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  • 1
    Electronic Resource
    Electronic Resource
    An analysis for forced convection heat transfer from external surfaces to non-Newtonian fluids (1986)
    Springer
    Heat and mass transfer 20 (1986), S. 219-227 
    Details
    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 eine theoretische Analyse für den Wärmeübergang bei Zwangskorivektion von äußeren in nicht-Newtonsche Fluide eintauchende Oberfläche unter Benutzung des Exponentialansatzes vorgeschlagen. Dabei wurde die früher für Newtonsche Fluide eingeführte Integralbehandlung erfolgreich auf nicht-Newtonsche Fluide erweitert, die über eine ebene Platte und einen Keil beliebigen Winkels strömen. Die integralen Impuls- und Energiegleichungen werden in ein Paar charakteristischer Gleichungen transformiert, die für den Geschwindigkeits-Formfaktor und für das Grenzschicht-Dickenverhältnis leicht gelöst werden können, wenn die Exponenten in den Ausdrücken für den Potenzansatz die Anströmgeschwindigkeit und die Änderung der Wandtemperatur spezifiziert sind. Es stellte sich heraus, daß eine asymptotische Näherung, die unter der Annahme großer Prandtl-Zahl abgeleitet wurde, für Fluide beliebigen Potenzansatzes praktisch gültig ist und dadurch für eine rasche und trotzdem genaue Abschätzung des örtlichen Wärmeübergangs an nicht-Newtonsche Fluide benützt werden kann.
    Notes: Abstract A theoretical analysis has been proposed for the forced convection heat transfer from external surfaces immersed in non-Newtonian fluids of the power-law model. The integral treatment previously introduced for Newtonian fluids has been successfully extended to the non-Newtonian fluids over a flat plate and a wedge of an arbitrary included angle. The integral momentum and energy equations are transformed into a pair of characteristic equations, which can readily be solved for the velocity shape factor and the boundary layer thickness ratio, once the exponents in the expressions for the power-law model, free stream velocity and wall temperature variation are specified. It has been also found that an asymptotic expression derived under the assumption of large Prandtl number, is valid practically for all power-law fluids, and hence, can be used for a speedy, and yet accurate estimation of the local heat transfer to non-Newtonian fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01303454
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  • 2
    Electronic Resource
    Electronic Resource
    Forced convection heat transfer to an elastic fluid of constant viscosity flowing through a channel filled with a Brinkman-Darcy porous medium (1993)
    Springer
    Heat and mass transfer 28 (1993), S. 295-297 
    Details
    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 Die Untersuchung bezieht sich auf die voll ausgebildete Strömung und den Wärmeübergang in einem von zwei parallelen Wänden begrenzten Kanal bei konstantem Wärmefluß am Rande. Der Kanalraum wird von einem hochporösem Medium ausgefüllt, das mit einem elastischen Fluid konstanter Zähigkeit getränkt ist. Der Einfluß des Reibungswiderstandes an den Kanalgrenzen auf das Wärmeübertragungsverhalten wird mit Hilfe des von Brinkman erweiterten Darcy-Transportgesetzes ermittelt. Die Lösung erfolgte unter Anwendung eines näherungsweisen gültigen Integralverfahrens.
    Notes: Abstract An analysis is presented of fully developed flow and heat transfer in a channel confined by two parallel walls subjected to uniform heat flux in a highly porous medium saturated with an elastic fluid of constant viscosity. The Brinkman-extended Darcy model is used for studying the effect of the boundary viscous frictional drag on the heat transfer characteristics. The approximate integral method is employed to obtain a solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01539495
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  • 3
    Electronic Resource
    Electronic Resource
    Deformation behavior of poly(vinylidene fluoride) (1986)
    s.l. : American Chemical Society
    Industrial and engineering chemistry 25 (1986), S. 277-282 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/i300022a026
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  • 4
    Electronic Resource
    Electronic Resource
    Rheograms for asphalt from single viscosity measurement (1982)
    Springer
    Rheologica acta 21 (1982), S. 333-339 
    Details
    ISSN: 1435-1528
    Keywords: Rheogram ; master curve ; single viscosity measurement ; softening point ; asphalt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract Asphalt materials are used in a variety of applications such as road paving, waterproofing, roofing membranes, adhesive binders, rust proofing and water resistant coatings. There are available in a number of grades distinguished in terms of their softening point and flow resistance. The selection of the proper grade of asphalt for a particular application is governed by the desired flow behaviour. A knowledge of the complete flow curve depicting the variation of melt viscosity with shear rate at the relevant temperatures is necessary not only for proper grade selection, but also for specifying processing conditions for aggregate mixing and spraying. The rheological data are also useful in assessing end use performance. The scientific techniques for generating the rheological data involve the use of expensive, sophisticated instruments. Generation of the necessary flow data using these instruments is beyond the financial and technical means of most processors of asphalt materials. The engineering techniques involving the use of inexpensive vacuum viscometers are relatively easy, but provide a single point viscosity measurement at low shear rate. In the present work, a method is proposed for unifying the viscosity versus shear rate a data at various temperatures for a number of asphalt grades. A master curve has been generated that is independent of the grade of asphalt and the temperature of viscosity measurement. The master curve can be used to generate rheograms at desired temperatures for the asphalt grade of interest, knowing its zero-shear viscosity at that temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01515721
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Rheological models for unified curves for simplified design calculations in polymer processing (1984)
    Springer
    Rheologica acta 23 (1984), S. 368-377 
    Details
    ISSN: 1435-1528
    Keywords: Rheological model ; melt flow index ; unified curve ; polymer melt ; engineering design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract A method has been proposed earlier by Shenoy et al. to estimate complete flow curves depicting the variation of melt viscosity over industrially relevant range of shear rate and temperature through the use of unified curves characteristic of each generic type of polymer. In the present paper, the unified curves have been fitted through modified forms of already known generalized Newtonian models. The advantage of fitting such rheological models to unified curves lies in the fact that calculations involving entrance length estimates, heat transfer, die design, mold design, etc. are greatly simplified. Knowing the model parameters, one needs to know only the melt flow index, which is a relatively easy parameter to obtain, to make any engineering design calculations. The modified generalized Newtonian models have been fitted to a number of polymers covering one or more from each group of olefinics, styrenics, cellulosics, vinyls and engineering thermoplastics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01329189
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of buoyancy on heat transfer during turbulent flow of drag reducing fluids in vertical pipes (1987)
    Springer
    Heat and mass transfer 21 (1987), S. 15-18 
    Details
    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 Einfluß des Auftriebes auf den Wärmeübergang bei turbulenter Aufwärtsströmung von widerstandsreduzierenden Fluiden in vertikalen Rohren theoretisch analysiert. Dabei wird ein Kriterium für die Begrenzung der Abnahme des Wärmeübergangs auf weniger als 5% für Fluide unterschiedlicher Widerstandsverringerung aufgestellt. Die endgültige mathematische Formulierung für die quantitative Beschreibung des Einflusses der natürlichen Konvektion auf die erzwungene Konvektion konnte sowohl auf Aufwärts-als auch auf Abwärtsströmung eines Fluids mit vermindertem Strömungswiderstand einfach dadurch angewandt werden, daß man ein Vorzeichen in dem die Strömung bestimmenden Term ändert.
