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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Heat and mass transfer 28 (1993), S. 185-193 
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Es wird die Abschwächung thermischer Strahlung in einer verdünnten Wolke aus pulverisierter Kohle und Asche experimentell und theoretisch für verschiedene Bereiche der Partikelgröße untersucht. Zur Bestimmung des Absorptions- und Emissionsvermögens einer Kohle/Asche-Wolke wird ein empirisch gefundener Ausdruck entwickelt, der außerdem Grundlage eines neuen Nomogramms ist.
    Notes: Abstract The attenuation of thermal radiation within a dilute cloud of pulverised coal and ash is investigated experimentally and theoretically, for different ranges of particle size. An empirical expression is developed for obtaining the absorptivity and emissivity of a coal/ash cloud. A new nomogram is also presented on the basis of this expression.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Es wird der Wärmeübergang bei laminarer Mischkonvektion in gleichmäßig beheizten waagrechten Rohren numerisch und experimentell untersucht. Einige experimentelle Befunde für gleichförmige Beheizung von Wasser in einem langen Kupferrohr werden mit den Ergebnissen eines numerischen Modells verglichen, um dessen Zuverlässigkeit zu eruieren. Die Einflüsse der Wärmeleitung in Umfangs-und Axialrichtung des Rohrmantels fanden darin Berücksichtigung. Der Vergleich der experimentellen und numerischen Ergebnisse liefert konkrete Hinweise, unter welchen Bedingungen der Auftrieb und die Konvektion, für Wandwärmeleitung Einfluß auf den konvektiven Wärmeübergang in horizontalen Rohren nehmen. Die Stärke des Auftriebs wird durch Rayleigh-Zahlen bis 5·106 repräsentiert, die der Zwangskonvektion durch zwei Werte der Reynolds-Zahl am Eintritt, 500 und 1000.
    Notes: Abstract Laminar combined convection in horizontal circular ducts is investigated both numerically and experimentally, under uniform wall heating. A series of experiments for the heating of water in a long horizontal copper tube are simulated numerically in order to assess the reliability of the theoretical results. Peripheral and axial wall conduction effects, inherently present in the experiments, are accounted for in the numerical model. The cross validation of experimental and numerical data allows significant conclusions to be reached on conjugate conduction and convection with buoyancy effects in horizontal duct flows. Buoyancy is considered for values of the modified Rayleigh number,Ra qo , up to 5·106; the forced convection contribution is considered for two values of the entry Reynolds number,Re o=500 and 1000.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Clean products and processes 1 (1999), S. 73-81 
    ISSN: 1436-722X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract  This paper illustrates, using data from test cases, how Life Cycle Assessment (LCA) may be used to enhance environmental management, particularly when used in conjunction with Environmental Management Systems. There are a number of areas where LCA can be helpful: in the identification of significant environmental effects; in the quantification of those effects; in the assessment of year-to-year changes in environmental performance and in the assessment of the environmental benefits (or disadvantages) arising from changes (actual or planned) in operating conditions, equipment, procedures, raw materials or products. There are some issues which cannot (at present) be adequately assessed using LCA and these are also discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of engineering mathematics 18 (1984), S. 219-233 
    ISSN: 1573-2703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Technology
    Notes: Summary We review the governing equations of fluid dynamics in general co-ordinates, and present forms particularly suitable for efficient numerical solution. Methods are given, both for compressible and incompressible flow, of eliminating explicit use of the connection coefficients and transformation matrix elements from the computations. Special problems associated with spacially varying viscosity and with eddy-viscosity turbulence models are also discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The measurement of16N and18F activity in the primary coolant of the JASON Argonaut reactor has been used to monitor in-core reactor power. The16N is produced by the16O(n, p)16N reaction and the 6.1 MeV photopeak was measured on-line using a BGO detector adjacent to the primary coolant circuit. These data provided a relative measure of power stability during steady state operation and a measure of linearity at different power levels. The18F is produced in the primary coolant by the18O(p, n)18F reaction and aliquots of primary coolant were sampled from the reactor dump tank for off-line radiochemical analysis. The18F was separated as trimethylfluorosilane and the activity was determined by measurement of the 0.511 MeV annihilation photopeak using a NaI(TI) detector. The measured18F activity was used to determine actual in-core reactor power using both ab-initio calculations and by comparison of results with a calibrated power reactor. The18F data also provided a method of nomalising the16N data for direct monitoring of in-core reactor power in JASON.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 13 (1991), S. 321-340 
    ISSN: 0271-2091
