bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of Vehicle Handling by Tethered Testing
Authors: Barter N. F. 
Published: June 2010

The technique of tethered testing is introduced as a method of measurement of vehicle steady state handling, where the vehicle under test is attached to a large parent vehicle by means of an arm attached at its centre of gravity, and the tyre forces, which in the normal free vehicle situation produce a centrifugal acceleration, are simply reacted by this arm. The tethered testing rig built at M.I.R.A. is described. It is shown that the concept of tethered testing leads naturally to the idea of describing vehicle steady state handling by means of a quantity which depends only on lateral acceleration, and suitable quantities are shown to be static margin and the slope of a curve of mean front wheel steer angle against vehicle slip angle. These quantities are defined and their derivation in terms of vehicle stability derivatives is outlined in an appendix. Some examples of tethered test measurements are given in the form of plots of static margin against lateral acceleration, and a tentative set of criteria for good steady state handling is given in terms of the behaviour of static margin with lateral acceleration.
Vehicle Handling Qualities
Authors: Hales F. D. 
Published: June 2010

The paper is concerned in general with quantitative methods of analysis for the general steady-state motion of an automobile and, in particular, for methods that are able to assess the non-linear characteristics of vehicles. In this context it is observed that any quantity used must satisfy three requirements; it must have a physical significance and be capable of prediction and measurement. For this purpose three basic handling concepts are considered, understeer, static margin and slip/steer gradient. Following the analysis of the perturbation motion about steady circular motion, the concepts are rationalized and related to the theoretical vehicle behaviour. In a discussion of this analysis the relationship between the three concepts are investigated and subsidiary vehicle parameters highlighted. The final stage of the quantitative method outlined is dealt with in a section on experimental procedures. Three procedures, response mapping, tethered testing and steering pad tests, are examined, and the required measurements and analysis processes needed to obtain measurements of the handling qualities are derived. Finally a typical set of experimental results from a response mapping experiment is included as an example of processes described. It is concluded that the concepts of understeer, static margin and slip/steer gradient can be successfully applied theoretically to the general non-linear cornering motion of an automobile, and that experimental techniques exist that yield measurements from which quantities defined by the theoretical analysis can be obtained, with the exception that measurement of static margin in the general non-linear motion condition is not satisfactory because of experimental problems. The tethered test technique and the steering pad test are also able to provide measures of the most important associated vehicle stability parameter.
Paper 6: Experiments on the Performance of Slow-Speed Hydraulic Motors for Use in Agricultural Tractors
Authors: Howson D. F. 
Published: June 2010

Two series of experiments were carried out. In the first series, drawbar performance tests were conducted with a tractor fitted with slow-speed hydraulic wheel motors of different capacities. The advantage to be gained from the use of dual-capacity motors may be assessed from the results of these tests. An experimental dual-capacity motor is described and details of its performance are given. In the second series of experiments, an attempt was made to isolate and analyse sources of output torque loss in a slow-speed motor of the radial piston type.
Paper 1: Paper 2: A Standard-Triumph Family Car Engine-its Design History during a Decade
Authors: Eley D. C. 
Published: June 2010

The paper gives the history of the conception and design details of a mass-produced four-cylinder 803 cm3 engine, its redesign to 948 cm3 and the design of a twin-carburettor version. Finally a further redesign to increase the capacity to 1147 cm3 for both single- and twin-carburettor versions. An initial appraisal was made of the type of unit required to power a small family saloon car. Engine performance requirements were established from a performance curve of the vehicle obtained from frontal area aerodynamic coefficient, estimated weight, etc. The configuration of the unit was fully investigated, the number and disposition of the cylinders, type of cooling, position of valves and type of valve gear were all explored, bearing in mind technical requirements, cost and ease of production and production plant requirements. Having decided upon a four-cylinder in-line liquid-cooled unit, a detailed description is given of the reasons for the design configuration of the major components and the disposition of the ancillary equipment. The need to extend the range of models of this vehicle brought about the first increase in capacity to 948 cm3 and design modifications are enumerated. A twin-carburettor version was a further requirement and design and development details are discussed. With the introduction of a completely new design of motor car using this power unit, the road holding and general handling characteristics of the vehicle were so outstanding that improved engine performance became a necessity to match the above qualities. The methods of increasing performance are discussed and the reasons given for the necessity to increase capacity. In view of already established transfer machinery for all major components, the minimum of change was essential and a history of the design and development of the unit is given. It is shown that careful study of existing equipment is vitally necessary when making extensive design changes. First designs made the minimum of change and only when test work showed shortcomings were further changes made. A series of designs and tests finally achieved a sound design giving excellent results from extended tests. This process established that all the modifications were vitally necessary to achieve the performance and reliability necessary for the engine to have a further period of production and enable progressive development to be successful.
Paper 2: Adhesion in Railway Braking
Authors: Hatch D. , Law J. , Parker R. C. 
Published: June 2010

