bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Piezo-Viscous Fluid, Rigid Solid Regime of Lubrication
Authors: Dowson D , Dunn J F , Taylor C M 
Published: February 2007

A general analysis of the lubrication of rigid-ellipsoidal solids by a piezo-viscous fluid is reported. Solutions based upon the Reynolds cavitation boundary condition are presented and details are given of the resulting pressure distributions and film thickness predictions. Four distinct forms of the fluid film lubrication of a general curved solid near a plane have previously been noted and described as: (i) rigid-isoviscous, (ii) elastic-isoviscous, (iii) elastic-variable viscosity (piezo-viscous), (iv) rigid-variable viscosity (piezo-viscous). Solutions already exist for the first three forms of lubrication for conjunctions formed between solids having curvatures in two principal directions, but the rigid-variable viscosity regime has not previously been analysed within the same general set of conditions. The results not only enable the film thickness between curved solids in nominal point contact to be predicted with reasonable confidence, but they indicate quite clearly the dominant physical effects governing the hydrodynamic performance of such conjunctions.
Design Study of a 375 kW Helicopter Transmission with Split-Torque Epicyclic and Bevel Drive Stages
Authors: White G 
Published: February 2007

A novel drive train based on a simple epicyclic gear that drives a bevel combining gear through counter-rotating pinions is developed into a main gearbox for a helicopter powered by a single engine. A design with an overall speed ratio of 17.6 : 1 is compared with an advanced technology version of a production transmission. The new design, based on an integral main shaft and bevel gear, has a dry weight of 46 kg and offers a 24 per cent reduction in weight while remaining competitive in respect of drive train losses and totals of gears and bearings.
Effect of Top-Relief and Rake Angles on the Gear Shaping Cutter Profile
Authors: Srinivasan N , Shunmugam M S 
Published: February 2007

Gear shaping cutters are provided with top-relief and rake angles. As a result of this, the profile representing the cutting edge is modified. This paper deals with the method of obtaining the effective profile on the rack-type and pinion-type cutters for spur gears. Analysis of the effective profile shows that the effective profile of the rack-type cutter is actually a straight-sided tooth form with different pressure angle and tooth thickness at the reference (pitch) line. In the case of the pinion-type cutter, tooth thinning takes place and the effective profile could not be identified with any involute form. This paper also deals with the methods of correcting the cutter profile form so that profile close to the theoretical form can be obtained on grinding the rake face. This approach would be quite useful to the designers and manufacturers of the shaping cutters.
Cost Effective Engineering Through Simulation
Authors: Hollocks B W 
Published: February 2007

Computer simulation is a well proven and powerful tool to assist engineers in the decision making which is part of plant design and operation. British Steel (BSC) was the pioneer in this field. The paper describes recent advances in simulation tools, and recent examples of their application. Drawing on BSC experience, the paper discusses where and how simulation should be used in order to secure the considerable potential benefits in reduced costs and improved plant performance.
Effect of Reducing the Blade Cooling Air Temperature and Mass Flow on Blade Life and Cycle Efficiency
Authors: Hay N , Taylor J H 
Published: February 2007

Reduction of the temperature of the air used for blade cooling to below the compressor exit temperature would allow the required mass flow to be reduced and might be expected to result in an improvement in engine performance. This is demonstrated and quantified in this paper. Improvements in both blade life and cycle efficiency are shown to be possible. For example by cooling the coolant by 50°C a reduction in coolant flow of 40 per cent is possible as well as an improvement of 20 per cent in blade life. Additionally a marginal increase in cycle efficiency is obtained and a 1.4 per cent increase in specific work output. A concept for an integrated cooling device for producing the required reduction in temperature of the blade cooling air is described and appraised. As envisaged at present, the device would be too bulky for airborne applications. However, with further development a feasible design might be evolved.
The Active Control of Noise and Vibration and Some Applications in Industry
Authors: Swinbanks M A 
Published: February 2007

During the last decade, advances in signal processing and microelectronics have brought to reality the development of active devices for suppressing noise and vibration. These have now been successfully demonstrated both in laboratory experiments, and under more rigorous conditions of large-scale industrial application. It is shown that close parallels exist between these novel active techniques and certain well-proven mechanical methods of reducing vibration. Examples of the latter are given which date back to the last century, and highlight the extent to which the basic principles of dynamic vibration cancellation have been applied with confidence by mechanical engineers. Now, in common with many other applications of control technology, the process of replacing simple mechanical linkages with more precise and responsive electronically activated servomechanisms has led to considerably improved flexibility and adaptability. In this respect the application of active control to vibration attenuation represents a natural and timely step in engineering development. A more recent advance, however, has been the application of these techniques to the direct control of airborne sound, which represents a greater departure from conventional engineering practice. A number of successful examples of such methods have now been demonstrated. It is proposed that more sophisticated devices, which will take even greater advantage of the power of modern signal processing, will be developed for the future. These devices promise to enhance considerably the overall scope of the technology.
Experience in Using Computer Aided Design and Draughting Equipment in the Mining Manufacturing Industry
Authors: Chandler D 
Published: February 2007