    Keywords: Swirling flow ; Helically ribbed surfaces ; Nuclear fuel ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Fully developed, steady flow through an annulus with a multistart, helical-ribbed inner cylinder is numerically predicted and compared with available data. To facilitate comparison, the transverse-ribbed case is included. It is predicted that substantial differences exist between turbulent flow over helical ribs and that over transverse ribs. The predictions clarify the experimental finding that helical-ribbed cylinders can be expected to have better pressure drop and heat transfer characteristics than transverse-ribbed cylinders. For this work the AERE Harwell code FLOW3D Release 2 was used.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 7 (1987), S. 277-289 
    ISSN: 0271-2091
    Keywords: Large eddie simulation ; Spectral methods ; Computer simulation of flows ; Distorted geometries ; Coordinate transformation ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Turbulence is essentially four-dimensional in character, and requires the corresponding treatment of the well-known Navier-Stokes equations. However, this has only been possible over the past twenty years and then by using the largest computers available. Interest is now turning from the initial, mainly smooth channel, simulations to geometries of eventual engineering significance. This paper reports a new code using the spectral methods of Orszag, but also incorporating a novel generalized co-ordinate transformation approach.Initial predictions for smooth channels agree well with published data. For distorted geometries, the initial velocity field has considerable influence on the success of the simulations. This is accommodated by gradual (step) changes towards the required distortion, so that the initial velocity field for the ‘new’ geometry is the final field from the previous step. Examples are given of different two-dimensional channel geometries achieved, and these include the successful prediction of recirculating flows.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 15 (1992), S. 453-489 
    ISSN: 0271-2091
    Keywords: Large-eddy simulation ; Recirculating flows ; Rib roughness ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Large-eddy simulation results are presented and discussed for turbulent flow and heat transfer in a plane channel with and without transverse square ribs on one of the walls. They were obtained with the finite-difference code Harwell-FLOW3D, Release 2, by using the PISOC pressure-velocity coupling algorithm, central differencing in space, and Crank-Nicolson time stepping. A simple Smagorinsky model, with van Driest damping near the walls, was implemented to model subgrid scale effects. Periodic boundary conditions were imposed in the streamwise and spanwise directions. The Reynolds number based on hydraulic diameter (twice the channel height) ranged from 10 000 to 40 000. Results are compared with experimental data, k-∊ predictions, and previous large-eddy simulations.
    Additional Material: 28 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 199-215 
    ISSN: 0271-2091
    Keywords: air-conditioning unit ; k-∊ model ; Reynolds stress model ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Details are given of a study to obtain experimental data in an idealized environment for the purpose of evaluating the corresponding computational predictions and which supplement parallel measurements made in actual packaged air-conditioning units. The system consisted of a purpose-built low-speed wind tunnel with a working section constructed to reproduce particular features of the real units. In the experiment, both the mean velocity profiles and turbulence properties of the flow are obtained from triple-hot-wire anemometry measurements. A numerical model, based on finite volume methodology, was used to obtain the solution of the Reynolds-averaged Navier-Stokes equations for incompressible isothermal flow. The Reynolds stress terms in the equations are calculated using the standard k-∊ model and second-moment closure (Reynolds stress) models. The accuracy of the two models was evaluated against the experimental measurements made 10 mm downstream of a baffle. The results show that the standard k-∊ model gave the better agreement except in regions of strong recirculation. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 21 (1985), S. 691-711 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In a solar energy application involving thermal storage, one of the heat transfer situations is that of combined convection in vertical annuli for rather complex wall thermal boundary conditions. Predictive data of a high order of reliability are needed for incorporation within the suite of programs treating the whole problem.The program reported here treats the complete equations for combined free and forced convection in a vertical annulus. It allows for viscosity and density variation with temperature, and a variable heat flux or temperature at the walls. It was developed from a similar program for circular tubes.Comparisons are made with published data for velocity profiles and heat transfer performance. These are good, and show the step-wise energy balance method is necessary and valid.The strategy of generation of the required data is explained, together with sample output. These data are themselves analysed computationally; the performance equations agree with original predictions typically to within ± 11 per cent, with a standard deviation of around 2 per cent.The working fluid is water with 37 per cent ethylene glycol. Upward heated and downward cooled flows give aided combined convection. For the given design, laminar flow is predicted for the Reynolds number range 1800-2200.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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