bluuebunny/crossref_metadata_2025_split huggingface dataset:
Velocity of Sound and Critical Discharge Pressure in Annular Two-Phase Flow
Authors: White R. F. , D'Arcy D. F. 
Published: June 2010

The effects of a rapid loss of coolant caused, for example, by the fracture of a pipe in the primary coolant circuit play an important part in the safety assessment of a water-cooled nuclear reactor. In particular, it is essential to know the rate of decrease of coolant density in the core and the rate of discharge of coolant into the containment space. It is uneconomic to obtain this information from experiments on each new reactor. Consequently computational methods, supported by experiments on basic elements of a coolant circuit, are being developed which will be applicable to a wide variety of reactors. An experiment is described in which fundamental information on fluid flow dynamics was obtained. In the experiment, a flow of two-phase water at high pressure was established in a straight pipe 15 ft long and 0–621 in i.d. At the downstream end of the pipe a rupture disc was suddenly burst. The pressure versus time histories at three locations along the pipe were recorded, using fast response pressure transducers and a multichannel oscilloscope. Experimental results are given for pre-blowdown pressures of 500 and 1000 lb/in2 (abs.) and steam qualities of 10–30 per cent. The mass flux was 0·6 times 106 lb/ft2 h, and the flow regime was annular. From the recorded pressure traces, the speed of the head of the rarefaction wave travelling upstream into the fluid was measured and also the pressure at critical flow conditions as functions of the pre-blowdown conditions. These measurements are compared with values calculated from steam tables.
An Investigation of Electrostatic Charging Effects in High-Speed Gas-Solids Pipe Flows
Authors: Cole B. N. , Baum M. R. , Mobbs F. R. 
Published: June 2010

A comparison is made between the pressure distributions in identical brass and nylon pipe-lines conveying polystyrene powder, showing that electrostatic charging of the solid particles has a negligible effect on highspeed, gas-solids pipe flow. A theory is presented for the prediction of the electrostatic charging rate of the solid particles. It is predicted and confirmed experimentally that the current to earth from electrically isolated sections of the brass pipe and from aluminium foil wrapped on a length of the nylon pipe varies linearly with the solids loading.
Effect of By-Pass Characteristics on Parallel-Channel Flow Instabilities
Authors: Carver M. B. 
Published: June 2010

Experiments on parallel-channel hydrodynamic stability frequently use one heated channel operating in parallel with an unheated by-pass. This arrangement is designed to simulate the operation of a particular channel in a boiling water reactor; the by-pass providing the essentially constant pressure drop which the remaining channels impose on the channel in question. If the ratio of by-pass flow to channel flow is large the changes in channel flow do not significantly affect the overall pressure drop; however, particularly in experiments using full-scale reactor fuel channels, loop capacity may limit this by-pass ratio. In this case the pressure drop is no longer constant. This paper shows, analytically, that a low by-pass ratio, resulting in a variable overall pressure drop, significantly affects the dynamic behaviour of the heated channel. Both the power at threshold of flow oscillation and the natural frequency of the system are shown to depend on by-pass characteristics. In particular, a heated channel operating with a low by-pass ratio is normally stable to much higher powers than it is with a high by-pass ratio. A linearized analysis is presented which illustrates the effect of by-pass resistance and inertia on the threshold power and natural frequency of flow oscillations. The analysis is incorporated in a computer code, and resulting threshold powers and oscillation frequencies are compared to data from experiments using a full-scale simulated reactor channel in parallel with a by-pass. It is concluded that the finite unheated by-pass does not accurately simulate the dynamic effect of the remaining reactor channels on a particular channel. However, the methods of this paper should prove useful in interpreting results from a flow-limited test loop and extrapolating to the full reactor case.
Current Design Activities on British Railways
Authors: Thring J. F. 
Published: June 2010

With the identification of profitable freight areas and the selection of growth traffics for development has come the need to review in detail the running gear and, in particular, the suspensions of both 4-wheeled and bogie vehicles. This design review has been aimed at ensuring a high-speed capability for all new freight vehicles coupled with safety at all times, low maintenance costs, and maximum availability. After reviewing traditional suspensions, in wide use, with reference to their known strengths and weaknesses, the paper discusses in some detail the philosophy now being applied in B.R. design offices to new freight running gear, for both 4-wheeled and bogie vehicles, to ensure satisfactory achievement of technical objectives. Examples of new developments are provided, together with comments on progress to date.
The Solution of the Heat Flow Equations in Large Electrical Machines
Authors: Roberts T. J. 
Published: June 2010

