Laminar Film Condensation on Surfaces Normal to Body or Inertial Forces

Leppert, G.; Nimmo, B.

doi:10.1115/1.3597451

Cited by 30 publications

(8 citation statements)

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“…For viscous flows over an inner rotating cylindrical surface, there have been few experimental studies, and they poorly agree with theoretical studies. Leppert and Nimmo [3] calculated heat transfer for condensation of vapor on a liquid film moving down a horizontal plate. It is shown that even when the mass force is normal to the condensation surface, heat removal can have a finite value if running-off on the edges is allowed.…”

Section: The Behavior Of a Liquid Layer Moving In A Mass-force Field mentioning

confidence: 99%

“…According to the analysis of the isothermal problem in [3,4], the film thickness in this process is a function of several variables:…”

Section: The Behavior Of a Liquid Layer Moving In A Mass-force Field mentioning

confidence: 99%

“…Postnikov [4] obtained a solution for the thickness of a laminar film moving over the inner surface of a rotating cylinder that requires one experimental value --the initial thickness of the film. Both solutions [3,4] have one feature in common: a sharp decrease to zero in the thickness of the moving liquid film, which is typical of a central flow region on the longitudinal coordinate.Early experimental studies in this field [5,6] were concerned with liquid flow in a rotating tube with broad rings at the edges. Dependences of the device capacity on the flow rate and angular frequency of rotation were obtained.…”

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confidence: 98%

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Experimental study of variations in the thickness of a liquid film moving over the inner surface of a rotating cylinder

Borzykh¹,

Volokitin²,

Karandashov³

et al. 1998

J Appl Mech Tech Phys

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Many technological devices used to intensify heat and mass transfer in a liquid or to spray it [i-8] are based on the phenomenon of motion of thin films in a field of centrifugal forces. In particular, when a glass-forming material is melted in a rotated plasmachemical reactor for producing mineral fiber, the molten mass moves over the inner surface of the device [8]. The properties of the material of the fibers produced are formed directly in the film moving under thermal and dynamic loading. Knowledge of the liquid-film thickness and its distribution along the axial coordinate in motion over the inner surface of a rotating cylinder allows one to calculate the heat exchange of such a film device.For an inner rotating cylindrical surface, Gol'dshtik [1] developed a theory of centrifugal sprayers, based on a model of potential motion of an inviscid liquid. However, comparison of the theoretical dependences obtained was performed with experimental results of studies of liquid-film spreading over a horizontal surface under gravity only. For viscous flows over an inner rotating cylindrical surface, there have been few experimental studies, and they poorly agree with theoretical studies. Leppert and Nimmo [3] calculated heat transfer for condensation of vapor on a liquid film moving down a horizontal plate. It is shown that even when the mass force is normal to the condensation surface, heat removal can have a finite value if running-off on the edges is allowed. In this case, the thickness of the condensate film and the resultant heat removal are controlled by varying the hydrostatic pressure across the film thickness. These results are applicable to condensation inside a rotating cylinder provided that the surface curvature is small and the rotational speed is high. However, to close a solution that describes this model, it is necessary to invoke two empirical parameters: the initial and final thicknesses of the condensate film. Postnikov [4] obtained a solution for the thickness of a laminar film moving over the inner surface of a rotating cylinder that requires one experimental value --the initial thickness of the film. Both solutions [3,4] have one feature in common: a sharp decrease to zero in the thickness of the moving liquid film, which is typical of a central flow region on the longitudinal coordinate.Early experimental studies in this field [5,6] were concerned with liquid flow in a rotating tube with broad rings at the edges. Dependences of the device capacity on the flow rate and angular frequency of rotation were obtained. Flow visualization using tracers in the form of a tinted liquid showed that the flow is of two-layer character. The main mass flow proceeded in a thin layer located closer to the center from the edge of the rings. The effect of viscosity on liquid flow in a rotating cylinder with various methods of feeding the liquid was studied experimentally in [7]. The results are somewhat unexpected: the thickness of the moving layer decreases with increase in viscosity. This effect was explained ...

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Section: The Behavior Of a Liquid Layer Moving In A Mass-force Field mentioning

confidence: 99%

“…According to the analysis of the isothermal problem in [3,4], the film thickness in this process is a function of several variables:…”

Section: The Behavior Of a Liquid Layer Moving In A Mass-force Field mentioning

confidence: 99%

mentioning

confidence: 98%

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Experimental study of variations in the thickness of a liquid film moving over the inner surface of a rotating cylinder

Borzykh¹,

Volokitin²,

Karandashov³

et al. 1998

J Appl Mech Tech Phys

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show abstract

“…The earliest study of film condensation heat transfer on a horizontal surface was performed by Popov [2]. In a later study, Nimmo and Leppert [3,4] conducted experimental and theoretical investigations into film condensation on a finite-size horizontal plate. In the theoretical study of Nimmo and Leppert [4] , the boundary condition at the edge of the plate was simply assumed by a particular boundary condition.…”

Section: Introductionmentioning

confidence: 99%

An analytical investigation into the Nusselt number and entropy generation rate of film condensation on a horizontal plate

Chang

Wang

2008

J Mech Sci Technol

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This study investigates the heat transfer characteristics and entropy generation rate of a condensate film formed on a horizontal plate with suction at the wall. Applying the minimum mechanical energy principle, the dimensionless liquid film thickness along the plate is found to vary as a function of the Rayleigh number, the Jakob number, the Prandtl number and the suction parameter. The governing differential equation of the condensate thickness is solved numerically by using a finite-difference shooting method. Closed-form analytical expressions are derived for the Nusselt number and the dimensionless overall entropy generation number. When there is no suction at the wall, the results obtained from the analytical expression for the Nusselt number are found to be in good agreement with those presented in the literature.

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“…Later, Gerstmann and Griffith [4] applied experimental and theoretical approaches to analyze condensation on the underside of a horizontal plate. Nimmo and Leppert [5,6] conducted experimental and theoretical investigations into film condensation on the upper surface of a horizontal plate. However, in their theoretical study [6], the thickness of the film condensation layer at the plate edge was assumed by a particular boundary condition.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Second Law Analyses for Laminar Film Condensation on a Finite-Size Horizontal Disk

Chang

2007

JTST

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This study applies the first and second laws of thermodynamics to investigate the problem of steady filmwise condensation on a finite-size horizontal disk. The boundary condition at the disk edge is obtained by applying the minimum mechanical energy principle. Closed form correlations for the Nusselt number and the dimensionless overall entropy generation number are established. For the case of without losing the condensation heat transfer coefficient, the present results suggest reducing the value of the parameter group ψ BrGr to minimize the dimensionless overall entropy generation number. Finally, a formula is derived to establish the value of Ra/Ja which minimizes the dimensionless overall entropy generation number for a specified value of the parameter group ψ BrGr .

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Laminar Film Condensation on Surfaces Normal to Body or Inertial Forces

Cited by 30 publications

References 0 publications

Experimental study of variations in the thickness of a liquid film moving over the inner surface of a rotating cylinder

Experimental study of variations in the thickness of a liquid film moving over the inner surface of a rotating cylinder

An analytical investigation into the Nusselt number and entropy generation rate of film condensation on a horizontal plate

Heat Transfer and Second Law Analyses for Laminar Film Condensation on a Finite-Size Horizontal Disk

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