Reasons are advanced why the processes of adhesion in braking may differ from those in traction, and limitations of adhesion-measuring machines are discussed. It is shown how the nature of the variation of braking torque with velocity may affect the driver's manner of applying the brakes. Incidence of pick-up from 2000 brake applications on three different types of brake (cast-iron tread, non-metallic tread, and disc) are studied to investigate the effect of load, the effect of moisture, and the effect of speed on adhesion. The incidence of pick-up is found to be less for a loaded than for an empty train and greater for wet than for dry rails, so confirming known facts and justifying the particular method of approach. A complex adhesion/speed characteristic with a minimum value in the range 40–50 miles/h for dry tare conditions is shown to exist, which demonstrates that relations generally accepted to be applicable to braking are invalid. On wet rails incidence of pick-up is higher on the leading bogie and the suggestion is made that brake forces to this bogie could be reduced. Off-tread braking increases vulnerability to wheel sliding but with wheel-slide protection the exacting demands of dense suburban traffic are adequately met.
Paper 7: Experiments Concerning the Aerodynamic Performance of Inward Flow Radial Turbines
Authors: Hiett G. F. , Johnston I. H. 
Published: June 2010

For some years, a programme of research into the aerodynamic performance of inward flow radial turbines has been conducted by Ricardo & Co. under the sponsorship of the Ministry of Aviation. The paper describes this experimental work and presents an edited version of the principal test results. The sensitivity of turbine performance to changes in the major design variables such as nozzle angle, rotor size, and rotor shape is illustrated and the effects of practical variables such as tip clearance and leakage flows are recorded.
Paper 8: Studies of Flow through Centrifugal Pump Impellers
Authors: Simpson H. C. , Cinnamond C. 
Published: June 2010

A photographic technique is used here to give quantitative measurements of the three-dimensional flow pattern in pump impellers operating at conditions of practical interest. This technique is used to study the flow through a series of impellers of outlet angle varying between 20° and 35° and inlet angles constant at 20°, operating over a range of throughflows. Attention is here focused on the flow patterns at, and below, the best efficiency point. Experimental results show that standing vortices can appear at both the leading surface near the impeller eye and at the trailing surface near the impeller tip, with the latter becoming more important as the throughflow is reduced. A qualitative explanation for the appearance of these vortices is given in terms of boundary-layer theory and the effect of the trailing surface vortex on the pump performance is discussed. Estimates are made of the internal slip coefficient and a study of the losses in the volute close to the impeller tip is made. The data are again analysed in terms of the Busemann potential flow theory. It is concluded that impeller design, by influencing the impeller flow pattern and introducing separation regions, can have an important effect on pump performance, particularly with reference to stability.
Paper 9: Unsteady Flow in Pipes with Gradual or Sudden Area Changes
Authors: Benson R. S. , Garg R. D. , Woods W. A. 
Published: June 2010

The paper describes a theoretical and experimental investigation into unsteady flows in pipes with cross-sectional area changes. One-dimensional unsteady flow theory using the method of characteristics is used for analysing the wave action in the pipes. Both homentropic and non-homentropic flows are investigated. For gradual area changes (effuser, diffuser) the generalized one-dimensional unsteady flow theories including friction are used. For sudden area changes quasi-steady flow theories at the area change are described to evaluate the boundary conditions. At a contraction the flow is assumed to be isentropic, whilst at an enlargement it is assumed that the flow is adiabatic but not isentropic. In the latter instance, it is assumed that there is a pressure recovery according to the conservation equations; this theory is equivalent to the sudden enlargement theory with pressure recovery at the plane of the area change. Steady flow experiments are described to test the validity of the above assumptions. These show excellent agreement with the theory for the contraction. In the case of the enlargement the tests show that the plane of recovery is some distance downstream of the area change, the distance depending on the dimensions of the area change and the pressure ratio. Extensive unsteady flow tests are described. Good agreement between the theoretical diagrams and experimental results is obtained from the gradual area changes and the sudden contraction. For the sudden enlargement the agreement is good at the pipe ends furthermost from the area change. In the region near the enlargement the flow is strongly three-dimensional. The plane of pressure recovery for unsteady flow is about half the distance downstream from the enlargement for steady flow. The results indicate that once one-dimensional flow is formed the agreement between the theoretical and experimental diagram is good. It is therefore concluded that for gradual area changes the generalized one-dimensional unsteady flow theories may be used, for sudden enlargements quasi-steady flow theories may be used for predicting the flow in the regions some distance from the area change (about four diameters). For sudden contractions there is no limit to the region for consistent results to be obtained.
Paper 13: Experimental Investigation of Turbulent Heat Transfer in a Pipe Preceded by a 180° Bend
Authors: Lis J. , Thelwell M. J. 
Published: June 2010