This paper describes the use of computer aided systems in connection with the design of powered roof supports to work on mechanized installations for the underground extraction of minerals, principally coal. Each roof support is made up of many structural components withstanding extreme loading conditions: hydraulic struts which hold up the roof advance the support, etc., and associated valve gear (both electronic and hydraulic control) to operate the supports. Each set of roof supports (approximately 150 per installation) is custom built to suit the particular mine's requirements. A computer aided design (CAD) system was installed in 1979 to help with the presentation of technical brochures for presentation with the quotation to prospective customers. This proved a great success especially in the pictorial representation of the proposed support to the customer. Since then the CAD facility has been expanded, especially in the structural design area, and is now used for design and analysis as well as normal draughting of components and assemblies. This paper emphasizes the use of CAD as a design and analysis tool rather than equipment that can produce detail drawings more quickly than manual methods. It also explores where CAD can be of benefit in hydraulic design in areas such as flow analysis and its extensions into CAD/CAM (computer aided manufacture) and general manufacturing.
The Mathematical Modelling of Hydrostatic Pumps and Motors
Authors: McCandlish D , Dorey R E 
Published: February 2007

Accurate mathematical models of hydrostatic pumps and motors are required in the synthesis and analysis of hydraulic systems. Increasingly the models are used in computer simulation work where the performance of the machines must be represented over a wide range of operating conditions. Examination of test data has shown significant differences in the real performance characteristics of hydrostatic machines compared to the characteristics predicted by classical models based on simple linear theory. This paper describes these differences and shows the way that the characteristics can change with different designs of machine. A mathematical model is developed which may be adapted to describe the wide range of characteristics associated with the different designs. This model has shown good agreement with test data. Recommendations are made for more comprehensive performance tests to provide the data required for more accurate models.
The Computation of Thick Axisymmetric Boundary Layers and Wakes around Bodies of Revolution
Authors: Markatos N C 
Published: February 2007

The paper is concerned with the computational investigation of thick, axisymmetric, turbulent boundary layers and wakes around bodies of revolution. The procedures employed take full account of the influence of longitudinal and transverse surface curvatures and normal pressure gradients on the development of the boundary layer and wake, and also the viscous—inviscid interaction in the tail region of the body. The method makes it possible to calculate the static pressure and the velocity profiles along the body as well as the drag components; and it is applicable to both two- and three-dimensional situations, enabling, for example, the prediction of flows around ships' and submarines' hulls to be made. The application of the fully-elliptic calculation procedure to a body of revolution is described, and comparisons made between predictions and experimental measurements. The calculated axial variation of skin friction and pressure coefficient, and the velocity profiles are shown to be in fair agreement with experimental values.
Influence of Induction Swirl and Piston Configuration on Air Flow in a Four-Stroke Model Engine
Authors: Vafidis C 
Published: February 2007

Measurements of ensemble-averaged mean, r.m.s. and cycle resolved instantaneous swirl velocities, obtained by laser—Doppler anemometry, are reported for the in-cylinder flow in a four-stroke model engine motored at 200 r/min. Variable induction swirl was created by 30° and 60° vanes located in axisymmetric and off-centre intake ports with flat and re-entrant bowl piston configurations. The results showed that the main features of the initial swirl velocity distribution, which are determined by the intake port/valve geometry, persist through the compression stroke. The swirl centre performed in all cases a helical motion whose development was a function of the clearance volume at top dead centre; the weakness of this motion made it susceptible to cyclic variations which were significantly reduced with the re-entrant piston bowl. High induction swirl resulted in lower turbulence intensity at top dead centre of compression, in the flat piston case, and more complex vortex pattern inside the re-entrant piston bowl. The angular momentum decay from inlet valve closure to top dead centre of compression was shown to depend on initial swirl ratio and velocity distribution and calculated to be about 30 and 45 per cent for the flat and re-entrant bowl piston, respectively.
A Car for the Nineties: BL's Energy Conservation Vehicle
Authors: King C S 
Published: February 2007

