 2010

It is necessary to develop experimental methods for measuring the local turbulent velocity and turbulent temperature fluctuations in the supercritical region in order to investigate the unusual heat transfer phenomena that occur in heating turbulent flows of fluids in this region.

The performance of the constant temperature hot wire anemometer has been investigated in isothermal turbulent flow of carbon dioxide in a pipe at supercritical pressures from 1075 to 1200 lb/in2 ( Pc = 1071 lb/in2) and at temperatures from 24·5 to 40°C ( Tc = 31°C), including the critical range of rapid variation in physical properties in which the fluid changes from liquid to gas. The wire temperature was varied and linear mean velocity calibrations were obtained which were found to be markedly sensitive to the pressure, the fluid bulk temperature, and the wire temperature. Measurements of turbulent velocity fluctuations agreed with the expected values for this isothermal case. The heat transfer from the wire showed no unusual characteristics and was correlated for variation in pressure, fluid bulk temperature, and wire temperature by using mean values of the physical properties over the wire to bulk temperature range.

Because of the sensitivity of the wire calibrations to temperature, measurement of the local fluid temperature is required to allow velocities to be measured in the presence of temperature gradients in the supercritical region. A probe has therefore been developed with a thin cold wire resistance thermometer, mounted close to a pair of crossed hot wires and with a sufficiently fast thermal response for the measurement of temperature fluctuations as well as mean temperature. Experiments are described with this probe in the presence of temperature gradients in turbulent flow, but so far only in air. Simultaneous measurements were made of both the radial velocity fluctuations and temperature fluctuations in a volume of air that was small compared with the scale of turbulence. The time-correlation of these two quantities was found to be strong near the wall of the tube and to fall to zero towards the centre. Further, the local radial turbulen theat flux calculated from the mean product of these two quantities agreed quantitatively with the known heat flux for various radial positions in the tube.

The remaining problem is to investigate the effects that temperature fluctuations in the supercritical region have upon the measurement of velocity fluctuations and on the local values of the density and specific heat.
Paper 5: Experience in Corrosion Control
Authors: Heslop S.
Published: June 2010

The term ‘corrosion’ is used to cover the many and varied effects of an environment upon a solid object. The environment may include solid, liquid and gaseous phases, vapours, electromagnetic radiation (visible light plus infra-red and ultra-violet rays), mechanical vibrations and energy, heat and electrical effects, or a combination of two or more characteristics which may promote or restrict its action upon the object subject to such influence.

An appreciation of the mechanisms which produce corrosive effects enables preventive action to be taken in the design stage. This in particular involves the correct selection of materials and finishes, but incorporates also a knowledge of the particular environment to which the part will be exposed. When there is a clear understanding of the possible sources of corrosion, then means of protection may be specified or developed.

The correlation of laboratory testing procedures to actual outdoor exposure is a difficult and time-consuming exercise which involves the selection of an open-air or part-covered site which has such constancy of conditions that it may be used all the year round without consideration of season, providing that the exposure time is not less than approximately three months.

In temperate zones the times of sunrise and sunset deviate more than four hours throughout the year and similarly the temperature, the water vapour content of the atmosphere, and the cloud cover may vary enormously. This leads to the conclusion that the location of a suitable test site must be on or near the equator, it must have a maritime exposure, and also have characteristic features of uniform temperature, consistent sunshine, high humidity, and copious rainfall.
Paper 45: Tribological Implications of Surfaces
Authors: Barwell F. T.
Published: June 2010

A major part of an engineer's concern with surfaces relates to their interaction within machine elements and to their degradation as a consequence of wear. Relevant work in this field is reviewed with particular reference to the Conference on Lubrication and Wear held at the Institution in September 1967.

Two important quantitative measures which relate surface finish with functional factors have been described. One, the Plasticity Index, relates the topographic with the material characteristics of a surface and is defined as follows:

where H = hardness, σ = standard deviation of asperity height distribution and β = asperity radius. γ1 and γ2 and E1 and E2 are the Poisson's ratios and moduli of elasticity of the materials of the two surfaces respectively. The other relates particularly to conditions of elastohydrodynamic lubrication and takes the form

where h = uniform macroscopic lubricant film thickness and σ1 and σ2 are the r.m.s. surface roughnesses of the two surfaces in contact respectively.
Paper 17: Microtopography of Surfaces
Authors: Williamson J. B. P.
Published: June 2010

This paper describes an approach to the study of surfaces based on the digital analysis of data obtained from profilometric examinations. This technique is used to determine several new surface texture parameters, including the surface density, height distribution, and mean radius of curvature of the asperities. Recent theories have shown that these are the parameters which control the nature of surface contact. The implications which these ideas have for the science of metrology are discussed.

The study also shows that many surfaces have height distributions which are Gaussian, and in particular that the heights of the upper half of most surfaces closely follow a Gaussian distribution.

By combining data obtained from many closely spaced parallel profiles it has been possible to reconstruct detailed maps of the surface texture. Two examples are discussed: bead-blasted aluminium, and a glass surface lightly blasted with alumina. One of the advantages of microcartography is that it permits the geometry of the contact between rough surfaces to be studied in detail. A map is given showing the manner in which the contact area between two bead-blasted aluminium surfaces splits into sub-areas, and how these sub-areas are distributed with respect to the surface features of the contacting solids.
Paper 2: Surface Topography Effects in the Estimation of Thermal and Electrical Contact Resistance
Authors: Yip F. C. , Venart J. E. S.
Published: June 2010

A method of determining the constrictional thermal contact resistance is proposed and discussed. Consideration is given to modelling the simultaneous effects of asperity distribution and roughness, and surface waviness. The resulting general analysis can be applied to any known surface topography in contact with another.

Application and comparison utilizing the method are made to the results of an electrical analogue study.