The local values of the heat-transfer coefficient to water flowing turbulently in a pipe were measured for the following entry conditions: (1) A long hydrodynamic calming section. (2) One of three bends, having a radius 2, 3, or 4 times that of the pipe, and itself preceded by the calming section. The experiments covered a range of Reynolds numbers from 10 000 to 94 000 and heat fluxes from 5 to 50 W/cm2. The dependence of the local and average values of the heat-transfer coefficient on the Reynolds number, length of the pipe, ratio of the bend to pipe radius and variation of physical properties of the fluid with temperature, is analysed and discussed. Correlations are proposed for the local and average values of heat transfer in the entrance region of the pipe and for the heat transfer under the fully developed flow conditions.
Paper 18: A New Graphical Representation of the Thermodynamic Properties of a Fluid in Motion, with Particular Reference to Air at High Velocities, Temperatures, and Altitudes
Authors: Cole E. H. , Spalding D. B. 
Published: June 2010

Diagrams are described which represent the equilibrium thermodynamic properties of air, account being taken of dissociation. The ordinates are the logarithm of specific enthalpy in both cases; the two abscissae are the logarithm of specific volume in one case and that of velocity in the other. The specific enthalpy varies from 10 to 104 Btu/lb, the specific volume from 1 to 106 ft3/lb, and the velocity from 102 to 105 ft/s; the corresponding ranges of temperature and pressure are respectively 45°R to 11 700°R and 10-4 arm to 102 atm. It is shown how constructions on the diagrams may be used for the representation and calculation of steady-flow processes involving compression and expansion, heating and cooling, shock waves, detonations, mixing, and combinations of these processes.
Paper 21: Some Aspects of Research at the National Gas Turbine Establishment on Internally Air-Cooled Turbine Blades
Authors: Barnes J. F. , Fray D. E. 
Published: June 2010

This paper describes some of the results obtained from a series of experiments on internally air-cooled turbine nozzle and rotor blades. These were formed by an extrusion process and had, respectively, sixteen and thirteen cooling passages of approximately elliptical cross-section. The cooling characteristics of both types of blade were measured in an experimental high-temperature turbine and further experiments were conducted in cascade tunnels. Some of the cascade experiments on the rotor blade were conducted at comparatively high Reynolds numbers and showed, in accordance with predictions, the extent to which chordwise non-uniformities in blade temperature become larger as Reynolds number is increased. Other experiments were conducted with the turbine to determine the effects on aerodynamic performance of discharging spent cooling air into the main gas stream. The results showed good agreement with predictions based on a simple flow model, and in particular indicated that flow separation, with its associated losses, did not occur. Finally the results of an endurance test are presented, together with a brief description of the way in which thermal plus centrifugal stress patterns can be redistributed by creep in non-uniformly cooled blades. Brief mention is made of those fields of research which require further attention, namely an investigation of the factors governing the local values of heat-transfer coefficient on the external surface of turbine blades and the testing of the assumptions used in calculating stresses in cooled blades.
Paper 24: The Development of a Controlled Wet-Steam Generator
Authors: Ryley D. J. , Fallon J. B. 
Published: June 2010

This paper describes what is believed to be the first attempt to make a wet-steam ‘wind’ tunnel. Saturated water is sprayed from a small high-speed rotating disc so that the globules are entrained by a stream of saturated steam at the same temperature in which the disc is immersed. The tunnel is designed for a maximum steam speed of 30 ft/sec in a circular working section of 16-in diameter with steam pressures ranging from a full vacuum to 10 lb/in2 gauge. The entrained globules range in size from 5 to 100 micron, and the minimum nominal dryness fraction is 94 per cent. A sampling technique was developed based on the impressions made by the globules on a prepared slide, and an attempt is made to relate the globule size to the disc size and speed, the injection water flow and the physical characteristics of the saturated liquid and vapour. Globule trajectories were calculated by computer allowing for variation of drag coefficient and acceleration of the entraining steam. In the paper the design of the equipment and the problems encountered both in generating the wet steam and in determining the size of the globules are discussed.
Paper 13: Tests beyond Yield on a Spherical Pressure Vessel Containing a Series of Oblique Nozzles
Authors: Townley C. H. A. , Procter E. , Gadd B. W. 
Published: June 2010

