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  • 1
    Electronic Resource
    Electronic Resource
    Transport coefficients of an evaporating liquid drop in creeping flow (1989)
    Springer
    Heat and mass transfer 24 (1989), S. 169-175 
    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 wurde eine theoretische Untersuchung der Wärme-, Massen- und Impulsübertragung eines verdampfenden kugelförmigen Fluidtropfens, welcher plötzlich in eine gleichgerichtete Fluidströmung höherer Temperatur eingeleitet wird, untersucht. Das Geschwindigkeitsprofil um den Fluidtropfen herum wurde als konstant und als ein Hadamard-Rybczynski-Profil angenommen. Unter Benutzung eines ADI-Schemas der Finiten-Differenzen-Methode wurden numerische Lösungen der Erhaltungsgleichungen für Energie und Dampfmasse gewonnen. Zeitliche Gesetzmäßigkeiten der durchschnittlichen Nusselt und Sherwood-Zahlen (Nu, Sh) und des Widerstandsbeiwertes (C D ) bis zur vollständigen Verdampfung des Tropfens wurden in Abhängigkeit von den zugehörigen Eingabeparametern nämlich der Anfangs-und momentanen Peclet-Zahl (Pe i ,Pe) der Lewis-Zahl und dem Verhältnis von freier Strömungstemperatur zur Eintrittstemperatur des Tropfens (T a ′ /T i ) berechnet. Ebenso werden die lokalen Nusselt und Sherwood-Zahlen in Abhängigkeit von der Peclet-Zahl im Bereich der stationären Verdampfung dargestellt. Es wurde festgestellt, daß Werte der Nusselt-Zahl im Bereich der stationären Verdampfung von Tropfen in guter Übereinstimmung mit den entsprechenden berechneten Größen aus der empirischen Gleichung von Eisenklam liegen.
    Notes: Abstract A theoretical analysis is made of the heat, mass and momentum transfer from an evaporative liquid sphere which is suddenly introduced into a parallel stream of fluid at a higher temperature. The velocity field around the liquid sphere is assumed to be steady and of the Hadamard-Rybczynski type. Numerical solutions of energy and the vapour mass continuity equations have been carried out using the alternate direction implicit scheme of finite difference method. Temporal histories of the average Nusselt and Sherwood numbers (Nu, Sh) alongwith the drag coefficient (C D ) during the life time of an evaporating drop have been predicted in terms of the pertinent input parameters, namely, initial and instantaneous Peclet number (Pe i ,Pe), Lewis number (Le), and the ratio of free stream to initial droplet temperature (T a ′ /T i ). Variations of local Nusselt and Sherwood numbers withPe, in the region of steady state evaporation, have also been presented. Values ofNu for steady state droplet evaporation are found to be in fair agreement with the corresponding values evaluated from the empirical equation of Eisenklam [5].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01590016
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  • 2
    Electronic Resource
    Electronic Resource
    Convective heat transfer in a superimposed streaming and swirling flow through a cylindrical duct (1985)
    Springer
    Heat and mass transfer 19 (1985), S. 31-39 
    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 werden theoretische Untersuchungen des lokalen konvektiven Wärmeüberganges im Eintrittsbereich eines zylindrischen Rohres mit kombiniertem axialen und tangentialen Eintritt eines Fluids mit zeitunabhängigem Verhalten nach dem Potenzgesetz vorgestellt. Randbedingungen waren dabei konstanter Wärmestrom und konstante Wandtemperatur. Das theoretische Modell verwendet eine integrale Näherung der hydrodynamischen und thermischen Grenzschichttheorie. Es folgt eine funktionale Beziehung zwischen der lokalen Nusseltzahl (Nu z ) und den relevanten Eingangsparametern wie der verallgemeinerten Reynoldszahl $$\left( {Re_{G_i } } \right)$$ und der verallgemeinerten Prandtlzahl (PrG), die mit der tangentialen Eintrittsgeschwindigkeit gebildet werden sowie dem Verhältnis der axialen und tangentialen Geschwindigkeiten am Rohreintritt (VR), der Kennzahl des Strömungsverhaltens des Fluids (n) und dem Verhältnis von axialer Länge zu Rohrdurchmesser (z/D).
