Investigations of the Marangoni effect on the regular structures in heated wavy liquid films

Lel, V. V.; Kellermann, A.; Dietze, Georg F.; Kneer, Reinhold; Павленко, А. Н.

doi:10.1007/s00348-007-0408-x

Cited by 60 publications

(23 citation statements)

References 14 publications

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“…of the free surface), without contamination from the bulk of the fluid deeper within the film, or from the solid substrate. For example, Lel et al [19,32] used an IR camera to measure the interfacial temperature of silicone oil films. Silicon fluids were selected as they allowed a wide range of viscosities to be spanned, with a corresponding range of Reynolds and Kapitza numbers.…”

Section: Case Study I: Heated Falling Filmsmentioning

confidence: 99%

“…Silicon fluids were selected as they allowed a wide range of viscosities to be spanned, with a corresponding range of Reynolds and Kapitza numbers. In this case the absorption coefficient allowed 99 % of the radiation to be absorbed within a thin (10 -15 µm) layer at the surface of the films [32]. IR thermography has also been used extensively in water film flows (e.g.…”

Section: Case Study I: Heated Falling Filmsmentioning

confidence: 99%

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Heat transfer augmentation in unsteady conjugate thermal systems – Part II: Applications

Mathie

Nakamura

Markides

2013

International Journal of Heat and Mass Transfer

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Many energy conversion and other thermal-fluid systems exhibit unsteady convective heat exchange. In such systems, generic spatiotemporal variations in the flow give rise to variations in the heat flux for a given fluid-solid temperature difference, which can be interpreted as spatiotemporal fluctuations of the instantaneous heat transfer coefficient. These variations can lead to unsteady conjugate heat transfer, in which the exchanged heat flux arises from an interaction between the bulk fluid temperature and the temperature in the solid. Further, the nonlinear coupling between the fluctuating temperature differences and the heat transfer coefficient can lead to an effect we refer to as augmentation, which quantitatively describes the ability of a particular arrangement to have a different time-mean heat flux from the product between the mean heat transfer coefficient and the mean temperature difference across the fluid. It is important to be able to understand and to model in a simple framework the effects of the material properties, the geometry and the character of the heat transfer coefficient on the thermal response of the fluid-solid system, and consequently to predict the overall heat transfer performance of these systems. This paper, which follows on from its predecessor (Mathie and Markides, 2012a), is concerned with the phenomenon of augmentation in simple, one-dimensional, unsteady and conjugate fluid-solid systems. A simple semi-analytical one-dimensional model of heat transfer with a time-varying heat transfer coefficient, which was presented in Mathie and Markides (2012a), is applied herein to two different paradigm problems. Such a model can be an important tool in the design of improved heat exchangers and thermal insulation, through for example, the novel selection of materials to exploit these augmentation effects. The first flow considered is a thin, wavy fluid film flowing over a heated plate. This film flow exhibits a periodic fluctuation in the heat transfer coefficient, that is linked to the wavy interfacial deformations of free surface of the liquid film. The second flow considered concerns the heat transfer behind a backwards-facing step, which exhibits broadband fluctuations in the heat transfer coefficient due to the flow separation and turbulence behind * Corresponding author.

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Section: Case Study I: Heated Falling Filmsmentioning

confidence: 99%

Section: Case Study I: Heated Falling Filmsmentioning

confidence: 99%

Heat transfer augmentation in unsteady conjugate thermal systems – Part II: Applications

Mathie

Nakamura

Markides

2013

International Journal of Heat and Mass Transfer

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“…and therefore (Lel et al, 2005), b) light beam path through a falling film (Lel et al, 2008) For the determination of δ W , the position y 3* has to be inserted into Eq. (3) instead of y 3 .…”

Section: Chromatic Confocal Imagingmentioning

confidence: 99%

“…6. a) Typical IR picture of quasi-regular metastable structures within the residual layer between large waves of laminar-wavy falling films, b) temporal evolution of the regular structure's "head" between two large parabola-shaped waves (zone marked in a), Re = 15, q "= 2.2 x 10 4 W/m² (Lel et al, 2008) The structure's "head" effect could be explained through interference of waves at the point of intersection of two large parabola-shaped waves. The visualisation of falling films in the work of (Alekseenko et al, 1994) and (Scheid et al, 2006) shows, that capillary waves in front of large waves generate an interference pattern.…”

Section: Regular Structures Within the Residual Layermentioning

confidence: 99%

Heat Transfer Phenomena in Laminar Wavy Falling Films: Thermal Entry Length, Thermal-Capillary Metastable Structures, Thermal-Capillary Breakdown

Lel¹,

Kneer²

2011

Heat Transfer - Theoretical Analysis, Experimental Investigations and Industrial Systems

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“…An investigation of the Marangoni effect in a heated liquid film with a developed wave motion is described in [5]. The film temperature fields were visualized by infrared thermography, and the film thickness was measured by confocal microscopy.…”

Section: Introductionmentioning

confidence: 99%

Thermocapillary rupture in falling liquid films at moderate Reynolds numbers

Shatskiy

Chinnov

2017

EPJ Web Conf.

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Abstract. An experimental study of the flow of a water film over a heated surface for Re = 15-50 was performed. The influence of the development of thermocapillary instability on the wave amplitudes, the deformation of the surface of the liquid film, and the formation of the first stable dry spot on the heater are investigated. It is shown that the interaction of waves with thermocapillary structures can lead to an increase in the critical heat flux corresponding to the rupture of the liquid film, as compared with the data known in the literature.

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Investigations of the Marangoni effect on the regular structures in heated wavy liquid films

Cited by 60 publications

References 14 publications

Heat transfer augmentation in unsteady conjugate thermal systems – Part II: Applications

Heat transfer augmentation in unsteady conjugate thermal systems – Part II: Applications

Heat Transfer Phenomena in Laminar Wavy Falling Films: Thermal Entry Length, Thermal-Capillary Metastable Structures, Thermal-Capillary Breakdown

Thermocapillary rupture in falling liquid films at moderate Reynolds numbers

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