    Notes: Abstract The effect of buoyancy on the heat transfer during upward turbulent flow of drag reducing fluids in vertical tubes has been theoretically analyzed. A criteria has been established for limiting the decrease in heat transfer to less than 5% for fluids of varying drag reducing ability. The final expression for quantitative evaluation of natural convection effect on forced convection could be applied to upward as well as downward turbulent flow of drag-reducing fluids merely by a change in sign of the controlling term.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01008213
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  • 7
    Electronic Resource
    Electronic Resource
    Interpretation of flow data for multicomponent polymeric systems (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 846-854 
    Details
    ISSN: 1435-1536
    Keywords: Melt flow index ; multicomponent polymeric systems ; altered free volume ; state concept
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A model based on the altered free volume state concept has been proposed here to predict the melt flow index values of multicomponent systems as a function of the amount of the dispersed phase. The predictions of the model have been compared with experimental results reported in the literature on a diverse range of multicomponent polymeric systems. The agreement between the model predictions and the experimentally determined values is good.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01421438
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Drag reduction with surfactants at elevated temperatures (1976)
    Springer
    Rheologica acta 15 (1976), S. 658-664 
    Details
    ISSN: 1435-1528
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zusammenfassung Ein ungewöhnliches Widerstandsverminderungs-Verhalten wird bei dem nicht-ionischen oberflächenaktiven Stoff Lubrol 17A10 in Anwesenheit des Elektrolyten K2SO4 beobachtet. Das System zeigt bei Zimmertemperatur ein normales Turbulenz-Verhalten, erlangt dagegen bei einer Temperatur in der Nähe des Trübungspunktes die Fähigkeit, die Reibung herabzusetzen. Die Konsequenzen eines derartigen Widerstandsverminderungs-Effekts bei erhöhter Temperatur werden unter dem Gesichtspunkt der Verwendbarkeit solcher Additive in Zentralheizungs-Systemen diskutiert.
    Notes: Summary An unusual drag reducing behaviour of the nonionic surfactant Lubrol 17 A 10 in the presence of the electrolyte K2SO4 has been observed. The system shows normal turbulent flow behaviour at room temperature, but depicts an ability to reduce friction when flowing at a temperature at and around its cloud point. The consequences of this elevated temperature drag reduction have been discussed from the viewpoint of using drag reducers in central heating systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01524753
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  • 9
    Electronic Resource
    Electronic Resource
    A review on drag reduction with special reference to micellar systems (1984)
    Springer
    Colloid & polymer science 262 (1984), S. 319-337 
    Details
    ISSN: 1435-1536
    Keywords: Drag reduction review ; micellar system ; polymer additive ; biological additive ; suspension ; theory of drag reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A state-of-the-art review on drag reduction has been presented in order to bring out some important aspects of the drag reduction phenomenon and its potential for practical use. The review is biased towards micellar systems and discusses in detail the morphological differences between drag reducing polymeric and micellar systems. Work relating to polymeric systems has not been dealt in detail as it has been the subject of earlier reviews. Studies relating to biological additives as well as suspensions have been briefly mentioned without detailed discussion as their potential for practical use presently appears] to be limited.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410471
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    From melt flow index to rheogram (1983)
    Springer
    Rheologica acta 22 (1983), S. 90-101 
    Details
    ISSN: 1435-1528
    Keywords: Melt flow index ; rheogram ; master curve ; polymeric melt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract A knowledge of the complete flow curve or rheogram of a polymeric melt depicting the variation of the melt viscosity over industrially relevant range of shear rate and temperature is essential in the design of polymer processing equipment, process optimization and trouble-shooting. These data are generated on sophisticated rheometers that are beyond the financial and technical means of most plastics processors. The only flow parameter available to the processor is the melt flow index of the material. In the present work, a method has been proposed to estimate the rheograms of a melt at temperatures relevant to its processing conditions with the use of a master curve, knowing the melt flow index and glass transition temperature of the material. Master curves that coalesce rheograms of different grades at various temperatures have been generated and presented for low density polyethylene, high density polyethylene, polypropylene, polystyrene and styrene-acrylonitrile copolymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01679833
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    Paper (German National Licenses)
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