The paper describes the first of a series of three tests designed to obtain information about the nozzle assemblies on reactor pressure vessels under a variety of loading conditions, with a view to predicting their behaviour in service. This first test is concerned with the effect of loadings which cause yielding in the nozzle region, and while overloads as severe as those described cannot occur in practice, the results enable a quantitative assessment to be made of the margins between operating pressure and failure pressure as far as shortterm yielding is concerned. They also provide data which will be of interest when improved design methods, involving higher working stresses, are considered. The test was carried out on a spherical vessel containing a small group of oblique nozzles, manufactured to represent a nozzle layout typical of reactor vessels, at scale size. The vessel was hydraulically pressurized up to 1670 1b/in2 gauge when failure occurred through the heat-affected zones of the nozzle to shell welds. The basic shell stress at failure was approximately equal to the ultimate tensile strength of the material. Strain readings recorded during the tests, and the results of the metrological surveys, carried out on the vessel before and after testing, are discussed in the report.
Paper 1: Bend-Buckling of Pressurized Cylindrical Shells
Authors: Coutie M. G. , Maunder L. 
Published: June 2010

Thin cylindrical shells subjected to high bending loads normally buckle by forming a number of diamond- shaped panels on part of their compressed surfaces. The values of the buckling loads show considerable scatter but are in general substantially less than those predicted by simple linear theory. This paper describes an attempt made a few years ago to improve the buckling strength and to reduce the scatter in the buckling loads of such shells by means of internal pressure. It was expected and confirmed that internal pressure would increase the buckling loads, but little improvement was obtained in the amount of scatter. Considerable modifications of the buckling deformations were observed; at sufficiently high pressures the diamond pattern disappeared entirely and was replaced by a single ridge of deformation extending circumferentially around the compressed side of the shell. An account is given of the experimental investigation together with some excerpts from the theoretical work. Most of the shells were formed from thin steel sheets bent into the shape of a cylinder then soldered down a generator. They were filled with water, plugged at their ends and put under pressure by means of a hand-pump. Observations made during bending included load, pressure, strain, deflections and mode of buckling. These are discussed and compared with the results of other investigations.
Paper 16: Effect of Thermal Cycling on Pre-Stressed Steam Pipelines
Authors: Jeal R. H. , Bindley D. 
Published: June 2010

Investigations into the effect of temperature and pressure cycling on a pre-loaded model main steam line of 0·5% Cr-0·5% Mo-0·25% V steel have shown that a relatively large increase in length occurred over a few cycles at 100 per cent cold pull, and a decrease in length occurred at 50 per cent cold pull. Using high temperature platinum-tungsten strain gauges, it has been found that large changes in strain occur round an expansion loop in the model pipeline. It is suggested that large changes in the design stress distribution in a main steam line occur during the commissioning stages of a generating unit, making creep behaviour of the line during base loading difficult to predict. It is further suggested that failure in pipelines when a unit is working under a twoshift system is due to low cycle fatigue, as the strain changes occurring do not appear to approach an equilibrium minimum under cycling conditions. It would appear that strain changes, and hence the effect of low cycle fatigue, can be minimized by choosing a level of cold pull between 50 and 100 per cent, the actual level depending upon the physical characteristics of the pipe material, the more important ones being thermal expansion and the change of yield stress with temperature. Using the plastic strain range measured in the test a prediction can be made regarding the time to failure.
Paper 2: Effect of Bending Moments on Nozzles with Forged Transition Pieces
Authors: Kitching R. , Jones N. 
Published: June 2010

An experimental study has been made of the elastic stress distributions arising in the vicinity of two transition rings of the type used to connect cylindrical ducts with large spherical pressure vessels. The effect of bending moments on the duct was considered and theoretical estimates of the stresses were made by modifying certain well-known analyses. Two of these methods gave results close to the experimental values in a region which included the position of maximum stress. This occurred near the weld between the spherical shell and the transition ring. In a further investigation it was found that, for the order of loads applied, the principle of superposition may be used to calculate the combined effect of a local bending moment and an internal pressure. When allowable bending moments at design pressure are calculated using a limiting stress concentration factor, the heavier transition piece is slightly superior to the other.
Paper 7: Operating Experience of Installed Gas Turbines
Authors: Auer W. P. 
Published: June 2010

Twenty-four years ago the first industrial gas-turbine unit, a Brown Boveri 4000 kW set installed by the City of Neuchâtel in Switzerland, started a new era of power generation. This new type of prime mover has since been widely introduced and generally accepted. It serves as base-load and as peaking plant. The fuels used range from natural and blast-furnace gases to diesel, crude, and heavy fuel oils. Extensive experience of running has accumulated in all applications which has permitted the analysis of the operating performance of the gas turbine. The paper reports on the performance of some characteristic gas-turbine installations that are representative of the different applications and fuels. In addition to providing interesting information on the general performance of the gas turbine, the experience gained under various conditions has also permitted the discovery, understanding, and control of special design problems not previously recognized. The more important of those discovered in recent years are discussed and corrective measures are explained.