To ensure that the materials used in the construction of a rotating electrical machine are utilized economically it is necessary to be able to predict the temperature distribution within the machine. A resistance network analogue representation of the stator core and windings is derived, based on the finite difference approximation to the heat flow equations. A solution of the analogue is achieved by matrix methods on a digital computer. The advantages of this particular analogue representation are that the effects of axial heat flow in the copper and changes in the air temperature in the radial air ducts are taken into account. The validity and accuracy of the analogue representation are checked by comparing the results with those obtained from detailed temperature measurements on a production machine. It is shown that the present standard methods of measuring winding temperature are inadequate for determining the actual copper temperature. Under certain circumstances high temperatures can be obtained in the endwinding region of a machine. These temperatures are undetected by the standard method of temperature measurement and are shown to be due to the low value of endwinding insulation thermal conductivity.
Determination of the Thermal Constants of the Heat Flow Equations of Electrical Machines
Authors: Roberts T. J. 
Published: June 2010

One of the major problems in obtaining accurate predictions of temperature distribution within an electrical machine is the values of the thermal constants used in the solution of the heat flow equations. A line source method is developed for anisotropic materials and is used to determine the thermal conductivity of sheet steel laminations. Results are given for three typical sheet steels showing the effect of varying core clamping pressure. The thermal conductivity of high-voltage insulation is obtained from tests on production machine coils and values are given for typical insulation systems. A model test is described for the evaluation of the heat transfer coefficients from the cooling surfaces of the radial air ducts, based on the assumption of a uniform distribution of air across the duct entrance. The heat transfer coefficients from the other cooled surfaces within the machine are determined from full-scale temperature measurements on production machines. The limitation of this latter method of determination of heat transfer coefficient is evaluated.
Heat Transfer Considerations in Superconducting Machines
Authors: Tinlin F. 
Published: June 2010

Problems of cryogenic heat transfer are discussed with particular reference to the IRD prototype superconducting motor. Experimental work on heat transfer in the nucleate boiling régime of liquid helium is described and the application to the design of a superconducting field coil is outlined. The design of gas-cooled high-current leads in a cryogenic environment is discussed and the practical solution is compared with the theoretically ideal design. Other heat transfer problems encountered in the machine design are those associated with the thermal isolation of the field coil from the environment. An assessment is given of the various heat loads due to conduction and radiation which make up the total refrigeration requirement of the machine.
Paper 4: An Investigation of Shock Wave Behaviour in Ducts with a Gradual or Sudden Enlargement in Cross-Sectional Area
Authors: Deckker B. E. L. , Gururaja J. 
Published: June 2010

This paper details some investigations relating to non-stationary wave interactions and their effects on the propagation of finite amplitude waves in ducts with either a gradual or sudden change in cross-section. The influence of the angle of divergence on the wave-front and the perturbed flow behind it has been examined in different diffuser configurations using Schlieren spark photography. The variation with incident pressure of the net pressure (superimposition pressure) and the transmitted pressure are presented for incident pressure ratios up to 3·4. The results have been compared with a quasi-steady one-dimensional analysis and with the theory of Chisnell. Differences between measured and predicted results are attributed to the failure of the theories to account for the wave interactions. A complete analytical solution does not appear possible in view of the complexities of the flow and wave action, and numerical methods have to be employed.
Paper 1: Relation between Blade Row Spacing and Potential Flow Interaction Effects in Turbomachines
Authors: Parker R. 
Published: June 2010

This paper develops a simple relationship between distance upstream and downstream of a row of blades and the velocity disturbances created by the passage of those blades. The relationship is compared with values obtained by numerical computation and measurement in an experimental axial flow compressor rig. The magnitude of vibration exciting forces and/or noise radiation sources due to potential flow interaction on a stationary row of blades is directly related to the magnitude of these velocity fluctuations. The analysis is therefore a basis ( a) for estimating the inter-row spacings for a turbomachine such that potential flow interactions are reduced below the levels of other forms of interaction, and ( b) of translating practical experience of noise and/or vibration excitation in existing machines to give reliable predictions for future designs. It is found that while potential flow interaction effects drop rapidly with increasing blade row spacing for low-speed machines, this is not the case for high speeds and very large spacings may, in fact, be required where the rotor blade speed is equivalent to a high value of Mach number. It is also found that the rate of decrease in effect is related to the circumferential wavelength of the disturbance, and comparisons between machines based on blade chords (as is the present normal practice) are meaningless unless the ratio pitch/chord is constant.
Paper 7: Mass Flow Prediction in Natural Circulation Boilers
Authors: Thomson A. S. T. , Scott A. W. , Rooney D. H. , Bradford A. M. 
Published: June 2010

