Study on laminar film condensation of saturated steam on a vertical flat plate for consideration of various physical factors including variable thermophysical properties

Shang, De-Yi; Adamek, Thomas

doi:10.1007/bf00715015

Cited by 20 publications

(6 citation statements)

References 7 publications

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“…In the present paper, a new similarity transformation is devised for non-Newtonian boundary layer problems. This transformation is an extension of a transformation introduced by Shang and Wang (1990) for Newtonian boundary layers and employed successfully to free convection by Shang and Wang (1990) and Shang et al (1993) and to ÿlm condensation by Shang and Adamek (1994) with the particular view to account for the variability of the thermophysical properties of the uid. Now, the transformation is generalized to non-Newtonian uids which obey the non-linear power-law equation-of-state and applied to gravity-driven ÿlm ow.…”

Section: Introductionmentioning

confidence: 99%

An extended study of the hydrodynamics of gravity-driven film flow of power-law fluids

Andersson

Shang

1998

Fluid Dyn. Res.

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A new similarity transformation has been devised for extensive studies of accelerating non-Newtonian ÿlm ow. The partial di erential equations governing the hydrodynamics of the ow of a power-law uid down along an inclined plane surface are transformed into a set of two ordinary di erential equations by means of the dimensionless velocity component approach. Although the analysis is applicable for any angle of inclination (06 ¡ =2), the resulting one-parameter problem involves only the power-law index n. Nevertheless, physically essential quantities, like the velocity components and the skin-friction coe cient, do depend on and relevant relationships are deduced between the vertical and inclined cases. Accurate numerical similarity solutions are provided for n in the range from 0.1 to 2.0. The present method enables solutions to be obtained also for highly pseudo-plastic ÿlms, i.e. for n below 0.5. The mass ow rate entrained into the momentum boundary layer from the inviscid freestream is expressed in terms of a dimensionless mass ux parameter , which depends on the dimensionless boundary layer thickness and the velocity components at the edge of the viscous boundary layer. , which is thus an integral part of the similarity solution, turns out to decrease monotonically with n. This parameter is of particular relevance in the determination of the streamwise position at which the entire freestream has been entrained and viscous stresses prevail all the way to the free surface of the ÿlm. A short-cut method to facilitate rapid and yet accurate estimates of the mass ux parameter is developed to this end.

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Section: Introductionmentioning

confidence: 99%

An extended study of the hydrodynamics of gravity-driven film flow of power-law fluids

Andersson

Shang

1998

Fluid Dyn. Res.

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“…It has been concluded that in the case when a difference between the wall temperature and the saturation temperature is less than 50°C, a deviation from the Nusselt s theory is less than 3 %. In [26], it was shown that a temperature difference lower than 100°C results in a change of the HTC to just a few percent with a maximal deviation for 100°C -5.1 %. During experiments the mean tem-vol.…”

Section: Temperature Dependent Variablesmentioning

confidence: 99%

The Condensation of Water Vapour in a Mixture Containing a High Concentration of Non-Condensable Gas in a Vertical Tube

2020

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This paper deals with the condensation of water vapour possessing a content of noncondensable gas in vertical tubes. The condensation of pure steam on a vertical surface is introduced by the Nusselt condensation model. However, the condensation of water vapour in a mixture with non-condensable gas differs from pure vapour condensation and is a much more complex process. The differences for the condensation of water vapour in a mixture containing a high concentration were theoretically analysed and evaluated. In order to investigate these effects, an experimental stand was built. Experiments were carried out in regards to the case of pure steam condensation and the condensation of water vapour with a non-condensable gas mixture to evaluate the influence of the variable non-condensable gas content during the process. A non-condensable gas in a mixture with steam decreases the intensity of the condensation and the condensation heat transfer coefficient. A gradual reduction of the volume and partial pressure of steam in the mixture causes a decrease in the condensation temperature of steam, and the temperature difference between steam and cooling water. The increasing non-condensable gas concentration restrains the transportation of steam towards the tube wall and this has a significant effect on the decrease in the condensation rate.

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“…Since the innovative similarity transformation was developed for hydrodynamics and heat transfer investigation of free and forced convection, its application has been extended to our study on convection hydrodynamics and heat and mass transfer with film boiling/condensation convection, such as free film boiling convection [4,8], free/forced film condensation convection of pure vapour [3,4,9,10], free/forced film condensation convection of vapour-gas mixture [3,4,11]. It is indicated that in all of these studies, the complicated physical factors including the coupled effect of variable physical properties were well considered, then, the heat and mass transfer results demonstrate their practical value.…”

Section: Extensive Application Of the Innovative Similarity Transformmentioning

confidence: 99%

An Innovative Similarity Transformation for In-Depth Research of Convection Heat and Mass Transfer

Shang¹,

Wang²,

Zhong³

2015

SJEE

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Our innovative similarity transformation for in-depth research of convection heat and mass transfer is presented.For solving convection heat and mass transfer issues, the boundary layer analysis method is used, and meanwhile, the FalknerSkan transformation is currently popular to treat the core similarity variables for velocity field similarity. But this type of transformation is inconvenient to do this core work, for similarity transformation of velocity field, because it is necessary to first induce flow function and group theory to d e r i v e a n intermediate function for an indirect similarity transformation of the velocity field. This case also allows a difficult situation on consideration of variable physical properties. With our innovative similarity transformation, the above inconvenient and difficult situations are avoided, and the velocity components can be directly transformed to the related dimensionless ones. Then, the similarity analysis and transformation of the governing partial differential equations can be simplified greatly. Furthermore, our innovative similarity transformation can conveniently treat variable physical properties and their coupled effect on heat and mass transfer for enhancement of the practical value of convection heat and mass transfer, and so is a better alternative transformation method to the traditional Falkner-Skan transformation. It was proved that the above two innovative methods have a wide practical application in industry.

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Study on laminar film condensation of saturated steam on a vertical flat plate for consideration of various physical factors including variable thermophysical properties

Cited by 20 publications

References 7 publications

An extended study of the hydrodynamics of gravity-driven film flow of power-law fluids

An extended study of the hydrodynamics of gravity-driven film flow of power-law fluids

The Condensation of Water Vapour in a Mixture Containing a High Concentration of Non-Condensable Gas in a Vertical Tube

An Innovative Similarity Transformation for In-Depth Research of Convection Heat and Mass Transfer

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