Several crises in the Middle East have resulted in the disappearance of cheap fuel oil. Further crises are possible and although considerable reserves exist, with the exception of the Middle East, production is bound to become more and more expensive. BL's answer is the conservation vehicle. Development ran through two preliminary phases, ECVI and ECV2, which were based on a small car prototype. The third phase ECV3, though profiting from the earlier vehicles, bears little resemblance to them; it is bigger, it shares few common parts and to a large extent is made from different materials. The objectives for the ECV are 0–60 mile/h acceleration in 12 s or less with an average fuel consumption of better than 50 mile/gal. It must be in no way inferior to existing medium sized family cars in performance, ride, handling, interior noise, vibration, safety and accommodation. It is designed for minimum whole life cost. This lecture describes the efforts made to meet these objectives.
Applications of Fibre Reinforced Plastic Composites in the Railway Industry
Authors: Batchelor J , Wilson J E 
Published: February 2007

This paper describes the use of fibre reinforced plastics in the railway industry. A description is given of various case studies, including seat shells, temporary overhead structures, pantograph heads, cab fronts and doors, in order to give a practical illustration of the various applications to which such plastics can be put. The paper also deals with design criteria such as stiffness, strength, flammability, durability and cost effectiveness, quoting comparative figures. Finally, the paper looks at future developments, specifically the use of higher performance carbon and aramid, fibres, both of which are discussed, after which a brief description is given of fibre reinforced thermoplastics for performance applications.
Tailoring Oils to Engines
Authors: Colyer C C 
Published: February 2007

Today's high performance automotive engines would not operate effectively without the progressive advancements in engine oil formulation technology. A communications network between the engine builders, additive suppliers, petroleum companies, and consumers is essential in the continuous tailoring of engine oils to meet new engine requirements. The SAE/ASTM/API tripartite Engine oil performance and engine service classification system is recognized worldwide as a base for adding further requirements for various geographic areas. Attempts to develop one worldwide specification system have been thwarted by lack of unified agreement within, as well as between, the pertinent geographic areas of the world. In addition, worldwide specifications would not provide cost/performance optimization for areas not requiring each of the included engine oil parameters, and oil formulation compromises required to meet total world requirements could weaken oil performance in a specific area. As new engine designs place additional burdens on engine oils, the role of chemical additives to meet these demands increases. Revised engine oil evaluation tests are an associated need. Continued efforts toward elusive worldwide engine oil specifications will provide benefits by consolidating the number of expensive laboratory engine tests required to define engine oil performance.
The Effect of Atmospheric Conditions on the Performance of an Air-Borne Two-Stroke Spark-Ignition Engine
Authors: Sher E 
Published: February 2007

The effect of changes in atmospheric pressure and temperature on the performance of a crankcase-scavenged spark-ignition two-stroke cycle engine has been investigated. A detailed computer code has been developed to simulate the two-stroke cycle and was used to evaluate an optimal engine design for best performances at high altitude conditions. The model which includes detailed computations of the scavenging process, calculations of the flows into and out of the engine, empirical expressions for the combustion process, and a practical approach for the heat transfer has been calibrated by using experimental results. An empirical correlation has been devised for the prediction of the indicated power and for the specific fuel consumption of an engine at any pressure and temperature using information obtained at normal atmospheric conditions. These are [Formula: see text] The correlations have been compared with some other suggested correlations and were found to best fit experimental observations for three different makes of engine.
The History of Safety Valves Leading to the Development of British Standards for Safety Valves
Authors: Fuller J A 
Published: February 2007

The Institution of Mechanical Engineers has stated, and the British Standards Institution has accepted, that a standard should reflect both the most up-to-date and reliable advice that can be applied within prevailing economic restraints, and the needs of supplier and user. The paper reviews some features of safety valve design from 1680 onwards and relates these to various requirements of British Standards for safety valves, BS 759 of 1937, and its subsequent revisions, BS 1123 of 1943, and its revisions, both of which are application standards, and BS 6759: 1984, which is a product standard. This latter standard for safety valves, which is in three parts, (Part 1. Safety valves for steam and hot water; Part 2. Safety valves for compressed air and compressed inert gas; Part 3. Safety valves for process fluids not covered by Parts 1 and 2) is introduced and described in some detail, particular attention being given to the sections dealing with the certification of performance of any given design.
Ceramics Technology—Application to Engine Components
Authors: Parker D A 
Published: February 2007