This paper presents results from a programme of steady-state natural circulation tests carried out on a two-tube experimental boiler. The circuit was constructed using normal commercial tubes and the tests covered the following range of variables: During the tests, measurements were taken of pressure, pressure difference, circulation rate, and density or void fraction at the top of the riser tube. The void fraction data are presented for use. A theoretical analysis was carried out using an annular type flow model in the riser tube with a simple two-phase friction pressure drop expression which required only void fraction data. A comparison was made between the theoretical results and the experimental data and the comparison was extended to include ( a) homogeneous flow, ( b) Martinelli–Nelson correlation, and ( c) Thom correlation. The results indicate that the analysis used, which requires only void fraction data, gave the best correlation over the range of natural circulation conditions covered.
Paper 9: Theoretical and Experimental Studies of Wet Steam Erosion in a Counter-Rotating Radial Steam Turbine
Authors: Söderberg E. O. , Widell K-E. 
Published: June 2010

Erosion test in a model counter-rotating radial flow turbine has been performed to assist in the design of a 460-MW radial flow turbine. Three rows of erosion specimens were inserted at different radial locations in the last blade ring upstream of the blades to investigate the influence of the radial distance between the stages. Results showed that small droplets were formed and that erosion diminished with increased radial spacing up to a certain distance. A theoretical model for calculating droplet trajectories, sizes, and impact velocities has been derived, taking full account of wake velocity, variable droplet drag coefficient, and atomization. The calculations explained all the experimental facts and made it possible to convert the model test results to the full-size turbine showing no risk of erosion in the latter.
Paper 12. The Inverted Tooth Chain as an Automotive Transmission Medium
Authors: Hoar M. S. 
Published: June 2010

Throughout the world's automotive industry, a great deal of thought is currently being directed towards achieving power transmission layouts which are both compact and weight-saving and which achieve the desired distribution of vehicle weight. This trend is particularly noticeable in Europe, where success in the market place depends to a large extent on giving greatest passenger space for the customer's money. However, it was on a very non-European passenger car that a product was introduced which is now helping designers obtain maximum transmission compactness at minimum cost. The car was the Oldsmobile Toronado, and the product the Morse Hy-Vo® inverted tooth chain.
Penetration and Vaporization of Diesel Fuel Sprays
Authors: Burt R. , Troth K. A. 
Published: June 2010

In the diesel engine, fuel is injected into the hot, compressed air in the combustion chamber. Thus the process of diesel combustion is essentially inhomogeneous, and the mixing of the fuel and air in the combustion chamber dominates the whole combustion process. Since fuel–air mixing is so important the distribution of the injected fuel has a major effect on combustion performance. This is particularly true of direct-injection diesel engines which have relatively low rates of air movement. In all diesel engines, fuel is injected into the combustion chamber at high pressure through small nozzles. The high-velocity liquid jet atomizes, after emerging from the nozzle, into a spray of liquid droplets. The penetration, distribution, and vaporization of the sprays, together with the air movement, govern the mixing of fuel and air. The penetration of fuel sprays is dealt with in Part 1 of the paper; Part 2 describes a study of the vaporization of fuel sprays.
Paper 3: Boiler Feed Pump Design for Maximum Availability
Authors: Weldon R. 
Published: June 2010

With increasing size of turbo-generator sets, the criterion of maximum availability for boiler feed pumps has assumed even greater importance. Capital cost, power consumption, and availability are all necessary considerations in the economic optimization of power-generation equipment design. The capital and running costs of the boiler feed pump are relatively small compared to the plant for which it is an auxiliary. However, such plant depends implicitly for its revenue-earning capacity on the reliability of the boiler feed pump. Awareness of these overall economic considerations has led to the maximum availability design concept for large boiler feed pumps. To achieve these ends, a high-speed, rigid-rotor design concept has been evolved which permits the machine to continue in satisfactory mechanical operation under vapour-locked conditions. A new cartridge principle of pump construction has been introduced, wherein the complete internal assembly, incorporating end covers and bearings, is withdrawn as a single unit leaving the casing in situ. The extensive research and development carried out to prove the individual features of the design are fully described, together with particulars of the complete prototype machine, which at the time of writing is believed to be the highest stage pressure boiler feed pump in commercial operation in any power station throughout the world.
Paper 6: Development of Boiler Feed Pumps in Czechoslovakia
Authors: Hladiš V. , Kupa J. 
Published: June 2010