    Notes: Abstract Theoretical studies have been carried out to investigate the convective heat transfer coefficients at different locations in the entrance region of a cylindrical duct with combined axial and tangential entry of time-independent power-law fluids. Investigations have been performed with uniform heat flux and uniform wall temperature boundary conditions. Theoretical model uses integral approach of hydrodynamic and thermal boundary layer theory to establish a functional relationship of local Nusselt number (Nu z ) with the pertinent input parameters such as generalised Reynolds number based on tangential velocity of injection $$\left( {Re_{G_i } } \right)$$ , generalised Prandtl number based on inlet tangential velocity (Pr G ), the ratio of axial-to-tangential velocity at the inlet to the duct (V R), the flow behaviour index of the fluid (n) and the ratio of axial-distance-to-duct-diameter (z/D).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01682544
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  • 3
    Electronic Resource
    Electronic Resource
    Coefficient of discharge and spray cone angle of a pressure nozzle with combined axial and tangential entry of power-law fluids (1986)
    Springer
    Flow, turbulence and combustion 43 (1986), S. 3-22 
    Details
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Flows of incompressible, time-independent purely viscous power-law fluids through pressure nozzle with combined axial and tangential entry are analysed. Theoretical predictions of coefficient of discharge and spray cone angle are made through an approximate analytical solution of hydrodynamics of flow inside the nozzle. In the converging section of the nozzle, the boundary layer equations have been derived with modified order approximation [O(δ/R)≈1, O(δ 2/R 2)≪1] of Navier-Stokes equations for a better accuracy. Smoother attainment of the free-stream condition at the edge of the boundary layer is ensured by requiring the appropriate shear rate terms, compatible with the above order analysis, to be zero. The pertinent independent input parameters which govern the flow field are the generalized Reynolds number at inlet to the nozzle based on the tangential velocity of injection $$\operatorname{Re} _{G_i } $$ , the ratio of the axial-to-tangential velocity at the inlet to the nozzle V R , the flow behaviour index of the fluid n, the length-to-diameter ratio of the swirl chamber L 1/D 1, the spin chamber angle 2α and the orifice-to-swirl-chamber-diameter ratio D 2/D 1. Experiments reported in the paper corroborate the qualitative trends of analytical results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385725
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  • 4
    Electronic Resource
    Electronic Resource
    Initiation of air core in a swirl nozzle using time-independent power-law fluids (1984)
    Springer
    Acta mechanica 51 (1984), S. 179-197 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Theoretical and experimental analyses have been carried out for determining the injection condition below which the formation of air core does not take place in the course of flow of a time-independent power-law fluid through a swirl nozzle. Analytical solution lends one distinct value of generalized Reynolds number at the inlet to a nozzle below which the air core is not formed. Experiments reveal that there exist two limiting values of such generalized Reynolds number regarding the formation of air core in a nozzle. One value being the upper limit below which steady flow occurs without air core, the other one is the lower limit above which steady flow with fully developed air core persists. In between these two limiting values, there prevails a transition zone through which fully developed air core is set up within the nozzle. For all the nozzles, theoretical results are in fair agreement with the experimental values of upper limit of generalized Reynolds numbers with respect to steady flow without air core. Amongst all the pertinent independent geometrical parameters of a nozzle, the orifice-to-swirl chamber-diameter ratio has the remarkable influence on generalized Reynolds number describing the initiation of air core.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01177071
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  • 5
    Electronic Resource
    Electronic Resource
    Theoretical and experimental investigations on the coeffizient of discharge and spray cone angle of a swirl spray atomizing nozzle (1980)
    Springer
    Acta mechanica 36 (1980), S. 79-102 
    Details
    ISSN: 1619-6937
    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 Aus den Beziehungen zwischen wichtigen Bestimmungsgrößen für den Zerstäuber einer Wirbeldüse mit ihren unterschiedlichen geometrischen Abmessungen wird die Grundlage einer einheitlichen Entwurfsrechnung zur Auslegung von Düsen für jeden vorgegebenen Verwendungszweck hergeleitet. Der Durchflußbeiwert und der Öffnungswinkel des Zerstäubungskegels sind zwei dieser wichtigen Bestimmungsstücke. In der vorliegenden Arbeit wurde der Versuch unternommen, nach theoretischen und experimentellen Befunden zum Einfluß der Düsengeometrie und Ausspritzbedingungen auf den Durchflußbeiwert und den Strahlöffnungswinkel zu kommen. Diese beiden Parameter wurden theoretisch aus der analytischen, hydrodynamischen Lösung für die Strömung in der Düse berechnet und abschließend ihre Abhängigkeit von den Düsenabmessungen, hauptsächlich Länge und Durchmesser der Wirbelkammer, Winkel des Mündungskegels und Öffnungsdurchmesser in Abhängigkeit der Ausströmbedingungen ausgedrückt durch die Reynoldszahl am Düseneingang theoretisch ermittelt. Eine Anzahl experimenteller Untersuchungen wurde durchgeführt, um die theoretischen Resultate zu belegen und zu vergleichen. Es fällt dabei auf, daß innerhalb eines bestimmten Bereichs mit wachsender Reynoldszahl Rei am Einlaß in die Düse der Durchflußbeiwert abnimmt und der Zerstäubungswinkel zunimmt. Unter allen Düsengeometrien wirkt ein größeres Verhältnis Öffnungsdurchmesserm zu WirbelkammerdurchmesserD 2/D 1, ein größerer Öffnungswinkel des Mündungskegels 2α oder ein kleineres Verhältnis Wirbelkammerlänge zu WirbelkammerdurchmesserL 1/D 1 verkleinernd auf den Durchflußbeiwert und vergrößernd auf den Zerstäubungswinkel.