In the development of engine components a number of special techniques are used to combat the hostile operating environment which usually includes high and cyclic forces, high and cyclic temperatures, sliding and often corrosion and/or erosion. Examples of the use of these techniques, namely the development of special materials for substrate and surface, of mathematical modelling verified by telemetry, and of special machining, to solve the problems of the operating environment, are given in respect of pistons, piston rings, cylinder liners, bearings, camshafts and valve seat inserts. It is noted that of the above techniques the development of special surface and substrate materials provides the most universal assistance. The application of materials technology to surface and substrate is illustrated with respect to ceramics, including silicon nitride, silicon carbide, zirconia and alumina. Applications under development include insulation, improvement of wear resistance, reduction of mass, increase of operating temperature and the reinforcement of metals, for example, reinforcement of aluminium alloys using alumina fibres incorporated by squeeze casting. The several means open to improve the properties of gravity cast aluminium silicon alloys are reviewed and the improvement of properties obtainable by squeeze casting without reinforcement are illustrated. The further enhancement of these properties by the design of an appropriate fibre reinforcement system, incorporated by squeeze casting, is then described. Its application to the reinforcement of a combustion bowl subject to high thermal stress is discussed and the performance of the resulting piston in relation to unreinforced pistons is described. In conclusion the market, product and process aspects of the development are correlated to demonstrate its overall value and to identify further applications.
Process Analysis of a Starter Clutch Sleeve Extrusion
Authors: Abdul N A 
Published: February 2007

The process of making the clutch sleeve for starter motors was discussed and the most difficult and final stage of backward extruding a preformed billet to produce the sleeve was examined experimentally. The conventional zinc phosphate/sodium stearate lubricant and six other cold-forming lubricants were applied to vary friction conditions at the tool/workpiece interfaces. The final stage was then analysed and the predicted variation of the reduced stress, the mean forming load as well as the length of the extruded part were presented against the punch movement for various frictional conditions. The predicted results were compared with the experimental results and a close agreement was observed.
The Volumetric Performance of Cavitating Centrifugal Pumps: Part 1: Theoretical Analysis and Method of Prediction
Authors: Grist E 
Published: February 2007

An exact analysis of cavitating flows in a centrifugal pump eludes engineers. A simplifying concept of notional spherical cavities is proposed which, it is suggested, has sufficient validity to be a very useful tool in predicting some aspects of volumetric performance. A method of applying an analysis based on this concept is given. The volumetric performance predicted for different pumped liquid properties or a different pump speed from data obtained in a single reference test are: (i) the value of nett positive suction head (NPSH) at generated head breakdown; (ii) the generated head/cavitation zone length curve.
The Volumetric Performance of Cavitating Centrifugal Pumps: Part 2: Predicted and Measured Performance
Authors: Grist E 
Published: February 2007

The predicted performance of a cavitating centrifugal pump, calculated using a method which applies the concept of notional spherical cavities, has been compared with measured performance values. From the close agreement evident in predicting the nett positive suction head at breakdown and the generated head–cavitation zone length curves the method and concept appear suitable for wider engineering application. The volumetric performance comparisons made use test data on water in the temperature range 2–1433°C.
A Continuously Variable Poppet Valve Actuator for Internal Combustion Engines
Authors: Charlton S J , Shafie-Pour M 
Published: February 2007

The paper describes a continuously variable poppet valve actuation system which may be applied to internal combustion engines to render the valve motion controllable while the engine is running. The first phase of a programme to develop the device is described. The results of a rigid-body dynamic analysis are presented followed by a dynamic simulation of the mechanism using a proprietary finite element program. These give an insight into its operation and clarify some of the problems to be solved if the device is to be successfully applied.
Integrated Rural Energy Centres for Agriculture-Based Economies
Authors: Locke H B , Choudhury S N R , Lecamwasam D C D 
Published: February 2007

After supplying (a) food materials (rice, cassava, coconut oil etc.) and (b) industrial products (coconut fibre, rubber, timber etc.) there are left (c) energy raw materials, which are often burnt inefficiently and wrongly thought of as wastes (coir dust, wood chips, bagasse pith etc.) Energy raw materials may be incinerated, or hydrolysed, or digested etc. for industrial purposes. They may also be used as fuels for combustion—in domestic cookers, or for steam raising in industry. Energy efficiency may be improved by briquetting energy raw materials to make them more satisfactory as fuels. In addition, modern methods of gasification of some of the briquettes can make producer gas to fuel small, ordinary internal combustion engines. The power may be mechanical as shaft power, or as electricity for lighting, operating machinery etc. Integrated rural energy centres (IRECs) involve this sequence of drying, briquetting, gasifying some of the briquettes to make power, and using the rest of the briquettes for industry for steam raising instead of the wood or oil that is so often the normal fuel. An alternative possibility, particularly for higher ranges of power generation (about 300–500 kW) is to burn the energy raw material at high efficiency in a fluidized bed combustor (FBC), and make use of the hot gases produced to generate power through steam or externally-fired gas turbines, Briquetting techniques are simple and capable of much further development. Gasification techniques are also simple (with proper design) and also capable of further development. Heat recovery for product drying, for example, can be a useful feature of a combined electrical and heat energy generation system, adopting the gasification or efficient direct burning in an FBC route.