The paper outlines the main features of the development of boiler feed pumps in Czechoslovakia, which took place in parallel with the development of Czechoslovak power engineering. The basic design arrangement of boiler feed pumps as separate sets and their design execution are described. The development of material selection is also reviewed. Some problems of rotor dynamics are referred to relative to the choice of speed and the influence of impeller packing ring design is emphasized. The cavitation qualities of the boiler feed pump are considered and new aspects concerning the evaluation of cavitation tests are discussed. The determining by visual observation of so-called evaporating curves, which explicitly limit the cavitationless operation of the pump, is explained.
Paper 8: The Dynamic Performance of Tractor–Implement Combinations
Authors: Dwyer M. J. 
Published: June 2010

The dynamic performance of tractor-implement combinations is considered theoretically in terms of the changes in load, weight transfer, and forward speed arising from variations in implement working depth. Two tractors, one having a top-link sensing control system and the other having a lower-link sensing control system, were modified so that the driving wheels ran eccentrically, imparting a sinusoidal variation in working depth to mounted implements and field tests were carried out using mouldboard and chisel ploughs. The draught and vertical forces between the tractors and implements were recorded continuously during the test runs, together with implement working depth, tractor engine speed, and forward speed. Measured variations in draught correlated well with the variations predicted from laboratory measurements of the tractor implement-control system characteristics. It is concluded, therefore, that field performance can be predicted from standard test data if such measurements are incorporated. The theoretical analysis is used to suggest optimum parameters for implement-control systems. With fully-mounted implements, no significant difference was found between top- and lower-link sensing systems which were otherwise similar. Chisel ploughs were shown to be more difficult to control than mouldboard ploughs. Higher sensititivies would be required to retain control at higher working speeds and also for operating semi-mounted implements with lower-link sensing systems. Semi-mounted chisel ploughs are likely to be more easily controlled than fully mounted ones, but semi-mounted mouldboard ploughs would be slightly more difficult to control than fully mounted ones. A small dead-band in the response characteristics of implement-control systems is shown to have negligible effect on performance, and current maximum rates of lift are likely to be adequate for control purposes.
Paper 12: Automatic Control of Tractor Mounted Implements
Authors: Cowell P. A. 
Published: June 2010

The development of implement control systems has been greatly influenced by the pattern set by the Te20 Ferguson tractor, and most three-point linkage draught control systems operate on the same principle. Such designs, whilst adequate for most purposes on level going, display poor depth control behaviour when traversing undulating ground. A full understanding of these systems has been limited by the absence of a mathematical theory capable of predicting their behaviour. This paper sets out to examine the problem in control theory terms. An experimental hydraulic control system has been built using pure draught force sensing, and its behaviour has been studied both mathematically and experimentally in the laboratory and in the field. To enable theoretical predictions of system behaviour to be made a second rig was constructed to study the transfer functions of implements. This rig can also serve as a simulator of field surface disturbances. The performance of the experimental system was compared with a popular commercial system using the second rig as a simulator and the results indicate that pure draught control sensing as used in the experimental system is feasible in practice. The paper concludes with a short discussion of alternative control strategies.
Paper 14: Brakes for Agricultural and Allied Tractors
Authors: Gannon J. E. 
Published: June 2010

The need for greater stress on all aspects of the safety of vehicles on the road has imposed, and continues to impose, greater emphasis on the braking performance of agricultural and industrial tractors. In view of this emphasis, the braking requirements of these vehicles over a range of sizes have been examined in detail, together with the present known design parameters of the brakes themselves. Existing types of brakes are discussed. and comparisons are drawn with the annular piston-type brake that is emerging on the latest tractor designs, Actuation of the brakes is discussed and, again, comparisons are drawn between the mechanical actuation currently used and the various forms of hydraulic actuation necessary to simplify tractor layout and to obtain the compensation required by the high rates of differential wear which can occur due to the spin-turning operation. The fact that a high degree of versatility will be required in order that the vehicle operator will be able to couple a variety of trailers to his tractors will be an important factor in system selection. The need for correct apportionment of the braking efforts between the tractor and trailer is discussed in detail, to illustrate the complexity of the problem when balanced and unbalanced trailers are considered. Suggestions are made for braking ratios that give a compromise solution to the problem.
Liquid Junction Potential between Different Solvents: The Component due to Solvent–Solvent Interactions Is Dipole Potential in Nature
Authors: Izutsu Kosuke 
Published: June 2010

Abstract
The liquid junction potential between different solvents contains three components, i.e., component (a) due to electrolyte concentrations and ionic mobilities, component (b) due to the solvation of ions, and component (c) due to solvent–solvent interactions. The values of component (b) are actually much smaller than the values calculated from theoretical equations, but other researchers considered the equation to be valid and came to the conclusion that component (c) depended on electrolytes. From electrolyte-independent characteristics and others, we report here that component (c) is not the diffusion potential but the dipole potential.