    Notes: Summary An understanding of the relation between the important sprary characteristics of a swirl nozzle with its different geometrical dimensions forms the basis of a unified design procedure of the nozzles for any preassigned performance. The coefficient of discharge and spray cone angle are two of such important performance characteristics. In the present paper, an attempt has been made towards a theoretical and an experimental investigations into the effects of nozzle geometries and injection condition on the coefficient of discharge and spray cone angle. These two parameters have been theoretically evaluated through the analytical solution of hydrodynamics of flow inside the nozzle and finally their dependence with the nozzle dimensions, namely, the length and diameter of the swirl chamber, angle of the spin chamber and the orifice diameter along with the injection condition expressed as the Reynolds number at inlet to the nozzle have been established theoretically. A series of experimental investigations have also been carried out to support and compare the theoretical results. It has been recognized that within a definite range, an increase in Reynolds number Rei at inlet to the nozzle decreases the coefficient of discharge and increases the spray cone angle. Amongst the nozzle geometries, an increase in the orifice to swirl chamber diameter ratioD 2/D 1, spin chamber angle 2α or a decrease in swirl chamber length to diameter ratioL 1/D 1 decreases the coefficient of discharge and increases the spray cone angle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01178238
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical and experimental investigations on the formation of air core in a swirl spray atomizing nozzle (1980)
    Springer
    Flow, turbulence and combustion 36 (1980), S. 173-196 
    Details
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Theoretical and experimental studies have been made to investigate the variations of air core diameter, the most important hydrodynamic picture inside a swirl nozzle, with the pertinent guiding parameters like injection condition expressed as the Reynolds number at inlet to the nozzle and the geometrical dimensions of the nozzle, namely, the length and diameter of the swirl chamber, angle of spin chamber and the orifice diameter. The theoretical relations have been established through an approximated analytical solution of the hydrodynamics of flow of a viscous incompressible fluid in a swirl nozzle. A series of experiments have been carried out to support and compare the theoretical results. Finally, it has been recognized that for any nozzle, the air core diameter becomes a direct function of Reynolds number Re i at inlet to the nozzle only at its lower range and then remains constant. Amongst the nozzle geometrics, the ratio of orifice to swirl chamber diameter D 2/D 1 has got the most predominant effect on the air core diameter. An increase in the ratio of orifice to swirl chamber diameter D 2/D 1, and in the spin chamber angle 2α and a decrease in the swirl chamber length to diameter ratio L 1/D 1 increase the ratio of air core to orifice diameter and vice versa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386470
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  • 7
    Electronic Resource
    Electronic Resource
    Theoretical and experimental studies on the formation of an air core in a swirl spray pressure nozzle using a power law non-Newtonian liquid (1983)
    Springer
    Flow, turbulence and combustion 40 (1983), S. 71-91 
    Details
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An extension of the recent work [15] has been made to evaluate the air core diameter both theoretically and experimentally in the case of a swirl nozzle using a time independent pure viscous power law non-Newtonian fluid. The theoretical predictions have been made through an approximated analytical solution of the hydrodynamics of flow inside the nozzle. A series of experiments has been carried out with solutions of CMC (carboxymethyl cellulose sodium salt) powder in water with different concentrations as the working fluids. The rheological properties of the working fluids were measured by a capillary tube viscometer. Finally it has been recognised from both the theory and experiment that, regarding the injection condition and the fluid properties, the generalised Reynolds number $$\operatorname{Re} _{G_i } $$ at the inlet to the nozzle and the flow behaviour index n of the fluid become the pertinent independent input parameters in non-dimensional forms. The air core diameter increased with $$\operatorname{Re} _{G_i } $$ and decreases with n. The effect of nozzle geometry on the air core diameter is similar to that in the case of Newtonian fluids [15].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539376
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  • 8
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    Thermodynamics of flame impingement heat transfer (2007)
    American Institute of Physics
    Details
    Publication Date: 2007-08-15
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics
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  • 9
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    Migration of a surfactant-laden droplet in non-isothermal Poiseuille flow (2017)
    American Institute of Physics
    Details
    Publication Date: 2017-01-01
    Print ISSN: 1070-6631
    Electronic ISSN: 1089-7666
    Topics: Physics
    Published by American Institute of Physics
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  • 10
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    Coefficient of discharge and spray cone angle of a pressure nozzle with combined axial and tangential entry of power-law fluids (1986)
    Springer
    Details
    Publication Date: 1986-03-01
    Print ISSN: 1386-6184
    Electronic ISSN: 1573-1987
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
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